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MCAT Bio > Bio #10 > Flashcards

Bio #10 Flashcards

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1
Q

if the diameter of the afferent arteriole is increased, there is _____ filtration

A

more

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2
Q

if the diameter of the efferent arteriole is increased, there is _____ filtration

A

less

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3
Q

micturition

A

the process of peeing

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4
Q

______ prevent backflow in the ureter

A

valves

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5
Q

roles of the excretory system

A

serves many functions, including the regulation of blood pressure, blood osmolarity, acid-base balance, and removal of nitrogenous waste.

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6
Q

what are the steps of blood entering the kidney and waste being excreted?

A

Structures in excretory pathway: Bowman’s space, proximal convoluted tubule, descending limb of the loop of Henle, ascending limb of the loop of Henle, distal convoluted tubule, collecting duct, renal pelvis, ureter, bladder, urethra

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7
Q

what are the structures in the vascular pathway of the kidney?

A

renal artery, afferent arteriole, glomerulus, efferent arteriole, vasa recta, renal vein.

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8
Q

how many ureters and urethra are there?

A

2 ureters, 1 urethra

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9
Q

where do the nephrons empty into?

A

renal pelvis

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10
Q

the renal pelvis narrows to form the ____

A

ureter

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11
Q

urine travels through the ureter to the ____

A

bladder

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12
Q

from the bladder, urine is transported through the ____ to exit the body

A

urethra

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13
Q

difference between the kidney cortex and medulla?

A

 Each kidney is subdivided into the cortex and a medulla.
• Cortex: the kidney’s outermost layer
• Medulla: sits within the cortex

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14
Q

renal hilum

A

deep slit in the center of its medial surface
• Location of entry and exit of the renal artery, renal vein, and ureter.

its recessed central fissure where its vessels, nerves and ureter pass.

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15
Q

renal pelvis

A

widest part of the ureter, spans almost the entire width of the renal hilum.

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16
Q

renal portal system

A

consists of two capillary beds in series through which blood must travel before returning to the heart.

glomerulus and vasa recta

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17
Q

where is the most concentrated urine in the kidney found?

A

renal pelvis

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18
Q

glomeruli

A

highly convoluted capillary tufts derived from the afferent arterioles.

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19
Q

afferent vs. efferent arterioles

A

Afferent arterioles carry blood toward the glomeruli and efferent arterioles carry blood away from the glomeruli and around the loop of Henle (known as vasa recta)

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20
Q

vasa recta

A

 After blood passes through a glomerulus, the efferent arterioles then form a second capillary bed.
• These capillaries surround the loop of Henle and are known as vasa recta.

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21
Q

bowman’s capsule

A

: cuplike structure around the glomerulus.
o Leads to a long tubule with many areas: proximal convoluted tubule, descending and ascending limbs of Loop of Henle, distal convoluted tubule, and collecting duct.

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22
Q

bowman’s capsule

A

: cuplike structure around the glomerulus.
o Leads to a long tubule with many areas: proximal convoluted tubule, descending and ascending limbs of Loop of Henle, distal convoluted tubule, and collecting duct.

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23
Q

detrusor muscle

A

is smooth muscle found in the wall of the bladder. The detrusor muscle remains relaxed to allow the bladder to store urine, and contracts during urination to release urine.

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24
Q

sphincters urine must pass through to leave the body

A
  • Internal urethral sphincter: consists of smooth muscle, contracted in its normal stare, under involuntary control
  • External urethral sphincter: consists of skeletal muscle and is under voluntary control.
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25
Q

micturition reflex

A

when the bladder is full, signal to nervous system, detrusor muscle contracts, internal sphincter relaxes
• Next step is up to the individual to relax the external sphincter and urinate or maintain the pressure (reflex goes away but will come back)

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26
Q

what is the difference between kidney filtration and secretion and reabsorption

A

Filtration: the movement of solutes from blood to filtrate at Bowman’s capsule
Secretion: movement of solutes from blood to filtrate anywhere besides Bowman’s capsule
Reabsorption: movement of solutes from filtrate to blood

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27
Q

filtrate

A

Collection fluid in Bowman’s capsule after filtration

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28
Q

Blood that remains in the glomerulus travels in the efferent arterioles which empty into the vasa recta. Filtrate is _____ to blood so that neither the capsule nor the capillaries swell

A

isotonic

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29
Q

movement of fluid into Bowman’s space is governed by _____

A

Starling forces.
• Hydrostatic pressure of glomerulus is greater than its oncotic pressure so the net flow is from the blood to the nephron.

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30
Q

secretion in kidneys

A

 Nephrons secrete salts, acids, bases, and urea directly into the tubule by either active or passive transport.
 What is secreted results in the bodies needs at the time.
 Ex: liver converts ammonia to urea, travels to the kidney and is secreted into the nephron for excretion in urine.

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31
Q

reabsorption in kidneys

A

 Solutes that are taken back up by the blood.
 Substances such as glucose, amino acids, and vitamins are almost always reabsorbed.
 ADH/vasopressin and aldosterone can alter the quantity of water reabsorbed within the kidney to maintain blood pressure.

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32
Q

The primary function of the nephron is to create urine that is _____ to the blood.

A

hypertonic

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33
Q

what is the horizontal and vertical orientation of the nephron?

A

Horizontal: Bowman’s capsule, proximal and distal convoluted tube: identity of particles, what is needed and what is not
Vertical: loop of Henle and collecting duct, focused on volume and concentration of urine.

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34
Q

what are the horizontal parts of the nephron focused on?

A

identity of particles, what is needed and what is not

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35
Q

what are the vertical parts of the nephron focused on?

A

volume and concentration of urine.

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36
Q

what does the kidney want to keep? remove?

A

the body doesn’t need:
 Keep: water, glucose, amino acids, some ions
 Remove: hydrogen and potassium ions, ammonia, and urea

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37
Q

proximal convoluted tubule

A

 Reabsorbed: water, amino acids, glucose, water soluble vitamins, and salts
 Solutes that enter the interstitium are picked up by the vasa recta to be returned to the bloodstream for reuse.
 Secreted: waste products including hydrogen ions, potassium ions, ammonia and urea.

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38
Q

loop of henle

A

 First is the descending limb of loop of Henle, dives into the medulla, then returns as the ascending limb of the loop of Henle
 Descending:
• Permeable only to water, water into interstitial space
• Due to increasing osmolarity as the descending limb travels deeper into the medulla.
• The kidney is capable of altering the osmolarity of the interstitial space to affect how much water is secreted out.
 Ascending
• Only permeable to salts and is impermeable to water.
• Takes advantage of decreasing medullary osmolarity.
• Diluting segment: transition from the inner to outer medulla where the loop of Henle becomes thicker.
o The cells lining the tube are larger.
o Have more mitochondria which allows the resorption of sodium and chloride by active transport.
o Only segment of the nephron that can produce urine that is more dilute than blood.

countercurrent multiplier system

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39
Q

ascending loop of henle

A

• Only permeable to salts and is impermeable to water.
• Takes advantage of decreasing medullary osmolarity.
• Diluting segment: transition from the inner to outer medulla where the loop of Henle becomes thicker.
o The cells lining the tube are larger.
o Have more mitochondria which allows the resorption of sodium and chloride by active transport.
o Only segment of the nephron that can produce urine that is more dilute than blood.

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40
Q

descending loop of henle

A
  • Permeable only to water, water into interstitial space
  • Due to increasing osmolarity as the descending limb travels deeper into the medulla.
  • The kidney is capable of altering the osmolarity of the interstitial space to affect how much water is secreted out.
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41
Q

diluting segment

A

transition from the inner to outer medulla where the loop of Henle becomes thicker.
o The cells lining the tube are larger.
o Have more mitochondria which allows the resorption of sodium and chloride by active transport.
o Only segment of the nephron that can produce urine that is more dilute than blood (because so much salt is reabsorbed while water is stuck)

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42
Q

countercurrent multiplier system

A

created by the vasa recta and the nephron: the flow of filtrate in the loop of Henle and blood through the vasa recta are in opposite directions, so filtrate is constantly exposed to hypertonic blood, allowing for maximum reabsorption of water.

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43
Q

hypertonic

A

Higher solute concentration.

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44
Q

distal convoluted tube

A

 Responds to aldosterone which promotes sodium reabsorption (carries water with it).
 Water secreted out
 Waste secreted in.

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45
Q

collecting duct

A

 Final concentration of urine depends largely on the permeability of the collecting duct which is influenced by aldosterone and ADH (they increase reabsorption of water)
• Affected by state of the body
 Permeability increases  more water absorption
 Point of no return
 Filtrate contains mostly urea, uric acid, and excess ions.

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46
Q

aldosterone

A

 Aldosterone: steroid hormone that is secreted by the adrenal cortex in response to decreased blood pressure. Increase blood pressure by increasing reabsorption of sodium (water flows with it).
• Decreased blood pressure stimulates release of renin from juxtaglomerular cells in the kidney. Renin cleaves angiotensinogen, a liver protein, to form angiotensin I. This peptide is metabolized by angiotensin-converting enzyme in the lungs to form angiotensin II, which promotes the release of aldosterone from the adrenal cortex.

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47
Q

antidiuretic hormone (ADH)

A

peptide hormone synthesized by the hypothalamus and released by the posterior pituitary in response to high blood osmolarity.
• Allows more water to be reabsorbed out of the collecting duct.

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48
Q

how does the cardiovascular system control blood pressure?

A

 Cardiovascular system controls blood pressure by vasoconstricting or vasodilating.

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49
Q

the kidneys and osmoregulation

A

 Osmotic pressure: the sucking pressure that draws water into the vasculature caused by all dissolved particles.
 Oncotic pressure: the osmotic pressure that is attributable to dissolved proteins specifically.
 When blood osmolarity is low, more water will be excreted and vice versa.

50
Q

the kidneys and acid base

A

 When blood pH is too low, the kidneys excrete more H+ ions and increase reabsorption of bicarbonate  raises the pH
• And vice versa.
 Slower than the respiratory response to alter blood pH but it is still highly effective.

51
Q

nail grows from the _____ and hair grows from the ____

A

epidermis

dermis

52
Q

why does hair stand up when its cold?

A

insulating layer

53
Q

vasodilation to ____ and vasoconstriction to ____

A

cool down

heat up

54
Q

what is the largest organ in our bodies by weight and size?

A

the skin

55
Q

what is another name for skin

A

integument

56
Q

what are the 3 major layers of skin from outer to inner

A

epidermis, dermis, hypodermis

57
Q

what are the 5 layers of the epidermis

A 
from outermost to innermost 
stratum corneum
stratum lucidum
stratum granulosum
stratum spinosum
stratum basale
58
Q

stratum basale

A

contains stem cells and is responsible for proliferation of keratinocytes, the predominant cells of the skin that produce keratin.

59
Q

stratum spinosum

A

cells become connected to each other, known as the site of Langerhans cells.

60
Q

stratum granulosum

A

keratinocytes die and lose their nuclei

61
Q

stratum lucidum

A

only present in thick, hairless skin, such as the skin on the sole of the foot or the palms, is nearly transparent.

62
Q

stratum corneum

A

contains up to several dozen layers of flatten keratinocytes, forming a barrier that prevents invasion and loss of fluids and salt.

63
Q

sebaceous glands

A

Lubricates skin and hair

64
Q

keratin

A

resistant to damage and provides protection against injury, water, and pathogens
Calluses: form from excessive keratin deposition in areas of repeated strain due to friction: provide protection for the future.
• Fingernails and hair are also formed from keratin and are produced by specialized cells in the skin.

65
Q

melanocytes

A

cell type derived from neural crest cells and found in the stratum Basale.
• Produce melanin: a pigment that serves to protect the skin from DNA damage caused by UV radiation.
• Once produced the pigment is transferred to keratinocytes.

66
Q

langerhans cells

A

special macrophages that reside within the striatum spinosum. Present antigens to T cells in order to activate the immune system.

67
Q

what are the layers of the dermis

A

papillary layer

reticular layer

68
Q

papillary layer

A

dermis

(just below the epidermis): consists of loose connective tissue.

69
Q

reticular layer

A

dermis

(below the papillary): denser than the papillary layer

70
Q

dermis

A

 Sweat glands, blood vessels and hair follicles originate in the dermis.
 Sensory receptors are also located in the dermis.

71
Q

merkel cells

A

located in the epidermal-dermal junction. connected to sensory neurons and responsible for deep pressure and texture sensation.

72
Q

what do free nerve endings respond to?

A

pain

73
Q

what do Meissner’s corpuscles respond to?

A

light touch

74
Q

what do Ruffini endings respond to?

A

stretch

75
Q

what do Pacinian corpuscles respond to?

A

deep pressure and vibration

76
Q

hypodermis

A

 Layer of connective tissue that connects the skin to the rest of the body. Contains fat and fibrous tissue.

77
Q

the ______ functions as a thermostat that regulates body temperature

A

hypothalamus

78
Q

what are the 4 processes for thermoregulation in the skin?

A

o Achieved by sweating, piloerection, vasodilation, and vasoconstriction

79
Q

sweating

A

cooling mechanism controlled by the autonomic NS
 Water and ions put onto skin and then the water evaporates, taking heat from the body.
vasodilation increases energy loss and provides this energy to increase the rate of sweating

80
Q

piloerection

A

Cold conditions, arrector pilli muscles contract, causing hairs of the skin to stand up on end.
 Traps a layer of heated air near the skin.

81
Q

shivering

A

requires a sizable amount of ATP, converted into thermal energy.

82
Q

white fat

A

insulates the body

83
Q

brown fat

A

very inefficient electron transport chain which means that more heat energy is released as fuel is burned.

84
Q

vasodilation

A

Vasodilation occurs so that blood vessels offer more heat to be taken.

85
Q

vasoconstriction

A

 Arterioles constrict, limiting the quantity of blood reaching the skin

86
Q

skin and osmolarity

A

• Skin helps maintain osmolarity

o Becomes a problem for burn victims or large losses of skin as tissues become dehydrated.

87
Q

analgesic

A

pain reliver

88
Q

what are the 3 portal systems?

A

renal portal system: glomerulus and vasa recta
hypophyseal portal system: hypothalamus and anterior pituitary
hepatic portal system: connects the gut tube and the liver

89
Q

glomerulus vs. Bowman’s corpuscle

A

glomerulus is a tuft of blood capillaries and Bowman’s capsule is around it, catching its filtrate

90
Q

renal corpuscle

A

consists of both the glomerulus and Bowman’s capsule (blood filtering system as a whole)

91
Q

if blood volume is low and blood osmolarity is high, what will happen?

A

most beneficial for the body to maintain water and so it is reabsorbed in the kidneys

92
Q

what are the 3 processes the kidney uses to regulate blood volume and osmolarity?

A

filtration, secretion, and reabsorption

93
Q

what are the two forces at play when blood is filtered in the glomerulus

A

hydrostatic pressure pushes fluid into Bowman’s capsule but oncotic pressure opposes this movement (due to osmolarity of the blood being higher).

94
Q

what happens if there is a lot of fluid buildup in the kidneys due to a kidney stone for example?

A

hydrostatic pressure in the glomerulus increases so hight that filtration can no longer occur

95
Q

are there cells and proteins in the filtrate in Bowman’s capsule?

A

not normally due to the small pores of the glomerulus filter

96
Q

ADH/vassopresin vs. aldosterone

A

ADH: water (acts at collecting duct), makes it more leaky to water
aldosterone: water and sodium (acts in DCT and collecting duct), increases sodium reabsorption which allows water to flow

97
Q

compare the vertical and horizontal parts of the nephron

A

vertical: volume and concentration of urine
horizontal: identity of particles, keep what the body needs and lose what it doesn’t

98
Q

interstitium

A

the connective tissue surrounding the nephron

99
Q

as the descending loop of Henle goes further into the medulla, what occurs?

A

greater osmolarity in the interstitium pulls out more water. The kidney can also control this depending on water needs.

100
Q

the ascending limb is impermeable to ____

A

water

takes advantage of decreasing medullary osmolarity to increase salt reabsorption

101
Q

what part of the nephron can possibly produce urine that is less concentrated than blood

A

ascending limb of the loop of Henle

102
Q

describe the volume of water from the beginning of the loop of Henle to the end?

A

decrease in volume which speaks to water reabsorption

103
Q

what is the process of aldosterone release due to low blood pressure?

A

decreased blood pressure stimulates the release of renin from juxtaglomerular cells in the kidney. Renin then cleaves angiotensinogen, a liver protein, to form angiotensin I. This is metabolized by angiotensin converting enzyme in the lungs to form angiotensin II, which promotes the release of aldosterone from the adrenal cortex.

104
Q

in addition to increasing sodium and water reabsorption, what does aldosterone do?

A

increases potassium and hydrogen ion excretion

105
Q

osmotic vs. oncotic pressure

A

osmotic: sucking pressure caused by all dissolved particles, draws water into the vasculature
oncotic: osmotic pressure that is attributable to dissolved proteins specifically

106
Q

list the order of the vessels in the renal vascular pathway

A

renal artery ==> afferent arteriole ==> glomerulus ==> efferent arteriole ==> vasa recta ==> renal vein

107
Q

what is the largest organ in our bodies?

A

the skin (by both weight and size)

108
Q

what are fingernails and hair formed from?

A

keratin

109
Q

where are melanocytes derived from and where are they found?

A

derived from neural crest cells

found in the stratum basale

110
Q

melanin

A

a pigment that serves to protect the skin from DNA damage caused by UV radiation.

111
Q

unlike all other postganglionic sympathetic neurons, neurons that innervate the sweat glands are ____

A

cholinergic

112
Q

white fat vs. brown fat

A

white fat: insulates the body
brown fat: less efficient electron transport chain which means that more heat energy is released as fuel is burned. has a lot more mitochondria

113
Q

what is the primary cell of the skin?

A

keratinocytes

114
Q

where is sodium NOT actively transported out of neprhon

A

thin acending loop of henle

115
Q

why is the thick ascending loop of henle thick?

A

more cells, more mitochondria, more ATP use to activity transport sodium and chloride in reabsorption

116
Q

where in the kidney is solute concentration the lowest?

A

cortex

117
Q

when you shiver what happens

A

skeletal muscles contract, increasing metabolic rate, more ATP burned, energy released

118
Q

should urine be hypertonic or hypotonic to blood?

A

hypertonic

119
Q

what layer of skin is loose connective tissue?

A

papillary layer

120
Q

what does the kidney get rid of to decrease pH

A

bicarbonate

121
Q

aldosterone promotes the secretion of ___

A

potassium and hydrogen ions

MCAT Bio (12 decks)

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