Brainscape's Knowledge GenomeTM

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


See full index

Renal Week 1 2017/18 > 9: Physiology 3 > Flashcards

9: Physiology 3 Flashcards

1
Q

What are the three barriers which make up the glomerular membrane?

A

Endothelium of glomerular capillaries

Basement membrane

Podocytes of Bowman’s capsule and their slit processes

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

Glomerular capillaries are more ___ than other capillaries.

A

permeable

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

What is the glomerular basement membrane made up of?

A

Type IV collagen

(Goodpasture’s syndrome is a Type II hypersensitivity reaction where antibodies attack the Type IV collagen of the basement membrane)

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

What charge does the glomerular basement membrane have?

A

Negative charge

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

What’s good about the negativity of the glomerular basement membrane?

A

Large negatively charged proteins can’t pass through it

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

Is filtration an active or passive process?

A

Active process

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

What is hydrostatic pressure?

A

Fluid pressure

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

What is oncotic pressure?

A

Pressure exerted by negatively charged plasma proteins

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

The glomerular capillaries have a high, constant ___.

A

pressure

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

What is the fluid pressure within Bowman’s capsule called?

Does it push fluid in or out of the glomerular capillaries?

A

Bowman’s capsule HYDROSTATIC pressure

Pushes fluid INTO capillary

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

What type of pressure keeps plasma proteins within the capillary?

What causes this?

A

Capillary oncotic pressure

Negatively charged basement membrane

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

What is the value of the oncotic pressure of Bowman’s capsule?

A

Zero

No plasma protein in the capsule

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

Which forces

a) aid filtration
b) block filtration?

A

a) Capillary blood pressure

b) Bowman’s capsule hydrostatic pressure, capillary oncotic pressure

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

What is the name for the total force which aids glomerular filtration?

What value does it have?

A

Net filtration pressure

10 mmHg

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

What is GFR?

A

Glomerular filtration rate

Rate of filtration of protein-free plasma into Bowman’s capulse per unit time

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

What is the equation for GFR?

A

GFR = Kf x net filtration pressure

Kf = filtration coefficient​, or how permeable the glomerular membrane is

Net filtration pressure was 10 mmHg according to last slide

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

What is the main determinant of GFR?

A

Capillary hydrostatic pressure

which is the strongest force pushing plasma out of the capillaries

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

What is the normal GFR?

A

120 ml/min

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

What extrinsically regulates GFR?

A

Sympathetic nervous system

via Baroreceptor reflex

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

Increasing glomerular capillary blood pressure also increases ___.

A

GFR

21
Q

What increases and decreases capillary blood flow and therefore blood pressure, GFR?

A

Vasodilation of afferent arteriole increases GFR

Vasoconstriction of afferent arteriole decreases GFR

22
Q

How do you calculate MABP?

A

((2 x diastolic) + (systolic)) / 3

23
Q

How does renal blood flow and therefore GFR react to short term changes in blood pressure?

A

Not very much

autoregulation to prevent water and electrolyte imbalance

24
Q

When is autoregulation of renal blood flow and GFR useful?

A

Exercise - BP increases but you don’t want to lose too much water and electrolytes

Low BP - you still want to filter adequately

25
Q

What is myogenic regulation of GFR?

A

Increased blood flow / BP causes walls of arteriole to stretch

Automatic constriction of smooth muscle to reduce blood flow > reduce GFR

Keeps GFR the same during short term hypertension/hypervolaemia

26
Q

Which part of the distal tubule regulates GFR?

A

Juxtaglomerular apparatus

27
Q

If solute concentration in the distal tubules increases, which cells cause smooth muscle constriction in the afferent arteriole to reduce blood flow and therefore GFR?

A

Macula densa cells detect inc salt

Granular/juxtaglomerular cells cause smooth muscle constriction

This is the short term regulation, juxtaglomerular apparatus also involved in RAAS which is the long term regulation

28
Q

How do kidney stones affect GFR?

A

Blockage in collecting system, buildup of filtrate

so Bowman’s hydrostatic pressure increases, stronger force AGAINST plasma movement into capsule from capillary, GFR decreases

29
Q

How does diarrhoea affect GFR?

A

Dehydrated

Same amount of plasma protein

Capillary oncotic pressure increases (against movement OUT of capillary into bowman’s)

GFR decreases

30
Q

What is Kf a measure of?

A

Filtration coefficient

i.e surface area available for filtration

31
Q

What is plasma clearance?

A

How effectively kidneys can clear blood of a substance

32
Q

What is the unit of plasma clearance?

A

Volume per MINUTE

33
Q

What is the equation for plasma clearance?

A

Plasma clearance = rate of excretion / [X]plasma

Where rate of excretion = [X]urine x urine flow rate

34
Q

What substance is used to determine the GFR of patients?

Why?

A

Inulin (not insulin)

It passes straight through glomerular membrane with no trouble, and isn’t reabsorbed, so Plasma clearance = GFR

35
Q

Inulin needs to be infused into the patient before determining their GFR.

What is naturally produced, freely filtered like inulin and can be used instead?

A

Creatinine

36
Q

Under normal circumstances, how much glucose is reabsorbed by the nephrons?

A

All of it

37
Q

What is the clearance of glucose in normal patients?

A

Zero

38
Q

What does glycosuria mean?

A

Glucose in the urine, i.e clearance isn’t zero, i.e kidney problem

diabetes, cushing’s, acromegaly…

39
Q

When may clearance be higher or lower than GFR?

A

When substance is reabsorbed into capillaries or secreted into tubules

40
Q

If clearance is less than GFR, the substance is being ___.

A

reabsorbed

41
Q

If clearance = GFR, the substance is being ___.

A

neither reabsorbed nor secreted

42
Q

If clearance > GFR then the substance is being ___.

A

secreted into the tubules

43
Q

What is the clearance of

a) glucose
b) creatinine
c) inulin
d) PAH?

A

a) 0

b) GFR

c) GFR

d) Equal to renal plasma flow (some reabsorbed and ALL secreted)

44
Q

What chemicals are used as

a) renal blood flow

b) GFR

markers?

A

a) PAH

b) Creatinine, inulin

45
Q

What is filtration fraction?

A

The proportion of plasma flowing through the glomeruli which is actually filtered

46
Q

How do you calculate filtration fraction?

A

Filtration fracture = GFR / Renal blood flow

47
Q

What percentage of blood is filtered in the

a) glomerulus
b) peritubular capillaries?

A

a) 20%

b) 80%

48
Q

How do you know that renal blood flow is 25% of cardiac output?

A

cuz you can use all of the above to calculate renal blood flow

Renal Week 1 2017/18 (9 decks)

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