Introduction to the GI Tract Flashcards
What organs are included in the GI tract?
The “tube” itself:
- Oesophagus
- Stomach
- Small intestine
- Large intestine (colon)
- Rectum
- Anus
Other organs of digestion also included:
- Liver
- Pancreas
- Galbladder
Purpose of the mouth in the GIT?
- Mastication
- Begins digestion with amylase
- Some absorption
Three stages of the pharynx?
- Nasopharynx
- Oralpharynx
- Laryngopharynx
Tip: Naso - nose
Oral - mouth
Laryngo - close to larynx
Function of the pharynx in the GIT?
Swallowing of food form the buccal cavity to the oesophagus
What is peristalsis?
The process of the involuntary contraction and relaxation of the muscles throughout the GI tract
Muscles of the Oesophagus
- Upper third are striated (voluntary)
- Lower third smooth (involuntary)
- Middle mixed
Sphincters of the oesophagus?
- Upper oesophageal sphincter - stops air getting into the GI
- Lower oesophageal sphincter - stops acid reflux
What is a hiatal hernia?
A hiatal hernia occurs when the upper part of the stomach pushes up into the chest through a small opening in the diaphragm, the muscle that separates the abdomen from the chest.
Sections of the stomach
- Cardia
- Fundus
- Body
- Antrum
- Pylorus (here is the pyloric sphincter after which is the small intestine)
Parts of the gastric mucosa
- Glands: secrete mucous to protect gastic mucosa form acidic environment
- Chief cells: secrete enzymes
- Parietal cells: secrete hydrochoric acid and intrinsic factor
- Endocrine cells: secrete grelin and gastrin
What do the gastric mucosa glands do?
Secrete mucous to protect the gastric mucosa
What do the chief cells do?
Secrete enzymes (pepsinogen)
What is the main enzyme in the stomach?
Pepsin
What do the parietal cells do?
Secrete hydrochloric acid to break down foods and intrinsic factor for b12 absorption
What do the endocrine cells of the gastric mucosa do?
Secrete grelin (hormone which promotes appetite) and gastrin (digestive hormone)