APHY 102 Midterm Ivy Tech - V2

Hormone and hormone action

Chemical messengers that bind to receptors in or on cells and control rates of certain chemical reactions. They air in transporting substances through membranes, regulate water balance, electrolyte balance, and blood pressure. Some play vital role in reproduction, development, and growth

Negative Feedback system role in hormone secretions

As hormone levels in blood increase and hormone exerts effect, negative feedback inhibits the system and hormone secretion decreases. This keeps blood levels of hormones and what they control relatively stable

Paracrine Gland

local hormone that is secreted and only affects nearby cells. Secreted into interstitial fluid. Ex: Histamine that comes from some WBCs and causes dilation of nearby blood vessels

Autocrine Gland

affect only the cell secreting the substance. Ex: Liver cells stimulating themselves to release iron

Endocrine Gland

Releases hormones into internal environment

Exocrine Gland

A gland (as a sweat gland, a salivary gland, or a kidney) that releases a secretion external to or at the surface of an organ by means of a canal or duct.

Location of thymus

Lies in mediastinum posterior to sternum and between lungs

location of pineal gland

Deep between cerebral hemispheres attached to upper portion of thalamus near roof of third ventricle

Location of Pancreas

Posterior to stomach between parietal peritoneum and posterior abdominal wall. A duct of this attaches to the duodenum of the small intestine

Location of Adrenal Glands

Sit atop each kidney and are embedded in adipose tissue

Location of parathyroid glands

posterior surface of the thyroid gland; most people have 4, but it's possible to have more

Location of thyroid gland

inferior to the larynx and anterior to the trachea

location of pituitary gland

sella turcica of the sphenoid bone at base of brain. Attached to hypothalamus by infindibulum

Steroid Hormones

Synthesized from cholesterol. Include carbon, hydrogen, and some oxygen. Includes sex hormones, secretions of adrenal cortex, and calcitriol. Insoluble in water.

Mechanism of action of steroid hormones

1. Endocrine gland secretes steroid hormone

2. Blood carries hormone (bound to hydrophilic protein in blood) through body

3. Unbound steroid hormone diffuses through plasma membrane of target cell entering cytoplasm or nucleus

4. Hormone combines with receptor molecule

5. Steroid Hormone-Receptor Complex binds to DNA and promotes transcription of mRNA

6. mRNA directs protein synthesis

7. Newly synthesized proteins produce hormone's specific effects

Non-Steroid Hormones

Hormones soluble in water. Derived from amino acids and can be amines, peptides, proteins, and glycoproteins

Mechanism of Action of non-steroid hormones

1. Endocrine gland secretes non-steroid hormone

2. Blood carries hormone molecules through body

3. Hormone combines with receptor site activating G Protein

4. Adenylate Cyclase molecules activated

5. Adenylate Cyclase converts ATP to Cyclic AMP

6. cAMP activates protein kinases

7. Protein kinases activate protein substrates in cell that change metabolic processes

8. Cellular changes produce hormone's specific effects

Amine Hormones

Non-steroid hormones derived from amino acid tyrosine and include epinephrine and norepinephrine. Synthesized by adrenal medulla. Thyroxine is also composed of tyrosine and is synthesized in thyroid gland. Melatonin is synthesized from amino acid tryptophan.

Protein Hormones

Non-steroid hormones. Include parathyroid hormone, growth hormone, and prolactin

Peptide hormones

Non-steroid hormones. Short chains of amino acids. Includes anti-diuretic hormones, oxytocin, and some hypothalamus secretions

Prostaglandins

Paracrine substances. Lipids synthesized by arachidonic acid. Produced in liver, kidneys, lungs, thymus, heart, pancreas, brain, and reproductive hormones

Regulation of Pituitary gland secretions

Hormone secretions and signals from hypothalamus regulate secretions of this gland

Tropic Hormones

hormones that stimulate other glands to release their hormones

Anterior Pituitary

Glandular tissue, controlled by hypothalamus via portal system. Releases growth hormone, prolactin, thyroid-stimulating hormone, adrenocorticotropic hormone, follicle-stimulating hormone, and luteinizing hormone

Posterior pituitary

Nervous tissue. Controlled by hypothalamus. Stores rather than synthesizes it's hormones. Secretes anti-diuretic hormone and oxytocin

Glucagon

Stimulates liver to break down glycogen into glucose and to covert non-carbohydrates into glucose. Stimulates breakdown of fats into fatty acid and glycerol. Secreted by pancreatic islets

Glycogenolysis

breakdown of glycogen to glucose

Gluconeogenesis

The formation of glucose from noncarbohydrate sources, such as amino acids.

Insulin

Protein secreted by pancreatic islets. Opposite effect of glucagon. Stimulates liver to form glycogen from glucose and inhibits gluconeogenesis. Promotes facilitated diffusion of glucose through plasma membranes of cells of adipose tissue, liver, and resting skeletal muscle. Decreases blood glucose levels towards normal. Stimulates adipose cells to synthesize and store fat

Stress response

1. Impulses sent to hypothalamus

2. Sympathetic impulses originating from hypothalamus increase blood glucose, blood glycerol, blood fatty acid, heart rate, and BP. Dilate air passages, shunt blood into skeletal muscles, and increases epinephrine release

3. Epinephrine intensifies and prolongs sympathetic actions

4. Hypothalamus secretes CRH, stimulating secretion of ACTH from anterior pituitary

5. ACTH stimulates cortisol release by adrenal cortex

6. Cortisol increases blood amino acids, releases fatty acids, and stimulates formation of glucose from non-carbohydrates

7. Secretion of glucagon from pancreas and growth hormone from anterior pituitary increase

8. Glucagon and growth hormone aid mobilization of energy sources and stimulate uptake of amino acids by cells

9. Secretion of ADH from posterior pituitary increases

10. ADH promotes retention of water by kidneys, increasing blood volume

11. Renin increases blood levels of angiotensin II, which acts as a vasoconstrictor and stimulates adrenal cortex to secrete aldosterone

12. Aldosterone stimulates sodium retention by kidneys

13. Long-term mobilization of nutrients depletes fat stores and leads to protein breakdown and eventual wasting

14. Persistent sodium retention in response to aldosterone can cause potassium depletion and acid-base imbalance

Aging's effect on endocrine system

1. Glands decrease in size and increase in proportion of each fibrous gland

2. Lipofuscin pigment accumulates

3. Hormone levels change

4. GH lowers, ADH increases

5. Thyroid gland shrinks and risk of thyroid cancel increases

6. Calcitonin declines

7. Blood glucose regulation becomes more difficult

Complement

Stimulates inflammation, attracts phagocytes, and enhances phagocytosis. Considered a chemical barrier

Macrophages

Found within the lymph nodes, they are phagocytes that destroy bacteria, cancer cells, and other foreign matter in the lymphatic stream.

Innate Barriers

Species resistance

Mechanical barriers (skin/mucous membranes)

Inflammation

Chemical barriers (enzymes, pH, interferons, collectins, and complements)

Natural Killer Cells

Phagocytosis

Fever

Adaptive Immunity

3rd line defense.

Resistance to particular pathogens or their toxins.

Ability to distinguish molecules as "self" or "non-self".

Antigens

Responses carried out by lymphocytes and macrophages that can recognize specific antigens

2 types: cellular immune response and humoral immune response

T Cells

Origin: Red Bone Marrow

Site of Differentiation: Thymus

Primary Location: Lymphatic tissues; 70-80% of circulating lymphocytes

Primary Function: Provide cellular immune response in which T cells interact directly with antigens or antigen-bearing agents and destroy them

B Cells

Origin: Red Bone Marrow

Site of Differentiation: Red Bone Marrow

Primary Locations: Lymphatic tissues; 20-30% of circulating lymphocytes

Primary Functions: Provide humoral immune response in which B cells interact indirectly, producing antibodies that destroy antigens, or antigen-bearing agents

Autoimmune Diseases

Attach by immune system against its own tissues

Failure to distinguish between "self" and "non-self"

Body produces autoantibodies

Cytotoxic T cells also attack body's tissues and organs

No single cause established

Passive Immunity

Temporary immunity obtained via antibodies; no antigen exposure; no immune response evoked

Lymph node locations

Along lymphatic vessels.

Major locations: cervical region, axillary region, supratrochlear region, inguinal region, pelvic cavity, abdominal cavity, and thoracic cavity

Not found in CNS

Pathway of Lymph

Lymphatic capillaries -> afferent lymphatic vessel -> lymph node -> efferent lymphatic vessel -> lymphatic trunk -> collecting duct -> subclavian vein

Functions of Lymph

1. Absorb dietary fats in small intestine and deliver to bloodstream

2. Return of small proteins filtered by blood capillaries to bloodstream

3. Collection of excess interstitial fluid

4. Delivery of excess fluid to bloodstream

5. Delivery of foreign particles to lymph nodes

6. Flap-like valves btw cells of lymphatic capillaries allow easy entry of tissue fluid

Lymphatic vessel

Similar to veins, but thinner.

3 layers: endothelial lining, middle layer of smooth muscle and elastic fibers, and outer layer of connective tissue. Some have semilunar valves which prevent back-flow of lymph.

Structure of lymph node

Cortex contains follicles with germinal centers, heavy with dividing B cells

Deep cortex houses T cells in transit

T cells circulate continuously among the blood,lymph nodes, and lymphatic stream.

Medulla contains macrophages and T cells

Types of immune cells

macrophages, phagocytes, neutrophils, monocytes, t lymphocytes, b lymphocytes, natural killer cells, and white blood cells

Antigen

Non-self molecules that can evoke an immune response on surface of lymphocytes. May be proteins, polysaccharides, glycoproteins, or glycolipids.

Antibody

Globular protein (immunoglobulins) with 4 amino acid chains (2 light and 2 heavy) forming a y-shaped protein.

5 types: IgG, IgA, IgM, IgD, and IgE

Respond to antigens directly using agglutination (clumping), precipitation (insolubility), and neutralization (cover toxic part of antigen

Respond indirectly by activating complement using opsonization, chemotaxis, agglutinaton, lysis, and neutralization

Localized changes (inflammation)

Agglutination

Clumping of microorganisms or blood cells, typically due to an antigen-antibody interaction.

Precipitation

Neutralization

Opsonization

coating antigen with antibody enhances phagocytosis

Chemotaxis

movement by a cell or organism in reaction to a chemical stimulus

Lysis

Thymus role in immunity

Lobules contain lymphocytes (inactive) which can mature into T cells

Thymosins stimulate T cell maturation

Large in infancy and childhood. Shrinks in adulthood

In elderly, lymphatic tissue is replaced by adipose and connective tissue

Primary Immune Responses

B and T cells specific for antigen become activated

Plasma cells release IgM and IgD

First antibodies appear in 5-10 days and remain for several weeks

Memory B cells also produced

Occurs at first exposure to an antigen

Secondary immune responses

Response to subsequent exposure to same antigen

Produces high concentration of antibodies in 1-2 days

Accomplished by memory B and T cells

Antibodies remain for months or years

Memory B cells live for many years

Interferon

Cytokine that blocks viral replication, stimulates macrophages to engulf viruses, stimulate B cells to produce antibodies, attack cancer cells

Active Immunity

permanent immunity obtained via antigen contact; immune response is evoked, and memory B cells are produced

Role of IgD

On surface of most B cells. Activated B cell

Role of IgG

Located in plasma and tissue fluid. Defends against bacteria, viruses, and toxins. Activates complement

Role of IgE

Located in exocrine gland secretions. Promotes inflammation and allergic responses

Role of IgA

Located in exocrine gland secretions. Defends against bacteria and viruses

Role of IgM

Located in plasma. Reacts with antigens on some RBC membranes following mismatched blood transfusions. Activates complement

Tissue rejection

When the donor's tissues are recognized as foreign; recipient's immune system will try to destroy foreign tissue. Resembles cellular immune response against antigens

graft versus host disease

complication that occurs following a stem cell or bone marrow transplant in which the transplant produces antibodies against recipient's organs that can be severe enough to cause death

Clinical treatments for Tissue rejection

Immunosuppressive drugs

Auricles

"flaps" on the atria to increase the volume of the chamber

Ventricles

the two lower chambers of the heart - pump blood to arteries

Right Atrium

Receives blood returning from systemic circuit (from superior and inferior vena cavae and coronary sinus) and pumps into right ventricle

Atria

the two upper chambers of the heart; receive blood returning to heart

Endocardium

inner lining of the heart; forms lining of all heart chambers. Membrane of epithelium and underlying connective tissue. Includes blood vessels and specialized fibers

Myocardium

muscular, middle layer of the heart

epicardium (visceral pericardium)

Serous membrane covering the heart; Adipose in thick layer in some places; Coronary blood vessels travel through this layer

Pericardial Cavity

space between the parietal and visceral pericardium

visceral pericardium (epicardium)

serous membrane covering the heart

parietal pericardium

Deep to fibrous pericardium; outer layer of serous membrane

fibrous pericardium

tough, white fibrous connective tissue that is the outer layer of the pericardium

Systemic Circuit

Transports oxygen-rich blood from heart to all body cells, and back to heart

Blood delivers nutrients to cells, and removes wastes

Pulmonary Circuit

carries oxygen-poor blood from the heart to the lungs and back.

Capillaries

Transports blood between arteries and veins and performs exchange of gas, nutrients, and waste

Antigens on RBC

A, B, AB, O

Antibodies in Plasma

A: anti-B

B: anti-A

AB: none

O: anti-A and anti-B

Rh factor incompatibility

When the mother is Rh-negative (lacks the Rh blood protein) and the father is Rh-positive (has the protein), the baby may inherit the father's Rh -positive blood type. If even a little of a fetus's Rh-positive blood crosses the placenta into the Rh-negative mother's bloodstream, she begins to form antibodies to the foreign Rh protein. If these enter the fetus's system, they destroy red blood cells, reducing the oxygen sypply to organs and tissues.

Components of blood

55% plasma (water, electrolytes, proteins, gases, wastes, nutrients, vitamins, and hormones), 45% formed elements (Platelets, RBCs, and WBCs)

Formed Elements of Blood

4.8% Platelets, 95.1% RBCs, 0.1% White Blood Cells

Shape and Function of RBC

7.5 micrometers in diameter, biconcave discs which supports transporting gases, non-nucleate

Hematocrit

The percent of the volume of whole blood that is composed of red blood cells as determined by separation of red blood cells from the plasma usually by centrifugation.

Normal levels of RBC

40-54% in males, 35-46% in females

Leukocytes

white blood cells, fight infection

Granulocytes

neutrophils, eosinophils, basophils

Agranulocytes

lymphocytes and monocytes

Plasma

Liquid part of blood

Serum

plasma fluid after the blood cells and the clotting proteins have been removed

Platelets effect on homeostasis

Forms a plug by adhering to any rough surface when a blood vessel is injured, helping control blood loss

clot formation steps

1. Vessel spasm- contracts and reduces blood flow

2. Formation of the platelet plug-von Willebrand factor

3.Development of an insoluble fibrin clot (coagulation cascade)

4.Clot retraction

5. Clot dissolution

function of cardiovascular system

to deliver oxygen and nutrients and to remove carbon dioxide and other waste products

Heart Location

mediastinum superior to diaphragm

pathway of blood into, through and out of the heart

vena cavea - right atrium - right ventricle - pulmonary arteries-lungs - pulmonary veins - left atrium - left ventricle - aorta - body

Right side - deoxygenated blood

Left Side - oxygenated blood

Pathway of cardiac conduction system

SA node, atrial syncytium, junctional fibers, AV node, AV bundle, bundle branches, purkinje fibers, ventricular syncytium

Describe an EKG

A recordable tracing of the electrical activity of the heart that the production and conduction of action potentials in the heart produces.