Digestion Flashcards
mechanical digestion
Mechanical digestion involves breaking up large pieces of food into smaller, usually insoluble pieces
mechanical digestion is important or teeth
- It gives the pieces of food a larger surface area for digestive enzymes to act on, making chemical digestion quicker and easier.
- It makes food easier to swallow.
incisor
Chisel-shaped with sharp, thin edges
At the front of the jaw.
To cut food.To bite off pieces of food.
canines
Next to the incisors.
Cone-shaped and pointed.
To grip food. To tear off pieces of food.
Pre molars
At the side of the jaw next
to the canines.
Havea fairly broad surface with two pointed cusps.
To crush and grind food.
Molars
At the back of the jaw next
to the premolars.
Have a broad surface with 4 or 5 pointed cusps.
To crush and grind food.
enamel
non-living. Covers the crown of the tooth. The hardest substance in the body. Resistant to chipping and relatively resistant to decay; however, it can be dissolved by acid produced by bacteria inthe mouth. Protects the tooth
dentine
bone-like. Contains channels of living cytoplasm from cells in the pulp cavity.
Forms the bulk of the tooth
pulp cavity
composed of living cells and blood vessels
blood vessels
supply the living cells with food and oxygen,and remove carbon dioxide and waste
gum
jawbone
nerves
senstive, in tooth decay, when the enamel and entine rot away, exposes nerves to the outisde
cement
covers the root of the tooth, bone-like
fibres
embedded in the cement at one end and the jawbone at the other end. Anchor the tooth in the jawbone and allows light movement for shock absorption
bolus
When chewing is complete, the food is rolled into a ball called a bolus. The bolus is pushed to theback of the mouth by the tongue and swallowed. It enters the stomach where contractions of the muscles in the stomach walls churn the food which continues the process of mechanical digestion.
Chemical digestion
Chemical digestion involves breaking down large, usually insoluble, food molecules into small, soluble food molecules by hydrolysis.
gall bladder –
stores bile
bile duct
provides the passage for bile from the gall bladder to enter into the duodenum
anal sphincter
– a muscle which relaxes
during egestion
pyloric sphincter –
–a muscle whichrelaxes periodically to release food from the stomach
salivary gland
produces saliva
mouth
digestion of starch
epiglottis
closes over the trachea during swallowing