Digestive system Flashcards Preview

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Flashcards in Digestive system Deck (52)
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1
Q

What are the 4 layers of the gut membrane?

A
  1. Mucosa
  2. Submucosa
  3. Muscularis externae
  4. Serosa (peritoneal membrane)
2
Q

What is the mucosa made up of?

A
  1. Epithelium
  2. Lamina propria
  3. Muscularis mucosae
3
Q

What is the lamina propria?

A

A connective tissue layer in the mucosa membrane which contains glands

4
Q

What is the composition of the submucosa?

A

A connective tissue layer containing glands, arteries, veins and nerves

5
Q

What 2 muscle types are found in the muscularis externa?

A

Longitudinal and circular

6
Q

What are the functions of the GI tract?

A

Mechanical and chemical digestion, food storage, kill pathogen, absorb nutrients, eliminate waste

7
Q

What does salvia contain?

A

Amylase, lipase, calcium, immunoglobulin A antibody

8
Q

What is the role of IgA in salvia?

A

It is bacteriostatic and so binds to bacteria, preventing them binding/entering the epithelium lining the GI tract

9
Q

What mechanical digestion occurs in the mouth?

A

Chewing by the teeth and movement by the tongue

10
Q

What is the transport that propels the bolus through the oesophagus

A

Peristaltic transport

11
Q

What is unusual about the gut wall in the oesophagus

A

It has no serosa

12
Q

What type of epithelium lines the oesophagus

A

Stratified squamous non keratinised

13
Q

What is the outer layer of the oesophagus if there is no serosa

A

A thin layer of connective tissue called the adventitia

14
Q

What mechanical digestion occurs in the stomach?

A

Churning

15
Q

What is different about the gut wall of the stomach?

A

Its muscularis externae has 3 layers (additional oblique smooth muscle)

16
Q

What is the folding in the stomach called?

A

Rugae

17
Q

Why can the stomach act as a food store?

A

It allows for receptive relaxation (wall relaxes preventing a rise in pressure)

18
Q

What is secreting into the lumen of the stomach?

A

Acid and enzymes

19
Q

What protects the lining of the stomach from the acid

A

Mucus

20
Q

What is chyme?

A

Partially digested food

21
Q

What is the Tonicity of the chyme?

A

Hypertonic as the food is broken down to lots of molecules, increasing the osmotic pressure

22
Q

What type of epithelium lines the stomach?

A

Simple columnar

23
Q

What can damage mucous secreting cells?

A

Alcohol and aspirin

24
Q

What is the role of parietal cells in gastric glands

A

Secrete hydrogen ions into the lumen to produce the HCL. Also produce bicarbonate ions into capillaries which moves to mucus cells to help make mucus

25
Q

What is the role of chief cells in the gastric glands

A

Secrete pepsinogens which are converted into Pepsins which hydrolyse proteins

26
Q

What is the role of enteroendocrine cells in gastric glands

A

Include G cell which secrete gastrin.

27
Q

What is the first section of the small intestine?

A

Duodenum

28
Q

What type of glands are found in the duodenum

A

Brunners glands

29
Q

What do brunners glands do

A

Secrete bicarbonate rich mucus to neutralise acidic chyme

30
Q

What happens to the Tonicity of the chyme in the duodenum

A

It becomes isotonic as water is drawn in to the chyme

31
Q

What is released into the duodenum

A

Bile, Alkali from the pancreas and liver and enzymes from the pancreas and liver.

32
Q

What does bile do?

A

Bile salts emulsified fats

33
Q

What does bile contain?

A

Water, Alkali and bile salts

34
Q

What is the second part of the small intestine?

A

Jejunum

35
Q

What are the extension in the jejunum called?

A

Plicae circulares

36
Q

What increases the surface area of the intestine?

A

Villi, micro villi, folding

37
Q

What type of epithelium lines the small intestine?

A

Simple columnar epithelium

38
Q

What is a lacteal and where is it found

A

Dilated Lymphatic vessel found in a microvilli

39
Q

What does the duodenum absorb?

A

Iron

40
Q

What does the jejunum absorb?

A

Sugars, amino acids and fatty acids

41
Q

What does the ileum absorb

A

Vitamin B12, bile acids and remaining nutrients

42
Q

What is the type of epithelia found in the large intestine

A

Simple columnar epithelium

43
Q

What is the role of the large intestine

A

Water recovery

44
Q

What is the uses of the bacteria in the colon?

A
  1. Synthesis vitamins K, B12, thiamine and riboflavine
  2. Breaks down primary bile acids to secondary
  3. Converts bilirubin to non pigmented metabolites
45
Q

What 3 mechanisms control the digestive system?

A

Neural, paracrine and endocrine

46
Q

Which 2 features are under the control of the somatic nervous system

A

Ingestion and excretion

47
Q

What post ganglionic neurones form plexuses in the GI tract

A

Submucosal plexus (between submucosa and muscularis externae) and myenteric plexus (between muscle layers)

48
Q

What substances are released for paracrine control of the GI tract?

A

Histamine (controls production of stomach acid) and vasoactive substances (affect blood flow)

49
Q

What gorges are released which are involved in the endocrine control of the GI tract?

A

Secretin, cholecystokinin, gastrin

50
Q

What is the role of secretin

A

Promotes bicarbonate secretion from cells in the pancreas. Promotes bile production in the liver. Inhibits secretion of acid by parietal cells

51
Q

What is the role of cholecystokinin (CCK)

A

Secreted by enteroendocrine cells
Release bile from gall bladder
Promotes release of digestive enzymes from pancreas

52
Q

What is the role of gastrin

A

Promotes HCl production by parietal cells