Brainscape's Knowledge GenomeTM

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


See full index

GI System > The Stomach > Flashcards

The Stomach Flashcards

1
Q

List 4 functions of the stomach

A
  • Temporary storage
  • Disinfection
  • Continue digestion, mainly proteins
  • Disruption of food via vigorous smooth muscle contraction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are 4 anatomical parts of the stomach

A
  • Cardia (Entrance to stomach, below LOS)
  • Fundus (Superior region)
  • Body (forms bulk of stomach)
  • Antrum (leads to Pyloric sphincter)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How does epithelia change from lower Oesophagus to stomach

A

Stratified squamous to simple columnar (for secretion)

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

What are 2 parts of the Lower Oesophageal Sphincter?

A

Inferior part: Intrinsic smooth muscle of stomach

Superior: Right Crus of Diaphragm

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

Other than LOS, describe a mechanism that prevents relfux

How are Rugae in the mucosa/ submucosa involved in this?

A

Receptive relaxation;
- Peristalsis causes reflex relaxation of proximal stomach, allowing Fundus to expand/ distend

  • When relaxed, folds called Rugae are present. These allow stomach to expand when needed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the layers of muscles in the stomach

What do these muscles do?

A

Innermost oblique
Inner circular
Outer longitudinal

Mechanical breakdown of food via forceful contractions

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

How does the shape of stomach influence movement of stomach contents

A
  • Larger fundus breaks down food into larger and smaller chunks
  • Smaller chunks accelerate and move faster towards Smaller Antrum

(This helps separate contents)

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

In the stomach the epithelia extend into the gastric pits/ glands

Name 4 of the cells found in these pits

A
  • Parietal
  • Chief (secrete pepsinogen)
  • Mucous
  • G cells (An enteroendocrine cell)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

List 4 secretions of the stomach

A
  • HCL
  • Intrinsic Factor
  • Pepsinogen
  • HCO3- in mucus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Why does the stomach need to be able to protect itself?

A

Designed to digest biological material so can digest itself

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

List and describe 4 methods of protection of the stomach

A
  • Mucin secreted by Surface Mucous Cells adheres to epithelia and prevents physical damage from food
  • HCO3 ions secreted into mucus layer to provides a pH neutral barrier against acid
  • Rich blood supply to gastric mucosa to remove and buffer acid that has breached mucus layer
  • High turnover of epithelial cells, so are replaced in only a few days
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Of the 4 methods of protection, which 3 are promoted/ sped up by the presence of Prostaglandins?

What drugs can reduce prostaglandin release

A
  • Mucin secretion by Surface Mucous/ Foveolar cells
  • HCO3 ion secretion into mucus
  • High blood flow to gastric mucosa
  • NSAIDS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Name 3 things that can break the stomach’s defences and state what they can cause?

A
  • Alcohol: Dissolves mucus layer
  • Helicobacter pylori: Chronic active gastritis
  • NSAIDS: Inhibit prostaglandin production
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which cells produce HCl in stomach?

List 8 stimulants for HCl production from these cells?

A

Parietal cells (by exchanging K+ for H+)

  • Gastrin
  • Histamine
  • ACh
  • Sensory triggers
  • Stomach stretch
  • Amino acid presence
  • Food taken in which acts as a buffer, raising pH
  • Chyme in duodenum (If continued, inhibits acid production)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How do Parietal Cells produce HCl?

A
  • Tubulovescicles (act as proton pumps, have no K+ permeability stimulated to move towards Canaliculi of Apical membrane
  • Apical membrane lined with microvilli and contains K+ channels
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

State the blood supply of the stomach

A

Blood supply- Coeliac trunk

Veinous drainage- Portal vein

17
Q

Identify the secretions from the;

  • Cardia
  • Fundus/ Body
  • Pylorus
A

Cardia: Mainly mucus

Fundus/ body: Mucus, HCl, Pepsinogen

Pylorus: Gastrin, Somatostatin

17
Q

Gastrin is secreted from G cells in the Antrum

List 4 stimulants of G cells

A
  • Amino acids/ peptides in stomach
  • Vagal stimulation
  • ACh
  • GRP (Gastrin releasing peptide)
19
Q

What does an Entero-Chromaffin Like cell release?

What are 2 things that stimulate it?

A
  • Produce histamine (Stimulates parietal cells)
  • Vagal stimulation via ACh
  • Gastrin via CCK receptor (Same family so can bind)
20
Q

Describe the Inhibition of HCl production (essentially G Cell inhibition)

A
  • Food leaves stomach-> pH drops-> Activates D cells
  • D cells release somatostatin-> Inhibiting G cells and ECL Cells
  • Reduced stomach distension due to reduced Vagal activity
21
Q

List the 3 Phases of Digestion

What percentage of total HCl production comes from each phase?

A
  • Cephalic, 30%
  • Gastric, 60%
  • Intestinal, 10%
22
Q

Describe the Cephalic phase of digestion

A
  • Parasympathetic stimuli (Smell/ taste/ chew/ swallow)
  • Vagus nerve directly stimulates parietal cells
  • Vagus nerve also stimulates G cells (GRP released)
23
Q

Describe the Gastric phase of digestion

A
  • Stomach distension stimulates vagus nerve-> G and Parietal cell simulation
  • Food acts as buffer in stomach removing inhibition on Gastrin production
24
Q

Describe the Intestinal phase of digestion

A
  • Chyme initially stimulates gastrin secretion as partially digested proteins are detected in duodenum
  • Shortly after, G cells inhibited
  • Lipid presence activates Enterogastric reflex, reducing Vagal stimulation
  • Chyme stimulates CCK and Secretin (Helps suppress secretion)
27
Q

Describe the chemical basis of how Parietal cells make HCl

A
  • Carbonic Anhydrase catalysts H2O + CO2-> H2CO3 which dissociates into H+ and HCO3-
  • HCO3- leaves cell through antiport, while Cl- enters cell through same channel.
  • H+ and Cl- leave Apical membrane via their own channels/ pumps and combine-> HCl
28
Q

What is the Alkaline Tide?

A

The increase in pH of veinous blood caused by HCO3- accumulation

29
Q

What are 3 receptors on a Parietal cell?

A
  • Gastrin receptors (Actually a CCK receptor but same family so gastrin can bind)
  • Histamine receptors
  • Muscarinic receptors
30
Q

What enzyme is needed to make HCl in the Parietal Cells, once Gastrin binds to a CCK receptor

A

H+/ K+ ATPase

GI System (26 decks)

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