Digestive System (Part of Human Body Science) Flashcards
What organs make up the Digestive System?
It includes salivary glands, stomach, gastrointestinal tract: which contains the mouth, pharynx, esophagus, stomach, small intestine, and large intestine, colon, and the anus.
What are the two main groups the organs of the Digestive System categorize into?
- The alimentary canal
(aliment = nourish) - The accessory structures
(includes liver, gall bladder and pancreas although also main to other systems of body)
What is digestion?
The chemical and mechanical break down of food in order to absorb nutrients.
What does the chemical break down of food refer to?
The chemical break down of food occurs when enzymes break down carbohydrates, proteins, and fats into nutrients.
What enzyme begins the from the salivary glands breaks down carbohydrates?
salivary amylase from the parotid salivary glands break down starch into glucose.
Process of Digestion
“Step 1”
Beginning of the swallowing and mastication of the food from the mouth, it travels down the esophagus.
Process of Digestion
“Step 2”
The food from the esophagus passes into the stomach.
Process of Digestion
“Step 3”
At this point, the cells in the stomach lining secrete mucus for lubrication and enzymes that digest proteins = protease, hydrochloric acid, and an intrinsic factor = absorbs vitamin B12. The stomach also breaks down food mechanically.
Process of Digestion
“Step 4”
At this point, there is a mixture of food, chemicals, and enzymes in the stomach called chyme. However, fat-chyme and carbo/protein-chyme travel differently; carbo/protein first, then fat-chyme into the small intestine.
Process of Digestion
“Step 5”
Chyme is able to pass to the small intestine because of something called – pyloric sphincter.
So, chyme ⇒ pyloric sphincter ⇒ small intestine.
Process of Digestion
“Step 6”
The small intestine is made up of three sequential divisions: duodenum, jejunum, and ileum. So once chyme reaches the duodenum, it stimulates the release of 2 hormones: secretin and cholecystokinin or CCK.
Process of Digestion
“Step 7”
The secretin travels to the pancreas which triggers the release of bicarbonate which in turn neutralizes the chyme that entered the duodenum. Secretin also triggers the release of pancreatic enzymes that push everything forward (digestion)
Process of Digestion
“Step 8”
The CCK released from duodenum (2nd hormone) triggers the release of bile from the gall bladder as well as the release of more enzymes so digestion can continue.
Process of Digestion
“Step 9”
While all of this is occuring, the small intestine is also the site where absorption of nutrients occurs. This is made possible by finger-like projections called villi and microvilli.
Villi and Microvilli in terms of Digestion
Villi and Microvilli in terms of Digestion
Villi and microvilli increase the surface area within the small intestine, which increases the surface area where absorption can take place during digestion. Each villus contains artieroles and lymphatic vessels which gives them the tools to perform their function.
