Lecture 24

Question 1

Main roles of urinary system?

Answer 1

Cleanses blood, regulates pH, regulates blood pressure, regulates solute concentration, produces EPO, activates vitamin D.

Question 2

Consequences of kidney failure?

Answer 2

Weakness, edema, anemia, acidosis, high potassium, arrhythmias, loss of homeostasis.

Question 3

What is incontinence?

Answer 3

Loss of voluntary control of urination.

Question 4

Kidney as a regulator?

Answer 4

Regulates plasma composition, not just urine production.

Question 5

Kidney blood flow?

Answer 5

Receives ~20–25% of resting cardiac output.

Question 6

Role of adrenal cortex?

Answer 6

Releases aldosterone → increases Na+ reabsorption.

Question 7

Role of adrenal medulla?

Answer 7

Releases catecholamines: epinephrine and norepinephrine.

Question 8

Renal pyramids function?

Answer 8

Carry urine via collecting ducts to the calyces.

Question 9

Renal columns function?

Answer 9

Separate pyramids and support blood vessels.

Question 10

Renal hilum?

Answer 10

Entry/exit point for renal pelvis, artery, and vein.

Question 11

What is a nephron?

Answer 11

Functional unit of the kidney responsible for filtration, reabsorption, and secretion.

Question 12

Three nephron processes?

Answer 12

Filtration, reabsorption, secretion.

Question 13

Secondary nephron functions?

Answer 13

Renin release, EPO production, vitamin D activation.

Question 14

Bowman’s capsule function?

Answer 14

Receives filtrate from glomerulus; forms renal corpuscle.

Question 15

Filtration slits?

Answer 15

Spaces between podocytes that allow filtrate movement.

Question 16

What cannot pass filtration barrier?

Answer 16

Cells and large proteins like albumin.

Question 17

Filtration influenced by charge?

Answer 17

Negative substances repelled; positive substances pass more easily.

Question 18

PCT specialization?

Answer 18

Mass reabsorption via microvilli brush border.

Question 19

Loop of Henle function?

Answer 19

Descending limb: water movement; ascending limb: solute transport.

Question 20

Cortical vs juxtamedullary nephrons?

Answer 20

Cortical: short loops; Juxtamedullary: long loops for concentration gradients.

Question 21

DCT features?

Answer 21

Shorter, fewer microvilli, fine-tunes filtrate.

Question 22

Macula densa function?

Answer 22

Senses Na+ and filtrate flow rate; releases ATP/adenosine.

Question 23

Juxtaglomerular (JG) cells function?

Answer 23

Release renin; respond to macula densa signals.

Question 24

High filtrate osmolarity effect?

Answer 24

JG cells contract → ↓GFR → ↓urine → fluid retained.

Question 25

Low filtrate osmolarity effect?

Answer 25

JG cells relax → ↑GFR → ↑urine → fluid lost.

Question 26

Purpose of GFR autoregulation?

Answer 26

Maintains stable filtration rate.

Question 27

Renin function?

Answer 27

Converts angiotensinogen → angiotensin I.

Question 28

Angiotensin II effects?

Answer 28

Vasoconstriction; stimulates aldosterone and ADH.

Question 29

Aldosterone effect?

Answer 29

Increases Na+ and water reabsorption → raises BP.

Question 30

Natriuretic hormone effect?

Answer 30

Increases Na+ excretion; inhibits aldosterone & ADH.

Question 31

Collecting duct purpose?

Answer 31

Final urine modification; collects from many nephrons.

Question 32

ADH effect on collecting ducts?

Answer 32

Inserts aquaporins → increases water reabsorption.

Question 33

Absence of ADH?

Answer 33

No aquaporins → dilute urine.