Brainscape's Knowledge GenomeTM

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


See full index

Alimentary > S1: Introduction to the Control of the Alimentary Tract > Flashcards

S1: Introduction to the Control of the Alimentary Tract Flashcards

1
Q

What ANS innervates the GI system?

Name 2 main supplies

A

The extrinsic parasympathetic : vagal
The sympathetic: splanchnic
Intrinsic enteric NS

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

Role of sympathetic and parasympathetic nervous system in the GI tract

A

Sympathetic:

  • inhibits digestive activity
  • stimulates glucose release by liver

Parasympathetic:

  • stimulates digestive activity
  • relaxes rectum
  • stimulates gallbladder
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What neurotransmitter causes ascending contraction of GI tract?

A

Acetylcholine is involved in smooth muscle contraction

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

What neurotransmitters cause descending relaxation of GI tract?

A

VIP and NO

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

What fibre links the gut muscle and mucosa to the brain?

A

Afferent vagus fibre

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

What links brain to ENS?

A

Vagus efferent fibre

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

What links the gut muscle and mucosa to the spinal cord?

A

Splanchnic fibres

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

What volume does an empty stomach have compared to accommodation?

A

50ml when resting

1.5L upon receptive relaxation of fundus and body of the stomach

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

What happens to the pyloric sphincter upon the arrival of a peristaltic eve?

A

The sphincter closes

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

Name the 4 types is factors controlling the GI tract

A

Endocrine
Paracrine
Neural (vago-vagal reflex, enteric/local reflex)
Metabolic

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

What type of hormones are produced by the GI tract?

A

Peptides

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

What produces gastrin?

A

The atrium of the stomach which has a thick muscle wall important for contractions

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

What is the site of action of gastrin?

A

The gastrin acts on the body of the stomach (thinner muscle layer).

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

Where is the fundus and it’s function?

A

It is the top bit of the stomach.
This acts as a pacemaker zone as the cells can spontaneously depolarise and produce pacemaker potentials. It therefore initiated peristalsis.

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

List the gastrin mediated effects

A
  • Gastrin released from G cells when stimulates from a neurone releasing GRP (gastrin releasing peptide)
  • G cells travels in the blood circulation and binds to ECL
  • The ECL then releases histamine
  • Histamine acts on H2 receptors on parietal cells stimulating the release of HCl

Gastrin can also have a direct effect in parietal cells stimulating release of HCl.

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

What cells release HCl?

A

Parietal Cells

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

What cells release Gastrin?

A

G cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What stimulates G cells?

A

Gastrin releasing peptide (GRP) is released when stimulated by a parasympathetic neurone

19
Q

What is the ECL?

A

A neuroendocrine cell found in the gastric glands and gastric mucosa
(Enterochromaffin)

20
Q

What stimulates ECL?

A
  1. GRP binding to ECL

2. ECL cells can be stimulated by acetyl choline released from neurones

21
Q

What three things stimulate HCl release?

A
  1. Gastrin mediated effects
    G cells - GRP- ECL- Histamine- H2 receptor - Parietal cells
  2. Gastrin having a direct effect on parietal cells
  3. Acetylcholine acting directly in parietal cells
22
Q

Where do hormones (endocrine) travel?

A

They go to target tissue via blood

23
Q

Where do Paracrine agents travel?

A

They travel via the interstitial fluid

24
Q

Mechanism of somatostatin on G cells

A

Presence of H+ will mean they bind to D cells.
This stimulates D cells to release somatostatin which binds to G cells
This inhibits Gastrin release and controls the acid production if the stomach

25
Q

What cells release somatostatin?

A

D cells

26
Q

What does the afferent vagus innervate?

A

Lower oesophagus
Fundic region
Duodenal area

27
Q

What is the vago-vagal reflex?

A

A reflex in which afferent (sensory) and efferent (motor) axons are in the vagus trunk

Vagal afferents from the gut enter the medulla and synapse at the NTS (nucleus tractus solitaries) . There is then processing of this information and vagal efferents originate and leave the medulla at the DMVN (dorsal motor vagal nucleus)

28
Q

What pathway does the vagus nerve trunk take?

A

The pathway is via the brain stem (medulla)

29
Q

What are the functions of the vago-vagal reflex?

A

Controls contraction of GI muscle layers in response to distension of tract by food

Allows accommodation of large amounts of food in GI

30
Q

What neurotransmitter does the short post-ganglionic vagal nerve release?

A

Acetylcholine which affects secretion and motility of the gut

31
Q

Which 2 nerve plexus are intrinsic to the gut?

A
  1. Myenteric plexus

2. Submucosal plexus

32
Q

Function of Myenteric plexus

A

Controls motor function

33
Q

Function of submucosal plexus

A

Control intestinal secretions

34
Q

The myenteric plexus and submucosal plexus are connected to the CNS by parasympathetic and sympathetic fibres?
What happens if they are disconnected?

A

They are able to function autonomously without these connections

35
Q

What nervous system (specific subdivision!) mediated the myenteric plexus and submucosal plexus?

A

The enteric nervous system which is a part of the ANS

36
Q

What is the most prominent plexus of the GI tract?

A

Myenteric plexus

37
Q

What does the cholinergic innervation of the myenteric plexus do?

A

It increases gastric motility and secretion

Parasympathetic system - ‘rest and digest’ therefore increases GI activity

38
Q

What does the adrenergic innervation of the myenteric plexus do?

A

It will decrease gastric motility and secretion

39
Q

What does the rate of emptying depend on?

A

The materials ability to be absorbed

40
Q

What type of food is quickest and slowest to be emptied into the duodenum?

A

Carbohydrates are emptied quickly into the duodenum
Proteins are slower emptying
Fatty acids are the slowest

41
Q

How does fatty acids in the duodenum cause decrease in gastric emptying?

A

It increases the contractility of the pyloric sphincter.

The pyloric sphincter is usually open so increasing the contractility keeps it closed more often

42
Q

Is peristalsis slower in the large intestine or small intestine?

A

It is slower in the large intestine

43
Q

What controls movement of peristalsis?

A

Vagal inhibitory and excitatory fibres

44
Q

What is the purpose of peristalsis?

A

The wave of propulsive contraction nice content of the gut towards the anus

Alimentary (18 decks)

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