Hemostasis: Renal Structure and Function

Question 1

cortex of the kidney

Answer 1

outer portion of kidney, has projections called renal columns, contain renal corpuscles and renal tubules (NOT loop of Henle though)

Question 2

medulla of kidney

Answer 2

innermost portion of kidney, composed of pyramids, loops on Henle, vasa rectae, collecting tubule

Question 3

pyramids of kidney

Answer 3

27-30 make up renal medulla, composed of interstitium, loops of Henle and vasa rectae

Question 4

minor and major calyces of kidney

Answer 4

surround apex of renal pyramids, collect urine from collecting ducts, merge to form major calyces, urine then flows into renal pelvis

Question 5

renal pelvis

Answer 5

funnel-like convergence at end of major calyces, carries urine to ureters

Question 6

renal interstitium

Answer 6

hypertonic, draws h20 from thin descending limb of loop of Henle and collecting ducts.

Question 7

afferent arterioles of the kidney

Answer 7

arise from cortical radial arteries, micro-vasculature that supplies blood to the glomerulus be filtrated

Question 8

efferent arterioles of the kidney

Answer 8

micro-vasculature that drains blood from the glomerulus. leave glomerulus to form the peritubular capillaries

Question 9

Bowman’s capsule

Answer 9

capsule that surrounds the glomerulus, composed of parietal layer and visceral layer of stellate cells (podocytes)

Question 10

podocytes

Answer 10

specialized stellate cells that make up the visceral layer of Bowman’s capsule

Question 11

glomerulus

Answer 11

bundle of specialized capillaries that facilitate the filtration of blood to form filtrate

Question 12

juxtaglomerular apparatus

Answer 12

area where the thick ascending portion of the loop of Henle lies adjacent to the glomerulus. contains the macula densa. vital for tubulo-glomerular feedback which stimulates or inhibits renin production and secretion.

Question 13

macula densa

Answer 13

portion of the juxtaglomeruluar apparatus that helps w/ tubulo-glomerular feedback

Question 14

proximal convoluted tubue

Answer 14

lies in the cortex of the kidney, picks up filtrate from glomerulus, 5/6 of Na+ and H2O are resorbed into the kidney interstitium in this portion

Question 15

distal convoluted tubule

Answer 15

follows macula densa portion of JGA, collects to the collecting duct

Question 16

descending loop of Henle

Answer 16

follows proximal tubule, primarily in the inner medulla, permeable to water but not solute

Question 17

ascending loop of Henle

Answer 17

ascends from hairpin turn of loop, permeable to solute but not water

Question 18

collecting duct

Answer 18

final section of nephron, collects urine, regulated by aldosterone. has aquaporins that can allow resorption of water if needed

Question 19

discuss four major non-excretory functions of the kidney

Answer 19

1. regulates BP via renin-angiotensin-aldosterone system
2. produces and secretes EPO
3. produces active form of vitD
4. produces renin

Question 20

average daily cardiac output

Answer 20

~7200L/day

Question 21

average daily renal blood flow

Answer 21

~1800L/day

Question 22

average glomerular filtration rate

Answer 22

~180L/day

Question 23

average daily urine output

Answer 23

~1.5L/day

Question 24

what is the general fluid content of filtrate as it passes through the fenestrated glomerular capillary walls?

Answer 24

nearly protein-free. this barrier allows passive of electrolytes, AAs, glucose, creatinine, and some other small molecules to pass through. most common substances are Na+, K+, Cl-, urea, some glucose.

Question 25

what types of cells secrete renin in the afferent arteriole of the kidney?

Answer 25

granular cells

Question 26

what factor stimulates renin production and secretion

Answer 26

large urine flow, renin acts to contraction of the afferent arteriole to slow filtrate formation

Question 27

proximal convoluted tubule resorption

Answer 27

resolves 50-60% of solute and water filtered at glomerulus. resorbs essential nutrients (organic solutes), NaHCO3 (bicarbonate), and NaCl

Question 28

thin descending limb of loop of Henle resportion

Answer 28

permeable to water but NOT solute, pulls water OUT of solute

Question 29

thick ascending limb of loop of Henle resportion

Answer 29

resorbs 30% of NaCl filtered at glomerulus, impermeable to H2O. plays a major role in creation of medullary osmotic gradient and counter-current exchange, can help to create either concentrated or dilute urine

Question 30

distal convoluted tubule resporption

Answer 30

diluting segment, resorbs NaCl. HCTZ acts to block channels in this portion of the glomerulus.

Question 31

collecting duct resorption

Answer 31

regulatory segment, regulated by aldosterone. aldosterone stimulates increase absorption of NaCl, creates a more acidic urine (removes H+ from blood),

Question 32

aldosterone action

Answer 32

secreted by the adrenal gland on top of the kidney. affects the collecting duct. increases BP. 1. drives Na/K pump to push Na INTO blood, K OUT of blood (leads to K+ increase in urine through K+ channels) 2. create Na+ channels to remove Na+ from urine to be pushed back into blood 3. this leads to movement of water back into blood (follows Na+ concentration increase in blood)

Question 33

how is GFR assessed?

Answer 33

concentration of certain compounds can help determine plasma concentration, which in turn gives an idea of GFR (elevated serum creatinine indicates decreased GFR)

Question 34

GFR

Answer 34

volume of filtrated that is formed/unit time