Enzymes and the digestion system

Made up of long muscular tube and its associated glands- the glands produce enzymes

the enzymes break down large moecules into small for absorption

digestion: process which large molecules are hydrolyses by enzymes into small molecules (can then be absorbed and assimilated)

Assimilated= convert (food) to substances suitable for incorporation into the body and its tissues

Oseophagus

carries food from mouth to the stomach

adapted for transport rather tahn digestion or absorption

Made up of thick muscular wall

Stomach

muscular sac with inner layer that produces enzymes

role= store and digest food (especially proteins)

glands that produce enzymes which digest protein

other glands in stomach wall produce mucus

mucus prevents stomach being digested by its own enzymes

Small intestine

long muscular tube

enzymes in the SI that are produced by its walls and by glands that pour secretions into it digest the food.

 inner walls of SI are folded into villi which have tiny projections on their epthelial cells-microvilli= large surface is created   this adapts the small intestine for absorbing the products of digestion into the bloodstream

Large intestine

Absorbs water

most of the water that is reabsorbed comes from the secreations of the many digestive glands

food within LI therefore becomes drier and thicker in consistency- forms faeces

Rectum

final section of intestines.

faeces are stored here before periodically being removed via the anus in a process called egestion.

Egestion:

Saliary glands

situated near mouth

pass their secretions via a duct into the mouth

these secretions contain the enzyme amylase, which breaks down starch into maltose.

large gland situated below the stomach

produces a secretion called pancreatic juice

this secreation contains:

• proteases to digest proteins
• lipase to digest lipids
• amylase to digest starch