The Alimentary Canal Flashcards
Overall what does the alimentary canal involve?
The breakdown and absorption of complex carbohydrates, proteins in fat molecules
What is the alimentary canal?
A continuous tube that makes up the digestive system
Define mechanical digestion
The mechanical breakdown of food into small particles where the food is not chemically changed
Define chemical digestion
The chemical breakdown of food into small molecules from large complex molecules
What is the function or purpose of mechanical digestion
To increase surface area to volume ratio which allows more area for enzymes to act on
What is the function of purpose of chemical digestion
In order for molecules to be absorbed
Name the organs in order of digestion
Mouth oesophagus stomach small intestine large intestine rectem
Where are the three types of mechanical digestion in the body
The mouth
The stomach
The small intestine
Explain mechanical digestive in the mouth
Three types of human teeth
1) incisor- biting/ cutting
2) canine- Tearing
3) molars pre-molars- grinding
How many of each type of teeth do humans have
Four incisors two canines 10 pre-molars on each jaw
Why do carnivorus animals need large canines
tearing role is important
Explain the chemical digester in the mouth
Saliva glands secrete saliva into the mouth which contains saliva amylase (breaks starch into disaccharides)
Besides chemical digestion, what is the other functions of saliva in the mouth
Makes food slippery forming a bolus of food
How is the the food moved throughout the system
by peristalsis- movement of contraction of smooth muscles which Squeezes the food along in a wave like motion in front of it
Name the two sphincters of the stomach
The gastric and pyloric
What is the stomach lining and what does it secretes
Mucosa, secretes gastric juice from gastric glands
What is in gastric juice
Hydrochloric acid mucus and enzymes
What is the function of mucus in the stomach
Protects lining from acid
What are the functions of hydrochloric acid in the stomach
Create conditions for pepsin
Kill bacteria
Explain chemical digester in the stomach
Pepsin breaks down protein into polypeptides
Explain the mechanical digestion of the stomach
Contractions of the muscle allows the churning- breaks into smaller
As the content leaves the stomach, what is it known as?
chyme
What are the purposes of the sphincters
prevents contents form moving without peristalsis
How long is the food in the stomach?
2-6 hours
How long is the small intestine
6 m
Name the three types of juices secreted into the duodenum and where they were made
Bile- made in liver, stored in gallbladder
Pancreatic juice- made in pancreas
Intestinal Juice- made and secreted from glands in lining
What are the two things bile does
- Neutralizes acid
- Emulcifies fats (forms mechanical digestion in SA)
Explain what enzymes are in Pancreatic juice and its substrates
- panc. amyl- (starch> disc)
- trypsin- (polypeptides> peptides)
- lipase (lipids> glycerol + fat. acids
Explain what enzymes are in intestinal juice and its substrates
- peptidase- (peptides- amino acids)
- intestinal amy- (disc- monosaccharides (simple sugars)
how long is Large int.
1.5 m
Are there any digestive juices secreted?
nope
What happens once in Lintestine
1) water absorbed (leaving semi solid waste)
2) bacteria breaks down remaining (some produce vitamins which are absorbed)
3) whats left= faeces
4) storage in rectum, sphincter, elimination
Why is fibre needed?
needed for peristalsis, ‘grab onto’
What does faeces contain?
water, undigested food, bacteria,some minerals, bile pigments (give colour), cells from lining
