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Flashcards in S1) Purpose of the Gut Deck (26)
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1

Label the following components of the digestive system:

2

Identify the 8 functions of the gut

- Port of entry for food into the body

- Mechanically disrupt the food

- Temporarily store the food

- Chemically digest the food

- Kill pathogens in the food

- Move the food along the tract

- Absorb nutrients from the resultant solution

- Eliminate residual waste material 

3

Which areas of the GI tract mechanically disrupt food?

- Mouth/teeth

- Stomach (vigorous contractions cause the food to be liquefied – chyme)

4

Describe how the upper and lower areas of the stomach mechanically disrupt food

Upper area creates basal tone (slow/sustained contractions)

- Lower area has powerful peristaltic contractions that effectively grind food (thicker muscle layer distally)

5

Why must the GI tract temporarily store food?

We eat faster than we digest

6

How does the stomach act as a storage facility?

- Distension – accommodates entry of food

- Receptive relaxation – maintains intraluminal pressures

7

Explain how the colon also acts as a temporary store

Contents are only evacuated several times a day from the colon (mass movements) 

8

In which areas does chemical digestion occur?

- Oral cavity (saliva)

- Stomach

- Duodenum/jejunum

9

Which substances are used for digestion by saliva?

- Amylase (starch)

- Lipase (fats)

10

Which substances are used for digestion by the stomach?

- Acid

- Pepsin (protein)

11

Which substances/structures are used for digestion by the duodenum/jejunum?

- Bile

- Exocrine pancreas secretions

12

What are the challenges to the GI's ability to kill pathogens?

- Thin epithelia

- Large surface area

13

What are the defences of the GI tract to pathogens?

- Saliva

- HCl

- Liver (kupffer cells)

- Peyers patches (immune surveillance)

I. Lymphoid follicles

II. Submucosa/mucosa (terminal ileum)

14

Different regions in the GI tract used different types of movement to move food along.

Identify them

- Peristalsis

- Segmentation

- Haustral shuttling

- Mass movements 

15

What type of muscle is found in the bowel?

- Small amounts of skeletal muscle

- Mainly smooth muscle 

16

What does the gut absorb?

- Digested food + secretions

- Fluids (fluid balance of the gut)

 

17

Which structural features of the gut aid absorption?

- Length of gut

- Folds

- Villi/microvilli 

18

Describe, briefly, how residual waste is eliminated from the colon by mass movement 

- Colon acts as temporary storage site, so the rectum is normally empty

- Internal/external anal sphincter open and residual waste is egested via the gastrocolic reflex 

19

What is the broad function of the mouth?

- Physical breakdown of food

- Initial digestive enzymes released

- Infection control 

20

Identify 3 functions of the oesophagus

- Rapid transport of bolus to stomach through thorax

- Upper oesophageal sphincter prevents air from entering GI tract

- Lower oesophageal sphincter prevents reflux into oesophagus 

21

Identify 4 functions of the stomach

- Storage facility

- Produces chyme (physical and chemical digestion)

- Infection control (HCl)

- Secretes intrinsic factor (Vit B12

22

Identify 2 functions of the duodenum

- Neutralisation/osmotic stabilisation of chyme (HCO3 rich secretions)

- Concluding digestion: pancreatic secretions and bile 

23

Identify 2 functions of the jejunum

- Final point of digestion

- Nutrient absorption 

 

24

Identify 3 functions of the ileum

- Water/electrolyte absorption 

- Bile recirculation

- B12 absorption (terminal ileum)

25

Identify 2 functions of the colon

- Final water absorption

- Final electrolyte absorption 

26

What is the main function of the rectum/anus?

Defaecation