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Hello! I'd be happy to help you prepare for your BIO 202L Final Exam. This is a comprehensive review guide, and we'll go through each section and question in detail to ensure you have a solid understanding of the material. Let's break down each topic:

BIO 202L Endocrine System

The endocrine system is a crucial regulatory system that uses hormones to control and coordinate various bodily functions.

1. Describe the hormone(s) produced and secreted by endocrine glands.

Endocrine glands are ductless glands that secrete hormones directly into the bloodstream. Here's a summary of major glands and their primary hormones:

Hypothalamus:

Produces releasing and inhibiting hormones (e.g., TRH, GnRH, CRH, GHRH, Somatostatin, Dopamine) that regulate the anterior pituitary, and also produces ADH and Oxytocin, which are stored and released by the posterior pituitary.

Pituitary Gland:

Anterior Pituitary:

Growth Hormone (GH), Thyroid-Stimulating Hormone (TSH), Adrenocorticotropic Hormone (ACTH), Follicle-Stimulating Hormone (FSH), Luteinizing Hormone (LH), Prolactin (PRL).

Posterior Pituitary:

Stores and releases Antidiuretic Hormone (ADH) and Oxytocin, which are produced by the hypothalamus.

Thyroid Gland:

Thyroid hormones (T3 and T4) and Calcitonin.

Parathyroid Glands:

Parathyroid Hormone (PTH).

Adrenal Glands:

Adrenal Cortex:

Mineralocorticoids (e.g., Aldosterone), Glucocorticoids (e.g., Cortisol), Adrenal Androgens.

Adrenal Medulla:

Catecholamines (Epinephrine and Norepinephrine).

Pancreas (Endocrine portion):

Insulin and Glucagon.

Pineal Gland:

Melatonin.

Thymus:

Thymosins (e.g., Thymosin alpha 1, Thymopoietin).

Gonads:

Ovaries (Females):

Estrogens and Progesterone.

Testes (Males):

Androgens (e.g., Testosterone).

2. Explain how the endocrine system influences other systems of the body.

The endocrine system exerts widespread influence over virtually all other body systems by regulating metabolism, growth, development, reproduction, and maintaining homeostasis. Here are some examples:

Nervous System:

Hormones can affect mood, behavior, and cognitive function (e.g., thyroid hormones are crucial for brain development and function; stress hormones like cortisol can impact memory).

Cardiovascular System:

Hormones like epinephrine and norepinephrine increase heart rate and blood pressure. Aldosterone regulates blood volume and pressure. ADH influences blood volume.

Musculoskeletal System:

Growth hormone promotes bone and muscle growth. Thyroid hormones are essential for normal skeletal development. Parathyroid hormone and calcitonin regulate calcium levels, which are vital for bone health and muscle contraction.

Digestive System:

Hormones like insulin and glucagon regulate blood glucose levels, impacting nutrient absorption and utilization. Gastrin, secretin, and cholecystokinin (CCK) regulate digestive processes.

Reproductive System:

FSH, LH, estrogens, progesterone, and testosterone are critical for the development and function of the reproductive organs, gamete production, and secondary sexual characteristics.

Immune System:

Glucocorticoids (like cortisol) can suppress the immune response. Thymosins from the thymus are essential for T-cell maturation.

Urinary System:

ADH regulates water reabsorption in the kidneys, influencing urine output and blood volume. Aldosterone regulates sodium and potassium balance.

3. Describe the hormones found in the anterior pituitary gland and hypothalamic hormones.

Anterior Pituitary Hormones (Tropic Hormones):

These hormones are released in response to hypothalamic releasing hormones and typically stimulate other endocrine glands.

Growth Hormone (GH):

Promotes growth of body tissues, especially bone and muscle; stimulates protein synthesis and fat breakdown.

Thyroid-Stimulating Hormone (TSH):

Stimulates the thyroid gland to produce and secrete thyroid hormones (T3 and T4).

Adrenocorticotropic Hormone (ACTH):

Stimulates the adrenal cortex to release glucocorticoids (e.g., cortisol).

Follicle-Stimulating Hormone (FSH):

In females, stimulates ovarian follicle development and estrogen production; in males, stimulates sperm production.

Luteinizing Hormone (LH):

In females, triggers ovulation and stimulates corpus luteum formation and progesterone production; in males, stimulates testosterone production by Leydig cells.

Prolactin (PRL):

Stimulates milk production in the mammary glands.

Hypothalamic Hormones (Regulating Hormones):

These hormones are produced by the hypothalamus and travel through the hypophyseal portal system to the anterior pituitary, where they either stimulate or inhibit the release of anterior pituitary hormones.

Thyrotropin-Releasing Hormone (TRH):

Stimulates TSH release.

Gonadotropin-Releasing Hormone (GnRH):

Stimulates FSH and LH release.

Corticotropin-Releasing Hormone (CRH):

Stimulates ACTH release.

Growth Hormone-Releasing Hormone (GHRH):

Stimulates GH release.

Somatostatin (Growth Hormone-Inhibiting Hormone, GHIH):

Inhibits GH and TSH release.

Dopamine (Prolactin-Inhibiting Hormone, PIH):

Inhibits PRL release.

4. Describe positive and negative feedback.

Feedback loops are mechanisms that regulate hormone secretion to maintain homeostasis.

Negative Feedback:

This is the most common type of feedback in the endocrine system. It works to

reverse

the initial stimulus and bring the body back to a set point. When the level of a hormone (or its effect) reaches a certain point, it inhibits further release of that hormone or the hormones that stimulate its release.

Mechanism:

Stimulus → Hormone release → Effect → Inhibition of further hormone release.

Example:

When thyroid hormone (T3/T4) levels in the blood rise, they inhibit the release of TSH from the anterior pituitary and TRH from the hypothalamus. This reduces the stimulation of the thyroid gland, bringing T3/T4 levels back down.

Positive Feedback:

This mechanism

amplifies

the initial stimulus, pushing the body further away from the set point. It's less common in the endocrine system and is typically involved in processes that require a rapid, intense burst of activity.

Mechanism:

Stimulus → Hormone release → Effect → Further stimulation of hormone release.

Example:

During childbirth, the stretching of the uterine wall stimulates the release of oxytocin from the posterior pituitary. Oxytocin then causes stronger uterine contractions, which further stretch the uterine wall, leading to even more oxytocin release. This cycle continues until the baby is delivered.

5. Describe the function of the pancreas.

The pancreas is a unique organ with both exocrine and endocrine functions.

Exocrine Function (Digestive):

The vast majority of the pancreas (about 99%) is dedicated to its exocrine function. It produces and secretes digestive enzymes (e.g., amylase for carbohydrates, lipase for fats, proteases like trypsin for proteins) and bicarbonate-rich fluid into the small intestine via ducts. This pancreatic juice helps neutralize acidic chyme from the stomach and digest food.

Endocrine Function (Hormonal):

Scattered throughout the exocrine tissue are clusters of cells called

pancreatic islets (Islets of Langerhans)

, which perform the endocrine function. These islets contain different cell types that produce hormones directly into the bloodstream:

Alpha (α) cells:

Secrete

glucagon

, which increases blood glucose levels by stimulating glycogenolysis (breakdown of glycogen) and gluconeogenesis (synthesis of glucose from non-carbohydrate sources) in the liver.

Beta (β) cells:

Secrete

insulin

, which lowers blood glucose levels by promoting glucose uptake by cells, glycogen synthesis in the liver and muscles, and conversion of glucose to fat.

Delta (δ) cells:

Secrete

somatostatin

, which inhibits the secretion of both insulin and glucagon, and also slows nutrient absorption from the GI tract.

PP cells (or F cells):

Secrete

pancreatic polypeptide

, which regulates pancreatic exocrine and endocrine secretions.

6. Describe the function of the red bone marrow and the lymphatic system.

Red Bone Marrow:

This is the primary site of

hematopoiesis

, the process of producing all types of blood cells (red blood cells, white blood cells, and platelets) from hematopoietic stem cells. It is found in the spongy bone of the skull, vertebrae, ribs, sternum, pelvis, and the proximal ends of the humerus and femur in adults. It also plays a role in the maturation of B lymphocytes.

Lymphatic System:

This system is a vital part of the immune system and also plays a role in fluid balance and fat absorption. Its main functions include:

Fluid Balance:

Draining excess interstitial fluid (lymph) from tissues and returning it to the bloodstream, preventing edema.

Fat Absorption:

Transporting dietary lipids and lipid-soluble vitamins absorbed from the gastrointestinal tract (via lacteals in the small intestine) to the bloodstream.

Immune Response:

Housing and transporting lymphocytes (T cells and B cells) and other immune cells, filtering lymph to remove pathogens and foreign substances, and initiating immune responses against invaders.

7. Identify the endocrine glands at the macroscopic and microscopic level. (Pituitary, hypothalamus, pineal, adrenal, thyroid, thymus, testes, ovaries, parathyroid glands, breast and axillary lymph nodes, and pancreas)

Pituitary Gland:

Macroscopic:

Small, pea-sized gland located at the base of the brain, inferior to the hypothalamus, within the sella turcica of the sphenoid bone. It has two main lobes: anterior (adenohypophysis) and posterior (neurohypophysis).

Microscopic:

Anterior Pituitary:

Composed of glandular epithelial tissue, with various cell types (e.g., somatotrophs, lactotrophs, corticotrophs, thyrotrophs, gonadotrophs) that stain differently and produce specific hormones.

Posterior Pituitary:

Composed of nervous tissue, primarily axons and axon terminals of hypothalamic neurons, and pituicytes (glial cells). It does not produce hormones but stores and releases ADH and oxytocin.

Hypothalamus:

Macroscopic:

Part of the diencephalon in the brain, located inferior to the thalamus. It forms the floor of the third ventricle.

Microscopic:

Contains various nuclei (clusters of neuron cell bodies) that produce neurohormones. It's a complex neural structure, not a typical glandular structure, but its neurosecretory cells function as endocrine cells.

Pineal Gland:

Macroscopic:

Small, cone-shaped gland located in the epithalamus, near the center of the brain.

Microscopic:

Composed mainly of pinealocytes, which produce melatonin, and glial cells. Often contains calcified structures called "brain sand" (corpora arenacea).

Adrenal Glands:

Macroscopic:

Two glands, each located superior to a kidney, resembling a cap. Each gland has an outer cortex and an inner medulla.

Microscopic:

Adrenal Cortex:

Divided into three distinct layers (zones): zona glomerulosa, zona fasciculata, and zona reticularis, each with characteristic cell arrangements and hormone production.

Adrenal Medulla:

Composed of chromaffin cells (modified postganglionic sympathetic neurons) that secrete catecholamines.

Thyroid Gland:

Macroscopic:

Butterfly-shaped gland located in the anterior neck, inferior to the larynx and anterior to the trachea. It has two lobes connected by an isthmus.

Microscopic:

Composed of numerous

thyroid follicles

, which are spherical structures lined by follicular cells that produce thyroid hormones (T3 and T4). The follicles are filled with colloid (a protein-rich fluid). Scattered between the follicles are

parafollicular cells (C cells)

, which produce calcitonin.

Thymus:

Macroscopic:

A bilobed organ located in the mediastinum, posterior to the sternum and anterior to the great vessels of the heart. It is largest during childhood and atrophies with age.

Microscopic:

Divided into an outer cortex and an inner medulla. The cortex is densely packed with immature T lymphocytes (thymocytes) and epithelial reticular cells. The medulla contains fewer lymphocytes and characteristic

Hassall's corpuscles

(thymic corpuscles).

Testes:

Macroscopic:

Paired oval organs located in the scrotum outside the abdominopelvic cavity.

Microscopic:

Contain numerous coiled

seminiferous tubules

(site of sperm production) and

interstitial cells (Leydig cells)

located between the tubules, which produce testosterone.

Ovaries:

Macroscopic:

Paired almond-shaped organs located in the pelvic cavity, lateral to the uterus.

Microscopic:

Consist of an outer cortex containing ovarian follicles at various stages of development (each containing an oocyte) and an inner medulla composed of connective tissue, blood vessels, and nerves. Follicular cells produce estrogens and progesterone.

Parathyroid Glands:

Macroscopic:

Typically four small, pea-sized glands embedded in the posterior surface of the thyroid gland.

Microscopic:

Composed mainly of

chief cells (principal cells)

, which produce parathyroid hormone (PTH), and fewer, larger oxyphil cells of unknown function.

Breast and Axillary Lymph Nodes:

Breast:

Primarily mammary glands (modified sweat glands) and adipose tissue. While influenced by hormones, the breast itself is a target organ, not a primary endocrine gland. It produces milk under hormonal influence (prolactin, oxytocin).

Axillary Lymph Nodes:

These are part of the lymphatic system, not endocrine glands. They are macroscopic structures (small, bean-shaped) located in the axilla (armpit) that filter lymph from the breast and upper limb. Microscopically, they have a cortex and medulla, containing lymphocytes, macrophages, and other immune cells.

Pancreas:

Macroscopic:

An elongated, flattened organ located posterior to the stomach, extending from the duodenum to the spleen.

Microscopic:

As described in question 5, it has both exocrine acini (producing digestive enzymes) and endocrine

pancreatic islets (Islets of Langerhans)

containing alpha, beta, delta, and PP cells.

8. Identify the structures of the following glands: thyroid, and adrenal)

Thyroid Gland Structures:

Lobes:

Right and left lobes, located on either side of the trachea.

Isthmus:

A narrow band of tissue connecting the two lobes anteriorly.

Pyramidal Lobe (variable):

A small, superior extension from the isthmus or one of the lobes, present in some individuals.

Thyroid Follicles:

Microscopic spherical units, the functional units of the gland, composed of follicular cells surrounding a lumen filled with colloid.

Follicular Cells:

Epithelial cells lining the follicles, responsible for producing thyroid hormones (T3 and T4).

Colloid:

A viscous fluid within the follicles, primarily composed of thyroglobulin, the precursor to thyroid hormones.

Parafollicular Cells (C cells):

Scattered cells located between the thyroid follicles, responsible for producing calcitonin.

Adrenal Gland Structures:

Adrenal Cortex:

The outer, yellowish portion of the gland, divided into three distinct zones:

Zona Glomerulosa:

The outermost layer, arranged in spherical clusters or arches. Produces mineralocorticoids (e.g., aldosterone).

Zona Fasciculata:

The middle and thickest layer, arranged in long, straight cords. Produces glucocorticoids (e.g., cortisol).

Zona Reticularis:

The innermost cortical layer, arranged in a branching network. Produces adrenal androgens.

Adrenal Medulla:

The inner, reddish-brown portion of the gland.

Chromaffin Cells:

Modified sympathetic postganglionic neurons that secrete catecholamines (epinephrine and norepinephrine) directly into the bloodstream.

9. Describe the functions of ADH

Antidiuretic Hormone (ADH), also known as vasopressin, is produced by the hypothalamus and released from the posterior pituitary. Its primary functions are related to water balance and blood pressure regulation:

Water Reabsorption (Primary Function):

ADH acts on the collecting ducts and distal convoluted tubules of the kidneys, increasing their permeability to water. This allows more water to be reabsorbed from the filtrate back into the bloodstream, thereby reducing urine volume and concentrating the urine. This helps to conserve body water and prevent dehydration.

Vasoconstriction (at high concentrations):

At very high concentrations (e.g., during severe blood loss), ADH can cause vasoconstriction of arterioles, leading to an increase in peripheral resistance and blood pressure. This is why it's also called vasopressin.

Regulation of Osmolality:

ADH release is primarily stimulated by an increase in plasma osmolality (i.e., when the blood becomes too concentrated, indicating dehydration) or a decrease in blood volume/pressure. Its action helps to restore normal plasma osmolality.

10. Identify the layers of the adrenal cortex and medulla and the hormones and the functions of each.

As described in question 8, the adrenal gland has two main parts: the cortex and the medulla, each with distinct layers/regions and functions.

Adrenal Cortex (Outer part):

Produces steroid hormones (corticosteroids) and is divided into three zones:

Zona Glomerulosa (Outermost layer):

Hormones:

Mineralocorticoids

, primarily

Aldosterone

.

Functions:

Regulates electrolyte balance, particularly sodium (Na+) and potassium (K+). Aldosterone promotes Na+ reabsorption and K+ excretion in the kidneys, leading to water retention (as water follows sodium) and an increase in blood volume and blood pressure.

Zona Fasciculata (Middle, thickest layer):

Hormones:

Glucocorticoids

, primarily

Cortisol

(hydrocortisone).

Functions:

Influences glucose metabolism (raises blood glucose by promoting gluconeogenesis), suppresses the immune system, reduces inflammation, helps the body cope with stress, and promotes fat and protein breakdown.

Zona Reticularis (Innermost layer):

Hormones:

Adrenal Androgens

(e.g., dehydroepiandrosterone, DHEA).

Functions:

Contribute to secondary sex characteristics, especially in females (e.g., pubic and axillary hair, libido). In males, their effects are usually masked by testicular androgens.

Adrenal Medulla (Inner part):

Part of the sympathetic nervous system.

Hormones:

Catecholamines

, primarily

Epinephrine (Adrenaline)

and

Norepinephrine (Noradrenaline)

.

Functions:

Mediate the "fight-or-flight" response. They increase heart rate, blood pressure, blood glucose levels (by promoting glycogenolysis and gluconeogenesis), dilate bronchioles, and shunt blood to skeletal muscles and the heart, preparing the body for immediate physical activity or stress.

BIO 202L Blood Final Exam Review Guide

Blood is a vital connective tissue that circulates throughout the body, delivering essential substances and removing waste products.

1. Describe the components and major functions of the blood.

Blood is composed of two main components:

Plasma (about 55% of blood volume):

The liquid extracellular matrix.

Components:

Approximately 92% water, 7% plasma proteins (e.g., albumin for osmotic pressure, globulins for transport and immunity, fibrinogen for clotting), and 1% other solutes (electrolytes, nutrients, gases, hormones, waste products).

Functions:

Transports blood cells, nutrients, hormones, waste products; maintains blood volume and pressure; regulates body temperature; participates in blood clotting and immunity.

Formed Elements (about 45% of blood volume):

The cellular components.

Erythrocytes (Red Blood Cells - RBCs):

Components:

Biconcave discs, anucleated, filled with hemoglobin.

Functions:

Primary function is oxygen transport from the lungs to tissues and carbon dioxide transport from tissues to the lungs.

Leukocytes (White Blood Cells - WBCs):

Components:

Complete cells with nuclei and organelles; categorized into granulocytes (neutrophils, eosinophils, basophils) and agranulocytes (lymphocytes, monocytes).

Functions:

Part of the immune system, defending the body against pathogens, foreign substances, and abnormal cells.

Platelets (Thrombocytes):

Components:

Cell fragments derived from megakaryocytes; lack nuclei.

Functions:

Essential for hemostasis (blood clotting) by forming a plug and releasing factors that promote coagulation.

Major Functions of Blood (Overall):

Transportation:

Transports oxygen, carbon dioxide, nutrients, hormones, metabolic wastes, and heat throughout the body.

Regulation:

Helps regulate body temperature, pH (through buffer systems), and fluid volume in the circulatory system.

Protection:

Protects against blood loss (via clotting) and infection (via immune cells and antibodies).

2. Describe the different blood types.

Blood types are determined by the presence or absence of specific antigens (agglutinogens) on the surface of red blood cells and antibodies (agglutinins) in the plasma. The two most important blood group systems are the ABO and Rh systems.

ABO Blood Group System:

Based on the presence or absence of A and B antigens.

Blood Type

Antigens on RBCs

Antibodies in Plasma

A

A

Anti-B

B

B

Anti-A

AB

A and B

None

O

None

Anti-A and Anti-B

* Universal Donor: Type O (specifically O-negative) because its RBCs lack A and B antigens, so they won't be attacked by anti-A or anti-B antibodies in the recipient's plasma.

* Universal Recipient: Type AB (specifically AB-positive) because its plasma lacks anti-A and anti-B antibodies, so it can receive RBCs with A or B antigens without agglutination.

Rh Blood Group System: Based on the presence or absence of the Rh (D) antigen.

Rh-positive (Rh+): Individuals who have the Rh (D) antigen on their RBCs. They do not naturally produce anti-Rh antibodies.

Rh-negative (Rh-): Individuals who lack the Rh (D) antigen. They do not naturally produce anti-Rh antibodies, but they will produce them if exposed to Rh-positive blood (e.g., through transfusion or during pregnancy).

Clinical Significance: Rh incompatibility is critical in pregnancy (hemolytic disease of the newborn) and blood transfusions. An Rh-negative person receiving Rh-positive blood for the first time will develop anti-Rh antibodies. A second exposure can lead to a severe transfusion reaction.

3. Describe the components of a complete blood count (CBC).

A Complete Blood Count (CBC) is a common blood test that provides information about the different cells in the blood. It's a broad screening test used to evaluate overall health and detect a wide range of disorders, including anemia, infection, and leukemia. Key components include:

Red Blood Cell (RBC) Count:

Measures the number of red blood cells per unit volume of blood. Low counts can indicate anemia; high counts can indicate polycythemia.

Hemoglobin (Hb or Hgb):

Measures the amount of oxygen-carrying protein in the blood. Directly related to the oxygen-carrying capacity of blood.

Hematocrit (Hct):

Measures the percentage of blood volume occupied by red blood cells. Reflects the proportion of RBCs in the blood.

Red Blood Cell Indices:

Provide information about the size and hemoglobin content of individual RBCs:

Mean Corpuscular Volume (MCV):

Average size of RBCs. Helps classify anemia (microcytic, normocytic, macrocytic).

Mean Corpuscular Hemoglobin (MCH):

Average amount of hemoglobin in a single RBC.

Mean Corpuscular Hemoglobin Concentration (MCHC):

Average concentration of hemoglobin in a single RBC.

Red Cell Distribution Width (RDW):

Measures the variation in RBC size.

White Blood Cell (WBC) Count (Leukocyte Count):

Measures the total number of white blood cells. Elevated counts (leukocytosis) can indicate infection or inflammation; low counts (leukopenia) can indicate immune suppression.

WBC Differential Count:

Measures the percentage of each type of white blood cell (neutrophils, lymphocytes, monocytes, eosinophils, basophils). This helps pinpoint specific types of infections or immune disorders.

Platelet Count:

Measures the number of platelets. Low counts (thrombocytopenia) can lead to bleeding problems; high counts (thrombocytosis) can increase the risk of clotting.

4. Describe the components of the circulatory system.

The circulatory system, also known as the cardiovascular system, is responsible for transporting blood throughout the body. It consists of three main components:

Heart:

The muscular pump that propels blood through the blood vessels. It is a four-chambered organ (two atria, two ventricles) that creates pressure gradients to drive blood flow.

Blood Vessels:

A network of tubes that carry blood to and from all parts of the body.

Arteries:

Carry oxygenated blood

away

from the heart to the body tissues (except pulmonary arteries, which carry deoxygenated blood to the lungs). They have thick, muscular, elastic walls to withstand high pressure.

Arterioles:

Smaller arteries that branch into capillaries. They regulate blood flow into capillary beds.

Capillaries:

Microscopic, thin-walled vessels that form extensive networks within tissues. They are the primary sites of exchange of gases, nutrients, hormones, and waste products between blood and tissues.

Venules:

Small veins that collect blood from capillaries.

Veins:

Carry deoxygenated blood

back

to the heart from the body tissues (except pulmonary veins, which carry oxygenated blood from the lungs to the heart). They have thinner walls and larger lumens than arteries and often contain valves to prevent backflow of blood.

Blood:

The fluid connective tissue that circulates within the heart and blood vessels, carrying out the functions described in question 1.

5. Describe the functions of platelets.

Platelets, or thrombocytes, are small, anucleated cell fragments crucial for hemostasis (the process of stopping bleeding). Their main functions include:

Vascular Spasm:

When a blood vessel is injured, platelets release serotonin and thromboxane A2, which cause vasoconstriction, reducing blood flow to the injured area.

Platelet Plug Formation:

Platelets adhere to exposed collagen fibers at the site of injury (platelet adhesion) and become activated. Activated platelets change shape, release granules containing clotting factors (e.g., ADP, serotonin, thromboxane A2), and aggregate together to form a temporary plug that seals the break in the vessel wall.

Coagulation (Blood Clotting):

Platelets provide a surface for the activation of clotting factors (coagulation factors) in the plasma. They release platelet factor 3 (PF3), which is essential for initiating the intrinsic pathway of coagulation, leading to the formation of a stable fibrin clot.

Clot Retraction and Repair:

After a clot forms, platelets contract (due to actin and myosin within them), pulling the edges of the broken vessel together and squeezing serum from the clot, making it more compact. They also release growth factors that stimulate repair of the damaged vessel wall.

6. Identify the different types of white blood cells at the microscopic level and describe the function of each. (Neutrophils, lymphocytes, monocytes, eosinophils, basophils)

White blood cells (leukocytes) are key components of the immune system. They are identified microscopically by their size, nuclear shape, and the presence/absence and staining properties of cytoplasmic granules.

Granulocytes (contain visible cytoplasmic granules):

Neutrophils:

Microscopic Appearance:

Most numerous WBC (50-70% of total WBCs). Nucleus is multi-lobed (polymorphonuclear, 3-6 lobes). Cytoplasm contains fine, pale lilac-colored granules that are difficult to see.

Function:

Phagocytize bacteria and fungi; primary responders to acute bacterial infections and inflammation. Release antimicrobial chemicals.

Eosinophils:

Microscopic Appearance:

2-4% of total WBCs. Nucleus is typically bi-lobed (figure-8 or ear-muff shaped). Cytoplasm contains large, coarse, reddish-orange (acidophilic) granules.

Function:

Kill parasitic worms (e.g., tapeworms, flukes); modulate allergic reactions and asthma by inactivating inflammatory chemicals.

Basophils:

Microscopic Appearance:

Rarest WBC (0.5-1% of total WBCs). Nucleus is usually U- or S-shaped, often obscured by large, coarse, dark purple (basophilic) granules.

Function:

Release histamine (a vasodilator and inflammatory chemical) and heparin (an anticoagulant) at sites of inflammation or allergic reactions, enhancing the inflammatory response.

Agranulocytes (lack visible cytoplasmic granules):

Lymphocytes:

Microscopic Appearance:

25-45% of total WBCs. Smallest WBCs. Large, spherical nucleus that often takes up most of the cell volume, with a thin rim of pale blue cytoplasm.

Function:

Crucial for specific immunity.

T lymphocytes (T cells)

directly attack virus-infected cells and tumor cells.

B lymphocytes (B cells)

produce antibodies.

Monocytes:

Microscopic Appearance:

3-8% of total WBCs. Largest WBCs. Kidney-shaped or U-shaped nucleus. Abundant pale blue cytoplasm.

Function:

Differentiate into macrophages in tissues. Macrophages are highly phagocytic cells that engulf bacteria, viruses, cellular debris, and activate lymphocytes to mount an immune response.

7. Describe the location of where B cells mature and location of the T-cells

B cells:

Mature in the

red bone marrow

. After maturation, they migrate to secondary lymphoid organs (e.g., lymph nodes, spleen, tonsils) where they can be activated.

T cells:

Originate in the red bone marrow but migrate to the

thymus

for maturation. In the thymus, they undergo a rigorous selection process to ensure they can recognize foreign antigens but do not react against self-antigens. After maturation, they also migrate to secondary lymphoid organs.

8. Describe the function of heparin and histamine.

Heparin:

Function:

An anticoagulant (blood thinner). It inhibits blood clotting by enhancing the activity of antithrombin III, which inactivates thrombin and other clotting factors. It prevents the formation of new clots and the enlargement of existing ones. Produced by basophils and mast cells.

Histamine:

Function:

A potent inflammatory mediator. It causes vasodilation (widening of blood vessels) and increases capillary permeability (making capillaries leakier). This leads to the classic signs of inflammation: redness, heat, and swelling, by increasing blood flow to the injured area and allowing immune cells and fluid to exit the bloodstream and enter the tissues. Produced by basophils and mast cells.

9. Describe the structures of hemoglobin.

Hemoglobin (Hb) is the protein responsible for oxygen transport in red blood cells. It is a complex quaternary protein structure:

Quaternary Structure:

Composed of four protein subunits (polypeptide chains).

Globin:

The protein portion, consisting of two alpha (α) chains and two beta (β) chains (in adult hemoglobin, HbA). Each globin chain is folded into a specific three-dimensional structure.

Heme Group:

Each of the four globin chains is bound to a non-protein, iron-containing pigment molecule called a

heme group

. There are four heme groups per hemoglobin molecule.

Iron Atom:

At the center of each heme group is a single iron (Fe2+) atom. This iron atom is the binding site for oxygen. Each iron atom can bind one oxygen molecule, so one hemoglobin molecule can carry up to four oxygen molecules.

This structure allows hemoglobin to efficiently pick up oxygen in the lungs (where oxygen concentration is high) and release it in the tissues (where oxygen concentration is low).

10. Describe the function of fibrin.

Fibrin is an insoluble, fibrous protein that forms the meshwork of a blood clot. Its primary function is to provide the structural framework for a stable blood clot during hemostasis.

Formation:

Fibrin is formed from its soluble precursor,

fibrinogen

, a plasma protein. During the coagulation cascade, the enzyme thrombin converts fibrinogen into fibrin monomers. These monomers then spontaneously polymerize to form long, insoluble fibrin threads.

Role in Clotting:

The fibrin threads create a dense, sticky mesh that traps red blood cells, platelets, and plasma, effectively sealing the damaged blood vessel and preventing further blood loss. This mesh also provides a scaffold for tissue repair.

11. Describe the Cardinal Signs of inflammation.

Inflammation is the body's protective response to injury or infection, aiming to eliminate the initial cause of cell injury, clear out necrotic cells and tissues, and initiate tissue repair. The five cardinal signs, first described by Celsus and later by Galen and Virchow, are:

Rubor (Redness):

Caused by

vasodilation

of arterioles leading to the injured area, increasing blood flow (hyperemia). This brings more oxygenated blood to the site.

Calor (Heat):

Also due to increased blood flow (hyperemia) to the site and increased metabolic activity of cells involved in the inflammatory response.

Tumor (Swelling):

Results from increased

vascular permeability

, allowing fluid (plasma proteins and water) to leak from capillaries into the interstitial space, forming exudate (edema).

Dolor (Pain):

Caused by the release of chemical mediators (e.g., bradykinin, prostaglandins, histamine) that stimulate nerve endings, and by the pressure exerted by the swelling on nerve endings.

Functio Laesa (Loss of Function):

This is a consequence of the swelling and pain, which can impair the normal movement or function of the affected tissue or organ.

12. Identify and describe the structures and functions of arteries, capillaries, and veins,

Blood vessels are tubes that transport blood. They differ in structure and function based on their role in circulation.

Arteries:

Structures:

Have thick, muscular, and elastic walls. Composed of three layers (tunics):

Tunica Intima (Innermost):

Endothelium (smooth lining), basement membrane, internal elastic lamina.

Tunica Media (Middle):

Thickest layer, primarily smooth muscle and elastic fibers. Allows for vasoconstriction/vasodilation and elasticity.

Tunica Externa (Outermost):

Connective tissue (collagen and elastic fibers) that protects and anchors the vessel.

Functions:

Carry blood

away

from the heart. Their elasticity allows them to stretch and recoil with each heartbeat, maintaining blood pressure and flow. Their muscularity allows for regulation of blood flow to different body regions.

Capillaries:

Structures:

Microscopic vessels, typically only one cell thick (endothelium) with a basement membrane. They are so narrow that RBCs often pass through in single file.

Functions:

Primary site of exchange of gases (O2, CO2), nutrients, hormones, and metabolic wastes between the blood and the interstitial fluid of tissues. Their thin walls and extensive networks maximize efficiency of exchange.

Veins:

Structures:

Have thinner walls and larger lumens (internal diameters) compared to corresponding arteries. Also have three tunics, but the tunica media is much thinner and less muscular. Many veins, especially in the limbs, contain

valves

(folds of the tunica intima) to prevent backflow of blood.

Functions:

Carry blood

towards

the heart. Their large lumens offer less resistance to blood flow. Valves and the action of skeletal muscles (skeletal muscle pump) help return blood to the heart against gravity.

13. List and identify the major arteries of the systemic circuit, including the arteries of the brain and the areas they serve.

The systemic circuit carries oxygenated blood from the heart to the body and returns deoxygenated blood to the heart. Here are major arteries and their served areas:

Aorta: The largest artery in the body, originating from the left ventricle.

Ascending Aorta:

Gives rise to the

Coronary Arteries

(supply the heart muscle).

Aortic Arch:

Branches into:

Brachiocephalic Artery:

Divides into:

Right Common Carotid Artery:

Supplies right side of head and neck.

Right Subclavian Artery:

Supplies right upper limb, neck, and part of thorax.

Left Common Carotid Artery:

Supplies left side of head and neck.

Left Subclavian Artery:

Supplies left upper limb, neck, and part of thorax.

Descending Aorta:

Continues as the Thoracic Aorta and then the Abdominal Aorta.

Thoracic Aorta:

Supplies thoracic organs and wall.

Abdominal Aorta:

Supplies abdominal organs and wall, then branches into Common Iliac Arteries.

Arteries of the Head and Neck:

Common Carotid Arteries (Right and Left):

Each divides into:

External Carotid Artery:

Supplies superficial head and neck structures (face, scalp, tongue, pharynx, thyroid gland).

Internal Carotid Artery:

Supplies brain, eyes, and forehead.

Vertebral Arteries (from Subclavian Arteries):

Pass through cervical vertebrae, unite to form the Basilar Artery, supplying posterior brain.

Arteries of the Brain (part of Circle of Willis and its branches):

Basilar Artery:

Formed by union of vertebral arteries; supplies brainstem and cerebellum.

Posterior Cerebral Arteries:

Branches of the basilar artery; supply posterior cerebrum (occipital lobe, temporal lobe).

Posterior Communicating Arteries:

Connect posterior cerebral arteries to internal carotid arteries.

Middle Cerebral Arteries:

Largest branches of internal carotid arteries; supply lateral cerebrum (frontal, parietal, temporal lobes).

Anterior Cerebral Arteries:

Branches of internal carotid arteries; supply medial cerebrum (frontal and parietal lobes).

Anterior Communicating Artery:

Connects the two anterior cerebral arteries.

Arteries of the Upper Limb:

Subclavian Artery:

Becomes the

Axillary Artery

in the armpit.

Axillary Artery:

Becomes the

Brachial Artery

in the upper arm.

Brachial Artery:

Divides into

Radial Artery

(lateral forearm/hand) and

Ulnar Artery

(medial forearm/hand).

Arteries of the Abdomen (from Abdominal Aorta, superior to inferior):

Celiac Trunk:

Short, large artery that immediately branches into:

Left Gastric Artery:

Supplies stomach and esophagus.

Splenic Artery:

Supplies spleen, pancreas, and part of stomach.

Common Hepatic Artery:

Supplies liver, gallbladder, duodenum, and pancreas.

Superior Mesenteric Artery:

Supplies small intestine, ascending colon, and most of transverse colon.

Renal Arteries (paired):

Supply kidneys.

Gonadal Arteries (Testicular/Ovarian, paired):

Supply testes/ovaries.

Inferior Mesenteric Artery:

Supplies distal transverse colon, descending colon, sigmoid colon, and rectum.

Arteries of the Lower Limb:

Common Iliac Arteries (paired):

Terminal branches of the abdominal aorta. Each divides into:

External Iliac Artery:

Supplies lower limb.

Internal Iliac Artery:

Supplies pelvic organs, gluteal region, and medial thigh.

Femoral Artery:

Continuation of external iliac artery in the thigh.

14. List and identify the major veins and arteries of the systemic circuit and areas they serve. (abdominal, aorta, renal, vena cava, testicular, celiac trunk, hepatic, spleen, axillary, brachial, radial, ulna, femoral, common iliac, external iliac, internal iliac, brachiocephalic, subclavian, jugular, common carotid, basilar, middle cerebral, anterior cerebral, posterior cerebral, posterior communicating, vertebral, internal and external jugular, mesenteric, basilic, median cubital, and great saphenous)

This question overlaps with question 13 for arteries. I will list both arteries and veins, focusing on the ones mentioned.

Arteries (reiterating from Q13 for completeness):

Aorta:

Largest artery, originates from left ventricle. Supplies systemic circulation.

Abdominal Aorta:

Continuation of thoracic aorta. Supplies abdominal organs and lower limbs.

Renal Arteries:

Paired arteries supplying the kidneys.

Testicular Arteries:

Paired arteries supplying the testes (gonadal arteries).

Celiac Trunk:

Short artery branching into Left Gastric, Splenic, and Common Hepatic arteries. Supplies stomach, spleen, liver, pancreas, duodenum.

Hepatic Artery (Common Hepatic Artery):

Branch of celiac trunk. Supplies liver, gallbladder, duodenum, pancreas.

Axillary Artery:

Continuation of subclavian artery in the armpit. Supplies shoulder and upper arm.

Brachial Artery:

Continuation of axillary artery in the upper arm. Supplies arm.

Radial Artery:

Branch of brachial artery in the forearm. Supplies lateral forearm and hand.

Ulnar Artery:

Branch of brachial artery in the forearm. Supplies medial forearm and hand.

Femoral Artery:

Continuation of external iliac artery in the thigh. Supplies thigh and leg.

Common Iliac Arteries:

Terminal branches of abdominal aorta. Supply pelvis and lower limbs.

External Iliac Artery:

Branch of common iliac. Supplies lower limb.

Internal Iliac Artery:

Branch of common iliac. Supplies pelvic organs, gluteal region, medial thigh.

Brachiocephalic Artery:

First branch of aortic arch. Supplies right head, neck, and upper limb.

Subclavian Artery:

Branches from brachiocephalic (right) or aortic arch (left). Supplies upper limb, neck, and part of thorax.

Common Carotid Artery:

Branches from brachiocephalic (right) or aortic arch (left). Supplies head and neck.

Basilar Artery:

Formed by vertebral arteries. Supplies brainstem and cerebellum.

Middle Cerebral Artery:

Branch of internal carotid. Supplies lateral cerebrum.

Anterior Cerebral Artery:

Branch of internal carotid. Supplies medial cerebrum.

Posterior Cerebral Artery:

Branch of basilar artery. Supplies posterior cerebrum.

Posterior Communicating Artery:

Connects posterior cerebral to internal carotid.

Vertebral Artery:

Branch of subclavian. Supplies posterior brain.

Mesenteric Arteries (Superior and Inferior):

Branches of abdominal aorta. Supply intestines.

Veins (return deoxygenated blood to the heart):

Vena Cava (Superior and Inferior):

The largest veins, draining into the right atrium.

Superior Vena Cava:

Drains blood from the head, neck, upper limbs, and thorax.

Inferior Vena Cava:

Drains blood from the abdomen, pelvis, and lower limbs.

Renal Veins:

Paired veins draining blood from the kidneys into the inferior vena cava.

Testicular Veins:

Paired veins draining blood from the testes. Right testicular vein drains into IVC; left testicular vein drains into left renal vein.

Hepatic Veins:

Drain deoxygenated blood from the liver into the inferior vena cava.

Splenic Vein:

Drains blood from the spleen, part of the stomach, and pancreas. Joins with superior mesenteric vein to form the hepatic portal vein.

Axillary Vein:

Continuation of brachial vein. Drains blood from the upper arm and shoulder.

Brachial Veins:

Deep veins of the arm, accompany the brachial artery. Drain into axillary vein.

Radial Veins:

Deep veins of the forearm, accompany the radial artery. Drain into brachial veins.

Ulnar Veins:

Deep veins of the forearm, accompany the ulnar artery. Drain into brachial veins.

Femoral Vein:

Deep vein of the thigh, accompanies the femoral artery. Drains into external iliac vein.

Common Iliac Veins:

Formed by the union of external and internal iliac veins. Unite to form the inferior vena cava.

External Iliac Vein:

Drains blood from the lower limb.

Internal Iliac Vein:

Drains blood from the pelvic organs and gluteal region.

Brachiocephalic Veins (Right and Left):

Formed by the union of subclavian and internal jugular veins. Unite to form the superior vena cava.

Subclavian Vein:

Drains blood from the upper limb.

Jugular Veins (Internal and External):

Internal Jugular Vein:

Drains blood from the brain, face, and neck. Joins with subclavian vein to form brachiocephalic vein.

External Jugular Vein:

Drains blood from the scalp and superficial face/neck. Drains into subclavian vein.

Mesenteric Veins (Superior and Inferior):

Superior Mesenteric Vein:

Drains small intestine and parts of large intestine. Joins splenic vein to form hepatic portal vein.

Inferior Mesenteric Vein:

Drains distal large intestine. Usually drains into splenic vein.

Basilic Vein:

Superficial vein of the arm. Joins with brachial veins to form axillary vein.

Median Cubital Vein:

Connects basilic and cephalic veins in the cubital fossa (elbow). Common site for venipuncture.

Great Saphenous Vein:

Longest superficial vein in the body, running along the medial aspect of the leg and thigh. Drains into the femoral vein.

15. Describe and identify the major branches that come off the abdominal aorta from superior to inferior.

The abdominal aorta begins at the diaphragm and descends to the level of the fourth lumbar vertebra, where it bifurcates into the common iliac arteries. Its major branches, from superior to inferior, are:

Inferior Phrenic Arteries (paired):

Supply the inferior surface of the diaphragm.

Celiac Trunk (unpaired):

A large, short artery that immediately branches into three arteries:

Left Gastric Artery:

Supplies the lesser curvature of the stomach and lower esophagus.

Splenic Artery:

Supplies the spleen, pancreas, and greater curvature of the stomach.

Common Hepatic Artery:

Supplies the liver, gallbladder, and parts of the stomach, duodenum, and pancreas.

Superior Mesenteric Artery (unpaired):

Supplies the small intestine (duodenum, jejunum, ileum), cecum, ascending colon, and the proximal two-thirds of the transverse colon.

Suprarenal (Adrenal) Arteries (paired):

Supply the adrenal glands.

Renal Arteries (paired):

Large arteries supplying the kidneys.

Gonadal Arteries (paired):

Testicular Arteries:

In males, supply the testes.

Ovarian Arteries:

In females, supply the ovaries.

Inferior Mesenteric Artery (unpaired):

Supplies the distal one-third of the transverse colon, descending colon, sigmoid colon, and rectum.

Lumbar Arteries (four paired sets):

Supply the posterior abdominal wall and spinal cord.

Median Sacral Artery (unpaired):

A small artery arising from the posterior aspect of the aorta, supplying the sacrum and coccyx.

Common Iliac Arteries (paired):

The terminal branches of the abdominal aorta, supplying the pelvis and lower limbs.

16. Define pulse and identify the general location of arteries where pulse is palpated.

Pulse:

The rhythmic throbbing of arteries as blood is propelled through them, caused by the expansion and recoil of elastic arteries with each heartbeat. It reflects the heart rate and the strength of the heartbeat.

General Locations for Pulse Palpation:

Pulse points are typically located where an artery runs close to the body surface and can be compressed against a bone or firm structure. Common sites include:

Radial Artery:

At the lateral aspect of the wrist, proximal to the thumb (most common site).

Carotid Artery:

On either side of the neck, lateral to the trachea (used in emergencies).

Brachial Artery:

In the antecubital fossa (bend of the elbow) or medial upper arm (used for blood pressure measurement).

Femoral Artery:

In the groin, midway between the pubic symphysis and anterior superior iliac spine.

Popliteal Artery:

Behind the knee.

Dorsalis Pedis Artery:

On the top of the foot.

Posterior Tibial Artery:

Behind the medial malleolus (ankle bone).

Temporal Artery:

Anterior to the ear, on the temple.

Facial Artery:

At the angle of the mandible (jawbone).

17. Describe blood pressure and how it is measured.

Blood Pressure (BP): The force exerted by blood against the walls of blood vessels. It is typically measured in millimeters of mercury (mmHg) and expressed as two numbers: systolic pressure over diastolic pressure.

Systolic Pressure:

The maximum pressure exerted by blood on arterial walls during ventricular contraction (systole). It represents the peak pressure.

Diastolic Pressure:

The minimum pressure exerted by blood on arterial walls during ventricular relaxation (diastole), when the heart is filling with blood. It represents the lowest pressure.

How it is Measured (Auscultatory Method using a Sphygmomanometer):

Patient Positioning:

The patient should be seated comfortably with their arm supported at heart level, feet flat on the floor, and relaxed for at least 5 minutes prior to measurement.

Cuff Placement:

An appropriately sized blood pressure cuff is wrapped snugly around the upper arm, with the lower edge about 1 inch above the antecubital fossa (elbow crease). The brachial artery should be aligned with the cuff's artery marker.

Inflation:

The cuff is rapidly inflated using a hand pump (bulb) to a pressure about 20-30 mmHg above the point where the radial pulse disappears (or to about 180-200 mmHg), which occludes the brachial artery.

Deflation and Auscultation:

A stethoscope is placed over the brachial artery in the antecubital fossa. The cuff is then slowly deflated (about 2-3 mmHg per second).

Systolic Pressure Reading:

As the cuff pressure drops, the first sound heard through the stethoscope (Korotkoff sound) indicates the

systolic pressure

. This sound is caused by the turbulent flow of blood through the partially occluded artery.

Diastolic Pressure Reading:

As deflation continues, the sounds become louder, then muffled, and finally disappear. The point at which the sounds disappear (or become very faint) indicates the

diastolic pressure

. This signifies that blood flow through the artery is no longer turbulent.

Recording:

The reading is recorded as systolic/diastolic (e.g., 120/80 mmHg).

BIO 202L Lymphatic Final Exam Review Guide

The lymphatic system is a vital part of the immune system and plays a crucial role in fluid balance.

1. Identify the functions of the lymphatic system.

The lymphatic system has three primary functions:

Fluid Balance (Drainage of Excess Interstitial Fluid):

It collects excess interstitial fluid (which becomes lymph once it enters lymphatic capillaries) from tissues and returns it to the bloodstream. This prevents edema (swelling) and maintains blood volume and pressure.

Fat Absorption:

Specialized lymphatic capillaries called

lacteals

in the villi of the small intestine absorb dietary lipids and lipid-soluble vitamins that are too large to enter blood capillaries. These fats are transported as chylomicrons via lymph to the bloodstream.

Immune Response:

It houses and transports lymphocytes (T cells and B cells) and other immune cells. Lymph nodes and other lymphatic organs filter lymph and blood, removing pathogens, cellular debris, and foreign substances, and initiating immune responses against them.

2. Describe the hormone(s) produced and secreted by endocrine glands.

(This question is a duplicate from the Endocrine section, Q1. Please refer to the detailed answer provided there.)

3. Explain how the endocrine system influences other systems of the body.

(This question is a duplicate from the Endocrine section, Q2. Please refer to the detailed answer provided there.)

4. Describe the hormones found in the anterior pituitary gland and hypothalamic hormones.

(This question is a duplicate from the Endocrine section, Q3. Please refer to the detailed answer provided there.)

5. Describe positive and negative feedback.

(This question is a duplicate from the Endocrine section, Q4. Please refer to the detailed answer provided there.)

6. Describe the function of the pancreas.

(This question is a duplicate from the Endocrine section, Q5. Please refer to the detailed answer provided there.)

7. Describe the structures of the lymphatic vessels and the location of where it drains into.

Structures of Lymphatic Vessels:

Lymphatic vessels form a one-way system that carries lymph from peripheral tissues back to the cardiovascular system. They are similar to veins but have thinner walls and more valves.

Lymphatic Capillaries:

Microscopic, blind-ended vessels that originate in the interstitial spaces. They are more permeable than blood capillaries, with unique mini-valves formed by overlapping endothelial cells that allow fluid, proteins, and even large particles (like pathogens) to enter easily.

Collecting Lymphatic Vessels:

Formed by the union of lymphatic capillaries. They have three tunics like veins but are thinner-walled and contain more valves, giving them a beaded appearance.

Lymphatic Trunks:

Formed by the union of collecting vessels. Major trunks include lumbar, bronchomediastinal, subclavian, jugular, and intestinal trunks.

Lymphatic Ducts:

The largest lymphatic vessels, into which the trunks drain.

Right Lymphatic Duct:

Drains lymph from the right upper limb, right side of the head and thorax. It empties into the

right subclavian vein

at its junction with the right internal jugular vein.

Thoracic Duct (Left Lymphatic Duct):

The largest lymphatic vessel, originating from the cisterna chyli in the abdomen. It drains lymph from the rest of the body (left side of head and thorax, left upper limb, and entire lower body). It empties into the

left subclavian vein

at its junction with the left internal jugular vein.

8. Identify the locations and names of the 3 types of tonsils

Tonsils are lymphoid organs that form a protective ring of lymphatic tissue around the entrance to the pharynx, trapping pathogens entering the body through the mouth and nose.

Palatine Tonsils:

Location:

Located on either side at the posterior end of the oral cavity. These are the largest tonsils and are most often infected.

Lingual Tonsil:

Location:

Located at the base of the tongue.

Pharyngeal Tonsil (Adenoids):

Location:

Located in the posterior wall of the nasopharynx. When enlarged, they are commonly called adenoids.

9. Identify the components (organ) of the lymphatic system. (lacteals)

The lymphatic system is composed of a network of lymphatic vessels and various lymphoid organs and tissues:

Lymphatic Vessels:

Lymphatic capillaries, collecting vessels, trunks, and ducts (thoracic duct, right lymphatic duct).

Primary Lymphoid Organs:

Sites where lymphocytes mature and become immunocompetent.

Red Bone Marrow:

Site of B cell maturation and production of all blood cells.

Thymus:

Site of T cell maturation.

Secondary Lymphoid Organs and Tissues:

Sites where mature lymphocytes encounter antigens and become activated.

Lymph Nodes:

Small, bean-shaped organs clustered along lymphatic vessels. They filter lymph and contain lymphocytes and macrophages.

Spleen:

The largest lymphoid organ, located in the upper left abdomen. It filters blood, removes old RBCs, stores platelets, and houses lymphocytes and macrophages.

Tonsils:

(Palatine, Lingual, Pharyngeal) Lymphoid tissues forming a ring around the pharynx.

Peyer's Patches:

Clusters of lymphoid tissue found in the wall of the distal small intestine (ileum).

Appendix:

A tubular offshoot of the large intestine containing lymphoid tissue.

MALT (Mucosa-Associated Lymphoid Tissue):

Lymphoid tissues found in mucous membranes throughout the body (e.g., respiratory, digestive, genitourinary tracts).

Lacteals:

Specialized lymphatic capillaries located in the villi of the small intestine. While technically a part of the lymphatic vessel network, they are specifically highlighted for their role in fat absorption.

10. Describe the lymphatic vessels that contain afferent vessels.

Lymph nodes are the lymphatic organs that contain afferent lymphatic vessels. Lymph nodes are strategically located along lymphatic pathways to filter lymph.

Afferent Lymphatic Vessels:

These vessels

carry lymph into

a lymph node. They enter the convex side of the node, bringing unfiltered lymph containing pathogens, cellular debris, and antigens to be processed by the immune cells within the node.

Efferent Lymphatic Vessels:

These vessels

carry filtered lymph out of

a lymph node, typically from the hilum (indented region) of the node. The filtered lymph then continues its journey through the lymphatic system.

11. Describe the largest lymphatic organ.

The spleen is the largest lymphatic organ in the body. It is located in the upper left part of the abdomen, inferior to the diaphragm and posterior to the stomach.

Functions of the Spleen:

Blood Filtration:

Filters blood, removing old, damaged, or abnormal red blood cells and platelets.

Immune Surveillance:

Houses lymphocytes (T cells and B cells) and macrophages, initiating immune responses against blood-borne pathogens.

Storage:

Stores platelets and iron (recycled from old RBCs).

Erythrocyte Production (Fetal Life):

In the fetus, the spleen is a site of red blood cell production, but this function typically ceases after birth.

BIO 202L Heart Final Exam Review Guide

The heart is a muscular pump that circulates blood throughout the body, ensuring oxygen and nutrient delivery and waste removal.

1. Describe the location and general features of the heart.

Location:

The heart is located in the

mediastinum

, the medial cavity of the thorax. It lies posterior to the sternum, anterior to the vertebral column, and superior to the diaphragm. Approximately two-thirds of its mass lies to the left of the midsternal line.

General Features:

Size:

Roughly the size of a person's fist.

Shape:

Cone-shaped, with a broad, flat

base

(superior aspect) directed towards the right shoulder and an

apex

(inferior point) pointing inferiorly and to the left.

Orientation:

The heart is tilted; its right side is more anterior, and its left side is more posterior. The apex is formed by the left ventricle.

Chambers:

Four chambers – two superior

atria

(receiving chambers) and two inferior

ventricles

(pumping chambers).

Valves:

Four valves ensure unidirectional blood flow: two atrioventricular (AV) valves and two semilunar (SL) valves.

Great Vessels:

Major blood vessels enter and leave the heart at its base (e.g., aorta, pulmonary trunk, vena cavae, pulmonary veins).

2. Describe the layers of the heart and sacks that surround it.

The heart wall is composed of three layers, and it is enclosed within a protective sac.

Sacks Surrounding the Heart (Pericardium): The heart is enclosed in a double-walled sac called the pericardium.

Fibrous Pericardium (Outer):

A tough, dense connective tissue layer that protects the heart, anchors it to surrounding structures (diaphragm, great vessels), and prevents overfilling of the heart with blood.

Serous Pericardium (Inner):

A thin, slippery, two-layered serous membrane.

Parietal Layer:

Lines the internal surface of the fibrous pericardium.

Visceral Layer (Epicardium):

Adheres to the external surface of the heart muscle. It is considered the outermost layer of the heart wall.

Pericardial Cavity:

The space between the parietal and visceral layers of the serous pericardium. It contains a small amount of

serous fluid

(pericardial fluid), which lubricates the surfaces and allows the heart to beat without friction.

Layers of the Heart Wall:

Epicardium (Visceral Layer of Serous Pericardium):

The outermost layer of the heart wall. It is a serous membrane that often contains fat, especially in older individuals.

Myocardium:

The thick, muscular middle layer. It is composed of cardiac muscle cells arranged in spiral or circular bundles. This layer is responsible for the heart's pumping action. The thickness of the myocardium varies in different chambers (thickest in the left ventricle).

Endocardium:

The innermost layer. It is a thin, smooth sheet of endothelium (simple squamous epithelium) that lines the heart chambers and covers the heart valves. It is continuous with the endothelium of the great vessels, providing a smooth surface that minimizes friction as blood flows through the heart.

3. Describe the structures involved with the pulmonary circuit.

The pulmonary circuit is responsible for carrying deoxygenated blood from the heart to the lungs for oxygenation and then returning oxygenated blood to the heart. The structures involved are:

Right Ventricle:

Pumps deoxygenated blood into the pulmonary trunk.

Pulmonary Semilunar Valve:

Prevents backflow of blood into the right ventricle from the pulmonary trunk.

Pulmonary Trunk:

Large artery arising from the right ventricle, which quickly divides into the right and left pulmonary arteries.

Pulmonary Arteries (Right and Left):

Carry deoxygenated blood to the lungs. These are the

only

arteries in the body that carry deoxygenated blood.

Pulmonary Arterioles:

Smaller branches of pulmonary arteries within the lungs.

Pulmonary Capillaries:

Networks of tiny vessels surrounding the alveoli (air sacs) in the lungs. This is where gas exchange occurs: CO2 diffuses from blood into alveoli, and O2 diffuses from alveoli into blood.

Pulmonary Venules:

Collect oxygenated blood from the pulmonary capillaries.

Pulmonary Veins (typically four: two from each lung):

Carry oxygenated blood from the lungs back to the left atrium of the heart. These are the

only

veins in the body that carry oxygenated blood.

Left Atrium:

Receives oxygenated blood from the pulmonary veins, completing the pulmonary circuit.

4. Describe the flow of blood through the heart, locating the major blood vessels (Ligamentum arteriosum, Fossa ovalis, Pectinate muscles, Trabeculae carneae, papillary muscles), chambers, and heart valves.

Blood flows through the heart in a specific, unidirectional path, driven by pressure changes and regulated by valves.

Deoxygenated blood

from the body enters the

Right Atrium

via three major veins:

Superior Vena Cava:

Drains blood from the head, neck, upper limbs, and thorax.

Inferior Vena Cava:

Drains blood from the abdomen, pelvis, and lower limbs.

Coronary Sinus:

Drains blood from the heart muscle itself.

From the Right Atrium, blood passes through the

Tricuspid Valve

(Right Atrioventricular Valve) into the

Right Ventricle

.

Structures in Right Atrium/Ventricle:

The internal surface of the right atrium has ridges of muscle called

Pectinate Muscles

. The internal walls of the ventricles have irregular ridges of muscle called

Trabeculae Carneae

. Cone-shaped muscle bundles called

Papillary Muscles

project into the ventricular cavities and attach to the chordae tendineae of the AV valves.

The Right Ventricle pumps deoxygenated blood through the

Pulmonary Semilunar Valve

into the

Pulmonary Trunk

.

The Pulmonary Trunk divides into the right and left

Pulmonary Arteries

, which carry deoxygenated blood to the lungs.

Fetal Remnant:

The

Ligamentum Arteriosum

is a fibrous remnant of the ductus arteriosus, a shunt that connected the pulmonary trunk to the aorta in the fetal heart, bypassing the non-functional lungs.

In the lungs, blood releases CO2 and picks up O2 in the pulmonary capillaries.

Oxygenated blood

returns from the lungs via four

Pulmonary Veins

to the

Left Atrium

.

Fetal Remnant:

The

Fossa Ovalis

is a shallow depression in the interatrial septum, marking the former location of the foramen ovale, an opening in the fetal heart that allowed blood to bypass the pulmonary circuit.

From the Left Atrium, blood passes through the

Mitral Valve

(Bicuspid Valve or Left Atrioventricular Valve) into the

Left Ventricle

.

The Left Ventricle, with its much thicker muscular wall, pumps oxygenated blood through the

Aortic Semilunar Valve

into the

Aorta

.

The Aorta distributes oxygenated blood to all parts of the body via the systemic circuit.

Summary of Flow:

Body → SVC/IVC/Coronary Sinus → Right Atrium → Tricuspid Valve → Right Ventricle → Pulmonary Semilunar Valve → Pulmonary Trunk → Pulmonary Arteries → Lungs (gas exchange) → Pulmonary Veins → Left Atrium → Mitral Valve → Left Ventricle → Aortic Semilunar Valve → Aorta → Body

5. Describe the structures of the heart chambers.

The heart has four chambers, each with distinct structural features reflecting their function:

Right Atrium:

Receiving Chamber:

Receives deoxygenated blood from the systemic circuit via the superior vena cava, inferior vena cava, and coronary sinus.

Walls:

Relatively thin-walled. The posterior wall is smooth, while the anterior wall and auricle (an ear-like flap) contain prominent ridges of muscle called

pectinate muscles

.

Interatrial Septum:

The wall separating the right and left atria. Contains the

fossa ovalis

(remnant of foramen ovale).

Valves:

Opens into the right ventricle via the

tricuspid valve

.

Right Ventricle:

Pumping Chamber:

Pumps deoxygenated blood to the pulmonary circuit.

Walls:

Thicker than atrial walls, but thinner than the left ventricular wall. The internal walls are marked by irregular ridges of muscle called

trabeculae carneae

.

Papillary Muscles:

Cone-shaped muscle bundles that project from the ventricular walls and attach to the chordae tendineae of the tricuspid valve, preventing valve prolapse during contraction.

Valves:

Opens into the pulmonary trunk via the

pulmonary semilunar valve

.

Left Atrium:

Receiving Chamber:

Receives oxygenated blood from the pulmonary circuit via four pulmonary veins.

Walls:

Smooth-walled, with a small auricle that may contain pectinate muscles.

Interatrial Septum:

Separates it from the right atrium.

Valves:

Opens into the left ventricle via the

mitral (bicuspid) valve

.

Left Ventricle:

Pumping Chamber:

Pumps oxygenated blood to the systemic circuit.

Walls:

Has the thickest myocardial wall of all chambers, reflecting its role in generating high pressure to pump blood throughout the entire body.

Trabeculae Carneae:

Prominent in its internal walls.

Papillary Muscles:

Larger and more robust than those in the right ventricle, supporting the mitral valve.

Valves:

Opens into the aorta via the

aortic semilunar valve

.

Interventricular Septum:

The muscular wall separating the right and left ventricles.

6. Describe the location of the apex, border, base, and origin of the heart.

Apex:

The pointed, inferior tip of the heart. It is formed by the inferolateral part of the left ventricle and points inferiorly, anteriorly, and to the left. It is typically located at the level of the fifth intercostal space, just medial to the midclavicular line.

Base:

The broad, superior aspect of the heart. It is formed primarily by the left atrium and a small portion of the right atrium. It is where the great vessels (aorta, pulmonary trunk, vena cavae, pulmonary veins) enter and leave the heart. It is directed towards the right shoulder.

Borders:

The heart has several borders:

Right Border:

Formed by the right atrium.

Left Border:

Formed by the left ventricle and a small part of the left atrium.

Inferior Border:

Formed by the right ventricle and a small part of the left ventricle.

Superior Border:

Formed by the great vessels and the atria.

Origin:

The heart itself doesn't have a single