Ch. 10: Homeostasis

Question 1

what organs comprise the excretory system

Answer 1

kidneys, ureters, bladder, urethra

Question 2

where is the cortex located inside the kidney

Answer 2

the outer layer

Question 3

where is the medulla located inside the kidney

Answer 3

the inner layer

Question 4

where is the renal pelvis

Answer 4

center of the medial surface of the kidney, widest aspect of the ureter which to connects the renal hilum

Question 5

what is the flow of blood in the kidney

Answer 5

renal artery –> afferent arterioles –> glomeruli –> efferent arterioles

Question 6

what are the vasa recta

Answer 6

the secondary capillary beds surrounding the loop of Henle

Question 7

what is a portal system

Answer 7

two capillary beds in series through which blood must travel before returning to the heart

Question 8

detrusor muscle location

Answer 8

muscle that lines the bladder and causes the internal urethral sphincter to contract under parasympathetic control

Question 9

what is the micturition reflex

Answer 9

stretch of bladder muscles –> detrusor muscle contraction –> internal sphincter relaxes

Question 10

what is the primary job of the kidneys (big picture)

Answer 10

regulate blood volume and osmolarity through filtration, secretion, and reabsorption

keep what the body needs, lose what it doesn’t, concentrate urine in order to save water

Question 11

what is the filtrate

Answer 11

the fluid pulled from the blood, through the glomerulus, into the Bowman’s space by starling forces

Question 12

how does the glomerulus filter the blood into filtrate

Answer 12

by size, blood is filtered through glomerular pores

Question 13

what is secretion

Answer 13

process in which solute is move from the blood into the filtrate anywhere outside of bowman’s capsule (usually in the nephrons)

ex: liver filters ammonia to produce urea, which travels in the blood to the nephron and is secreted into the filtrate

Question 14

what kids of substances are secreted

Answer 14

substances in excess concentration in the blood that are too large to pass through the glomerular pores

Question 15

what is reabsorption

Answer 15

process in which some compounds that have been filtered are reabsorbed back into the blood

ex: glucose, vitamins

Question 16

What are the major waste products excreted in the urine

Answer 16

H+, urea, NH3, K+

Dump the HUNK

Question 17

what occurs in the proximal convoluted tubule (PCT)

Answer 17

• filtrate enters here first
• solutes (Na+, CL-, H2O) and water are reabsorbed
• waste products are secreted
• solute is isotonic

Question 18

what is the descending limb of the loop of Henle permeable to

Answer 18

water only

Question 19

what occurs to the filtrate as it travels through the descending limb of the loop of Henle

Answer 19

• interstitum becomes more salty as the limb descends further into the medulla
• the filtrate becomes hypotonic relative to its surroundings
• the filtrate becomes more concentrated as water flows down the concentration gradient

Question 20

what occurs in the countercurrent multiplier system

Answer 20

• flow of filtrate through loop of Henle is opposite in direction from blood in vasa recta
• filtrate is constantly exposed to hypertonic blood to maximize water reabsorption

Question 21

what is the ascending limb of the loop of Henle permeable to

Answer 21

salts only

Question 22

what occurs to the filtrate as it travels through the ascending limb of the loop of Henle

Answer 22

• intertial fluid becomes less salty
• FIRST Na+ and Cl- passively flow to hypotonic surroundings
• SECOND Na+ and Cl- are actively transported to hypertonic surroundings

Question 23

what is the net change in the filtrate after passing though the entirety of the loop of Henle

Answer 23

• filtrate is slightly dilute in comparison to blood

- volume of filtrate significantly reduced

Question 24

what occurs in the distal convoluted tubule

Answer 24

• NaCl is transported out of the filtrate
• Water follows the flow of NaCl from the filtrate
• Waste products are secreted into filtrate

Question 25

what hormone acts on the DCT

Answer 25

aldosterone

Question 26

what hormones act on the collecting duct

Answer 26

aldosterone and ADH/vasopressin

Question 27

what occurs in the collecting duct

Answer 27

filtrates last pass through the nephron where final concentration of urine is determined, permeability to water/salt depends on hormone control

Question 28

how does aldosterone work (big picture)

Answer 28

- steroid hormone (long onset, long lasting) - secreted by adrenal cortex in response to decreased blood pressure - increases DCT and collecting duct's ability to reabsorb Na+ - as Na+ is reabsorbed, H2O is reabsorbed, and BP increases

Question 29

pathway of aldosterone release

Answer 29

low BP --> renin released from juxtaglomerular cells --> renin cleaves angiotensinogen, forming angiotensin I --> angiotensin-converting enzyme converts AGI --> AGII --> aldosterone is released from the adrenal cortex

Question 30

what will be excreted when aldosterone is released

Answer 30

increased levels of K+ and H+

Question 31

how does ADH/vasopressin work (big picture)

Answer 31

- peptide hormone (fast onset, short-term affects) - released by posterior pituitary in response to high blood osmolarity - increases permeability of collecting duct to water and making cell junctions leaky - H2O is reabsorbed

Question 32

skin layers from inside out

Answer 32

hypodermis (subcutaneous), dermis, and epidermis

Question 33

from what germ layer is the skin derived from

Answer 33

the ectoderm

Question 34

what does the stratum basale do

Answer 34

- stem cells | - produces keratinocytes which produce keratin

Question 35

where is the stratum lucid found

Answer 35

thick, hairless, skin (soles of feet and palms)

Question 36

layers of skin from superficial to deep

Answer 36

Come, Let's Get Sun Burned corneum, lucidum, granulosum, spinosum, basale

Question 37

how do calluses form

Answer 37

keratin is deposited in excess due to repeated strain of friction

Question 38

what does melanin do

Answer 38

- produced by melanocytes in the basal layer - pigment that protects DNA from UV radiation - melanocytes increase in production in response to UV radiation (tan)

Question 39

what do the Lanerhans cells do

Answer 39

- macrophages in the spinosum | - present antigens to t-cells to activate the immune sytem

Question 40

where are most sensory receptors located

Answer 40

the dermis - Merkel cells (deep pressure) - Meissner's corpuscles (light touch) - Ruffini endings (stretch) - Pacinian corpuscles (deep pressure and vibration)