Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

year 2 > renal physiology part 1 > Flashcards

renal physiology part 1 Flashcards

1
Q

what is osmolarity

A

the concentration of osmotically active particles that are present in a solution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the units of osmolarity

A

osmol/l or mosmol/l

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what kind of solutions are body fluids

A

weak salt solutions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what 2 factors are needed to calculate osmolarity

A

molar concentration of the solution

the number of osmotically active particles present

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the osmolarity of 150mM NaCl

A

150 x 2 = 300 mosmol/L

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are the units of osmolality

A

osmol/Kg of water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is tonicity

A

the effect a solution has on a cell volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what impact does an isotonic solution have on the cell volume

A

no impact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what impact does a hypotonic solution have on the cell volume

A

increase in cell volume due to water entering the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what impact does a hypertonic solution have on the cell volume

A

decrease in cell volume due to water leaving the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what happens to a red blood cell in a hypotonic solution

A

cell lysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

is there movement of water between isotonic solutions

A

yes just not in one net direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is bilirubin a biproduct of

A

breakdown of haemoglobin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is uric acid a biproduct of

A

breakdown of purines e.g. adenosine and guanine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what does tonicity take into accound that osmolarity doesnt

A

the ability of a solute to cross the cell membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is urea a biproduct of

A

breakdown of protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

will urea cause cell lysis.

why/why not

A

yes

can easily flow across the membrane of red blood cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

will sucrose cause cell lysis

why/why not

A

no

it is a very polar molecule so will not pass across the membrane so the cell will not swell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

is urea hypo/hyper/iso tonic

A

hypotonic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

is sucrose hypo/hyper/iso tonic

A

isotonic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what % of males is water

A

60%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what % of females is water

A

50%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

why do females have lower % body water

A

more fat tissue which contain less water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what 2 compartments does TBW exist as

A

intra and extracellular fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

intracellular fluid is what % of TBW

A

67%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

extracellular fluid is what % of TBW

A

33%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what is extracellular fluid made up of

A

plasma
interstitial fluid
lymph (negligable)
transcellular fluid (negligable)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what % of the ECF is plasma

A

20%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what % of the ECF is interstitial fluid

A

80%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

how are body fluid compartments measured clinically

A

tracers of known volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

how is TBW measured

A

3H20

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

how is ECF measured

A

inulin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

how is plasma measured

A

labelled albumin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

what is the equation for volume of distribution

A

V(litres) = Dose (D) / Sample concentration (C)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

what is total fluid input/output per day in normal temperature

A

2500ml/day

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

what happens to fluid input/output in hot weather

A

increases to around 3400

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

what happens to fluid input/output in prolonged heavy exercise

A

increases to around 6700

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

what are the main ions in the ECF

A

Na, Cl and HCO3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

what are the main ions in the ICF

A

K, Mg and negatively charged proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Na is in higher concentration in ECF or ICF

A

ECF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

K is in higher concentration in ECF or ICF

A

ICF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Cl- is in higher concentration in ECF or ICF

A

ECF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

HCO3 is in higher concentration in ECF or ICF

A

ECF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

what separates the ECF and ICF

A

selectively permeable plasma membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

are the osmotic concentrations of the ICF and ECF the same or different?

A

identical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

what is the osmotic concentration of ECF / ICF

A

300 mosmol/L

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

what is fluid shift

A

movement of water between the ICF and ECF in response to an osmotic gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

what effect will ECF NaCl gain have on the ECF and ICF

A

change in fluid osmolarity

  • increase in ECF
  • decrease in ICF (Na excluded from ICF)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

what effect will ECF NaCl loss have on the ECF and ICF

A

change in fluid osmolarity

  • ECF loss
  • ICF gain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

what effect will gain or loss of water have on the ECF and ICF

A

change in fluid osmolarity

- they will both increase or decrease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

what effect will the gain or loss of an isotonic fluid e.g. 0.9% NaCl have on the ECF and ICF

A

no change in fluid osmolarity - only the ECF volume changes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

what is an electrolyte

A

any salt that will dissociate to give ions in a solution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

why are Na and K 2 of the most important electrolytes

A

major contributors to osmotic concentrations of ECF and ICF

directly affect functioning of cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

why do minor fluctuations in plasma K ion concentrations have detrimental consequences

A

K plays a key role in establishing membrane potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

what are some consequences of changes in plasma K ion concentration

A

muscle weakness/paralysis

cardiac arrhythmias/arrest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

where is renin released from

A

granular cells (juxtaglomerular cells) within the juxtaglomerular apparatus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

what is erythropoietin

A

hormone released by kidney in response to hypoxia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

what is the name of active vitamin D

A

calcitrol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

what role does calcitrol (active vitamin D) play in calcium absorption

A

promotes Ca2+ absorption from GI tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

how is vitamin D converted to its active form

A

addition of 2 hydroxy groups (OH)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

where is the 1st hydroxy group added to vitamin D

A

liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

where is the 2nd hydroxy group added to vitamin D

A

kidney

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

what is the functional unit of a kidney

A

nephron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

what are the 2 types of nephron

A

juxtamedullary

cortical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

what is the more common type of nephron

A

cortical (80%)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

compare the loop of henle in juxtamedullary nephrons and cortical nephrons

A

juxtamedullary nephrons - much longer loop of henle that extends into the medulla
cortical nephron - loop of henle is much shorter and only slightly extends into the medulla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

do juxtamedullary nephrons have peritubular capillaries

A

no - have a single capillary called a vasa recta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

which type of nephron can produce much more concentrated urine

A

juxtamedullary nephrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

do cortical nephrons have a vasa recta

A

no they have a peritubular network of capillaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

does the efferent or afferent arteriole have a greater diameter

A

afferent arteriole has a greater diameter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

what makes up the inner wall of the bowmanns capsule

A

specialised cells called podocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

how is a filtration system created by the podocytes

A

they have foot like projections that interdigitate with the cells adjacent to them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

true/false

glomerular capillaries have pores in them which are much smaller than capillaries elsewhere in the body

A

false

glomerular capillaries have pores in them that are 100 times bigger than capillaries elsewhere in the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

what % of plasma of afferent arteriole is filtered into bowmans capsule

A

20%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

what are the macula densa cells

A

salt sensitive cells that sense how much salt is in the tubular fluid as it passes along - they can secrete vasoactive chemicals which can influence the smooth muscle in arterioles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

what is urine

A

modified filtrate of the blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

what are the 3 renal processes

A

glomerular filtration
tubular reabsorption
tubular secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

what is the equation for rate of excretion for any substance

A

rate of excretion = rate of filtration + rate of secretion - rate of reabsorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

what is the rate of filtration of X

A

the mass of X filtered into the bowmans capsule per unit time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

what is the equation for rate of filtration of X

A

[X]plasma x GFR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

what will happen to the rate of filtration of X if the concentration of X in the plasma increases

A

rate of filtration of X will increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

what is the rate of excretion of X

A

mass of X excreted per unit time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

what is the equation for the rate of excretion of X

A

[X]urine x Vu

Vu is the rate of urine production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

if the rate of filtration > rate of excretion, net _____ has occured

A

if the rate of filtration > rate of excretion, net reabsorption has occured

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

what is the equation for the rate of reabsorption of X

A

rate of filtration of X - rate of excretion of X

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

if the rate of filtration < rate of excretion, net ____ has occured

A

if the rate of filtration < rate of excretion, net secretion has occured

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
87
Q

what is the equation for the rate of secretion of X

A

rate of secretion of X = rate of excretion of X - rate of filtration of X

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
88
Q

what is the normal urine flow rate

A

Vu = 0.001 litre/min - very variable depending on body conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
89
Q

what 3 layers make up the glomerular filtration barrier

A

glomerular capillary endothelium
basement membrane
slit processes of podocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
90
Q

what is the net charge of the basement membrane and why is this

A

negative

to repel large negatively charged proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
91
Q

what are the 2 forces pushing out from the blood vessels into the filtrate

A

glomerular capillary pressure

bowmans capsule oncotic pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
92
Q

what is the glomerular capillary pressure roughly

A

55mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
93
Q

what is the bowmans capsule oncotic pressure

A

0mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
94
Q

why is the bowmans capsule oncotic pressure 0

A

no plasma proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
95
Q

what determines oncotic pressure

A

plasma proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
96
Q

what are the 2 forces pushing back and resisting the movement from the blood vessels into the filtrate

A

bowmans capsule hydrostatic pressure

capillary oncotic pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
97
Q

what is bowmans capsule hydrostatic pressure

A

15mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
98
Q

what is the capillary oncotic pressure

A

30mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
99
Q

what is the net filtration pressure equation

A

(BPgc + COPbc) - (HPbc + COPgc)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
100
Q

what contributes most to net filtration pressure at the glomerulus

A

BPgc (glomerular capillary blood pressure)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
101
Q

what are the forces that balance hydrostatic pressure and osmotic forces known as

A

staring forces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
102
Q

what is the GFR

A

the glomerular filtration rate at which protein-free plasma is filtered from the glomeruli into the Bowman’s capsule per unit time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
103
Q

what is the equation for GFR

A

Kf x net filtration pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
104
Q

what is Kf

A

filtration coefficient - how holey the glomerular membrane is

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
105
Q

what is GFR normally

A

125ml/min

0.125L/min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
106
Q

what is the major determinant of GFR

A

glomerular capillary fluid pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
107
Q

how is GFR regulated extrinsically

A

sympathetic control via the baroreceptor reflex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
108
Q

how is the GFR regulated intrinsically (autoregulation)

A

myogenic mechanism

tubuloglomerular feedback mechanism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
109
Q

an increase in arterial blood pressure ____ the blood flow into the glomerulus. This in turn _____ the glomerular capillary blood pressure and net filtration pressure therefore _____ the GFR

A

increases
increases
increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
110
Q

how is the blood pressure between afferent and efferent arteriole kept constant

A

as you lose volume the diameter decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
111
Q

afferent arteriole (vasoconstriction/vasodilation) will increase the GFR

A

afferent arteriole vasodilation will increase the GFR because blood flow into the glomerulus is increased

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
112
Q

afferent arteriole (vasoconstriction/vasodilation) will decrease the GFR

A

afferent arteriole vasoconstriction will decrease the GFR because blood flow into the glomerulus is decreased

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
113
Q

a fall in blood volume does what to arterial blood pressure

A

decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
114
Q

what detects changes in arterial blood pressure

A

aortic and carotid sinus baroreceptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
115
Q

if baroreceptors detect a fall in ABP what do they do

A

reduced firing of baroreceptors causing increase in sympathetic activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
116
Q

what effect does increased sympathetic activity have on the arterioles

A

generalised arteriolar vasoconstriction

constriction of afferent arterioles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
117
Q

what does constriction of afferent arterioles due to sympathetic stimulation do to the GFR

A

decreased blood pressure in the glomerular capillaries (BPgc) so GFR is reduced - less urine produced to help compensate fall in blood volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
118
Q

does systemic arterial BP change always result in change in GFR

A

no - autoregulation prevents short term changes in systemic arterial BP affecting GFR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
119
Q

GFR remains constant despite a large increase in MAP

true or false

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
120
Q

in situations such as haemorrhage, does intrinsic or extrinsic control of GFR take over

A

extrinsic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
121
Q

what does autoregulation of GFR mean

A

intrinsic to kidneys - needs no external input

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
122
Q

describe the intrinsic myogenic control

A

if vascular smooth muscle is stretched (arterial pressure is increased) it contracts thus constricting the arteriole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
123
Q

what does the tubuloglomerular feedback involve

A

juxtaglomerular apparatus - if NaCl increases within the distal tubular fluid i.e. GFR has increased, the macula densa senses this and release vasoactive chemicals which causes contraction of smooth muscle in the walls of the afferent arterioles to reduce GFR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
124
Q

what kind of feedback do the macula densa cells exert on GFR

A

negative feedback

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
125
Q

what effect does a kidney stone have on the GFR and why

A

decreases GFR

- blockage downstream so bowmans capsule fluid pressure increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
126
Q

what effect does diarrhoea have on the GFR and why

A

GFR decreases
- patient will be dehydrated so plasma proteins within the blood are more concentrated and exert a greater osmotic force (capillary oncotic pressure increases)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
127
Q

what effect do severe burns have on the GFR and why

A

increase the GFR
-plasma proteins are lost so conc. within the blood decreases exerting a weaker osmotic effect (capillary oncotic pressure decreases)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
128
Q

what is plasma clearance

A

volume of plasma completely cleared of a particular substance per minute (ml/min)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
129
Q

what is the equation for clearance of a substance

A

clearance of a substance = rate of excretion/plasma conc

= (( [X]urine x Vurine )) / [X]plasma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
130
Q

what is the plasma clearance of inulin equal to

A

GFR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
131
Q

why is the plasma clearance of inulin equal to GFR

A

it is freely filtered at the glomerulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
132
Q

is inulin reabsorbed

A

no

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
133
Q

is inulin secreted

A

no

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
134
Q

is inulin metabolised by the kidney

A

no

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
135
Q

is inulin toxic

A

no

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
136
Q

can inulin be easily measured in the urine

A

yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
137
Q

what is the inulin clearance rate in a person with normal GFR

A

125ml/min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
138
Q

true/false

amount of inulin filtered per unit time = amount of inulin excreted per unit time

A

true

139
Q

what is another chemical that can be used instead of inulin to measure GFR

A

creatinine

140
Q

what is a benefit to using creatinine

A

occurs naturally so doesnt have to be given to the patient

141
Q

what is a disadvantage to using creatinine

A

some creatinine is secreted in the tubules

142
Q

what is the plasma clearance of glucose

A

0

143
Q

why is the plasma clearance of glucose 0

A

completely reabsorbed in the proximal tubule

144
Q

clearance of a substance will be 0 if… (2 scenarios)

A

filtered, entirely reabsorbed and not secreted
or
not filtered and not secreted

145
Q

give an example of a substance that will have a plasma clearance rate of < GFR

A

urea

146
Q

why is the clearance of urea less than the GFR

A

urea is filtered, partly reabsorbed and not secreted

i.e. only a portion of the plasma is cleared of the substance

147
Q

give an example of a substance that has a clearance > GFR

A

H+

148
Q

why is the clearance of H+ > than GFR

A

H+ is filtered, secreted but not reabsorbed

i.e. all of the filtered plasma is cleared of the substance, as is the peritubular fluid from which it is secreted

149
Q

true/false

more H+ is excreted that was initially filtered because it is drawn out of the blood vessels and not reabsorbed

A

true

150
Q

if clearance is < GFR the substance is …

A

reabsorbed

151
Q

if clearance = GFR the substance is…

A

neither reabsorbed not secreted

152
Q

if clearance > GFR the substance is …

A

secreted

153
Q

how is renal plasma flow calculated

A

clearance of PAH (para-amino huppuric acid)

154
Q 
PAH is 
freely filtered/not filtered
secreted/not secreted
reabsorbed/not reabsorped
completely cleared/not completely cleared
A

freely filtered
secreted
not reabsorbed
completely cleared

155
Q

does the blood leaving the kidneys contain any PAH

A

no

156
Q

what is creatinine a breakdown product of

A

muscle

157
Q

what is the clearance value of PAH

A

650ml/min = RPF

158
Q

what is used to estimate GFR

A

creatinine

159
Q 
creatinine is :
produced at a constant/near constant rate
freely filtered/not filtered
reabsorbed/not reabsorbed
secreted/not secreted
A

near constant rate
freely filtered
not reabsorbed
slightly secreted

160
Q

a GFR marker should be …

A

freely filtered
not secreted
not reabsorbed

161
Q

an RPF marker should be

A

freely filtered
completely secreted
not reabsorbed

162
Q

what is the equation for filtration fraction

A

GFR/RPF

163
Q

What is the filtration fraction value

A

125/650 = 0.19 = 20%

164
Q

what does the filtration fraction tell us

A

20% of the plasma entering the glomeruli is filtered - remaining 80% moves onto the peritubular capillaries

165
Q

how many litres a day does a GFR of 125ml/min equate to

A

180 litres per day

166
Q

what is the equation for RBF

A

RPF x 1/ 1-Hct

167
Q

what does renal blood flow roughly equate to

A

1200 ml/min

168
Q

what is the CO in litres/min

A

5 litres

169
Q

what % of the CO do the kidneys receive

A

around 24%

170
Q

what % of fluid is reabsorbed by the kidneys

A

99%

171
Q

what % of salt is reabsorbed by the kidneys

A

99%

172
Q

what % of glucose is reabsorbed by the kidneys

A

100%

173
Q

what % of amino acids are reabsorbed by the kidneys

A

100%

174
Q

what % of urea is reabsorbed by the kidneys

A

50%

175
Q

what % of creatinine is reabsorbed by the kidneys

A

0%

176
Q

is reabsorption or filtration more specific

A

reabsorption

177
Q

of the 125ml of glomerular filtrate, how many ml is reabsorbed in the PCT and therefore how much is left to go into the loop of henle

A

80ml is reabsorbed in the PCT

45ml goes on to the loop of henle

178
Q

true/false

the fluid filtered changes osmolarity from the bowmans capsule to the proximal tubule

A

false - doesnt change osmolarity from the bowmans capsule to the PCT

179
Q

fluid reabsorbed in the PCT is hyperosmotic/isoosmotic/hypoosmotic with the filtrate

A

isoosmotic

180
Q

give 5 things reabsorbed in the PCT

A 
sugars
amino acids
phosphate
sulfate
lactate
181
Q

give 6 things secreted in the PCT

A 
H+
hippurates
neurotransmitters
bile pigments
uric acid
drugs
toxins
182
Q

what are the 2 pathways used in reabsorption

A

transcellular and paracellular

183
Q

describe the transcellular pathway

A

absorption across the cell of the tubular wall

184
Q

describe the paracellular pathway

A

absorption across spaces in the cells of the tubular wall

185
Q

what are the names of the junctions between tubular epithelial cells

A

tight junctions

186
Q

what are the 2 membranes of the tubular epithelial cells and which borders the tubular lumen and which borders the interstitial fluid

A

luminal membrane - in contact with filtrate

basolateral membrane - in contact with interstitial fluid

187
Q

what is primary active transport

A

energy is directly required to operate the carrier and move the substrate against its concentration gradient

188
Q

what is secondary active transport

A

carrier molecule is transported coupled to the concentration gradient of an ion (usually Na+)

189
Q

what is facilitated diffusion

A

passive carrier-mediated transport of a substance down its concentration gradient

190
Q

what is facilitated diffusion usually used for

A

substances that do not easily move across the lipid bilayer

191
Q

where is the Na+/K+/ATPase transport mechanism expressed ALWAYS AND EXCLUSIVELY

A

basolateral membrane of epithelial cells

192
Q

what does the Na+/K+/ATPase channel pump out of the cell

A

3 sodium

193
Q

what does the Na+/K+/ATPase channel pump into the cell

A

2 potassium

194
Q

why does the Na+/K+/ATPase channel require energy from hydrolysis of ATP

A

pumping sodium and potassium against their concentration gradients

195
Q

the intracellular concentration of Na is kept low by the Na+/K+/ATPase allowing Na to ——– from the tubular lumen into the cell —– a concentration gradient

A

the intracellular concentration of Na is kept low by the Na+/K+/ATPase pump allowing Na to diffuse from the tubular lumen into the cell down a concentration gradient

196
Q

how does fluid reabsorption occur across the leaky PCT epithelium

A

standing osmotic gradient

oncotic pressure gradient

197
Q

in what direct do the mechanisms on the apical membrane of the PCT move Na

A

into the cell

198
Q

in what direction do the mechanisms on the basolateral membrane of the PCT move Na

A

out of the cell into the interstitial fluid

199
Q

what are the 3 mechanisms at the apical border that bring Na into the cell

A

Na+/glucose
Na+/amino acids
Na+/H+

200
Q

what kind of transport are the Na+/glucose and Na+/amino acid mechanisms

A

secondary active transport

201
Q

what kind of transport is the Na+/H+ mechanism

A

countertransport

202
Q

how is Cl- reabsorbed from the filtrate

A

paracellular route along an electrochemical gradient set up by the reabsorption of sodium ions

203
Q

how does water get reabsorbed in the PCT

A

paracellular mechanism due to the osmotic gradient created by Na and Cl (osmosis)

204
Q

how does glucose cross the apical membrane of the tubular cell from the filtrate into the cell

A

Na+/glucose

cotransport/symport/secondary active transport

205
Q

how does glucose cross the basolateral membrane of the tubular cell

A

facilitated diffusion

206
Q

the Na+/K+/ATPase channel is an example of what kind of transport

A

primary active transport

207
Q

what % of glucose in the filtrate is reabsorbed in the PCT

A

100%

208
Q

why is there glucose in the urine of people with diabetes

A

transport maximum exists as transporters can only move so many molecules in a given time - if there is too much glucose present in the filtrate they become saturated - no more glucose can be reabsorbed

209
Q

what is the Tm of glucose

A

approx 2mmol/min

210
Q

how much of salt and water is reabsorbed in the PCT

A

2/3

211
Q

what % of amino acids are absorbed in the PCT

A

100%

212
Q

what drives the Na reabsorption in the PCT

A

basolateral Na+/K+/ATPase channels

213
Q

the tubular fluid is hyperosmotic/isoosmotic/hypoosmotic when it leaves the PCT

A

isoosmotic - same osmolarity as plasma (around 300mosmol/l)

214
Q

why is the tubular fluid isoosmotic when it leaves the PCT

A

salt and water have been reabsorbed in correlating amounts

215
Q

why does the vasa recta have a higher oncotic pressure than the afferent arteriole

A

same number of plasma proteins but 20% of plasma has gone so increased concentration of plasma protein

216
Q

what is the function of the loop of henle

A

generates a corticomedullary solute concentration gradient enabling the formation of hypertonic urine

217
Q

where does the loop of henle originate

A

junction between the cortex and medulla

218
Q

where is the concentration gradient found that is created by the loop of henle

A

interstitial fluid

219
Q

what is the term for the opposing flow in the 2 limbs of the loop of henle

A

countercurrent flow

220
Q

the entire loop functions as a _____ _____ _____

A

counter current multiplier

221
Q

together the loop and the vasa recta establish a hyper/iso/hypo osmotic medullary interstitial fluid

A

hyperosmotic medullary interstitial fluid

222
Q

what happens to Na and Cl along the entire length of the ascending limb

A

Na and Cl are reabsorbed

223
Q

how is Na and Cl reabsorption achieved in the upper thick ascending limb

A

active transport

224
Q

how is Na and Cl reabsorption achieved in the lower thin ascending limb

A

passive movement

225
Q

is water reabsorbed in the ascending limb

A

no - ascending limb is relatively impermeable to water so little/no water is follows salt

226
Q

is NaCl reabsorbed in the descending limb

A

no

227
Q

is water reabsorbed in the descending limb

A

yes - highly permeable to water

228
Q

why does water move out of the descending limb

A

follows the osmotic gradient created by the interstitial fluid - originally created by reabsorption of NaCl from ascending limb

229
Q

what pumps ions out of the thick ascending loop of henle

A

Na+/K+/Cl- triple cotransporter

230
Q

what drugs block the Na+/K+/Cl- triple cotransporter

A

loop diuretics

231
Q

the Na+/K+/Cl- triple cotransporter causes the tubular fluid to become ____ and the osmolality of the interstitial fluid to ____

A

dilute

increase

232
Q

can interstitial fluid enter the descending limb

A

no - impermeable to ions

233
Q

water leaves the descending limb by ____ causing the fluid in the descending limb to be _____

A

osmosis

concentrated

234
Q

on the way down the descending limb there is _____ in osmolality due to _____

A

increase

reabsorption of water

235
Q

on the way back up the ascending limb there is _____ in osmolality due to ____

A

decrease

active salt reabsorption

236
Q

horizontal gradient is much larger/smaller than the vertical gradient in the loop of henle

A

smaller

237
Q

tubular fluid is hyper/iso/hypo osmotic when it leaves the loop of henle to enter the DCT

A

hypoosmotic

238
Q

what is countercurrent multiplication

A

the reabsorption of NaCl and urea from the ascending loop of henle followed by the reabsorption of water from the descending loop of Henle forming the corticomedullary gradient

239
Q

approximately how much of the medullary osmolarity is contributed by the urea cycle

A

1/2

240
Q

what is the two salt hypothesis

A

corticomedullary concentration is set up by salt movement but also by other substances such as urea

241
Q

the purpose of countercurrent multiplication is to enable the kidney to produce a urine of different volume and concentration according to the amounts of circulating ___

A

ADH

242
Q

urine production is usually around 1ml/min but what can it vary between

A

0.3 - 25 ml /min

243
Q

what runs along side the loop of henle of juxtamedullary nephrons acting as a countercurrent exchanger

A

vasa recta

244
Q

what happens to the osmolality of the blood in the vasa recta as it dips into the medulla

A

osmolality rises as it dips down into the medulla - water is lost and solute is gained

245
Q

what happens to the osmolality of the blood as it goes back up to the cortex

A

osmolality falls as blood goes back up to the cortex as water is gained and solute is lost

246
Q

the blood is said to —— with the corticomedullary gradient

A

equilibrate

247
Q

what two things form the counter current system

A

the loop of henle (countercurrent multiplier) and the vasa recta (countercurrent exchanger)

248
Q

how is the medullary gradient preserved

A

passive exchange across endothelium - blood equilibrates at each layer - ensures the solute is not washed away

249
Q

how does the vasa recta minimise the washing away of NaCl and urea by essential blood flow through the medulla (3)

A

vasa recta capillaries follow hairpin loops
vasa recta capillaries are freely permeable to NaCl and water
blood flow to the vasa recta is low - only a few juxtamedullary nephrons

250
Q

blood entering and leaving the vasa recta is of different/the same osmolarity

A

the same (300mosmol/L)

251
Q

the tubular fluid leaving the loop of henle entering the distal tubule is hyper/iso/hypertonic to plasma

A

hypotonic (100mosmol/L)

252
Q

tissue surrounding the distal tubule (renal cortext interstitial fluid) is at around ___mosmol/L

A

300

253
Q

where do the distal tubules empty

A

cortical collecting ducts

254
Q

the collecting duct is bathing in progressively increasing/decreasing concentration of surrounding interstitial fluid as it decends through the medulla

A

increasing

255
Q

when the distal tubules reach the collecting ducts, what % of filtered ions have been reabsorbed

A

95%

256
Q

ADH causes water ____

A

reabsorption

257
Q

Aldosterone _____ Na reabsorption and _____ H+/K+ secretion

A

aldosterone increases Na reabsorption

aldosterone increases H+/K+ secretion

258
Q

Atrial natriuretic hormone ____ Na+ reabsorption

A

decreases

259
Q

Parathyroid hormone ____ Ca2+ reabsorption and ____ phosphate reabsorption

A

increases Ca2+ reabsorption

decreases phosphate reabsorption

260
Q

the distal tubule has a ____ permeability to water and urea, meaning urea is _____ in the tubular fluid

A

low

concentrated

261
Q

the distal tubule can be split into 2 sections:

A

early and late

262
Q

what occurs in the early tubule and via what transporter

A

NaCl reabsorption

Na+/K+/2Cl- transport

263
Q

what occurs in the late tubule

A

Ca reabsorption

H+ secretion, Na+, K+ reabsorption

264
Q

the collecting duct is also split into 2 sections:

A

early and late

265
Q

the early collecting duct is similar to the ____ distal tubule

A

late

266
Q

the late collecting duct has ____ ion permeability

A

low

267
Q

what influences the permeability of the late collecting duct to water and urea

A

ADH

268
Q

where is ADH synthesised

A

supraoptic and paraventricular nuclei in the hypothalamus

269
Q

where is ADH stored

A

granules in the posterior pituitary

270
Q

how is ADH transported from the hypothalamus to vesicles in the posterior pituitary

A

transported down nerves

271
Q

how is ADH released into blood

A

when APs down the nerves lead to Ca2+ dependent exocytosis

272
Q

dehydration leads to an ____ in plasma osmolarity which _____ the release of ADH

A

increase

stimulated

273
Q

what kind of hormone is ADH

A

peptide

274
Q

what is the half life of ADH

A

10-15 minutes

275
Q

ADH will bind to Type _ vasopressin receptors on the ______ membrane

A

type 2 vasopressin receptors on the basolateral membrane

276
Q

what does the binding of ADH to V2 receptors cause

A

increase in amount of intracellular cAMP which increases expression of aquaporins on the apical membrane

277
Q

where are aquaporins usually found

A

within vesicles in the cytoplasm of the cell

278
Q

where do aquaporins move when stimulated

A

to the apical membrane where they are inserted

279
Q

when there is no more ADH stimulation where do aquaporins go

A

back into the cytoplasm

280
Q

low plasma ADH produces ____ urine

A

hypotonic

281
Q

high plasma ADH produces _____ urine

A

hypertonic

282
Q

high levels of ADH ____ the permeability of the collecting duct cells to water

A

increase

283
Q

what do type 1 vasopressin receptors cause

A

smooth muscle contractions and vasoconstriction

284
Q

tubular fluid _____ with interstitium via ____

A

equilibrates via aquaporins

285
Q

when dehydrated, there is an _____ in plasma concentration causing more/less ADH to be released. Osmolarity of the tubular fluid will ____ because

A

when dehydrated there is an increase in plasma concentration causing more ADH to be released. Osmolarity of the tubular fluid will increase because water starts to move out as it passes down the osmotic gradient of the kidney (set up by the loop of henle)

286
Q

a dehydrated person will produce a _____ volume of ___ urine

A

small volume of concentrated

287
Q

with low levels of ADH, the collecting ducts are ______ to water

A

relatively impermeable to water

288
Q

why does water not move out of the collecting ducts when there is low levels of ADH despite the osmotic gradient it is exposed to

A

low ADH so less aquaporins are expressed so no pathway for water to take - high volume of dilute urine

289
Q

what are the 2 types of diabetes insipidus

A

central and nephrogenic

290
Q

what is the issue in central DI

A

person cannot secrete ADH

291
Q

what is the issue in nephrogenic DI

A

ADH is produced but isnt influencing or causing a response in the cells of the collecting duct

292
Q

true/false

DI is usually hereditary

A

true

293
Q

what are the main s/s of DI

A

large volumes of dilute urine (20L per day)

constant thirst

294
Q

what is the treatment for central DI

A

ADH replacement

295
Q

what is the treatment for nephrogenic DI

A

thiazide diuretics

296
Q

what are the 2 types of receptor which stimulate ADH release and which is more important

A

hypothalamic osmoreceptors - most important

left atrial stretch receptors

297
Q

what does decreased left atrial pressure lead to

A

increased ADH release

298
Q

what does nicotine do to ADH release

A

stimulates

299
Q

what does alcohol do to ADH release

A

inhibits

300
Q

what does ecstasy do to ADH release

A

inhibits

301
Q

stimulation of stretch receptors in upper GI tract exerts feed-_____ ______ of ADH

A

feed forward inhibition

302
Q

what kind of hormone is aldosterone

A

steroid

303
Q

where is aldosterone secreted from

A

adrenal cortex

304
Q

aldosterone is secreted in response to _____ K+ concentration or _____ Na+ concentration and in activation of the _____ system

A

increasing K+
decreasing Na+
RAAS

305
Q

aldosterone stimulates the ____ of Na and ____ of K+

A

reabsorption of Na

secretion of K

306
Q

around ___% of K is reabsorbed in the PCT.

when aldosterone is absent the remainder is ____

A

90%

reabsorbed in the distal tubule

307
Q

an increase in plasma K+ concentration (directly/indirectly) stimulates the adrenal cortex to release aldosterone causing the ____ of K

A

directly

secretion

308
Q

a decrease in plasma Na+ concentration (directly/indirectly) promotes the secretion of aldosterone

A

indirectly by means of the juxtaglomerular apparatus

309
Q

what causes release of renin from the kidney

A

increased sympathetic activity due to reduced BP
reduced NaCl
reduced pressure in the afferent arteriole

310
Q

where is renin released from

A

granular cells in the JGA

311
Q

granular cells are directly innervated by the ______ nervous system - causes renin release

A

sympathetic

312
Q

where does aldosterone increase Na+ reabsorption

A

distal tubule and collecting duct

313
Q

what channels does aldosterone increase the expression of

A

K/Na pumps on the basolateral membrane

Na channels on apical membrane

314
Q

renin converts what to what

A

angiotensinogen to angiotensin I

315
Q

what converts angiotensin I to angiotensin II

A

ACE

316
Q

angiotensin II stimulates the adrenal cortex to produce ____

A

aldosterone

317
Q

angiotensin II causes arterior _____

A

vasoconstriction

318
Q

angiotensin II causes ___ thirst

A

increased

319
Q

where is ANP produced

A

heart

320
Q

where is ANP stored

A

atrial muscle cells

321
Q

when is ANP released

A

when atrial muscle cells are mechanically stretched due to an increase in the circulating plasma volume

322
Q

ANP promotes ____ of Na+ therefore ____ plasma volume

A

excretion

decreasing

323
Q

ANP has the ____ effects on the kidney to aldosterone

A

opposite

324
Q

ANP ____ RAAS

A

inhibits

325
Q

ANP causes smooth muscle of afferent arteriole to ____

A

relax/dilate

326
Q

ANP _____ the sympathetic nervous system to _____ TPR and CO

A

inhibits

decrease

327
Q

what 2 mechanisms control micturation

A

micturation reflex

voluntary control

328
Q

what stimulates the micturation reflex

A

stretch receptors in the bladder wall

329
Q

what is the micturation reflex

A

involuntary emptying of the bladder by simultaneous bladder contraction and opening of both the internal and external urethral sphincters

330
Q

how can micturation be prevented

A

voluntarily prevented by deliberate tightening of the external sphincter and surrounding pelvic diaphragm

331
Q

what is water diuresis

A

increased urine flow but not an increased solute excretion

332
Q

what is osmotic diuresis

A

increased urine flow as a result of primary increase in salt excretion

333
Q

true/false

any loss of solute in the urine must be accompanied by water

A

true

334
Q

true/false

any loss of water in the urine must be accompanied by solute loss

A

false

water loss can occur without the loss of solute

335
Q

the collecting duct absorbs around __% of urea

A

50%

336
Q

is the distal tubule permeable to urea

A

no

337
Q

parasympathetic/sympathetic nervous system causes the bladder to contract

A

parasympathetic

338
Q

stretch receptors ____ motor neurone to the external sphincter

A

inhibit

339
Q

voluntary control: cerebral cortex ____ motor neurone to the external sphincter

A

stimulates

340
Q

when motor neurone to external urethral sphincter is stimulated, the external urethral sphincter ____

A

remains closed

341
Q

what receptors detect and initiate the primary mechanism for regulation of ECF osmolarity

A

hypothalamic osmoreceptors

342
Q

renal mechanisms suffice in water excess or deficit?

A

excess

in deficit it is essential to increase intake

343
Q

kidneys produce erythropoietin which stimulates

A

stem cells in bone marrow to produce RBCs to increase O2 supply in tissues

344
Q

when do kidneys produce more erythropoietin

A

if O2 supply in tissues is too low

year 2 (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions