10.1 Renal system

Question 1

Vasa recta vs peritubular capillaries

Answer 1

capillary for O2, runs parallel to loop of Henle vs capillary for nutrients, collects solutes from renal tubules to blood, runs around PCT and DCT

Question 2

What is in the renal hilum? What’s in the renal corpuscle?

Answer 2

Renal artery, renal vein, ureter. Glomerulus + Bowman’s capsule

Question 3

What parts do collection only?

Answer 3

Renal calyces, renal pelvis

Question 4

What other main function are the kidneys in charge of?

Answer 4

homeostasis (pH, bp, osmolarity, expelling waste like urea)

Question 5

What is the glomerulus?

Answer 5

Site where filtration happens

Question 6

What is Bowman’s capsule and Bowman’s space? Which substances can pass thru Bowman’s capsule?

Answer 6

Collects filtrate/fluid that comes out of glomerulus; open space
Glucose, water and ions can pass thru, proteins can’t cuz too big for podocytes

Question 7

How do nutrients in blood move from glomerulus to Bowman’s capsule?

Answer 7

Fenestrated endothelial cells of blood vessels, semi-permeable basement membrane (it’s neg charged to prevent proteins from entering filtrate), podocytes from tubular epithelial cells

Question 8

Know the effects of inc/dec diameter of afferent/efferent arterioles on filtration rate

Answer 8

Aff: direct relationship, eff: inverse relationship

Question 9

Know the proximal tubule, loop of Henle, and distal tubule of nephron

Answer 9

in thick ascending loop: salts are pumped out to salty medulla thru salt permeable membrane via ATP => active transport, thin ascending in inner medulla is passive transport; in thin descending loop: only water is pumped out in rxn to salty medulla –> water reabsorption. PCT is site of bulk reabsorption of glucose, aa, water-soluble vitamins, salt reabsorption, water excretion and HUNK secretion; DCT responds to aldosterone, salt reabsorption (ex: Na+ into filtrate and K+ into blood), water excretion and HUNK secretion

Question 10

Which side of bladder do ureters connect to?

Answer 10

Posterior side

Question 11

How is urine expelled in males and females?

Answer 11

Males: renal calyx –> renal pelvis –> ureters –> bladders internal urethral sphincter (smooth) –> prostatic urethra –> external urethral sphincter (skeletal) –> spongy urethra (penis) –> out
Females: renal calyx –> renal pelvis –> ureters –> bladder –> internal urethral sphincter –> external urethral sphincter –> out

Question 12

Why do ureters have valves?

Answer 12

to prevent urine backflow; if there is backflow –> stasis –> greater risk of infection => UTI (shorter urethras also pose greater risk of infections –> more UTIs for them)

Question 13

What does ADH/vasopressin do? Does aldosterone act on collecting ducts?

Answer 13

Increase water reabsorption; acts on collecting ducts by telling it to reabsorb water (so if ADH wasn’t present, water would nmlly be absorbed only in descending loop of Henle). Yes, it does the same thing as ADH: inc water reabsorption at collecting duct (indirectly tho); it also inc Na+ reabsorption at collecting duct

Question 14

T/F: proximal tubule only collect solute, thus its not involved in osmolarity

Answer 14

T

Question 15

Detrusor muscle

Answer 15

Muscular lining of bladder. It contracts cuz of parasympathetic nervous system

Question 16

Micturition reflex

Answer 16

When IUS relaxes because stretch receptors are telling parasympathetic nervous system you need to empty bladder

Question 17

Filtration vs secretion vs reabsorption

Answer 17

Solute moving from blood to filtrate via bowman’s capsule vs solute moving from blood to filtrate via anywhere else besides bow’s cap vs solute moving from filtrate to blood

Question 18

Starling forces

Answer 18

What causes fluid movement into Bowman’s space. Takes account hydrostatic pressure and oncotic pressure (osmotic pressure induced by proteins)

Question 19

Why is urea excreted thru urine?

Answer 19

When we digest proteins, ammonia becomes a byproduct from amino group. Ammonia is a base that can disturb pH —> liver converts it to urea to be excreted

Question 20

Major waste products in urine. Under nml circumstances, urine should be..?

Answer 20

H+, urea, ammonia, K+ (HUNK). Urine should be hypertonic to blood

Question 21

Countercurrent multiplier system

Answer 21

When loop of Henle creates a conc gradient via single effect and flow of fluid. Single effect - when Na+/K+/2Cl- cotransporter reabsorbs all 3 ions at thick ascending limb (ie. Remove the 3 ions from thick ascending limb) —> water will flow in or out of descending limb to equilibriate
This system allows urine osmolarity to exceed blood osmolarity

Question 22

An excess of acetylcholamine leads to what?

Answer 22

Activation of all parasympathetic neurons

Question 23

Erythropoietin vs thrombopoietin

Answer 23

Secreted by kidneys to stimulate development of erythrocytes/RBCs vs secreted by liver and kidneys to stimulate development of thrombocytes/platelets

Question 24

Macula densa

Answer 24

Chemoreceptors in DCT where DCT touches glomerulus, sensitive to NaCl in body; they also stimulate juxtaglomerular cells to release renin —> dilate afferent arteriole to inc filtration rate (macula densa + juxtaglomerular cells = juxtaglomerular apparatus)

Question 25

High vs low urine osmolarity

Answer 25

High urine, low Na+ vs low urine, high Na+

Question 26

Relationship b/w bp and filtration rate

Answer 26

Low bp means low filtration rate

Question 27

How does blood vol affect blood pressure?

Answer 27

Inc in blood vol —> inc in bp. Inc Na+ reabsorption (thanks to aldosterone) —> reduced water loss into urine —> inc in blood vol

Question 28

There’s net loss of fluid in capillary fluid movement

Answer 28

Bc there’s more fluid being forced out of arterial end of capillary than being reabsorbed in venule end