Chapter 10- Homeostasis

Question 1

excretory system

Answer 1

regulating blood pressure, blood osmolarity, acid-base balance, removal of nitrogenous wastes

Question 2

anatomy of excretory system (in order)

Answer 2

kidneys, ureters, bladder, urethra

Question 3

kidney

Answer 3

filters blood to form urine. Regulates blood volume and osmolarity. made up of: cortex (outermost layer) and medulla (within the cortex)

Question 4

glomeruli

Answer 4

highly convoluted capillary tufts derived from afferent arterioles

Question 5

vasa recta

Answer 5

capillaries that surround loop of Henle

Question 6

detrusor muscle

Answer 6

lining of bladder. parasympathetic activity causes contraction.

Question 7

internal and external urethral sphincter

Answer 7

internal- smooth muscle (involuntary muscle)

external- skeletal muscle (voluntary muscle)

Question 8

micturition reflex

Answer 8

full bladder causes stretch receptors to tell nervous system (parasympathetic) to contract detrusor muscle. this contraction causes the internal sphincter to relax

Question 9

3 processes involved in kidney function

Answer 9

1. filtration (movement of solutes from blood to filtrate at Bowmans capsule)
2. secretion (movement of solutes from blood to filtrate anywhere besides Bowmans capsule)
3. absorption (movement of solutes from filtrate to blood)

Question 10

filtrate

Answer 10

collected fluid after it has passed through glomerulus/ bowmans space

Question 11

starling forces

Answer 11

governs movement of fluid into bowmans space. accounts for different pressure (higher P in glomerulus, so fluid will move into the nephron)

Question 12

if blood or protein is found in the urine, what does that indicate?

Answer 12

health problem at level of glomerulus in the kidney

Question 13

liver converts ammonia to…?

Answer 13

urea, which travels to kidney and is secreted into nephron for excretion with urine.

Question 14

what compounds are almost always reabsorbed?

Answer 14

glucose, amino acids, and vitamins (water depending on levels of ADH)

Question 15

parts of the nephron

Answer 15

1. proximal convoluted tube
2. loop of henle
3. distal convoluted tube
4. collecting duct

Question 16

proximal convoluted tube

Answer 16

controls solute identity. reabsorbing vitamins, amino acids, and glucose. while secreting K, H, ammonia, and urea

Question 17

interstitium

Answer 17

connective tissue surrounding the nephron. solutes that enter this are picked up by the vasa recta to be returned to the bloodstream for reuse within the body.

Question 18

2 parts of loop of henle

Answer 18

1. descending limb (permeable only to water, using medullary concentration gradient)
2. ascending limb (permeable only to salts)

Question 19

countercurrent multiplier system

Answer 19

created by the vasa recta and nephron. flow of filtrate through loop of Henle is in opposite direction from flow of blood through vasa recta. the filtrate is then constantly being exposed to hypertonic blood which allows for maximal reabsorption of water.

Question 20

diluting segment of loop of henle

Answer 20

at transition from inner to outer medulla, the loop of henle becomes thicker (cells lining tube are larger)

Question 21

distal convoluted tube

Answer 21

important for solute identity by reabsorbing salts while secreting K, H, ammonia, and urea.

Question 22

collecting duct

Answer 22

responsive to both aldosterone and ADH/vasopressin. permeability will depend on how hydrated the person is. point of no return (if it doesnt leave here then it will be excreted from the body)

Question 23

2 important hormones for maintenance of blood pressure

Answer 23

aldosterone and ADH/vasopressin

Question 24

aldosterone

Answer 24

steroid hormone secreted by adrenal cortex in response to decreased blood pressure. alters ability of distal convoluted tubule and collecting duct to reabsorb sodium thus water will follow to increase bp.

Question 25

cascade to stimulate aldosterone release

Answer 25

decreased bp stimulates release of renin from juxtaglomerular cells in kidney. Renin cleaves angiotensinogen (liver protein) to form angiotensin I then metabolized to form angiotensin II which promotes the release of aldosterone from adrenal cortex.

Question 26

Antidiuretic hormone (ADH/ vasopressin)

Answer 26

peptide hormone synthesized by hypothalamus and released by the posterior pituitary in response to high blood osmolarity. alters permeability of collecting duct. allowing more water to be reabsorbed by making cell junctions of duct leaky. (ONLY WATER, so result is decreased blood osmolarity)

Question 27

what inhibits ADH release?

Answer 27

alcohol and caffeine. causes frequent excretion of dilute urine.

Question 28

osmotic vs oncotic pressure

Answer 28

osmotic- “sucking” pressure drawing water into vasculature caused by dissolved particles
oncotic- osmotic pressure attributable to dissolved proteins specifically

Question 29

when blood osmolartiy is low vs. high

Answer 29

low- excess water will be excreted

high- water will be absorbed (more solutes will be excreted)

Question 30

when blood pH is too low…

Answer 30

kidneys excrete more hydrogen ions and increase reabsorption of bicarbonate, resulting in higher pH

Question 31

when blood pH is too high…

Answer 31

kidneys can excrete more bicarbonate and increase reabsorption of hydrogen ions, resulting in lower pH

Question 32

vessels in renal vascular pathway

Answer 32

renal artery, afferent arteriole, glomerulus, efferent arteriole, vasa recta, renal vein

Question 33

bowmans capsule

Answer 33

site of filtration (for size). water, ions, amino acids, vitamins, and glucose pass

Question 34

3 layers of skin (deepest to most superficial)

Answer 34

1. hypodermis (subcutaneous layer)
2. dermis
3. epidermis
   * skin is derived from ectoderm

Question 35

epidermis (and its 5 layers in order from deepest to most superficial)

Answer 35

outer-most layer of skin. subdivided into strata.

1. basale (stem cells/ proliferation of keratinocytes which produce keratin)
2. spinosum (site of langerhans cells, connectedness here)
3. granulosum (keratinocytes die and lose nuclei)
4. lucidum (only present in thick, hairless skin)
5. corneum (contains 3 dozen layers of flattened keratinocyes for protection)
   * in opposite order: Come Lets Get Sun Burned*

Question 36

keratin

Answer 36

resistant to damage and provides protection against injury, water, and pathogens.

Question 37

calluses

Answer 37

form excessive keratin deposition in areas of repeated strain due to friction.

Question 38

melanocytes

Answer 38

cell type derived from neural crest cells and found in stratum basale. produce melanin to give pigment to skin.

Question 39

langerhans cells

Answer 39

special macrophages that reside within stratum spinosum. capable of presenting antigens to T-cells in order to activate immune system

Question 40

Dermis (with its multiple layers)

Answer 40

superficial to deep
papillary layer- loose connective tissue
reticular layer- sweat glands, blood vessels, hair follicles originate here
most sensory cells are also in dermis.

Question 41

hypodermis

Answer 41

connective tissue that connects the skin to the rest of the body. this layer contains fat and connective tissue.

Question 42

4 mechanisms for thermoregulation by skin

Answer 42

1. sweating (cooling mechanism due to evaporation of sweat from skin by autonomic NS)
2. piloerection (heating mechanism caused by arrector pili muscles to trap a layer of heated air near skin)
3. vasodilation (cooling)
4. vasoconstriction (heating)

Question 43

white fat vs. brown fat

Answer 43

white- helps to insulate body

brown- much less efficient ETC which means more heat energy is released as fuel is burned (especially in infants)

Question 44

skin permeability

Answer 44

skin is relatively impermeable to water

Question 45

passage of blood through vessels of kidney

Answer 45

renal artery, afferent arterioles, glomerulus, efferent arterioles, vasa recta, renal vein