Anatomy and physiology of GI tract

Question 1

What makes up the GI tract

(gastrointestinal tract)

Answer 1

Oral cavity
Esophagus
Liver
Stomach
Pancreas
S/L intestine
Gallbladder
Appendix
Rectum
Anus

Question 2

Role of the GI system

Answer 2

Ingest, digest and absorb nutrients to function

Question 3

What is Mechanical digestio and chemical digestion

Answer 3

Mechanical:
* Mastication:chewing/cutting
* Peristalsis: smooth muscle contraction push food along the GI tract

(technically breaking food down into smaller components)

Chemical digestion
* uses digestive enzymes

Question 4

The mouth

Answer 4

Create a bolus that can be swallowed.
Two steps:
Mastication-mechanical breakdwon
Hydrolysis-chemical breakdown

Question 5

What clinical conditions affect the mouth

Answer 5

• Cleft lip/palate can cause structural anomalies
• Cerebral palsy/ developmental delay can casue unsafe swallowing
• Tongue tie- diffculty feeding

Question 6

Pharynx and oesophagus

Answer 6

Pharynx- connect mouth to stomach
Activated by pressure of food bolus.

Swallowing= food passes the upper oesophageal sphincter (voluntary)- triggers peristalysis

when it reaches the loweroesophageal sphincter it dilates, food passes into stomach

Question 7

Oesophagus clinical conditions

Answer 7

• Dysphagia – difficulty swallowing
• Gastro-oesophageal reflux (GORD)

Both inhibit children obtaining nutrients

GORD- acid from the stomach leaks up into the oesophagus.

Question 8

Stomach

Answer 8

• mixes and grinds bolus
• Process enhanced by gastric juices.
• Digestion of proteins/carbs
• Chyme produced- Bolus—>semi solid substance
• specialised cells in stomach wall secrete:
  1. gastrin and pepsin- chemical digestion
  2. hydrochloric acid- kills bacteria
  3. Mucus- Protects the stomach

Question 9

Small intestine

Answer 9

Three segments:
1. Duodenum
2. Jejunum
3. Ileum

Chyme is also mixed with bile and pancreatic juices- aids absorption

Small intestine- where most nutrients are absorbed

Question 10

Segment of Small intestine

Duodenum

Answer 10

• chemical digestion
• Secretions from gallbladder (bile) and pancreas merge in a common structure:
  Hepatopancreatic ampulla
• Enters the duodenum at the duodenal papilla

Question 11

Clinical condition which affects Duodenum

Answer 11

Biliary Atresia – blocked or obstructive bile
ducts / gallbladder

Question 12

Segment of Small intestine

Jejunum

Answer 12

SA needed for optimal absorption
Microvilli triple the SA
Microvilli also allow the chyme to slow down —-> more time for absorption

Question 13

Segment of Small intestine

The Ileum

Answer 13

Food spends longest time here and most water and nutrients absorbed here

Also has a immunological function, helps with B12 and fatty acids absorption

Question 14

large intestine

Answer 14

Water/electrolytes absorbed and faeces formed