chapter 24 urinary system

Question 1

represent the functional unit of the kidney

Answer 1

nephrons

Question 2

the function of a kidney is to

Answer 2

filter the blood and form urine and maintain homeostasis of body fluids”;

Question 3

blind, cup-shaped end of a renal tubule that completely surrounds the glomerulus

Answer 3

Glomerular (Bowman’s) capsule

Question 4

composed of cuboidal cells with numerous microvilli and mitochondria

Answer 4

Proximal tubule

Question 5

Proximal tubule

functions

Answer 5

Functions primarily for selective reabsorption of solutes (especially, nutrients, such as glucose, amino acids, vitamins, etc.)
 Selective reabsorption moves solutes from the filtrate and back into the blood stream

Question 6

a long, hairpin-shaped loop of the renal tubule

Answer 6

Nephron loop (Loop of Henle

Question 7

Nephron loop (Loop of Henle functions

Answer 7

Functions to concentrate extracellular fluid in the medullary tissue

Question 8

from the proximal tubule

Answer 8

Descending limb

Question 9

leads to distal tubule

Answer 9

Ascending limb

Question 10

cuboidal cells that mostly lack the abundant microvilli

Answer 10

Distal tubule

Question 11

Distal tubule

functions

Answer 11

The DCT functions more in tubular secretion than in reabsorption
 Tubular secretion involves the movement of solutes from the bloodstream into the filtrate or forming urine
 Substances that are secreted across the DCT include ions such as K+ and H+, organic dyes, certain antibiotics, etc.

Question 12

Receive filtrate from nephrons

 Run through the medullary pyramids

Answer 12

Collecting ducts

Question 13

Collecting ducts

functions

Answer 13

Collecting ducts function primarily for the selective reabsorption of water from the forming urine; movement of water from the filtrate back into the interstitial fluids results mostly from osmosis
 Permeability of the collecting duct to water molecules is facilitated by the influence of ADH from the posterior pituitary gland
 Collecting tubules converge to form papillary ducts, which deliver urine to minor calyces

Question 14

small artery that supplies an individual nephron

Answer 14

Afferent arteriole

Question 15

(Glomerular capsule containing a glomerulus)

Answer 15

Renal corpuscle

Question 16

a high-pressure, capillary tuft that is supplied by the afferent arteriole and which occurs within the glomerular capsule; this capillary is specialized for filtering the blood, forming glomerular filtrate, which is then processed by the remainder of the nephron to form urine;

Answer 16

Glomerulus

Question 17

a small blood vessel that drains the glomerulus and supplies the peritubular capillary

Answer 17

Efferent arteriole

Question 18

low-pressure capillary specialized for reabsorption of water, nutrients, and other materials and tubular secretion of other materials

Answer 18

Peritubular capillary

Question 19

long, straight efferent arterioles, capillaries, and venules of juxtamedullary nephrons which extend into the renal medulla and surround the loop of Henle

Answer 19

Vasa recta

Question 20

Flow Chart

Answer 20

 Blood in arteriole
 Glomerulus
o 99% of filtrate now enters efferent arteriole, then peritubular capillary bed, then venules
o 1% of the filtrate continues its flow through the nephron
 Glomerular capsule
 Proximal tubule
 Descending limb of nephron loop
 Ascending limb of nephron loop
 Distal tubule
 Collecting duct
 Papillary duct
 Minor calyces
 Major calyces
 Renal pelvis
 Ureter

Question 21

The filtrate:

 Contains all plasma components except

Answer 21

protein

Question 22

Urine formation and adjustment of blood composition involves three major processes:

Answer 22

Glomerular filtration
 Tubular reabsorption
 Tubular secretion

Question 23

The glomerulus is more efficient than other capillary beds because:

Answer 23

Its filtration membrane is significantly more permeable
 Glomerular blood pressure is higher
 It has a higher net filtration pressure

Question 24

Plasma proteins are not filtered and are used to maintain

Answer 24

osmotic pressure of the blood

Question 25

Glomerular Filtration Rate is directly proportional to the Net Filtration Pressure
 If the GFR is too high:

Answer 25

Needed substances cannot be reabsorbed quickly enough and are lost in the urine

Question 26

Glomerular Filtration Rate is directly proportional to the Net Filtration Pressure
If the GFR is too low

Answer 26

Everything is reabsorbed, including wastes that are normally disposed of

Question 27

Three mechanisms control the GFR

Answer 27

Renal autoregulation (intrinsic system)
 Neural controls
 Hormonal mechanism (the renin-angiotensin system)

Question 28

Autoregulation entails two types of control

responds to changes in pressure in the renal blood vessels

Answer 28

Myogenic mechanism

Question 29

Autoregulation entails two types of control

senses changes in NaCl concentration

Answer 29

Tubuloglomerular feedback

Question 30

Hormonal: Renin-Angiotensin Mechanism:

 Is triggered when specific cells in the kidney release

Answer 30

renin

Question 31

Renin acts on angiotensinogen to release

Answer 31

angiotensin I

Question 32

Angiotensin I is converted to

Answer 32

angiotensin II

Question 33

Angiotensin II:
 Causes mean arterial pressure to ?
 Stimulates the adrenal cortex to release?
 As a result, both systemic and glomerular hydrostatic pressure?

Answer 33

rise
aldosterone
rise

Question 34

Neural control:
 When the sympathetic nervous system is at rest:
 Renal blood vessels are ?
 Autoregulation mechanisms

Answer 34

maximally dilated

prevail

Question 35

neural control
Under stress:
 Norepinephrine is released by the ?
 Epinephrine is released by the ?
Afferent arterioles constrict and filtration is inhibited
 The sympathetic nervous system also stimulates the ?

Answer 35

sympathetic nervous system
adrenal medulla
renin-angiotensin mechanism

Question 36

A process where most tubule contents are returned to the blood

Answer 36

Step 2 of Urine Formation: Tubular Reabsorption

Question 37

Step 2 of Urine Formation: Tubular Reabsorption
All organic nutrients are ?
Water and ion reabsorption is?
 Reabsorption may be an active (requiring ATP) or passive process

Answer 37

reabsorbed

hormonally controlled

Question 38

Loop of Henle reabsorbs

Answer 38

H2O in the descending limb

 Several types of solutes in the ascending limb

Question 39

During glomerular filtration, is the main force pushing water and solutes out of the blood and across the filtration membrane.

Answer 39

glomerular hydrostatic pressure (the glomerular blood pressure)

Question 40

GHP = glomerular hydrostatic pressure

GHP is opposed by 2 forces that drive fluids back into capillaries:

Answer 40

1. Colloid osmotic pressure of glomerular blood (GCOP)
    Colloid osmotic pressure = Pressure created by large nondiffusible molecules
2. Capsular hydrostatic pressure (CHP) exerted by fluids in the capsule