Brainscape's Knowledge GenomeTM

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


See full index

HUBS192 > 24 > Flashcards

24 Flashcards

1
Q

Functions of GI tract

A

Obtain nutrients required for
• Growth
• Energy needs

Replace fluid and salts lost
• In urine & faeces
• Sweating
• Breathing

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

The enteric nervous system can act independently of the central and
autonomic nervous systems : True or False?

A

True

  • own pace maker cells
  • ability to regulate itself
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How Conditions in intestinal lumen are regulated

A

Receptors in the wall of GI tract
- Respond to
- Stretch – food in the lumen
- Change in composition
- pH, osmolarity, amino acids, sugars, fats

Effectors are smooth muscle and glands
- Reflexes stimulated by receptors stimulate
- Smooth muscle contraction
- Gland secretion

Nervous and hormonal regulation of GI function

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

Nervous regulation oof GI function - Central Nervous system

A

Coordinates activity over long distances

  • parasympathetic nervous system
    • stimulates motility and secretion
  • sympathetic nervous system
    • inhibits motility and secretion

!modulates activity of enteric nervous system!
- no direct innervation of parasympathetic and sympathetic

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

Submucosal plexus - regulates secretion (little bit of absorbtion )
Myenteric plexus - regulates motility

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

Regulation of GI function - enteric nervous system ENS

A
  • submucosal plexus - regulation of secretion
  • myenteric plexus - regulation of motility

Involved in local reflexes
Totally self contained

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Regulation of GI Function - Hormonal regulation

A

GI tract largest endocrine organ in body
- Endocrine and paracrine functions

Sensor cells are called enteroendocrine cells: (censors r on their microvili)
- they are Epithelial cells pretty much that :
- Detect luminal content
- Release hormones (on base) - target cells at a large distance — also can affect next door epithelial cells - PARACRINE EFFECT

Critical hormones:
- Gastrin
- Gastric inhibitory peptide (GIP)
- Secretin
- Cholecystokinin (CCK)

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

 Which of the following best describes peristalsis?
A. Contraction of circular muscle ahead of food, relaxation of
circular muscle behind food and contraction of longitudinal muscle.
B. Relaxation of circular muscle ahead of food, contraction of
circular muscle behind food and contraction of longitudinal muscle.
C. Contraction of circular muscle ahead of food, relaxation of
circular muscle behind food and relaxation of longitudinal muscle.
D. Relaxation of circular muscle ahead of food, contraction of
circular muscle behind food and relaxation of longitudinal muscle.

A

B

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

Motility in the GI tract - tonic contratctuions definition

A

Tonic contractions - sustained contractions for minutes to hours (e.g. sphincters)

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

Motility in the GI tract- phasic contractions

A
  • waves of contraction and relaxation, each wave lasting seconds (e.g perisralsis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Motility / motility pattern =

A

any pattern of contraction or relaxation
of GI tract smooth muscle.

  • some motility patters are a combination of two or more simpler patterns (e.g retropulsion )
  • sometimes relaxation can be motility pattern (e.g storage in the stomach)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

 Movement / Propulsion =

A

motility patterns that specifically move / propel GI contents along the tract.

17
Q

What type of muscle in the GI

A

Smooth muscle

18
Q

Properties of smooth muscle in GI motility

A
  • spontaneously active
    • contracts without external input
    • contains pacemaker cells
  • frequency of contraction is a property of the GI region
    • stomach 3 per min
    • duodenum 12 peer min
    • ileum 9 per min
  • strength of contraction regulated by nervous and hormonal input
19
Q

Generalised motility patters - fasting

A

MIGRATING MOTOR COMPLEX:
- 4h after a meal
- repeats every 2h until eat again
- house keeping - helps clears undigested material

20
Q

Generalised motility patterns - FEEDING

A
  • storage
    • stomach and colon
    • relaxation of smooth muscle allows volume to increase without change in pressure (example of relaxation being a motility pattern)
  • propulsion / movement
    • esophagous, stomach, small and large intestine
    • perisgtalsis
  • mixing
    • stomach
      • retropulsion
    • small and large intestine
      • segmentation
21
Q
A
22
Q
A

Yes

23
Q

Chewing and swallowing

A

Chewing
 Reduce size of food
 Allows ingestion, reduces size  Mixes with saliva – taste  Voluntary – skeletal muscle  Reflex control of strength, frequency / rhythm

Swallowing
 Rapid transfer of material from mouth to stomach
 Initiated at will, proceeds reflexivel

24
Q

Gastric motility functions:

A
  1. Storage
    - fundus and body of stomach
  2. Mechanical digestion
    - antrum
  3. Mixing
    - antrum
  4. Controlled delivery to duodenum
    - pyloric sphincter
25
Q

Fasting gastric motility

A

Stomach shrinks to ≈ 50 ml in volume

Migrating motor complex:
- Occurs 4 h after a meal
- Continues until eat
- 2 h of inactivity
- 50 min uncoordinated activity
- 10 min coordinated activity

Functions:
- House keeping
- Removes residual secretions
- Removes undigested material
- Promotes epithelial cell turnover

26
Q

Feeding gastric motility I

A

Storage
- Receptive relaxation & gastric accommodation
- Nervous regulation - vagus nerve
- Increase in volume with minimal change in pressure
- Fundus and body
Propulsion / Movement
- Peristalsis
- Initiated on greater curvature & spreads to antrum
- 3 contractions per min
- First 60 min following meal gentle
- 60 - 300 min more intense activity

27
Q

Pressure in stomach gets maintained a little bit higher / lower then eosophagous

A

Lower
- stops acidic chyme from refluxing back up esophagous

28
Q

Gastric acomindaytin

A
  • when stomach stetches it activates receptors
  • sends a message up to the CNS\
  • starts relaxing rugae
  • and u get more volume
  • so u dont change pressi=ur
29
Q

Feeding gastric motility II - mixing and breakdown

A
  • Mixing and mechanical breakdown
  • Retropulsion
  • Combination of peristalsis and closure of the pyloric sphincter
30
Q

Gastric emptying - result of motility

A
  • combination of peristalsis and periodic opening/relaxation of the pyloric sphincter
  • rate matches digestive capacity of intestines
  • regulated by feedback from duodenum (receptors)
  • factors affecting gastric emtyping … ?
31
Q

Factors affecting gastric emptying

A
  • Size of meal - larger the meal faster the emptying
  • Composition of meal
    • Fluids faster than solids
      • Related to role of stomach in digestion
        -Reduction in size of food particles, increase in surface
        area of food
    • Fats slow gastric emptying
      - Fats difficult to digest and need support of bile salts
    • Acids slow gastric emptying
      - Need to neutralize
32
Q
A
33
Q

Function of small intestine motility

A
  • Mixing with secretions from pancreas, biliary system (liver/gallbladder) and intestine
  • Controlled movement / propulsion
  • Exposure of products of digestion to absorptive surfaces
34
Q

Small intestinal motility patterns

A
  • Motility patterns
    • Between meals
      • Migrating motor complex
  • After meal
    • The main motility pattern - Segmentation for mixing and
      exposure to absorptive surfaces
      - Contributes to movement also
    • Some - peristalsis for propulsion
35
Q

Colonic or large intestinal motility - functions

A
  • Storage of faeces
36
Q

Colonic or large intestinal motility

A
  • large periods of inactivity
  • Segmentation
    • Exposure to absorptive surfaces
    • Absorption of fluid and salt from faeces
  • Mass movement (propulsion)
    • 1-2 time a day following meals
    • Peristaltic wave
      • Drives faeces into rectum
      • Initiates defecation
37
Q
A

Yes

38
Q
A

Uighur

HUBS192 (39 decks)

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