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MCAT > MCAT Biology Urinary System > Flashcards

MCAT Biology Urinary System Flashcards

1
Q

The small artery that carries blood toward the capillaries of the glomerulus

A

Afferent arteriole

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2
Q

The principle mineralcorticoid secreted by the adrenal cortex

A

Aldosterone

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3
Q

This steroid hormone target the kidney tubules and increases renal reabsorption of sodium

A

Aldosterone

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4
Q

The __ is the long muscular “tube” that includes the mouth, esophagus, stomach, small intestine, and large intestine

A

Alimentary canal

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5
Q

A normal blood protein produced by the liver that is converted to angiotensin 1 by renin (secreted by the kidney when blood pressure falls).

A

Angiotensinogen

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6
Q

When is renin secreted by the kidney?

A

When blood pressure falls

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7
Q

Angiotensin 1 is further converted to angiotensin 2 by ____

A

ACE (angiotensin converting enzyme

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8
Q

___ is a powerful system vasoconstrictor and stimulator of aldosterone release, both of which result in an increase in blood pressure

A

Angiotensin 2

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9
Q

A layer of collagen fibers that separates epithelial tissue from connective tissue is known as __

A

basement membrane

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10
Q

The region of the nephron that surrounds the glomerulus

A

Bowmans capsule

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11
Q

The __ collects the plasma that is filtered from the capillaries in the glomerulus

A

Bowman’s capsule

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12
Q

The portion of the nephron where water reabsorption is regulated via antidiuretic hormone (ADH)

A

Collecting ducts

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13
Q

This is the final region through which urine must pass on its way to the ureter

A

Collecting duct

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14
Q

The small artery that carries blood away from the capillaries of the glomerulus

A

Efferent arteriole

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15
Q

A hormone produced and released by the kidney that stimulates the production of red blood cells by the bone marrow

A

Erythropoietin

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16
Q

In the kidney __ refers to the movement of plasma across the capillary walls of the glomerulus, into the capsule and tubule of the nephron

A

Filtration

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17
Q

Filtration at the glomerulus is driven by blood pressure

A

Filtration

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18
Q

The ball of capillaries at the beginning of the nephron where blood filtration takes place

A

Glomerulus

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19
Q

The cells of the afferent arteriole at the juxtaglomerular apparatus

A

Juxtaglomerular cells

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20
Q

__are the baroreceptors that secrete renin upon sensing a decrease in blood pressure, located in the afferent arteriole

A

Juxtaglomerular cells

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21
Q

The loop of the nephron tubule that dips downward into the renal medulla

A

Loop of Henle

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22
Q

The __ sets up a concentration gradient in the kidney so that from the cortex to the renal pelvis osmolarity increases

A

Loop of Henle

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23
Q

The __ of the loop of Henle is permeable to water, but not to sodium

A

Descending limb of Loop of Henle

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24
Q

The __ of the loop of Henle is permeable to sodium, but not water (here active transport of sodium out of the filtrate occurs)

A

Ascending Loop of Henle

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25
Q

The cells of the distal tubule at the juxtaglomerula apparatus

A

Macula densa

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26
Q

These are receptors that monitor filtrate osmolarity as a means of regulating filtration rate.

A

Macula densa

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27
Q

If a drop in osmolarity is sensed, the macula densa will ___

A

Dilate the afferent arteriole (to increase blood pressure in the glomerulus and thus increase filtration)
AND
stimulates the juxtaglomerular cells to secrete renin (to raise systemic blood pressure)

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28
Q

The functional unit of the kidney is the__

A

nephron

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29
Q

This is where blood filtration and subsequent modification of the filtrate occurs

A

Nephron

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30
Q

The __ empties into the collecting ducts, which empty into the ureter

A

Nephron

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31
Q

The first portion of the nephron tubule after the glomerulus

A

Proximal convoluted tubule

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32
Q

The __ is the site of most reabsorption

A

Proximal convoluted tubule

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33
Q

All filtered nutrients are reabsorbed here as well as most of the filtered water

A

Proximal convoluted tubule

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34
Q

The movement of a substance from the filtrate (in the renal tubule) back into the bloodstream

A

Reabsorption

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35
Q

The portion of the nephron after the glomerulus and capsule

A

Renal tubule

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36
Q

The region of the nephron where the filtrate is modified along its path to becoming urine

A

Renal tubule

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37
Q

The movement of substances from the blood to the filtrate along the tubule. This increases the rate at which substances can be removed from the body

A

Secretion

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38
Q

A waste product of protein breakdown, produced by the liver and released into the bloodstream to be eliminated by the kidney

A

Urea

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39
Q

The capillaries that surround the tubules of the nephron. The ___ reclaims reabsorbed substances, such as water and sodium ions

A

Vasa Recta

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40
Q

The ___ is responsible for excreting waste by chemically modifying them and releasing them into the bile

A

Liver

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41
Q

The ___ delas with hydrophobic or large waste products, which cannot be filtered out by the kidney

A

Liver

42
Q

The kidney can only eliminate small __ dissolved in plasma

A

Hydrophils

43
Q

___ is a carrier of xs nitrogen because free ammonia is toxic

A

Urea

44
Q

The __ reabsorbes water and ions (sodium, calcium, etc.) from feces

A

large intestine

45
Q

What are the 3 excretory/Homeostatic roles of the kidney?

A
  1. Excretion of hydrophilic aste
  2. Maintenance of constant solute concentration and constant pH
  3. Maintenance of constant fluid volume (important for blood pressure and cardiac output)
46
Q

The internal sphincter of the bladder is made of __

A

smooth muscle (involuntary)

47
Q

The external sphincter of the bladder is made of ___

A

skeletal muscle (voluntary)

48
Q

Why does the medullary pyramid have those pyramid-shaped striations

A

The collecting ducts

49
Q

Urine empties fro mthe collecting ducts and leaves the medulla at the tip of the pyramid known as a__

A

papilla

50
Q

Each papilla empties into a space called a CALYX, and these calyces converge to form the ___ which is a large space where urine collects, this is what empties into the ureter

A

Renal pelvis

51
Q

What are the two components of the nephron?

A
  1. Rounded region surrounding the capillaries where filtration takes palce = CAPSULE
  2. a coiled tube known as the RENAL TUBULE.
    • the tubule receives filtrate from the capillaries in the capillaries in the capsule at one end and empties into a collecting duct at the other end. The collecting duct dumps urine into the renal pelvis
52
Q

Constriction of the efferent arteriole results in __

A

high pressure in the glomerulus, which causes fluid to leak out of the glomerular capillaries

53
Q

Roughly 70% of the volume of filtrate is reabsorbed here

A

Proximal convoluted tubule

54
Q

The term secretion refers to the movement of substances INTO the filtrate (usually via active transport) most secretion takes place at the __

A

Distal convoluted tubule and the collecting duct

55
Q

Before discarding filtrate into the ureter as urine the urine volume and osmolarity are adjusted appropriately in the ____

A

distal nephron which includes:

Distal convoluted tubule and collecting duct

56
Q

The distal nephron is controlled by __ and ___

A

ADH and Aldosterone

57
Q

Under conditions of low blood volume and high blood osmolarity (high solute concentration in the blood) __ is released

A

Antidiuretic hormone (vasopressin) from the posterior pituitary gland

58
Q

___ prevents diuresis (water loss in the urine) by increasing water reabsorption in the distal nephron

A

ADH

59
Q

ADH makes ____ permeable to water, without ADH, this region is impermeable to water

A

distal nephron (Distal convoluted tubule) and the collecting duct

60
Q

The reason alcohol causes people to have water loss in the urine (diuresis) is that ___

A

It inhibits ADH secretion by the posterior pituitary

61
Q

When the blood pressure is LOW, __ is released by the adrenal cortex

A

Aldosterone

62
Q

__ causes increased reabsorption of Na+ by the distal nephron

A

Aldosterone

63
Q

What is the result of increased reabsorption of Na+ by the distal nephron when aldosterone is released?

A

it increases plasma osmolarity, which leads to icreased thirst and water retention, which raises the blood pressure

64
Q

How do ADH and Aldosterone work together?

A

Aldosterone causes sodium reabsorption, which results in increased plasma osmolarity. This causes ADH to be secreted, which results in increased water reabsorption and thus increased plasma volume

65
Q

Bowman’s capsule empties into the __

A

proximal convoluted tubule

66
Q

___ and __ are located in the renal cortex (outer layer of the kidney)

A

Bowman’s capsule, and the proximal convoluted tubule

67
Q

The PCT empties into the __

A

loop of Henle

68
Q

The DCT dumps into a__

A

collecting duct

69
Q

the __ forms a loop that helps maintain a high concentration of salt in the medulla

A

Vasa recta

70
Q

The ___ return to the bloodstream any water that is reabsorbed from the filtrate

A

Vasa recta

71
Q

Because the blood in the vasa recta moves in the opposite direction of the filtrate in the nephron, the ___ perform counter current exchange

A

Vasa recta

72
Q

The ___ is a specialized contact point between the afferent arteriole and the distal tubule

A

Juxtaglomerular apparatus (JGA)

73
Q

At the JGA, the cells in the afferent arteriole are called ___ and those in the distal tubule are known as __

A

juxtaglomerular cells and those in the distal tubule are known as macula densa

74
Q

___are baroreceptors that monitor systemic blood pressure

A

Juxtaglomerular cells (JG)

75
Q

Explain the renin angiotensin system

A
  1. Decrease in blood pressure, JG cells secrete enyme renin
  2. Renin catalyzes the conversion of angiotensinogen (plasma protein made by the liver) into angiotensin 1
  3. Angiotensin 1 converted to Angiotensin 2 by angiotensin-converting enzyme (ACE) in the lungs.
  4. Angiotensin 2 is a powerful vasoconstrictor that immediately raises the blood pressure. It stimulates release of aldosterone which raises blood pressure by increasing sodium (and indirectly) water rettention
76
Q

The cells of the macula densa are __

A

chemoreceptors, monitor filtrate osmolarity in the DISTAL TUBULE

77
Q

When filtrate osmolarity decreases (indicating reduced filtration ratE), the cells of the macula densin stimulate the JG cells to release __

A

renin

78
Q

The macula densin also causes ___ increasing blood flow (along with blood pressure and filtration rate) in the glomerulus

A

direct dilation of the afferent arteriole

79
Q

when plasma pH is too high,____

A

HCO3- is excreted in the urine

80
Q

When the plasma pH is too low,___

A

H+ is excreted

81
Q

The enzyme __ is found in epithelial cells throughout the nephron, except in the squamous cells of the thin ascending loop of Henle

A

Carbonic anhydrase

82
Q

By exhaling excess CO2, the lungs remove ___

A

an acid (H2CO3) from the blood, raising the pH

83
Q

Hyperventilation (deep rapid breathing) ___

A

raises plasma pH

84
Q

__ secrete calcitonine when the serum (Ca2+) is too high

A

C cells in the thyroid gland

85
Q

Calcitonin causes (Ca2+) to be removed from the blood by

A
  1. deposition in bone
  2. reduced absorption by the gut
  3. excretion in urine
86
Q

The function of __ is the opposite that of calcitonin

A

PTH parathyroid hormone

87
Q

___ is secrted when the serum (Ca2+) level is too LOW

A

PTH

88
Q

When blood oxygen content falls __ is released

A

erythropoietin, it causes icnreased synthesis of red blood cells in the bone marrow

89
Q

Circulating blood enters the glomerulus through the __ and exits through the ___

A

Enters through the afferent arteriole and exits through the efferent arteriole

90
Q

Aldosterone is released in response to ____ or __

A

IN response to RAS activation or to an increased serum level of K+

91
Q

Aldosterone acts on the ___ and ___ to promote reabsorption of Na+ and secretion of K+

A

Aldosterone acts on the distal convoluted tubule and collecting duct

92
Q

__ promotes water reabsorption by increasing the permeability of the distal convoluted tubule and collecting duct to water, it also induces vasoconstriction of blood vessels to promote increased blood pressure

A

ADH

93
Q

___ is the force extered by a liquid on the walls of its container

A

Hydrostatic pressure

94
Q

When blood osmolarity is high the kidneys respond by ______

A

Increasing water reabsorption and decreasing solute reabsorption

95
Q

When blood osmolarity is low the kidneys respond by __

A

decreasing water reabsorption and increasing solute reabsorption

96
Q

__ increases as solute concentration increases

A

Osmotic pressure

97
Q

INCREASED hydrostatic pressure of the renal artery promotes glomerular retention _____

A

increases urinary output

98
Q

INCREASED osmotic pressure of filtrate draws fluid back into nephrons;___

A

increases urinary output

99
Q

INCREASE of hydrostatic pressure of Bowman’s capsule pushes fluid into glomerular capillaries___

A

decreases urinary output

100
Q

INCREASE osmotic pressure of peritubular capillaries draws fluid back into blood stream ___

A

decreases urinary output

101
Q

Blood is filtered in the glomerulus by ____ which forces excess fluid and waste products across the porous endothelium and into Bowman’s space

A

High hydrostatic [blood] pressure

MCAT (45 decks)

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