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ESA 3 - Gastrointestinal System > Overview of Gastrointestinal Function > Flashcards

Flashcards in Overview of Gastrointestinal Function Deck (99)
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1

What do metabolic processes need? 

A specific range of small molecule

2

What does food have? 

A wide range of mostly large molecules

3

What is the problem with food? 

The large molecules are locked into complex structures

It may be contaminated with pathogens

4

What does digestion do to food? 

Makes it into a sterile, neutral, and isotonic solution of small sugars, amino acids and small peptides, small particles of lipids, and other small molecules

5

What can happen once food has been digested? 

It is now ready for absorption and excretion 

6

Give the processes that occur in the GI tract, from eating food to excreting it

  1. Initial physical disruption 
  2. Ingestion and transport to storage
  3. Initial chemic disruption and creation of suspension (Chyme)
  4. Disinfection
  5. Controlled release of Chyme
  6. Diluration and neutralisation 
  7. Completion of chemical breakdown
  8. Absorption of nutrients and electrolytes
  9. Final absorption of water and electrolytes
  10. Producing faeces for controlled excretion

7

What are the regions of the GI tract? 

  • Mouth and Oesophagus
  • Stomach
  • Duodenum 
  • Small intestine 
  • Large intestine 
  • Rectum

8

What are the functions of the mouth and oesophagus? 

  • Mastication
  • Saliva
  • Swallowing

9

What is the purpose of saliva? 

  • Protects mouth
  • Lubricates food for mastication and swallowing
  • Starts digestion

10

How does saliva protect the mouth? 

  • Wets
  • Bacteriostatic
  • Alkaline
  • High Ca2+

11

How does saliva lubricate food? 

  • Wet
  • Mucus

12

What does the saliva digest?

Sugars

13

What is the function of the mouth and oesophagus in swallowing? 

  • Formation of bolus
  • Rapid oesophageal transport

14

What is the function of the stomach? 

  • Storage
  • Initial disruption 
  • Delivers Chyme slowly into duodenum 

15

How does the stomach acheive it's storage function? 

It relaxes to accommodate food 

16

How does the stomach acheive initial disruption? 

  • Contracts rhythmically to mix and disrupt
  • Secretes acid and proteolytic enzymes to break down tissues and disinfect 

17

What happens once stomach has performed initial disruption of food? 

The food is now called Chyme 

18

What is the function of the duodenum? 

Dilation and neutralisation of Chyme 

19

How does the duodenum dilate and neutralise Chyme? 

  • Water drawn in from ECF. The stomach is impermeable, the duodenum is permeable 
  • Alkali (bile) added from liver and pancreas
  • Enzymes added from pancreas and intestine

20

What is the function of the small intestine? 

  • Absorption of nutrients and electrolytes
  • Absorbs the majority of water 

21

How does the small intestine absorb nutrients and electrolytes?

  • Fluid passes very slowly through the small intestine
  • Large surface area
  • Epithelial cells absorb molecules 
  • Pass into hepatic portal circulation

22

How do epithelial cells absorb molecules?

Some actively, some passive

Often coupled to Natransport

23

How much water does the small intestine absorbed?

Compare to large intestine 

1.5L

Compared to 0.15L in large intestine

24

What is the function of the large intestine? 

  • Final absorption of water
  • Faeces form and accumulate 

25

How fast is transit in the large intestine? 

Very slow

26

Where does faeces form and accumulate in the large intestine? 

In the descending and sigmoid colon

27

What happens to faeces after formation and accumulation in the large intestines? 

It is propelled periodically into the rectum

28

What happens once the faeces has been propelled into the rectum? 

You get the urge to defecate, and there is controlled relaxation of sphincters and expulsion of faeces

29

Label this diagram of the alimentary canal

  • A - Salivary glands
    • ai - Parotid
    • aii - Submandibular
    • aiii - Sublingual 
  • B - Oral cavity
  • C- Pharynx
  • D - Tounge 
  • E - Oesophagus
  • F - Pancreas 
  • G - Stomach
  • H - Pancreatic duct
  • I - Ileum (small intestine)
  • J - Anus
  • K - Rectum
  • L - Appendix 
  • N - Cecum 
  • N - Colon 
    • ni- Transverse colon
    • nii- Ascending colon 
    • niii- Descending colon
  • O - Common bile duct
  • P - Duodenum 
  • Q- Gallbladder
  • R - Liver

30

What does the alimentary canal consist of? 

From the oval cavity to the anus

Four layers