Chapter 17 - kidneys

Question 1

What 5 things do the kidneys regulate?

Answer 1

a. Volume of blood plasma (affects blood pressure)
b. Wastes
c. Electrolytes
d. pH
e. Secrete erythropoietin

Question 2

How is urine created and how is it excreted?

Answer 2

Urine made in the kidney nephrons drains into the renal pelvis, then down the ureter to the urinary bladder.
It passes from the bladder through the urethra to exit the body.

Question 3

How is urine transported?

Answer 3

Using peristalsis

Question 4

What are the 2 regions of the kidney?

Answer 4

Renal cortex
Renal medulla, made up of renal pyramids and columns

Question 5

How do renal medulla pyramids drain into the renal pelvis?

Answer 5

Each pyramid drains into a minor calyx → major calyx → renal pelvis.

Question 6

Functional unit of the kidney?

Answer 6

Nephron

Question 7

What does the nephron consist of?

Answer 7

small tubules and associated blood vessels

Question 8

How does blood turn into urine?

Answer 8

Blood is filtered, fluid enters the tubules, is modified, then leaves the tubules as urine

Question 9

What are the renal blood vessels?

Answer 9

Renal artery →
Interlobar arteries →
Arcuate arteries →
Interlobular arteries →
Afferent arterioles
Glomerulus →
Efferent arterioles →
Peritubular capillaries →
Interlobular veins →
Arcuate veins →
Interlobar veins →
Renal vein

Question 10

What surrounds glomerulus?

Answer 10

Glomerular (Bowman’s) capsule
glomerulus

Question 11

What makes up the renal corpuscle?

Answer 11

Glomerular (Bowman’s) capsule

Question 12

Filtrate from the renal corpuscle passes into what?

Answer 12

proximal convoluted tubule

Question 13

Nephron tubules:
Fluid passes into the descending and ascending limbs of the _____________

Answer 13

Loop of Henle

Question 14

Where does fluid pass after the loop of Henle?

Answer 14

The distal convoluted tubule

Question 15

In nephron tubules, where is the last place fluid passes before it drains into the minor calyx?

Answer 15

the collecting duct

Question 16

What does it mean for the capillaries of the glomerulus if it has large pores allow water and solutes to leave but not blood cells and plasma proteins?

Answer 16

Capillaries of the glomerulus are fenestrated

Question 17

Fluid entering the glomerular capsule is called?

Answer 17

Filtrate

Question 18

In Glomerular Corpuscle, what must the filtrate pass through?

Answer 18

a. Capillary fenestrae
b. Glomerular basement membrane
c. Visceral layer of the glomerular capsule composed of cells called podocytes with extensions called pedicles

Question 19

return of filtered molecules to the blood?

Answer 19

Reabsorption

Question 20

What is the obligatory water loss?

Answer 20

A minimum 400 ml must be excreted to rid the body of wastes

Question 21

______ L of water is filtered per day, but only ___ to ____ L is excreted as urine.

Answer 21

180 L of water is filtered per day, but only 1 to 2 L is excreted as urine.

Question 22

85% of reabsorption occurs in the?

Answer 22

proximal tubules and descending loop of Henle

Question 23

What does it mean if the osmolality of filtrate in the glomerular capsule is equal to that of blood plasma?

Answer 23

It is iso osmotic

Question 24

__________ is actively transported out of the filtrate into the peritubular blood to set up a concentration gradient to drive ________.

Answer 24

Na+ is actively…
…to drive osmosis

Question 25

Reabsorption in the Proximal Tubule - Active transport (copy paste)

Answer 25

a. Cells of the proximal tubules are joined by tight junctions on the apical side (facing inside the tubule). b. The apical side also contains microvilli. c. These cells have a lower Na+ concentration than the filtrate inside the tubule due to Na+/K+ pumps on the basal side of the cells and low permeability to Na+. d. Na+ from the filtrate diffuses into these cells and is then pumped out the other side.

Question 26

Reabsorption in the Proximal Tubule - Passive transport (copy paste)

Answer 26

a. The pumping of sodium into the interstitial space attracts negative Cl− out of the filtrate. b. Water then follows Na+ and Cl− into the tubular cells and the interstitial space. c. The ions and water diffuse into the peritubular capillaries.

Question 27

What ion do you actively transport in water reabsorption Which ions follow?

Answer 27

Na+ Cl- and H2O

Question 28

What is the significance of proximal tubule reabsorption? (copy paste)

Answer 28

a. 65% of the salt and water is reabsorbed, but that is still too much filtrate b. An additional 20% of water is reabsorbed through the descending limb of the Loop of Henle. Happens continuously and is unregulated The final 15% of water (~27 L) is absorbed later in the nephron under control of the hormone Anti-Diuretic Hormone (ADH). Fluid entering loop of Henle is isotonic to extracellular fluids.

Question 29

How does the collecting duct (and ADH) work?

Answer 29

ADH binds to receptors on collecting duct cells → cAMP → Protein kinase → Vesicles with aquaporin channels fuse to plasma membrane. a) Water channels are removed without ADH.

Question 30

What is ADH made from? (kidney chapter)

Answer 30

is produced by neurons in the hypothalamus but stored and released from the posterior pituitary gland a) Release stimulated by an increase in blood osmolality

Question 31

Permeability to water depends on the number of ___________________ in the cells of the collecting duct

Answer 31

aquaporin channels

Question 32

What is renal clearance?

Answer 32

remove excess ions and wastes from the blood.

Question 33

Memorize this about renal clearance (copy paste)

Answer 33

b. Filtration in the glomerular capsule begins this process. c. Reabsorption returns some substances to the blood (decreases renal clearance) d. Secretion finishes the process when substances are moved from the peritubular capillaries into the tubules. (increases renal clearance)