Part 5: Digestive systems

Question 1

What is digestion?

Answer 1

The breakdown of foods until it reaches a point where it can be taken up by the animal

Question 2

What are the types of digestion?

Answer 2

Extracellular
Bacteria, Fungi, Spider
Intercellular
within a cell (amoeba, paramecium)

Question 3

What is incomplete digestive tract?

Answer 3

One opening that serves as both mouth and anus. Body cavity called gastro-vascular cavity.
Epidermal cells release enzymes into the GV cavity, where food that is passed through the month begins to be digested. The animal then sends in more particles for digestion. Food particles that are digested then mix up with non-digested ones. After animal will try to absorb it, and as soon as the cavity gets filled, it will contract releasing all that is inside of it.
Not one way flow

Question 4

What are the main facts about the complete digestive tract?

Answer 4

Two openings - mouth and anus.
One way flow, allows for specialization along the digestive tube.
Storage - stomach
Intestine - absorption of nutrients, villi line inside the intestines, lumen is the interior space of the intestines

Question 5

What are five events associated with the complete digestive tract?

Answer 5

1. Mechanical processing ex. chewing
2. Enzyme secretion
   ex. to break food down
3. Digestion
   ex. breaking down the food
4. Absorption
   ex. nutrients
5. Elimination
   ex. wastes

Question 6

What are main facts about stomach?

Answer 6

3 layers 
creates chime
glandular epithelial cells
Gastrin is produced (pepsin +HCl)
1.5 to 2.5 acidity
goblet cells protect epithelial cells from HCl, they release mucin
Food is processed about 4-6h

Question 7

What happens in small intestine?

Answer 7

Contains numerous enzymes, carbohydrates, lipase, other proteases
Pancreas releases numerous enzymes/bicarbonate to neutralize the acidity or none of it will work.
Duodenum (lipids are bing digested) - jejunum - ileum
parts of intestine