Digestive System Flashcards Preview

Body Logistics > Digestive System > Flashcards

Flashcards in Digestive System Deck (33)
Loading flashcards...
1

What are the four layers of the gut?

Mucosa, submucosa, external muscle layers, serosa

2

What are the three layers of the mucosa?

Epithelia, Lamina propria, muscularis mucosae

3

What is the submucosa?

A layer of connective tissue bearing glands, arteries, veins and nerves

4

What are the major functions of the gastrointestinal tract?

mechanically disrupt, temporarily store, chemically digest food
Kill pathogens in food, move food, absorb nutrients and eliminate waste

5

What is digestion?

The conversion of what we wet by physical and chemical disruption into a solution from which we can absorb our nutrients

6

What is saliva used for?

Starts digestion with amylase and lipase
Bacteriostatic, high in calcium, alkaline, assists swallowing, protects mouth

7

What does the mouth do to food?

By using teeth, tongue and saliva's enzymes forms a bolus

8

How does the oesophagus move food?

Rapid Peristaltic transport

9

What is the Muscularis externa?

smooth muscle layers which move food by peristalsis

10

What is the Adventitia?

Thin outermost layer of connective tissue

11

How does the stomach physically and chemically disrupt food?

Physically- By churning with the three muscle layers
Chemically- By acid and enzymes

12

What does the stomach do?

Store, initial disruption and disinfection

13

How does the stomach protect itself from the acid?

Secretes mucus which contains HCO3- which neutralise the stomach

14

What is Rugae?

Folds of gastric mucosa forming longitudinal ridges in empty stomach

15

What can damage mucus cells in the stomach?

Alcohol and aspirin

16

What is the duodenum?

Connects the liver and pancreas
Dilutes and neutralises chyme
Draws in water to make chyme isotonic otherwise would damage the liver

17

What do enzymes do from the pancreas and intestine?

Cleave peptides to amino acids
cleave polysaccharides to monosaccharides
Break down and re-form lipids
Break down nucleic acids

18

What does absorption require?

Lots of energy, large surface area, good blood supply

19

What are the three parts of the small intestine?

Duodenum- absorbs iron
Jejunum- absorbs most sugars, aa and fatty acids
Ileum- absorbs vitamin B12, bile acids and remain nutrients

20

What does the large intestine do?

continues water recovery so by the end is semi-solid

21

What does the bacteria in the large intestine do?

syntheisie vitamin K, B12, thiamine and riboflavine, breaks down 1 to 2 bile acids, converts bilirubin into non-pigmented metabolites

22

Where contains most bacteria in the GI tract?

Colon

23

How much food is converted not faeces?

1kg into 0.15kg of faeces via 14 litres of fluid

24

What is the problem with fluid balance?

delicate balance and gut is dealing with large quantities

25

How is the fluid balance controlled?

Neural, Paracrine and Endocrine systems

26

How is the fluid balance controlled neurally?

Somatic- ingestion and excretion
Autonomic- gut nervous system, neurotransmitters, post ganglion neurones

27

How is the fluid balance controlled by the paracrine system?

Substances act locally e.g. histamine (production of acid control) and Vasoactive substances(blood flow to gut control)

28

How is the fluid balance controlled by the endocrine system?

Range of hormones control the secretion of acid, alkali and enzymes
These are Secretin, Cholecystokinin and Gastrin

29

What does secretin do?

Promotes HCO3- secretion from duct cells of pancreas
Promotes bile production by the liver
inhibits secretion of acid by parietal cells of stomach

30

What does cholecystokinin do?

Promotes release of digestive enzymes from the pancreas
Promotes relase