Gastro-intestinal physiology: structure/function Flashcards
What is the GI tract made up of?
The mouth, pharynx, oesophagus, stomach, small intestine, liver, gall bladder, pancreas and large intestine.
What is the function of the oesophagus?
Transport of food.
What are the subdivisions of the stomach that are involved in the GI tract?
The fundus, body and antrum.
What is the body of the stomach?
The middle portion of the stomach that secretes mucus, pepsinogen, and HCl that is involved in storage and secretion.
What is the fundus of the stomach?
The upper portion of the stomach that secretes mucus, pepsinogen and HCl that is involved in storage of food.
What is the antrum of the stomach?
The lower portion of the stomach that is invlved in mixing, digestion and emulsification.
before it enters the small inestine
What subdivisions of the small intestine are involved in the GI tract?
The duodenum, jejunum and ileum.
What is the duodenum?
The first portion of the small intestine that is involved in regulation, coordination and digestion.
What is the jejunum?
The middle segment of the small intestine that is involved in dietary product absorption and rendering them to form suitable products to be taken up by the body.
What is the ileum?
The final, longest segment of the small intestine that is involved in water re-absorption.
What are the subdivisions of the large intestine?
The ascending colon, the transverse colon, the descending colon, the sigmoid colon and the rectum/anus.
What is the function of the pharynx?
Swallowing - voluntary control.
What are the liver, gall bladder and pancreas involved in?
Secretion.
What are the ascending, transverse and descending colon involved in?
Water re-absorption.
What is the sigmoid colon involved in?
Storage.
What is the rectum/anus involved in?
Storage and elimination - voluntary control.
How may diarrhea occur?
If parts of the large intestine are not functioning correctly, water will not have enough time to reabsorbed if the faeces is being secreted too quickly.
Where is faeces stored?
In the descending colon/sigmoid colon.
What is peristalsis?
Moving packets of partially digested products along the length of the intestine due to smooth muscle contraction and relaxation.
What is another word for peristalsis?
Segmentation.
What is the purpose of saliva?
Provides lubrication and protection - it contains lysozymes that are antibacterial and can break down the cell walls of bacteria. It also begins the process of digestion by containing alpha amylase that attacks complex carbohydrates, as well as lipase that attacks the fats present in food.
What glands are the main contributors to producing saliva?
The sublingual gland and the submandibular gland - these are underneath the tongue and produce around 75% of the total saliva.
thick and viscous
What glands produce thin and watery saliva?
The parotid duct and the parotid gland.
What are the main roles of the stomach?
Mixing, protein digestion (using HCl and pepsin) and fat emulsification.
What is chyne?
Partially digested food.
What are rugae?
Folds they increase the surface area for exchange.
allow for expansion when stomach fills by flattening
What do the three layers of muscle in the stomach allow for?
They help the walls of the stomach to contract, change shape and extend to move the food.
What is the spinchter and what is its purpose?
It ensures that food is retained until it is appropriate for it to be release into the duodenum and continue its journey.