Human Nutrition (11)

The alimentary canal and accessory organs.

An 8.5m muscular tube. Its essential function is to digest and absorb food.

Ingestion and mastication to break down food into a bolus.

Transports bolus of food from back of the mouth to the oesophagus.

Takes the bolus from the pharynx to the stomach by peristelsis.

Breaks down food mechanically by muscles and chemically by proteases. Secretes hydrochloric acid which provides an acid medium for action of enzymes)

Receives acidic enzyme from stomach as well as bile to neutralize it.

Receives bile from the gall bladder and pancreatic juice.

Secretes intestinal juice and starts absorption.

Secretes intestinal juice and is the area of most digestion and absorption.

Receives undigested food, removes excess water, reabsorption of water and forms faeces.

Storage of faeces.

Sphincter muscle that controls defaecation.

Teeth, tongue, salivary glands, pancreas, liver and gall bladder.

Secretes saliva, which has carbohydrase, salivary amylase. Also for lubrication if food and tasting.

Helps with chewing and tasting.

Secretes pancreatic juice and produces the hormone insulin to control blood sugar levels.

Receives absorbed nutrients which it processes and stores. Also makes bile (for emulsification of fats and providing alkali medium)

Stores bile until it is needed.

Keeps stomach closed and opens to receive anything that comes down the Oesophagus.

Keeps stomach closed and allows chyme to move into the duodenum.

• Makes bile which is stored in the gall bladder. • Regulates substances -Excess glucose is stored as glycogen -Reconverts glycogen back into glucose when energy is needed. -Excess amino acids are broken down into urea and glucose -Some amino acids form plasma proteins. • Makes vitamin A from Carotene • Breaks down or detoxifies drugs, alcohols and hormones. • Forms cholesterol from certain fats. • Stores fat-soluble vitamin A, D, B12 and Iron

Stored by the gall bladder. • Emulsifies large globules into smaller fat droplets, this increases the surface area on which lipase can act. • Provides alkali medium for action of enzymes in pancreatic and intestinal juices. 3.Bile helps with the absorption of fats.