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MCAT Bio Flashcards

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1
Q

functions of kidneys

A

excretion of hydrophilic wastes, maintenance of constant solute concentration and constant ph, maintenance of constant fluid volume

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2
Q

three processes of the kidneys

A

filtration, selective reabsorption, secretion

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3
Q

blood enters the kidney from a

A

renal artery

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4
Q

purified blood from the kidney is returned to the circ system by the

A

renal vein

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5
Q

collecting duct dumps urine into

A

renal pelvis

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6
Q

blood plasma leaks out of the glomerular capillaries into ______ and enters _____

A

glomerular basement membrane, bowman’s capsule

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7
Q

peritublar capillaries drain into

A

venules that lead back to the renal vein

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8
Q

function of peritubular capillaries

A

return selectively absorbed substances to the blood stream

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9
Q

where does most of solute reabsorption occur in the nephron

A

PCT VIA SECONDARY ACTIVE TRANSPORT

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10
Q

where does most of water reabsorption occur in the nephron

A

PCT

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11
Q

selective reabsorption in the DCT is more ____ than the PCT, usually via _____

A

regulated, hormones

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12
Q

how much glucose is reabsorbed by epithelial cells of tubules

A

100%

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13
Q

secretion is usually via what kind of transport

A

active

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14
Q

most secretion takes place in

A

DCT and collecting duct

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15
Q

where does urine concentration and dilution take place

A

distal nephron: DCT and collecting duct

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16
Q

urine concentration and dilution is regulated by

A

ADH and aldo

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17
Q

where is ADH released from

A

post pit

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18
Q

under what conditions is ADH released

A

low blood volume and high blood osmolarity (or a drop in bp)

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19
Q

effect of ADH

A

increases water reabsorption in distal nephron by making the collecting duct permeable to water

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20
Q

why does alcohol cause people to diurese

A

it inhibits adh secretion by post pit

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21
Q

when is aldo released

A

when bp is low (also low blood osmolarity, low blood volume, and angio II)

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22
Q

where is aldo released from

A

adrenal cortex

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23
Q

effect of aldo

A

increased reabsorption of Na and K by the distal nephron, which increases plasma osmolarity, which leads to increased thirst and water retention, which raises bp

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24
Q

descending loop of henle is thick or thin

A

thin

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25
thin portions of the tubule are composed of
squamous epithelial cells (not metabolically active)
26
thick portions of tubule are composed of
cuboidal epithelial cells (active transport)
27
descending limb of loop of henle is permeable to
water
28
collecting duct secretes
k and h
29
thick ascending loop of henle
actively transports Na, K, and cl out of filtrate, passive return of K to filtrate
30
thick ascending loop of henle permeable to
ions
31
counter current multiplier causes
medulla to be very salty which facilitates water reabsorption from the collecting duct. this is how the kidney is capable of making urine with a much higher osmolarity than plasma
32
vasa recta function
return reabsorbed water to the bloodstream
33
JGA is
a specialized contact point between the afferent arteriole and the distal tubule
34
at the JGA, cells in the afferent arteriole are called
JG cells
35
at the JGA, cells in the distal tubule are called
macula densa
36
macula densa
the cells in the distal tubule at the JGA
37
JG cells are
baroreceptors
38
renin is secreted from
JG cells
39
when is renin secreted
when there is decrease in bp
40
function of renin
catalyzes the conversion of angiotensinogen into angiotensin I
41
angiotensinogen is made in
liver
42
angiotensin II
vasoconstrictor that immediately raises bp and stimulates release of aldo
43
cells of macula densa are
chemoreceptors
44
function of macula densa cells
monitor filtrate osmolarity in the distal tubule. when filtrate osmolarity decreases (indicating a reduced filtration rate), the cells of the macula densa stimulate the JG cells to release renin. the macula densa also cause a direct dilation of the afferent arteriole, increasing blood flow to (and then bp and filtration rate in) the glomerulus
45
decreased filtrate osmolarity indicates
decreased filtration rate
46
carbonic anhydrase is found in (kidney)
epithelial cells throughout the nephron except the squamous cells of the thin loop of henle
47
carbonic anhydrase catalyzes
co2 into carbonic acid which dissociates into bicarb and H
48
what type of hormone is aldo
steroid
49
moa aldo
increasing synthesis of na/k-atpase in distal nephron
50
where is calcitonin made
c cells (thyroid gland)
51
c cells secrete calcitonin when
serum ca is too high
52
calcitonin causes
ca to be removed from the blood by deposition in the bone, reduced absorption by the gut, and excretion in the urine
53
pth released when
serum ca is too low
54
pth causes
ca to be secreted into blood by increased absorption by the gut and increased reabsorption in the kidneys
55
EPO causes
increased synthesis of RBC in bone marrow
56
when is EPO released
when blood o2 content falls
57
pancreatic lipase breaks down
1 triglyceride and 2 water into 2 fatty acids and 1 monoglyceride
58
ptyalin breaks down
polysaccharides into di
59
pancreatic amylase breaks down
polysaccharides into di
60
what enzymes breakdown disaccharides into mono
brush border disaccharidases
61
what breaks down polypeptides into dipeptides and tripeptides
gastric acidity, pepsin, pancreatic proteases
62
what breaks down dipeptides and tripeptides
brush border peptidases
63
gi tract is derived from the cavity produced by _____ during embryogenesis
gastrulation
64
anus is derived from
blastopore
65
innermost lining of the lumen is composed of
epithelial cells
66
the surface of the epithelial cell which faces into the lumen is the
apical surface
67
epithelial cells are attached to a
basement membrane
68
the apical surface is separated from the remainder of the cell surface by
tight junctions
69
serosa
connective tissue
70
mucosa
epithelial tissue
71
submucosa
connective tissue
72
circular muscularis
smooth muscle
73
longitudinal muscularis
smooth muscle
74
gi smooth muscle exhibits
automaticity
75
gi muscle is
functional syncytium
76
function syncytium
when one cell has an ap the impulse spreads to neighboring cells
77
heterochromatin
densely packed
78
euchromatin
loosely packed
79
gram positive
stain strongly, one thick peptidoglycan layer outside of the cell membrane
80
gram negative
stain lightly, thin layer of peptidoglycan in cell wall AND an additional outer layer containing lipopolysaccharide
81
nucleus function
contain and protect dna, transcription, partial assembly of ribosomes
82
mitochondria function
produce atp via krebs and ox phos
83
RER
localization of synthesis/modification of secretory, membrane-bound, and organelle proteins
84
SER
detoxification and glycogen breakdown in liver, steroid synthesis in gonads
85
golgi apparatus
modification and sorting of proteins, some synthesis
86
free ribosomes
synthesize proteins that go to peroxisomes, mitochondria, nucleus, or cytoplasm
87
lysosomes
contain acid hydrolases that digest various substances
88
peroxisomes
metabolize lipids and toxins using h2o2
89
NTM of rods and cones
glutamate
90
upon absorption of photon, photoreceptors
release LESS glutamate (hyperpolarize)
91
in the dark, photoreceptors
release glutamate (depolarize)
92
off-center cells response to glutamate
depolarization (stimulated) SIGN CONSERVING
93
on-center cells response to glutamate
hyperpolarized (inhibited) sign reversing
94
upon absorbing a photon of light, retinal
is converted to all trans form which closes Na channel and cell hyperpolarizes
95
tonic receptors
fire APs as long as stimulus continues (subject to adaptation)
96
phasic receptors
only fire APs when the stimulus begins (important for communicating changes in stimuli)
97
+ RNA viruses
must encode RNA dependent RNA pol
98
RNA dependent RNA pol
copies RNA genome for viral replication (host never makes RNA from RNA)
99
+ RNA viruses can cause
common cold, polio, and rubella
100
- RNA viruses
must carry RNA dependent RNA pol
101
genome of a -RNA virus is
complementary to the piece of RNA that encodes viral proteins (the genome of a -RNA virus is the template for viral mRNA production)
102
retroviruses
must encode reverse transcriptase (these are +RNA viruses that undergo lysogeny.. in order to integrate into our dsDNA genome, a viral genome must also be composed of dsDNA and must undergo reverse transcription to make DNA from an RNA template)
103
reverse transcriptase is also called
RNA dependent DNA pol
104
double stranded DNA viruses
often encode enzymes required for dNTP synthesis and dna replication (the host cell only makes dNTPs in preparation for replication. if the virus wants to reproduce without waiting for the host to do so, it must encode its own enzymes for the synthesis of DNA building blocks. note that rna viruses don't do this because transcription is always occurring in all cells so NTPs are always present)
105
what is a factor likely to limit the size of RNA genomes
the error rate in rna synthesis is higher than dna synthesis (no mechs to proofread and correct errors in RNA synthesis). if the rna genome were too large, every copy of the viral genome synthesized would suffer from so many errors that no infectious viruses would be produced)

MCAT Bio (1 decks)

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