Gastrointestinal Tract Flashcards
What is the “GI lumen”?
The inside of the GI tract
What are the 3 parts of the small intestine in order?
- duodenum
- jejunum
- ileum
What stomach cell produces gastric acid?
Parietal cell
Which organ secretes most of the digestive enzymes?
Pancreas
What kind of epithelium is the lining of the mouth, esophagus and anus made of?
Stratified squamous epithelium
What is added in the duodenum to return neutralize?
Bicarbonate
What do parietal cells respond to?
Histamine, acetylcholine and gastrin.
What are the chief cells responsible for?
When in contact with acid, they release pepsinogen which initiates the digestion of proteins
What do G cells secrete and what is its purpose?
Gastrin
- stimulates the release of gastric acid from parietal cells
What is the only secretion from the esophagus?
mucus for lubrication
What are the two main enzymes in saliva?
Amylase: breakdown of carbohydrates
Lipase: breakdown of fats
What does starch, glycogen, sucrose and lactose digest into?
Glucose, fructose, galactose
How are proteins broken down in the stomach?
peptidase
What do proteins digest into once they are broken down?
Amino acids
What do triglycerides digest into and from what enzyme?
Lipase
- monoglycerides and fatty acids
What is something our body cannot digest?
Cellulose / fibre
What is tonic contraction?
Contractions maintained for a long time
- sphincters and upper stomach
- allows stomach to be low pressure so so contents can easily enter
What are phasic contractions?
Short and rapid contractions
What is peristalsis?
The circular contraction of muscles to move a food bolus towards it target
What is segmentation?
The mixing and churning of food to increased surface area fro absorption
What is cephalic phase? Is it sympathetic or parasympathetic?
When your body is anticipating food, it begins to increase motility
- parasympathetic
What is gastric phase?
Increased motility stimuli: , distension, peptides and acidity in stomach
- swallowed food begins to activate gastric activity
What is secondary peristalsis?
LOCAL CONTROL:
- distension of esophagus to clear out any leftover food
Stomach lining consists of _____ to ________.
- Rugae folds
- Increase surface area
