A&P 2nd Semester Course Review

Endocrine System

  • Endocrine vs. Exocrine Glands:

    • Exocrine glands produce non-hormonal substances like sweat and saliva.
    • Endocrine glands release hormones into surrounding tissue fluid.
    • Exocrine glands release secretions into ducts.
    • Endocrine glands have a rich vascular system for hormone reception.

  • Feedback Mechanisms:

    • Negative Feedback:
      • Increase in blood glucose stimulates pancreas to secrete insulin.
      • Low thyroxine levels cause pituitary to release thyroid-stimulating hormone (TSH), stimulating the thyroid to release more thyroxine.
      • Low water concentration in blood causes release of antidiuretic hormone (ADH), leading to water retention.
    • Positive Feedback:
      • Childbirth contractions cause oxytocin release, stimulating further contractions.
      • Suckling stimulates oxytocin release, causing milk letdown, stimulating more suckling.

  • Endocrine vs. Nervous System:

    • The nervous system uses electrochemical impulses for rapid, short-term responses.
    • The endocrine system uses hormones for slower, long-term responses.

  • Hormone Types and Action (Honors):

    • Amino acid-based hormones: Cannot diffuse through the plasma membrane; require a secondary messenger.
    • Steroid-based hormones: Diffuse through the plasma membrane and directly affect the nucleus.

  • Effects of Hormones on Target Cells (Honors):

    • Alters plasma membrane permeability.
    • Stimulates protein synthesis.
    • Activates or deactivates enzymes.
    • Induces secretory activity.
    • Stimulates mitosis.

  • Hormone-Target Cell Interaction:

    1. Endocrine gland is stimulated to release hormone.
    2. Hormone is released into the bloodstream.
    3. Hormone finds its target cell based on protein receptors on the cell's plasma membrane; hormone attaches to receptors and causes a change in the cell.

  • Stimuli for Hormone Release:

    • Humoral Stimuli: Gland stimulated by changing blood levels of ions/nutrients.
    • Neural Stimuli: Gland stimulated by nerve fibers.
    • Hormonal Stimuli: Gland stimulated by a hormone released from another gland.

  • Major Endocrine Glands:

    • Pituitary, parathyroid, testes, ovaries, pancreas, adrenals, thyroid, thymus.

  • Hormones Released and Their Actions:

    • Pituitary Gland:
      • Growth Hormone (GH): Influences growth of bones and skeletal muscles, promotes protein synthesis and mitosis. Target: Bones and skeletal muscles.
      • Thyroid Stimulating Hormone (TSH): Stimulates the thyroid to release its hormones. Target: Thyroid gland.
      • Follicle Stimulating Hormone (FSH): Stimulates the gonads to produce sperm and eggs and sex hormone production. Target: Testes and ovaries.
      • Luteinizing Hormone (LH): Stimulates ovulation, egg release from the ovary into the fallopian tubes. In males, it stimulates sex hormone release. Target: Ovaries and testes.
      • Prolactin: Stimulates the mammary gland to produce milk. Target: Mammary glands.
      • Antidiuretic Hormone (ADH): Prevents urine formation. Target: Kidneys.
      • Oxytocin: Stimulates uterine contractions. Target: Uterus.
    • Thyroid Gland:
      • Thyroxine (TH): Body’s major metabolic hormone, increases metabolism and body heat production. Target: All somatic (body) cells.
      • Calcitonin: Inhibits osteoclast activity, stimulates calcium uptake and incorporation into the bony matrix. Target: Skeleton.
    • Parathyroid Gland:
      • Parathormone (PTH): Stimulates osteoclasts to break down bone and release calcium. Target: Skeleton, kidneys, and intestine.
    • Adrenal Gland:
      • Epinephrine and Norepinephrine: Fight or flight response. Target: Sympathetic nervous system.
    • Pancreas:
      • Insulin: Decreases blood glucose levels by changing the permeability of the plasma membrane of body cells. Target: All body cells.
      • Glucagon: Increases blood glucose levels by stimulating liver to perform glycogenolysis. Target: Liver.
    • Gonads:
      • Testes (Testosterone): Male secondary sex characteristics, sperm production. Target: All body cells.
      • Ovaries (Estrogen): Female secondary sex characteristics, egg production. Target: All body cells.
      • Ovaries (Progesterone): Uterine lining development, female secondary sex characteristics. Target: All body cells.

  • Hormone Secretion Disorders:

    • Hypersecretion: Excessive secretion of hormone; example: hypersecretion of human growth hormone results in gigantism.
    • Hyposecretion: Abnormally low or slow secretion; example: in diabetes mellitus, the pancreas hyposecretes insulin.

Blood

  • Major Components of Blood:

    • Plasma (55%)
    • Formed Elements (45%)

  • Blood as Connective Tissue:

    • Cells: Formed Elements: erythrocytes, leukocytes, and platelets.
    • Fibers: Fibrin forms from platelets but only during blood vessel damage.
    • Ground Substance: Plasma is the liquid matrix.

  • Components of Blood and Their Descriptions:

    • Erythrocyte:
      • Biconcave disc.
      • Causes blood to change to a scarlet red color when it bonds with oxygen.
      • Contains hemoglobin.
      • Produced in red bone marrow.
      • Specialized for oxygen transport.
    • Leukocyte:
      • The only formed element that is an actual cell.
      • Uses chemotaxis and amoeboid motion in tissues.
      • Performs diapedesis.
      • Produced in red bone marrow.
      • An elevated number of these indicates infection.
    • Plasma:
      • Contains proteins that help with osmotic balance.
      • 55% of blood is composed of this.
      • Solvent for carrying other substances.
    • Thrombocyte:
      • Essential for blood clotting.
      • Fragments of megakaryocytes.
      • Produced in red bone marrow.

  • Hematopoiesis:

    • Definition: Blood cell formation - all formed elements arise from a common type of stem cell.
    • Location: Red bone marrow in adults in the flat bones of the skull, pelvis, ribs, sternum, and proximal epiphysis of long bone.
    • Influences on Differentiation: Hormones determine which formed element the stem cell will differentiate into.

  • Hemostasis:

    • Vascular spasms: Blood vessel constricts so blood loss can be decreased until clotting occurs.
    • Platelet Plug Formation: Injury to lining of blood vessel exposes collagen fibers so platelets can adhere. Platelets get large and sticky and then release chemicals that attract more platelets to adhere to the area (positive feedback) thus plug formation.
    • Coagulation: Chemicals released from platelets and damaged blood vessels initiate the clotting cascade. During this process inactive substances become active which lead eventually to the activation of fibrin. Fibrin forms a meshwork of fibers that stabilizes the clot so that it can heal (this step is essential and clotting cannot occur without fibrin).

  • Blood Types:

    • AB:
      • RBC antigens present: A and B.
      • Plasma antibodies present: None.
      • Blood that can be received: A, B, AB, O (universal recipient).
      • Blood that can be donated to: AB.
    • A:
      • RBC antigens present: A.
      • Plasma antibodies present: Antibody B.
      • Blood that can be received: A, O.
      • Blood that can be donated to: A, AB.
    • B:
      • RBC antigens present: B.
      • Plasma antibodies present: Antibody A.
      • Blood that can be received: B, O.
      • Blood that can be donated to: B, AB.
    • O:
      • RBC antigens present: None.
      • Plasma antibodies present: Antibody A and Antibody B.
      • Blood that can be received: O.
      • Blood that can be donated to: A, B, AB, O (universal donor).

  • Rh Factor:

    • Positive (+) means erythrocytes carry the Rh antigen; negative (-) means they do not.

  • Transfusion Reactions:

    • Improperly matched blood groups lead to antibodies recognizing foreign antigens, causing agglutination (clumping). Clumps break and release hemoglobin into the bloodstream, potentially causing renal failure.

Cardiovascular System

  • Blood Vessels:

    • Arteries carry blood away from the heart.
    • Veins carry blood towards the heart.
    • Capillaries are the site of nutrient/gas/waste exchange between tissue cells and blood.

  • Heart Structures:

  • Circulation Circuits:

    • Systemic Circulation: F,E,D,L, J, B, M, O
    • Pulmonary Circulation: G, H,E, C, K, J, A, N, I

  • Blood Flow Through the Heart:

    • Superior/Inferior vena cava → Right atrium → AV Tricuspid Valve → Right ventricle → Pulmonary Semilunar Valve → Pulmonary arteries → Lungs → Pulmonary veins → Left atrium → AV bicuspid Valve → Left ventricle→ Aortic Semilunar Valve → Aorta

  • Valve Function:

    • AV valves prevent backflow into the atria when the ventricles are contracting.
    • Semilunar valves prevent backflow into the ventricles when the ventricles are relaxing.

  • Blood pressure:

    • Pressure exerted by the blood against the blood vessel walls

  • Cardiac output:

    • The amount of blood pumped out of left ventricle
    • Factors that are directly related to blood pressure

  • Constriction of blood vessels:

    • Event primarily responsible for peripheral resistance

  • Diastolic blood pressure:

    • Blood pressure during heart relaxation

  • Over arteries:

    • Site where blood pressure determinations are normally made

  • Peripheral resistance:

    • Amount of friction blood encounters as it flows through blood vessels
    • Factors that are directly related to blood pressure

  • Systolic blood pressure:

    • Blood pressure during heart contraction

  • Pressure and Structure of Blood Vessels:

    • Arteries:
      • High pressure.
      • Elastic arteries to stretch and recoil with high pressure
    • Veins:
      • Lowest pressure.
      • Wider lumens and valves to catch blood before it falls
    • Capillaries:
      • Lower pressure.
      • Designed more for diffusion

  • Factors Affecting Blood Pressure:

    • Increased diameter of blood vessels: Decrease
    • Increased blood viscosity: Increase
    • Increased cardiac output: Increase
    • Anxiety, fear: Increase
    • Physical exercise: Increase
    • Hemorrhage: Decrease
    • Nicotine: Increase
    • Arteriosclerosis: Increase
    • Increase urine output: Decrease
    • Physical training: Decrease

  • Cardiac Cycle:

    • Mid-to-late diastole (ventricular filling): Total heart relaxation. Blood flowing passively into and through the atria into the ventricles. Semilunar valves closed and AV valves open then atria contract.
    • Ventricular systole (atria in diastole): Ventricles contract, AV valves close and semilunar valves open. Blood pushed up into arteries. Blood filling into atria
    • Early diastole: Ventricles relax, semilunar valves shut, AV valves open and ventricles fill with blood again.

  • Heart Sounds:

    • Lub sound: Closing of the AV valves.
    • Dup sound: Closing of the semilunar valves.

  • ECG Diagram (Honors):

    • P- Nerve impulse that stimulates the atria to contact.
    • QRS- Nerve impulse that stimulates the ventricles to contract
    • T- Recharging of the heart for next cycle.

  • ECG Matching (Honors):

    • Bradycardia
    • Myocardial infarction
    • Normal
    • Tachycardia

  • Comparison of Capillaries, Arteries, and Veins (Honors):

    • Capillaries:
      • Thickness of walls: Thin.
      • Layers in walls: Tunica intima.
      • Valves: No.
    • Arteries:
      • Thickness of walls: Thick.
      • Layers in walls: Tunica externa, Tunic media (very thick) and Tunica intima
      • Valves: No.
    • Veins:
      • Thickness of walls: In between.
      • Layers in walls: Tunica externa, tunica media (not as thick), tunica intima
      • Valves: Yes

  • Hypertension vs. Atherosclerosis:

    • Hypertension:
      • Cause: Increased peripheral resistance
      • Effect: Heart has to work harder to push blood flow results in high blood pressure and can eventually weaken the heart walls and blood vessels
    • Atherosclerosis:
      • Cause: Thickening of inside of walls of blood vessels due to accumulation of plaques
      • Effect: Hypertension

  • Fetal Vascular Modifications:

    • Umbilical cord: Nutrients and oxygen move from mother’s blood to fetal blood in placenta through umbilical cord
    • Ductus venosus: Bypasses the fetal liver
    • Foramen ovale: Shunt which assist in blood bypassing the lungs, since they are not functional
    • Ductus arteriosus: Shunt which assist in blood bypassing the lungs, since they are not functional

  • Major Arteries and Veins:

  • Hepatic Portal System (Honors):

    • A series of veins that carry nutrient-rich blood from the intestines, spleen, and pancreas to the liver.

  • Myocardium Oxygenation (Honors):

    • The myocardium receives oxygenated blood via coronary circulation, which is a series of arteries arising from the aorta that contain oxygenated blood. As the blood moves into capillaries of the myocardium the oxygen is taken up and waste products are collected in the veins which drains out in the coronary sinus found in the right atrium.

Lymphatic System and Body Defenses

  • Relationship of Lymphatic Vessels to Blood Vessels:

  • Steps Tissue Fluid Takes in the Lymphatic System:

    1. Fluid leaks out of capillaries into surrounding tissue
    2. Lymph capillary
    3. Lymph vessel
    4. Lymph node
    5. Lymph duct
    6. Lymph enters back into bloodstream

  • Lymphoid Organs:

    • Tonsils:
      • Location: Ring the pharynx.
      • Function: Trap and remove bacteria or other foreign pathogens entering the throat
    • Thymus:
      • Location: Throat overlying the heart
      • Function: Peaks during youth produces hormones to help develop T lymphocytes
    • Spleen:
      • Location: Left side of the abdominal cavity, just beneath the diaphragm
      • Function: Filters and cleanses blood of bacteria, viruses and other debris. Site for lymphocyte proliferation and immune surveillance. Destroys worn RBC

  • Function of the Immune System:

    • The body’s defenders against pathogens

  • Innate vs. Adaptive Defense Systems:

    • The innate defense system, also known as nonspecific defense, responds immediately to protect the body form all foreign substances.
    • The adaptive system, also known as specific defense mounts the attack against specific foreign substances.

  • Components of Immune System:

    • Innate: Skin, Fever, Inflammation, Saliva, Mucous
    • Adaptive: Lymphocyte, Antibodies, B cell

  • Nonspecific Responses:

    • Skin and mucous membranes: Considered the first line of defense, Can contain sticky mucus to trap microorganisms.
    • Phagocytes: Engulfs foreign particles through phagocytosis
    • Inflammatory Response: Triggered whenever the body tissue is injured
    • Fever: Abnormally high temperature

  • Adaptive Defense:

    • Important Aspects: It is systemic, It is antigen specific, It has memory

  • Branches of Adaptive Defense:

    • Cellular immunity
      • Lymphocyte: T cell
      • How does it attack antigen?: Direct attack by lysing foreign cells or indirectly by releasing chemicals to enhance inflammation or activate other immune cells
      • Types of antigens it attacks: Virus infected, cancer or foreign graft cells. Target cells that are foreign or infected.
    • Humoral immunity
      • Lymphocyte: B cell
      • How does it attack antigen?: Release antibodies that find pathogen and inactivate them
      • Types of antigens it attacks: Pathogens found in fluids like bacteria, fungus

  • Types of Humoral Immunity:

    • Active:
      • When B cells encounter antigens and produce antibodies against them
      • Artificially acquired when we receive vaccines
      • Naturally acquired during bacterial and viral infections
    • Passive: *When antibodies are obtained from the serum of an immune human or animal donor
      • Naturally occurs when a fetus receives the mother’s antibodies across the placenta or through breast feeding
      • Artificially occurs when one receives an immune serum such as antivenom or a tetanus shot.

  • Treatments:

    • Vaccines treat viral infections, while antibiotics treat bacterial infections.

  • Explanation of Treatments:

    • Vaccines: Contain pathogens that are dead or attenuated (living, but extremely weakened) that prime the immune response so if you were to actually get the virus your immune system would be ready to fight it.
    • Antibiotics: Use some sort of mechanism to destroy bacteria like destroy cell wall of bacteria or inhibit an enzyme in bacteria so it cannot complete its metabolic processes.

Respiratory System

  • Pathway of Air:

    • Nares → Nasal cavity → Pharynx → Larynx → Trachea → Bronchi → Bronchioles → Alveoli

  • Statements with Parts of Respiratory System:

  • Histology of the Respiratory System (HONORS):

    • Nasal cavity:
      • Structure/Histology: Lined with respiratory muscoa rich in blood vessels and olfactory receptors
      • Function: Warms, moistens and filters incoming air. Sense of smell
      • Location in respiratory tract: Upper respiratory tract (nose)
    • Tracheal cartilage/Bronchi:
      • Structure/Histology: C-shaped rings of hyaline cartilage lined with ciliated mucosa
      • Function: Trap dust and debris and move it away from lungs with cilia. Passageway for air into lungs.
      • Location in respiratory tract: Anterior to esophagus
    • Bronchioles:
      • Structure/Histology: Smooth muscle
      • Function: To accommodate volume of air moving into lungs
      • Location in respiratory tract: Inside lungs
    • Alveoli:
      • Structure/Histology: Simple squamous epithelium with a layer of surfactant (fluid) to keep it inflated
      • Function: Site of gas exchange
      • Location in respiratory tract: At the end of bronchioles

  • Pulmonary Ventilation:

    • The process of air moving into and out of the lungs is called pulmonary ventilation. Air flowing into the lungs is called inspiration. Air leaving the lungs is called expiration. This mechanical process depends on volume changes occurring in the thoracic cavity which results in changes in pressure. Air will always move from a high pressure to a low pressure gradient.

  • Pulmonary Ventilation Chart:
    | | Activity of diaphragm | Internal volume of thorax (increase or decrease) | Internal pressure of thorax (increase or decrease) | Size of lungs (increase or decrease) | Direction of air flow (into body or out of body) | Inspiration or expiration? |
    | :-------------------------------- | :----------------------------- | :----------------------------------------------- | :------------------------------------------------- | :----------------------------------- | :------------------------------------------------- | :------------------------- |
    | Inspiration | Contracted, moves downward | Increases | Decreases | Increases | Into body | Inspiration |
    | Expiration | Relaxed, moves superiorly | Decreases | Increases