Week 5 - The GI System Flashcards
define nutrition
- process by which food and nutrients affect the cellular function, growth, and development, health and disease
define elimination
- the excretion of waste products primarily thru the urinary system & the GI system
what is the primary role of the digestive system (2)
- breakdown (digest) food we consume
- absorb the digested fragments into the blood
what is the GI tract? what is another name for it?
- aka alimentary canal
- muscular tube that opens at both ends (anus & mouth)
what is included in the GI system?
- GI tract
- accessory digestive organs
what are some examples of accessory digestive organs in the GI tract
- salviary glands
- pancreas
- liver
- gallbladder
what is the main function of the accessory digestive organs
- produce secretions that contribute to the digestion of foodstuffs
ex. saliva, bile, and digestive enzymes
what are the 4 layers of the GI tract
from inside to out:
- mucosa
- submucosa
- muscularis externa
- serosa
what is the mucosa? what is the function
- the inner epithelial layer
- which produces mucus & some digestive enzymes
- absorbs nutrients
what is the submucosa? what does it do?
- connective tissue layer
- contains nerves, blood & lymph vessels
what is the muscularis externa? what does it do?
- smooth muscle layer
- allows peristalsis
what is the serosa?
- outer connective tissue
what 3 things does the serosa form?
- mesentry
- visceral peritoneum around the bowel
- peritoneal peritoneum around the abdominal cavity
what does the GI secrete that helps with digestion of food?
- secretes fluid (~7 litres)
- includes bile, enzymes, and mucus
explain fluid turnover in the GI tract including fluid ingested, secreted, absorbed, and lost in the stool
- ingested = 2 L
- secretions = 7 L
- absorbed/reabsorbed = 8.8 L
- balance in stool = 0.2L
