GI System Flashcards
The GIS absorbs nutrients from food such as?
Fats, proteins, carbohydrates, vitamins, minerals and water
Name the six sections of the GIS?
Mouth and Pharynx Oesophagus Stomach Small intestine Large Intestine Rectum and Anus
Name the GI accessory organs?
Teeth, tongue, salivary glands, gall bladder, liver, pancreas
What is the function of the GIS?
The breakdown and absorption of food
What are the two mechanisms for digestion?
Mechanical digestion and chemical
What mechanisms drive mechanical digestion?
Chewing, mixing, propulsion
What is involved in mechanical digestion?
The breakdown of large food molecules into small molecules.
I.e - Large carbohydrates = glucose
What occurs following mechanical and chemical digestion?
The digestion products are absorbed by epithelial cells, nutrients transferred to blood vessels and thereby delivered to tissues
The structure of the GIS is more or less consistent from start to finish, describe it ?
(Inner to Outer) Mucosa Submucosa Muscularis Serosa
Describe the Mucosa
MUCOSA
Layer of simple columnar epithelial cells
-Lamina propria, containing connective tissue, blood vessels & supportive of epithelial layer
-Muscularis Mucosa - inner muscular layer
Describe the submucosa?
Dense connective tissue, blood vessels and connects mucous to musclaris
Describe the Muscularis?
Composed of inner circular layer that works to narrow the gut followed by outer longitude layer of muscle that works to shorten the gut.
Describe the Serosa?
Outer layer of Gut
Forms mesentery where blood vessels and nerves enter and leave the gut
Describe the function of the oral cavity in digestion?
-Mastication
-Mixing with saliva containing amylase
-Tasting safeguard
-Bolus formation
Pharynx is passage at back of mouth for food and air
Describe the function of the oesophagus in digestion?
Collapsible muscular tube which transports food to stomach with no enzymes or absorption.
Secretes mucous to lubricate and protect oesophagus wall
Projects bolus downwards by peristalsis
What is the function of the lower oesophageal sphincter?
Ring of smooth muscle at entrance of stomach that prevents acid reflux.
Describe the internal wall of the stomach?
It has many folds called to rugae.
What are the functions of the stomach?
i) Food storage
ii) mechanical digestion
iii) Chemical digestion