Animal nutrition - physical digestion

Definition of physical digestion

Breakdown of food into smaller pieces without chemical changes ot the food molecules. Also increase surface area of the food which makes it easier for enzymes to break down.

Where does physical digestion start?

In the mouth - teeth are used to chew food into smaller pieces.

Incisors location

Front of the mouth

Incisors structure

Chisel shaped with sharp edges

Incisors function

Cutting and bitting off pieces of food

Canines location

Either side of incisors

Canines structure

Slightly larger and more pointed than incisors

Canines function

Cutting and tearing food into bite sized pieces

Premolars location

Behind the canines

Premolars structure

One or two roots, two cusps

Premolars function

Crushing and grinding food into smaller pieces

Molars location

Back of the motuh

Molars structure

Two or three roots, four or five cusps

Molars function

Crushing and grinding food into smaller pieces

Enamel

Hard, resistant substance, protects componets of tooth, lines dental crown

Dentine

Main supporting structure of tooth

Pulp

Soft centre of tooth, contains nerves and blood tissues

Nerves

Helps control amount of forces used when chewing

Blood vessels

Supplies oxgyen and nutrients, essential for maintaince of tooth

Cement

Lines the root, helps the tooth grip to it’s bony socket in the jaw.

Function of stomach

Muscular walls churn and mix food, breaks down food into a liquid, smaller surface area for enzymes

Bile

Secred by the liver, stored in the gall bladder, released into the duodenum through the bile duct, emulsifies fat

Emulsification

Breakdown of large liqid particles into small droplets - increase surface are for chemical digestion by enzymes.