Chapter 14 Flashcards
Why is a digestive system needed in humans?
Provides nutrients-CPF
- body needs for cellular activities
- respiration- energy released- used for growth/movement/ tissue repair
Digestive system breaks down-
-small/soluble molecules- absorb into bloodstream-used by body to release energy through cellular respiration
(if too large/insoluble-cannot diffuse into cell)
CPF - carbohydrates, protein and fats
What are the 7 parts of a digestive system?
Mouth
Gullet
Stomach
Small intestine
Large intestine
Rectum
Anus
What is Physical process?
- food is being broken up into smaller pieces
- Exp: chewing
What is Chemical process?
- food is being broken down into smaller molecules
- Exp: Enzyme
food changes from being complex to simple
What does enzyme do?
- enzyme are specific.
- they speed up the break down of large food molecules into smaller, soluble food molecules of only one type of nutrient
without enzymes, most chemical reactions would take too much time to complete!
What are the three main nutrients and their end products?
- carbohydrates digested by carbohydrase into simple sugar
- proteins digested by protease into amino acids
- fats digested by lipase into fatty acid+ glycerol
What does mouth do?
Physical digestion : crush food into smaller pieces
Chemical digestion: saliva that contains carbohydrases, partially digested starch
Other functions: saliva softens food which is therefore easier to swallow
carbohydrates digested by carbohydrase into partially digested carbohydrates
What does the gullet do?
Physical digestion: NONE
Chemical digestion : NO DJ. Starch from mouth continues to be digested by carboydrases that are mixed with the food.
Other functions: muscles of gullet pushes food to the stomach
What does the stomach do?
HELP- (1 point for chemical and physical process)
( 3 point for other functions)
Physical process: churns food into small pieces
Chemical process: releases gastric juice containing protease to digest protein
Other function:
- thick layer of mucus to protect tissues from being damaged by hydrochloric acid/protease in gastric juice.
- muscles at both ends of stomach, controls the food from leaving/entering the stomach
- releases gastric juice - hydrochloric acids, which kills microorganisms (right condition for proteases to act)
protein digested by proteases into partially digested proteins
hydrochloric acids contains gastric juice from the stomach kills harmful microorganisms
What does the small intestine do?
(4 points for chemical process & 3 main nutrients)
Physical process** : NONE
**Chemical process
- small intestine (main site for chemical digestion) – due to many enzymes released.
- fats digested first due to lipase present in digestive juices.
- CPF fully digested
- water absorbed
carbohydrate digested by carbohydrase into simple sugar
protein digested by protease into amino acids
fat digested by lipase into fatty acid + glycerol
What does the large intestine do?
- Absorb remaining water/mineral salts
What does the rectum do?
- Indigestable food/waste forms here (FIBRE)
- Temporalily stored here before leaving body
What does the anus do?
- Faeces released through this opening
What is simple sugar used for?
- Used by cells for respiration to release energy used to carry out other functions growth/movement/tissue repair
What is fatty acids/glycerol used for?
- More fats in body-keep warm
