Lecture 61/63/64 Flashcards

1
Q

Excretion

Kidneys - excrete ___soluble things

Liver - things soluble in ___

A

water

fat

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

What are the waste contents of urine

A

H+, creatinine (from the muscles), Urea (protein metabolism by product)

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

What are the two major functions of the Kidney?

and three minor ones?

A
  1. Maintain the volume and composition of the ECF
  2. Excrete waste products

also:

Control of blood pressure
activates Vitamin D
make EPO - message to bone marrow to make RBCs

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

From what us urine made mostly?

A

Plasma

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

How much plasma does it take to make 2 litres of urine?

A

200 Litres

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

What percentage of cardiac output goes to the Kidneys?

A

20-25%

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

The amount of solute excreted is the

=______ - _____ + _______

A

Amount filtered - amount reabsorbed + amount secreted

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

______inter-digitate over the surface of the capillaries.

The “truck” around with the capillaries wrap themselves is the mesangial cell

A

podocytes inter-digitate over the surface of the capillaries.

The “truck” around with the capillaries wrap themselves is the mesangial cell

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

Filtered substances pass through ___________ _____ and filtration slits

A

Filtered substances pass through endothelial pores and filtration slits

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

What happens to the Glomerular filtration rate when the afferent arteriole dilates?

A

It increases

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

What happens to renal blood flow when the afferent arteriole dilates?

A

it inncreases

overcomes Resistance of efferent arteriole

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

What is the glomerular filtration rate? (GFR)

A

Volume of plasma filtered by the glomerulus per unit time

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

Inulin is the ideal substance for determining GFR because…

A

It is not reabsorbed, secreted or metabolised.

It is exogenous (comes from outside the body)

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

How do you check, with inulin

A

Check the amount that is in the blood and the urine, to determine how much was filtered. Clearance

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

What is renal clearance?

A

Clearance is defined as the rate of urinary excretion of a substance, relative to its plasma concentration.

“How much you see in the urine?”

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

What normally happens to the GFR if mean arterial pressure increases from 90 to 110 mmHg

A

It doesn’t change

MAP doesn’t really affect

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

__________maintains a nearly constant GFR when mean arterial blood pressure is between 80 and 180 mm Hg

A

Autoregulation maintains a nearly constant GFR when mean arterial blood pressure is between 80 and 180 mm Hg

18
Q

What cells line the wall of the tubule, between the afferent arteriole and the distal convoluted tubule

A

macula densa

19
Q

Macula densa acts, in the presence of too much volume in the distal tubule to:

A

releases paracrine:

afferent arteriole constricts
resistance in afferent arteriole increases
hydrostatic pressure in glomerulus decreases
GFR decreases

20
Q

Renal excretion can be altered by what:

A

Renin-angiotensin system
SNS
Atrial natriuretic peptide (comes from heart - if too much blood)
Vasopressin

21
Q

Atrial natriuiretic peptide is released when there is ________ of the muscular walls of the heart.

Its a signal that there is too much ______ _____ in the system

A

Atrial natriuiretic peptide is released when there is stretching of the mscular walls of the heart.

Its a signal that there is too much blood volume in the system

22
Q

where does aldosterone comes from?

A

Adrenal glands

23
Q

What does the renin-angiotensin (and aldosterone) system regulate?

A

The renin-angiotensin system (RAS) or the renin-angiotensin-aldosterone system (RAAS) is a hormone system that regulates blood pressure and water (fluid) balance.

It increases BP and blood volume by aloowing reabsorption of

24
Q

How does noradrenaline help reduce blood volume?

A

SNS messages

Noradrenaline contrictrs the pre-glomerular arteriole

25
Q

what does aldosterone do?

A

Aldosterone causes the tubules of the kidneys to increase the reabsorption of sodium and water into the blood. This increases the volume of fluid in the body, which also increases blood pressure.

26
Q

True or False:

ANP will act on the post-gromerular arteriole to dilate and increase the GFR

A

False.

ANP will act on the pre-glomerular arteriole to dilate and increase GFR

27
Q

True or False:

ANP also has an action on the collecting duct to inhibit the reabsorption of Na+

A

True

28
Q

Which tubular activity is bigger?

A

Reabsorption (200L down to 2L of urine)

29
Q

Where in the nephron is reabsorption the greatest?

A

proximal tubule

want to get the bulk processing done early

30
Q

What is the most important solute to be reabsorbed? Why?

A

Sodium

the reabsorbtion of sodium, so many other things won’t happen properly

31
Q

True or False

Na+ is reabsorbed by active transport

A

True

32
Q

When Na+ is moves across back into the ECF, what follows?

A

Anions (charge)

H20 (osmotic gradient created, follows) - through aquaporins

K+/Ca2+/urea start to get concentration in the tubule so they also cross

33
Q

What is cotransported out of the lumen with Na+?

A

Glucose

34
Q

Glucose appears in the diabetics urine because diabetes….

A

There’s a certain capacity on the amount of glucose that can be reabsorbed. Diabetic plasma exceeds the amount that can be reabsorbed.

35
Q

___% of the oxygen consumption by the kidney is due to sodium reabsorption.

A

80% of the oxygen consumption by the kidney is due to sodium reabsorption.

36
Q

Sodium balance:

Input is from ___

Output is mostly urine, but also ___ and ___

A

Sodium balance

Input is from diet

Output is mostly urine, but also faeces and skin

37
Q

There is a lag phase in terms of sodium balance due to…

A

There is a lag phase in terms of sodium balance due to the renin-angiotensin and aldosterone acting on the collecting duct

38
Q

Infusion of 1L of normal saline will cause a change in blood volume of:

A

3/4 of ECF is in the interstitial spaces

therefore 0.25L will increase in the plasma volume

39
Q

The body detects sodium balance through…

A

carotid baroreceptors

Renal arterial pressure receptors in the afferent arteriole

40
Q

Renin will be released when ___ is _____

Which is detected by:

A

Volume is Low:

which is detected by:

Fall in pressure at preoglomerular arteriole

Reduction in sodium chloride delivery to macula densa

SNS activation