Alimentary system Flashcards
What is the opening to the alimentary canal
The mouth
What are the 4 components of the teeth
Enamel
Dentine
Cementum
Dental pulp
What is the function of the digestive tract
To process food (digestion) and absorption
What is absorption
The transfer of nutrients to circulation
Some examples of accessory organs in the alementary system
-Salivary glands
-Gall bladder
-Liver
What is mixed seromucinous or seromucous saliva
Mixed watery (serous) and mucous/thick secretions
What is the function of saliva in the digestive system
Saliva helps buffer the mouth pH, protects the surface of the mouth and gut, has an antimicrobial action, maintains tooth structure and aids in taste and to a lesser extent with digestion
What is the role of the gall bladder as an accessory organ
The gall bladder helps store and concentrate bile which is produced by the liver, and helps with fat digestion
What is the pharynx
A muscular tube approx 12-15cm which is responsible partly for food to pass through, as well as air.
Where can the oesophagus be found
A muscular tube which varies in length from approx 20-25cm. This extends from the pharynx and reaches down to the stomach passing behind the heart and also the trachea/windpipe
What happens in the stomach
The first major part of digestion occurs. The stomach secretes acid and enzymes that will continue the digestion from the amylase in the oral cavity in saliva
Where is the stomach located
On the upper left of the abdomen
(left hypochondrium)
What is the name of the food leaving the stomach
Chyme
What are the 3 sections of the small intestine
Duodenum, Jejunum and Ileum
What are the sections within the large intestine
-Caecum (including appendix)
-Ascending, transverse and descending colon
-Rectum
-Anus
What does the mucosa consist of
-Epithelium
-Lamina propria
-Mucosae
What is the lamina propria
A thin layer of loose connective tissue which lies beneath the epithelium. It contains inflammatory cells and provides support and nutrients to the overlying epithelium
What is the adventitia
An outer layer of fibrous connective tissue surrounding an organ. In the gut, this would be at the oral cavity, upper end of the oesophagus in the chest, or thorax, and ascending colon and rectum. A serosa would be that part of the tissue that is fixed, in other words the rest of the gastrointestinal tract. In addition, the serosa or serous membrane allows for reduction of friciton
Structure of the gastrointestinal tract (histologically)
-Mucosa
-Submucosa
-Muscularis propria
-Adventitia/Serosa
What epithelium is typical of the oral cavity and pharynx
Stratified squamous epithelium which is ideal for their location to help with repeated trauma e.g. due to food and drink.
It is non-keratinised due to the moisture in the gastrointestinal tract to prevent it from drying out
G.O.R.D.
Continuous reflux of acid to oesophagus can cause damage to epithelium (indigestion, heart burn)
what is Barret’s oesophagus
Epithelium becomes changed to simple columnar from stratified squamous (metaplasia - change of one epithelium to another) in this case is pathological. This could go further to change epithelium again which is dysplasia, increase in abnormal growth, cell production and division which could lead to oesophageal cancer
What epithelium is found in the stomach
Simple columnar
What gastric glands can be found in the stomach
-Cardiac glands
-Fundic glands
-Pyloric glands
