Anatomy and Physiology

Adrenal glands- on top of kidneys- attached to kidneys via connective tissue capsule-cortex- stimulated by ACTH3 layers1. – zona glomerulosa – releases mineral corticoids- aldosterone: anti-diuretic. Retain na+ –> leads to h2o retention (Low levels of aldosterone)–>. Hypovolemia- low blood volume–>. leads to low blood pressure

2. – zona fasciculata- glucocorticoids- cortisone, cortisol -resist stressors. -increase glucose in blood-increase protein synthesis : by releasing amino acids into blood -increase fatty acids in blood3. -zona reticularis- secretes androgens : testosterone-in females: testosterone is responsible for muscle tone, sex drive Pathologies of adrenal cortex1. -Addison’s disease: underproduction of corticosteroids- mineral and gluco-corticoids-symptoms: weight loss, decreased sodium levels–> high potassium, water loss from blood–> hypovolemia & low BP , fatigue, dehydration -hyposecretion: increase ACTH- looks molecularly similar to MSH- melanin stimulating hormone -excessive amounts of ACTH stimulate melanocytes to produce melanin 2. -Cushing’s disease: hypersecretion of corticosteroids

– increase sodium retention, edema, increase glucose levels in blood, redistribution of fat in belly or trunk, moon face (fat around face), buffalo hump (fat build up behind neck around C7) Adrenal medulla- center of adrenal gland

-produces Epinephrine and norepinephrine- mimic and enhance sympathetic nervous system and response – increase heart rate, dilate pupils, increase metabolism, shunt blood supply(more to skeletal muscle)

Lymphatic system-Functions:- produce & maintain lymphocytes to defend against pathogens -return excess fluid that has leaked out of capillary beds to venous circulation

Lymphoid organs- thymus, spleen, tonsils, adenoids, lymph nodes Lymph nodes- 1mm-25mm in diameter. Hilum(where you plug stuff in) -larger collections of nodes in neck, axillary region, and inguinal (groin)** Lymphadenopathy- enlargement of lymph nodes

-typically in cancer or chronic infection-Thymus- pink granular organ. -lies over the great vessels, posterior to sternum – most active during first 1-2 years, that’s when your most exposed to new antigens -after puberty activity is decreased

-involution: shrinks, turns to adipose tissue-thymosin: stimulates certain stem cells divisions–> t (thymositic) lymphocyte Spleen- located in left upper quadrant-has visceral surface that faces the stomach and intestines -has diaphragmatic surface that faces the diaphragmHistology:-red pulp: contains large amounts of RBC’s- white pulp: contains mainly lymphocytesMajor lymph ducts-1. Thoracic duct- left of vertebral column, posterior-receives lymph from left half of the thorax and from abdomen, pelvis & lower limbs

2. Right lymphatic duct- drains right side of body above diaphragm (Both drain into subclavian veins)3. Cisterna chyli- receives lymph from abdomen and pelvis and drains into thoracic duct Immune systemNon-specific and specific defensesNon-specific: physical barriers to infection1.skin- thick epithelium -acidity of secretions (sweat) -inhibitsbacterial growth 2.mucus membranes- line body cavities. – mucus traps bacteria and viruses 3.saliva and tears- both contain lysozyme (enzyme that breaks down bacteria) 4.fever

5.inflammation- red tissues, swelling, and pain6.Cellular non-specific:-macrophages: wander through peripheral tissues scavenging for dead cell debris and foreign invaders -natural killer cells: immune surveillance. -Lyse and destroy cancer cells and viruses -perforins: poke holes in cell membrane of a pathogen Specific: recognize “self” from “non-self”

DefinitionsAntigen- any substance that is recognized as foreign therefore elicits an immune response Antibody- protein made by certain B lymphocytes that bind specifically to antigens Specific immunity is provided by T cells and B cells **

-cellular and humoral (blood borne) immunity-cellular specific immunity: T cells : Tc = Cytotoxic T cell -in peripheral tissues to physically or chemically attack viruses or virally infected cells Th= helper T cells- stimulate the production of and activate T cells & B cells Suppressor Tcells- Inhibit both T and B-cells; make sure you dont have an over immune respone.