Brainscape's Knowledge GenomeTM

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


See full index

PHSL233 > Lecture 8 - Absorptive and Secretory Epithelia > Flashcards

Lecture 8 - Absorptive and Secretory Epithelia Flashcards

1
Q

How is electroneutrality achieved in the absorption of Na+ and water?

A

Movement of Cl-

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

What type of process is Na+ coupled solute cotransport of SGLT1 and GLUT2?

A

Electrogenic process

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

What type of transport is the movement of glucose?

A

Active transport for glucose to get inside cell and then passive to get from inside cell to basolateral

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

What SGLT do we have in the early PT?

A

In the early prox. tubule SGLT2 re-absorbs 90% of the filtered glucose

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

What SGLT do we have in the late PT?

A

In the late prox. tubule SGLT1 is the main glucose
transporter

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

What are the common principles of Na+ coupled solute cotransport in the kidney? (e.g. glucose)

A
  • Secondary active (Na+ coupled) uptake through apical membrane (uphill)
  • Facilitated diffusion through basolateral membrane (downhill)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What type of osmotic absorption is Na+ coupled solute cotransport in leaky absorptive epithelium?

A

Isosmotic absorption

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

What type of osmotic absorption is Na+ transport in tight absorptive epithelium?

A

Hyperosmotic absorption

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

Glucose is
A. absorbed at the basolateral membrane in a sodium dependent manner.
B. absorbed entirely via facilitated diffusion.
C. secreted.
D. transported against its gradient at the apical membrane.

A

D. transported against its gradient at the apical membrane.

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

What are the electrical properties of secretory epithelia?

A

– leaky for water secretion
– tight (e.g. K+ secretion in cortical duct)

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

What is the ion transport (water secretion) in secretory epithelia?

A

– actively secrete Cl- ions
– Na+ and water follows passively
– secretion of isosmotic NaCl solution

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

What are the apical membrane properties (water secretion) of secretory epithelia?

A

High permeability to Cl- due to the presence of Cl channels
Cl- channels need to be activated to open

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

What is the driving force for Cl- exit through apical membranes?

A

Driving force is electrical gradient not concentration gradient

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

What are the two important epithelial Cl- channels?

A

cAMP-activated Cl- channel
Ca2+-activated Cl- channel (TMEM16A)

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

What is Ca2+-activated Cl- channel (TMEM16A) activated by?

A

Activated by an increase in intracellular Ca2+

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

What is TMEM16A?

A

Ca2+-activated Cl- channel

17
Q

What is CFTR?

A

Cystic Fibrosis Transmembrane conductance
Regulator (CFTR)

18
Q

What type of channel is CFTR?

A

cAMP-activated Cl- channel

19
Q

What channel is defective in cystic fibrosis?

A

Cystic Fibrosis Transmembrane conductance
Regulator (CFTR) - cAMP-activated Cl- channel

20
Q

What is the hydraulic conductivity of secretory epithelia?

A

– high
– secretion of isosmotic NaCl solution

21
Q

What is the hormonal/nervous control of secretory epithelia?

A
  • under precise control
  • low basal rates of secretion increased by nervous or hormonal control as required
22
Q

What are some examples of secretory epithelia?

A

Exocrine glands
– Sweat glands
– Salivary glands
– Pancreas
– Liver
Small & Large intestine
Respiratory epithelium
Reproductive tract
– Male - epididymis
– Female - vagina, uterus and fallopian tubes

23
Q

What is the physiological function of secretory epithelia in the GIT?

A

Gastrointestinal tract, both exocrine glands and intestinal epithelium
Secretion of enzymes for the digestion of food

24
Q

What is the physiological function of secretory epithelia in the respiratory epithelium?

A

Keep surface moistened to maintain mucociliary clearance

25
Q

What is the physiological function of secretory epithelia in the reproductive tract?

A

– Male - maturation of sperm
– Female - survival and fertilisation of gamete

26
Q

What is the physiological function of secretory epithelia in sweat glands?

A

Thermoregulation

27
Q

How do the two important types of epithelial Cl- channels differ?

A

How they are regulated differs, Changes in cAMP levels in cell vs changes in intracellular calcium

28
Q

What is NKCC?

A

Na+, K+, 2Cl- secondary active cotransporter
Cl– uptake against its electrochemical gradient

29
Q

What are the common functional concepts in absorptive and secretory epithelia?

A
  • Electrochemical gradients determine transport of charged solutes (e.g. ions)
  • ‘Two membranes’ (different transporters)
  • Combination of active (uphill) and passive (downhill) transport for each ion/solute to cross the epithelium.
30
Q

What are the active and passive transporters for Na+?

A

Active: Na/K-ATPase
Passive: ENaC

31
Q

What are the active and passive transporters for Cl-?

A

Active: NKCC
Passive: CFTR

32
Q

What are the active and passive transporters for Glucose?

A

Active: SGLT
Passive: GLUT

33
Q

Water secretion
A. takes only place in the kidney.
B. is mainly facilitated by chloride ions.
C. is mainly facilitated by sodium ions.
D. requires glucose absorption.

A

B. is mainly facilitated by chloride ions.

34
Q

What type of ion movement is impaired in cystic fibrosis?

A

Cl– secretion is impaired in cystic fibrosis

35
Q

Why do people with cystic fibrosis have viscous mucus in various organs?

A

No CFTR (mutation)
Cl- secretion decrease
water secretion decrease

36
Q

What is VIP?

A

VIP – vasoactive intestinal peptide (hormone) that activates Cl– secretion

PHSL233 (32 decks)

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