7- The Urinary System

Question 1

3 general kidney functions

Answer 1

1. Regulate various properties of blood
2. Produce hormones
3. Excrete waste and foreign substances

Question 2

kidneys regulate which properties of blood

Answer 2

• ionic composition
• blood pH
• volume
• blood pressure (renin)
• glucose level

Question 3

Which hormones do kidneys produce

Answer 3

Calcitriol-form of vitamin d

Erythropoietin-stimulate RBC production

Question 4

Name the 2 parts of the nephron, the functional unit of the kidney

Answer 4

1. Renal corpuscle - where blood plasma is filtered (Cortex)

2. Renal tubule (cortex and medulla)

Question 5

Describe components of renal corpuscle of nephron

Answer 5

Glomerulus and glomerular capsule

-blood filtered from capillary network (glomerulus = ball of capillaries) into capsule => proximal convoluted tubule

Question 6

Describe components of renal tubule of nephron

Answer 6

• proximal convoluted tubule (cortex)
• loop of Henle (extends into the deeper renal medulla)
• distal convoluted tubule (cortex)

Question 7

Difference bw cortical and juxtamedullary nephrons

Answer 7

Cortical - renal corpuscle (glomerulus) in outer cortex with short loop of Henle
Juxtamedullary - renal corpuscle deep in cortex with long loop of Henle
Only 20% are juxtamedullary nephrons

Question 8

In the – – step of urine formation, water and solutes are pushed from blood plasma in glomerulus into glomerular capsule

Answer 8

Glomerular (capillary network) filtration

Question 9

Name the 3 pressures regulating glomerular filtration

Answer 9

1. Glomerular blood hydrostatic pressure - blood pressure in glomerulus PROMOTES
2. Capsular hydrostatic pressure - pressure in capsule against filtration membrane OPPOSES
3. Blood colloid osmotic pressure - presence of proteins in blood draws water BACK into blood plasma OPPOsES

Question 10

Tubular reabsorption vs secretion

Answer 10

Reabsorption = return to blood stream
Secretion = return from blood to glomerular filtrate (secreted out of body)

Question 11

First step in renin-angiOtensin-aldOsterone pathway

Answer 11

Decrease in blood pressure -> decreased blood flow to kidneys caused by loss if sodium and water ==> increased renin secretion

Question 12

What angiotensin does in raas pathway

Answer 12

AngiOtensin - tensing up, so decreases glomerular filtration
O means round from water, Na, cl reabsorption
Stimulates adrenal cortex to secrete aldosterone

Question 13

What aldosterone does

Answer 13

O means round from water reabsorption

Question 14

Anti diuretic hormone

Answer 14

Produced by pituitary gland

Diuretic makes you pee, so the ANTI-diuretic hormone conserves pee

Question 15

What atrial natiuretic hormone does (think heart)

Answer 15

Released by heart in response to hear failure and blood volume increases
*increases urine output = decrease blood volume = decrease arterial pressure

Question 16

Parathyroid hormone

Answer 16

Opposite effect of calcitonin (decrease amount of Ca2+) by stimulating cells in distal convoluted tubule to REABSORB Ca

Question 17

3 major solutes contributing to concentrated urine gradient

Answer 17

Na+, cl-, urea

Question 18

Flow in Descending limb of loop of Henle

Answer 18

Loss of water = tubular fluid becomes more concentrated

Question 19

Flow in ascending limb of loop of Henle

Answer 19

Loss of Na and cl (ions reabsorbed into body) => tubular fluid becomes more dilute as it flows back up to renal cortex

Question 20

More water reabsorbed with increasing – –

Answer 20

Osmotic gradient (difference in concentration bw 2 solutions on either side of a permeable membrane)

Question 21

Kidneys help maintain homeostasis via 3 steps

Answer 21

1. Filtration: filtering blood plasma
2. Reabsorption: returning water and useful solutes to blood stream
3. Secretion: selectively eliminating unneeded substances