Digestive System Flashcards
What are the 2 main components/systems of the digestive system?
- Alimentary canal
2. Accessory structures
What does the Alimentary structure system consist of?
- Mouth
- Esophagus
- Stomach
- Small intestines
- Large Intestines
- Anus
The 3 sections of the small intestine
- Duodenum
- Jejunum
- ileum
What are the Accessory structures?
- Teeth
- Salivary glands
- Pancreas
- Liver
- Gallbladder
Role surface area plays in digestion
Digestive systems spends less work breaking nutrients down
Where does the majority of nutrient absorption take place?
In the small intestines
Length of the average adult small intestine
7 metres
Surface area of the small intestine
250 square metres
Where does digestion begin?
At the mouth
What are enzymes?
Chemicals that break down proteins, carbohydrates and fats into nutrients that can be absorbed
What is the enzyme used in the mouth to start digestion, what does it breakdown and what it converts what into what?
Salivary amylase, carbohydrates, starch into glucose
Where is salivary amylase produced?
Parotid salivary gland
From the mouth, the bolus travels through what before reaching the stomach?
Pharynx and esophagus
What prevents food and liquid from entering the trachea?
Epiglottis
How does the Epiglottis work?
When swallowing, the tissue flap blocks the trachea
Define Peristalis
Wave like rhythmic muscle contractions that propel food through the digestive track
What are the muscles found in the stomach called?
Rugae & gastric folds
General composition of Gastric juice
Hydrochloric acid, intrinsic factor, pepsin, mucus and water
Ph of hydrochloric acid
1
What is a Protease?
A category of enzyme (specifically dealing protein-digesting)
What is Pepsin
An enzyme that breaks down proteins into amino-acids
What is intrinsic factor and what produces it?
Molecule that binds with B-12 allowing it to survive the hydrochloric acid in the stomach and be passed down to the small intestines for absorption. Produced by cells (in gastirc pits) in the stomach called Parietal cells
Insufficient stomach mucus leads to which disorder?
Peptic ulcers
What is Chyme?
A mixture of food, chemicals and enzymes in the stomach
Where does Chyme go after leaving the stomach?
Pyloric sphincter
What does the pyloric sphincter do?
Regulates how much Chyme gets into the small intestine and when it gets there
What is the first part of the small intestine?
Duodenum
What are the 2 hormones that the duodenum releases?
- Secretin
2. Cholecystokinin (CCK)
What is the purpose of Secretin?
Stimulates the pancreas to trigger release of bicarbonate which neutralizes stomach acid entering the duodenum
What is function of Cholecystokinin (CCK)?
Stimulates the gallbladder to release bile and the stomach to decrease acid production
(Physically) Describe small intestinal nutrient absorption (structures)
Finger like projections called villi and microvilli increase the surface area of the small intestine for absorption increasment. Each villus contains arterioles lymphatic vessels for absorption
What is an emulsion?
A mixture of two or more liquids that normally are not mixable
What is bile salt and its purpose (what does it break down and into what?
An emulsifier. It takes hydrophobic fat molecules and breaks them up into fatty acids and monoglycerides so it can be absorbed
Where is bile-salt produced and stored?
Produced in the liver and stored in the gallbladder
Where does the chyme travel after the small intestine?
Enters the Cecum (beginning of the large intestine)
Function of the large intestine
Remove most of the water and bile-salts from the chyme and storage/formation of feces
Which tube is located at the end of the Cecum?
The appendix
Believed function of the appendix
Safe house for good bacteria with sample of gut bacteria which is secreted to help recolonize after illness (eg. food poisoning)
Where does feces travel after leaving the large intestine?
Through the two anal sphincters
