Vander's Ch. 1 Function and Anatomy

Question 1

Functions of the kidney

Answer 1

1) Waste excretion
2) Blood pressure regulation
3) Regulates RBC production
4) Produces vitamin D
5) Gluconeogenesis (although most occurs in the liver)

Question 2

How do the kidneys regulate RBC production?

Answer 2

Release of erythropoietin (stimulated by decrease in partial pressure of O2 in the kidneys)

Question 3

How many nephrons are in each kidney?

Answer 3

1 million

Question 4

What is the function of the renal corpuscle?

Answer 4

separation of a protein-free filtrate from plasma (initial step in urine formation)

Question 5

What forms the renal corpuscle?

Answer 5

Combination of glomerulus and Bowman’s capsule

Question 6

What is the glomerulus?

Answer 6

tuft of interconnected capillary loops where blood flows to be filtered

Question 7

What is Bowman’s capsule?

Answer 7

hollow capsule that surrounds the glomerulus (has fluid filled space called Bowman’s space that holds filtered fluid)

Has two ends:

1) vascular pole
2) filtrate pole (has opening that leads into 1st portion of the tubule)

Question 8

What 3 cell types make up the Juxtaglomerular apparatus?

Answer 8

1) Granular cells (secrete renin)
2) Macula densa
3) Extraglomerular mesangial cells (phagocytes)

Question 9

What are the 3 layers of the filtration barrier in the renal corpuscle?

Answer 9

1) capillary endothelium of glomerular capillaries
2) Thick basement membrane
3) single-celled layer of epithelial cells

Question 10

What do podocytes sit on?

Answer 10

glomerular capillary loops inside Bowman’s space

Question 11

What are the characteristics of the capillary endothelium, the first barrier in filtration?

Answer 11

• fenestrated

- permeable to everything in blood except RBC and platelets

Question 12

What are the characteristics of the capillary basement membrane?

Answer 12

gel-like acellular meshwork of glycoproteins and proteoglycans

Question 13

What are the characteristics of the 3rd barrier, the epithelial cells?

Answer 13

podocytes! sit on basement membrane; pedicels (foot like processes) interdigitate with each other and spaces between them form path thru which filtrate enters Bowman’s space

Question 14

Podocytes are linked by what type of cellular connection?

Answer 14

slit diaphragms (widened versions of tight junction)

Question 15

What are the two segments of the proximal tubule and where does it start?

Answer 15

1) Proximal convoluted tubule (coiled segment)
2) Proximal straight segment (descends toward medulla)

prox tubule starts at end of Bowman’s capsule

Question 16

The proximal tubule drains into what….

Answer 16

the descending thin loop of Henle

Question 17

What are the specialized cells in the thick ascending limb closest to Bowman’s capsule?

Answer 17

Macula densa

Question 18

The macula dense marks the end of the ____________ and the beginning of the ___________

Answer 18

thick ascending limb; distal convoluted tubule

Question 19

Flow of filtrate from distal tubule:

Answer 19

cortical collecting duct–>large ducts–> papillary collecting ducts –> calyx

Question 20

Pathway of fluid flow in a nephron

Answer 20

cortex (Bowman’s capsule) –> medulla (descending loop) –> cortex (thick ascending loop) –> medulla (medullary collecting tubule –> CALYX

Question 21

True or false: the tubular epithelium has a one-cell thickness throughout

Answer 21

true

Question 22

________ arteries go into the glomerulus, ________ arteries come out of it

Answer 22

afferent; efferent

Question 23

Which part of the kidney receives greater blood flow, the cortex or the medulla?

Answer 23

CORTEX (no glomeruli in the medulla)

Question 24

What are the vasa recta?

Answer 24

straight, parallel vessels that penetrate deep into the medulla

Question 25

3 kinds of nephrons

Answer 25

1) superficial cortical nephrons
2) midcortical nephrons
3) juxtamedullary nephrons

(all have differing lengths of loop of Henle)

Question 26

What is the macula densa responsible for?

Answer 26

detecting luminal content of nephron at end of thick ascending limb and contribute to GFR

Question 27

Definition of filtration

Answer 27

process by which water and solutes in blood leave vascular system thru filtration barrier and enter Bowman’s space

Question 28

Definition of secretion

Answer 28

process of moving substances into tubular lumen from cytosol of epithelial cells from the walls of the nephron (either come from interstitium or originate from cells)

Question 29

Definition of reabsorption

Answer 29

process of moving substances from lumen across the epithelial layer into the surrounding interstitium (then onto blood vessels - 2 step)

Question 30

Definition of excretion

Answer 30

exit of substance from the body

Question 31

True or False: the filtrate present in Bowman’s space is very chemically similar to blood plasma

Answer 31

True BUT filtrate does not contain much protein

Question 32

What is the avg GFR in a young, adult male?

Answer 32

180L/day

total plasma volume is 3L so it is filtered 60 times a day!

Question 33

Once tubular cells reabsorb material, where does it go to get back to the body’s main system?

Answer 33

peritubular capillaries (branches of efferent arterioles)

Question 34

What percentage of the plasma is filtered into Bowman’s space?

Answer 34

20%

Question 35

What are the 3 basic renal processes?

Answer 35

1) glomerular filtration
2) tubular reabsorption
3) tubular secretion

Question 36

What do sympathetics control in the kidney?

Answer 36

1) renal blood flow
2) glomerular filtration
3) release of vasoactive substances (renin-angtiotensin)

Question 37

What does aldosterone regulate and from where is it secreted?

Answer 37

sodium and potassium excretion

secreted from adrenal cortex

Question 38

What does the proximal tubule reabsorb?

Answer 38

2/3 of the filtered water, sodium, and chloride

Question 39

What does the loop of henle reabsorb?

Answer 39

20% of the filtered sodium
10% of filtered water

(reabsorbs slightly more salt than water to make the luminal fluid more dilute than plasma)

Question 40

What part of the nephron do aldosterone and ADH act on specifically?

Answer 40

cortical collecting tubule

Question 41

How do aldosterone and ADH differ?

Answer 41

Aldosterone: enhances Na reabsorption and K secretion

ADH: enhances water absorption