Chapter 7 contin.. Flashcards
Alimentary Canal
What is the Alimentary canal?
The Alimentary canal is a tube running through the body. Food is digested here.
What is Mucus?
Mucus is a slimy liquid that lubricates the lining of the canal, protecting from wear and tear.
It also protects the lining from attack of digestive enzymes.
What are the 5 processes that occur in the Alimentary canal?
Ingestion, Digestion (Mechanical & Chemical), Absorption, Assimilation and Egestion.
What is Ingestion?
Ingestion is taking in substances through the mouth.
What is Mechanical Digestion?
Mechanical digestion is the breakdown of food into smaller pieces without chemical change. (By teeth)
What is Chemical Digestion?
Chemical Digestion is the breakdown of large insoluble molecules into small soluble ones. (By enzymes)
What is Absorption?
Absorption is the movement of the small molecules through the intestine wall into the blood.
What is Assimilation?
Assimilation is the movement of digested food molecules into cells where they are used and become part of the cells.
What is Egestion?
Egestion is the passing out of food that has not been digested or absorbed, as faeces through the anus.
What is Peristalsis?
- Peristalsis is the wave of contraction that passes along the canal, pushing food through it.
- It is one contraction after another, causing a wave.
*Antiperistalsis would be vomiting.
What is Diarrhoea?
Diarrhoea is the loss of watery faeces.
This is caused by bacterial or viral infections.
How is Diarrhoea caused?
- It caused by the bacteria that damage the intestines.
- This results in too much fluid secreted into the colon.
- Undigested food moves too quickly, and theres not enough time to absorb water from it.
- This causes dehydration.
What is ORT/ORS?
Oral Rehydration Therapy/Solution is the treatment for Dehydration.
This involves drinking a solution of water and salts with electrolytes to build back the water concentration in the body.
What is Cholera? (points)
Cholera is a disease caused by the bacteria Vibrio Cholera.
- It causes Acute Diarrhoea, that cant be treated with ORS.
- Treatment involves injecting a solution or using Tetracycline to kill the bacteria.
- It can also cause Kidney failure.
How is Cholera caused?
It is caused by taking in impure water. The bacteria Vibrio Cholera are in it, and once ingested, they multiply in the SMALL INTESTINE, and then release toxins that damage it.
- This results in secretion of large amounts of water and salts.
Why is food first mechanically digested?
- Physical digestion increases the
surface area of food for the action of enzymes in chemical digestion.
What are the 4 types of teeth?
These are:
- Incisors; chisel shaped, bite off food
- Canines; more pointed, bite off food
- Premolars; 2 points/cusps, 1-2 roots. Tear and grind food
- Molars; 4-5 cusps, 2-3 roots. Chew and grind food
What is the structure of a tooth?
The tooth has enamel, dentine, pulp cavity, nerves and blood vessels and cement.
What is the crown and root?
The crown is the tooth visible (above the gum line).
The root is the rest of the tooth in the jaw bone.
How is the tooth embedded in the gums?
The enamel layer is replaced with cement in the root, which allows the tooth to grip to its bony socket in the jaw.
How is dental decay caused?
Dental decay causes cavities.
This occurs when bacteria feed on sugar on our teeth, respiring them and producing acid.
The acid dissolves calcium salts in the Enamel, and then the dentine.
The acids cause toothache and irritate nerve endings.
What is the Critical PH?
Critical PH is the PH BELOW which the enamel is attacked (normal PH is 7)
Enamel is under an acid attack for 10 minutes.
