Brainscape's Knowledge GenomeTM

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


See full index

NME > Salt and Water Transport in the GI Tract > Flashcards

Salt and Water Transport in the GI Tract Flashcards

1
Q

Osmolality

A

concentration of dissolved particles of chemicals and minerals within a solution

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

Hypertonic solution

A

a solution with osmolality is more than that of plasma
water moves in

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

hypotonic solution

A

a solution with osmolality less than that of the plasma
water leaves the solution

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

Purpose of regulation of water and electrolyte transport mechanisms

A

1) a medium for digestion and waste elimination in the
lumen
2) a replacement of daily loss of body fluids in sweat,
urine, lungs and faeces

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

Regulation of water and electrolyte transport mechanisms:

A
  • gut lumen
  • enteric nervous system
  • autonomic neural mechanisms
  • hormonal and immunogenic signs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Regulation of water and electrolyte transport mechanisms:

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

Disruption to absorption leads to

A

secretory diarrhoea, potential for dehydration and electrolyte imbalance

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

Electrolytes table

A

Na+, K+, Cl-

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

Water moves down an osmotic gradient

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

Movement of ions require membrane proteins

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

Principles of enterocytes transport: adaptations of gut lumen:

A
  • polarised with an apical and basolateral membrane
  • tight junction sprovide a barrier to free flow of gut
    lumen contents, although these tight junctions are
    more permeable in proximal small intestine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Tonicity definition

A

measure of the osmotic pressure gradient (i.e. concentration of a solution)

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

Tonicity of chyme entering the duodenum affects

A

bidirectional fluid flux

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

principles of enterocyte transport: 2 routes:

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

Principles of enterocyte transport: transcellular routes:

A

transcellular absorption may be against the conc grad and requires ATP

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

Principles of enterocyte transport: paracellular routes:

A

do not require additional external energy

17
Q

Principles of enterocyte transport: transcellular and paracellular routes:

A

para = between cells, no energy

18
Q

Types of enterocyte transport (3):

A
  • passive
  • solvent drag
  • active
19
Q

Types of enterocyte transport: passive:

A

down an electrochemical gradient through ion channels or carriers or permeable tight junctions

20
Q

Types of enterocyte transport: solvent drag:

A

water moves to reach osmotic equilibrium and takes ion (i.e. proximal small intestine, where tight junctions are more permeable)

PARACELLULAR ROUTE

21
Q

Types of enterocyte transport: active:

A

requiring ATP
- Na+/K+ ATPase pump depletes cellular Na+ and
draws K+ across apical membrane via channel and
cotransporter

22
Q

What type of enterocyte transport is depicted below?

A

solvent drag: paracellular route

23
Q

Differences between enterocytes in crypts and villi:

A
  • villi: enterocytes are absorptive and dominate
    nutrient transport
  • crypts: enterocytes are secretory with minimal
    nutrient transport
24
Q

Villi enterocytes and crypt enterocytes

A
25
Q

Which of the following structures are absent in the large intestine?

  • villus
  • crypts
A

villus

26
Q

Why do villus and crypt enterocytes have different functions?

A

the enterocytes express different combinations of transport proteins

27
Q

What does the small intestine contain?

A

water and key electrolytes Na+, K+, Cl- and HCO3- from ingested food and secretions of the GI Tract.

28
Q

How is isotonic chyme formed?

A

the duodenum acts to rapidly equilibrate the osmotic potential of the chyme through the movement of water, Na+, Cl- through permeable tight junctions using the solvent drag mechanism

29
Q

What is reabsorbed in the jejunum?

A

Na+, K+, Cl-, H2O

30
Q

What is secreted in the ileum?

A

HCO3-

31
Q

What does the large intestine reabsorb?

A

Na+, Cl-, H2O

32
Q

What does the large intestine secrete?

A

K+, HCO3-

33
Q

Na+ absorption in the small intestine

A
  • drives absorption of other ions and organics
  • driven by basolateral active transport of Na+ via
    Na+/K+ ATPase pump into the interstitial fluid which
    creates an electrochemical gradient (basolateral side)
    ( 3 Na+ out, 2 K+ in)
  • secondary active transport occurs at apical carrier
    proteins for Na+ absorption (re) (Na+ in down conc
    grad, Cl- against but no ATP)(Na+ in down conc grad,
    H+ in against but not ATP)
34
Q

Cl- absorption (2 ways)

A
  • in the jejunum, Na+ absorption with nutrients is
    electrochemical and leads to net negative charge in
    the lumen and net positive charge in the paracellular
    spaces
  • this provides an electrochemical gradient for Cl-
    absorption (symporter of Na+, Cl- (Na+ down))???
  • in the jejunum and distal ileum Cl- absorption occurs
    passively through the apical membrane Cl- ion
    channels and in exchange for HCO3- (hence secreted)
35
Q

NaCl absorption in the large intestine

A
  • driven NA+/K+ ATPase pump
  • Sodium entry by:
    • f.d Na+ channels
    • diffusion under aldosterone control; increases Na=
      channels and absorption at the expense of K+
  • K+ secretion when lumen conc low
  • Cl-/HCO3- provide buffer for acid produced by
    bacteria and moves Cl-
  • tight junctions ensure no ion backflow; less
    permeable than in proximal duodenum
36
Q

Absorption of water

A
  • totally dependent on the absorption of solutes,
    especially Na+
  • Na+/K+ ATPase pumps lead to a build up of NaCl in
    the paracellular spaces between enterocytes
  • osmotic gradient draws H2O into enterocytes and the
    paracellular spaces
37
Q

Water moves to reach osmotic equilibrium and takes ions along with it. What is this process called?

A

solvent drag

38
Q

What is the primary function of crypts of Lieberkhun?

  • excretory
  • absorptive
  • secretory
  • facilitative
A

secretory

39
Q

Na+/glucose symporter is an example of:
- diffusion
- primary active transport
- secondary active transport
- osmosis

A

secondary active transport

NME (52 decks)

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