digestive system Flashcards
(15 cards)
what is the function of the digestive system?
is to breakdown food so nutrients can be absorbed into the blood and taken into cells
what are 2 other names for the digestive system?
alimentary canal and gastro- intestinal tract
what are the accessory organs?
liver, gall bladder, pancreas
what are the 6 basic function of the digestive system?
what do they do?
A- Absorption- putting nutrients into blood to get to cells
M- Movement- pushing food down tract
M- mechanical- physical
I- ingestions- intake of food
C-chemical- using enzymes to breakdown chemical structures
E- egestion- getting rid of undigested wastes
what is mechanical digestions? what is its aim?
the physical breakdown of food particles occurs in mouth, oesophagus, small intestine.
aim is to break down the food into smaller pieces so there is an increase in surface area.
what is chemical digestion?
breakdown food from large to small particles/nutrients chemically using enzymes
what basic functions occurs in the mouth?
ingestions, mechanical and chemical digestion
describe what occurs in the mouth mechanically and ingestion?
ingestion- intake of food
mechanical digestion-
food is chewed by a process called mastication
mastication- chewing of food by muscles, teeth, jaw
4 teeth involved
incisors- used for bitting and cutting(x4 in mouth)
canines- used for tearing(x2 in mouth)
molars and premolars- grinding(6x in mouth)
-tongue shapes food into bolus, to swallow tongue moves backwards and upwards.
what occurs in the mouth chemically?
as food is chewed, mixed with saliva produced from salivary glands.
salivary glands secretes saliva which contains mucus and digestive enzyme( salivary amylase)
enzyme breaks down carbohydrates
breaks start into disaccharides (maltose)
what occurs in the oesophagus?
mechanical digestion-
double layer of muscle- circular and longitudinal
as food enters, circular muscle behind it contracts to push food down
the muscles carry out peristalsis, wave like movements of contractions and relaxations of muscles.
assisted by secretion of mucus to move food down
what mechanically occurs in the stomach?
3 layers of muscles( circular, longitudinal, oblique ) carry out peristalsis
having 3 muscles layers allows the stomach to contract in various ways to churn the food and mix it with gastric juices( juices from stomach wall) to form chyme.( thick, soupy liquid)
what chemically occurs in the stomach?
The lining of the stomach = mucosa, secretes gastric juice by gastric glands.
gastric juice contains 3 things
HCI- creates an acidic environment to allow for the inactive enzyme pepsinogen to the active pepsin
start of protein digestion.
- pepsin can break down proteins to amino acids
- nucleic acid to RNA/DNA
Mucus- lubricates food and protects the lining of the stomach
Gastric protease- breakdown proteins
what does the small intestine basic functions include
mechanical, chemical, absorption
what does the small intestine do mechanically?
it is achieved in 2 ways segmentation- (peristalsis in SI)
contractions of circular muscles narrow intestine, help breakup bolus and mix it with juices and bile.
Bile- emulsify the fat, breaking it into tiny droplets
bile is secreted into SI through bile duct
what does the small intestine do chemically?
achieved by 2 juices
-pancreatic -works 1st
-intestinal -works 2nd
juices are secreted from the mucosa layer of the intestine. contain enzyme amylase, protease
