Brainscape's Knowledge GenomeTM

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


See full index

I've got kidney disease > Lecture 8: Epithelia 2 > Flashcards

Lecture 8: Epithelia 2 Flashcards

1
Q

What happens if Na+/K+ ATPase is damaged?

A

from eg. no O2

We can’t make ATP and so some basic functional processes are broken down

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

What are the two mechanisms for apical membrane transport for Na+ in leaky absorptive epithelia?

A
  • Na+ coupled cotransport

- Na+ coupled counter-transport

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

Na+ coupled counter transport is an example of what type of transport?

A

secondary active transport

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

Give an example of an Na+ coupled counter transport and describe how it works

A

Na+/H+ exchanger

this is in the apical membrane and it uses the energy from the gradient pushing Na+ into the cell to pump H+

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

What is the main mechanism for apical membrane transport of Na+ in tight absorptive epithelia?
Is this a passive or active process? Why?

A

channels

this is a passive process because they are using their gradient to be transported in a certain direction

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

Give an example of a channel that facilitates Na+ transport in tight absorptive epithelia and describe how it works

A

ENaC

This uses Na+ electrochemical gradient to passively get it into the cell.

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

Is the transport of Na+ into the tight absorptive epithelia via ENaC an electrogenic or an electroneutral process?

A

electrogenic

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

What can block ENaC and what cannot?

A

amiloride blocks it and TTX does not

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

How many subunits does ENaC have and what are these called?

A

3 subunits:
α ENaC subunit
β ENaC subunit
γ ENaC subunit

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

Where can you find a good summary of Na+ transport across the apical membrane?

A

slide 38

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

Tight absorptive epithelia express what?

A

ENaC

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

The transport of ions is linked to the transport of what?

A

water

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

What is the driving force for the movement of water in the body?

A

osmosis

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

Absorptive epithelia absorb Na+ and _________

A

water

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

Na+ can enter the cell via which two things?

A

channels or transporters

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

Describe the Na+/glucose cotransport in leaky absorptive epithelia and how it leads to the movement of water across the membrane

A

On the apical membrane, there is the Na+/glucose cotransporter (SGLT1) which brings glucose into the cell. Glucose is pumped out of the cell on the basolateral membrane via a transporter (GLUT2). Na+ is pumped out of the cell actively via the Na+/K+ ATPase in basolateral membrane. K+ in being brought into the cell in this exchange and so it is removed passively via a channel in the basolateral membrane.
Na+ is now in the interstitial fluid and Cl- follows paracellularly to maintain charge neutrality and water follows

17
Q

Is glucose being brought in via the Na+/glucose co-transporter an electrogenic or electroneutral process?

A

electrogenic

18
Q

In the early proximal tubule ________ reabsorbs 90% of the filtered glucose, whereas in the late proximal tubule ________ is the main glucose transporter

A

SGLT2

SGLT1

19
Q

Describe the Na+ transport in tight absorptive epithelia and how it leads to the movement of water across the membrane

A

Na+ passively enters the cell on the apical surface and then it is pumped out of the basolateral membrane into the interstitial fluid by Na+/K+ ATPase in basolateral membrane. K+ in being brought into the cell in this exchange and so it is removed passively via a channel in the basolateral membrane.
Na+ is now in the interstitial fluid and Cl- follows paracellularly to maintain charge neutrality and water follows

20
Q

Glucose is transported against its gradient at the ________ membrane

A

apical

21
Q

What is the difference between absorb and secrete?

A

absorbing is taking it up whereas secreting is producing it and discharging it

22
Q

What are the electrical properties of secretory epithelia?

A
  • leaky for water secretion

- tight

23
Q

Secretory epithelia actively secrete ________ ions and then Na+ and _________ follow passively which leads to a secretion of what?

A

Cl-
water
NaCl solution

24
Q

The apical membrane has a high permeability to Cl- due to the presence of Cl- ___________

A

channels

25
Q

Why does Cl- exit through the channels across the apical membrane, even though this is against its concentration gradient?

A

because the inside of the cell is negatively charged and the electrical gradient pushes it out of the cell

26
Q

What are the two important types of Cl- channels? Give an example of each

A
  • cAMP-activated Cl- channel eg. CFTR

- Ca2+ activated channel (TMEM16A)

27
Q

Ca2+ activated Cl- channels are activated by what?

A

an increase in intracellular Ca2+

28
Q

Is the hydraulic conductivity high or low in secretory epithelia?

A

high

29
Q

Describe the hormonal/nervous control of secretory epithelia

this is under ________ control
there is a _______ basal rate of secretion that are _______ by __________ or ___________ control as recovered

A

this is under precise control

there is a low basal rate of secretion that are increased by nervous or hormonal control as recovered

30
Q

What is the physiological function of the secretory respiratory epithelia?

A

to keep the surface moistened to maintain mucociliary clearance

31
Q

________ secretion drives water secretion

A

Cl-

32
Q

Describe the Cl- secretion

A

NKCC in the basolateral membrane uses the energy from the Na+ gradient to take Na+, a K+ and 2 Cl- into the cell. Na+ is pumped out of the cell via Na+/K+ ATPase in the basolateral membrane. K+ passively leaves the cell via the K+ leak channel in the basolateral membrane.
Cl- is driven out of the cell because of its electrical gradient through a channel on the apical membrane. Na+ follows paracellularly and water follows

33
Q

What determines the transport of ions?

A

electrochemical gradients

34
Q

Water secretion is mainly facilitated by which ion?

A

Cl-

35
Q

What is impaired during cystic fibrosis?

A

Cl- secretion

36
Q

Describe how cystic fibrosis impairs Cl- secretion and what effect that has

A

Due to a mutation, CFTR is not working properly and so there is decreased Cl- secretion via the apical membrane and therefore there is reduced water secretion so the mucus is too thick in various organs

I've got kidney disease (43 decks)

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