MENU OF THE DAY Describe the functions of main regions of the alimentary canal and the associated organs: mouth, salivary glands, oesophagus, stomach, duodenum, pancreas, gall bladder, liver, ileum, colon, rectum, anus, in relation to ingestion, digestion, absorption, assimilation and egestion of food, as appropriate. Functions of a typical amylase, protease and lipase (listing the substrate and end-products)

Nutrition in animals

How does…..

“ You are what you eat.” - Jean Anthelme Brillat-Savarin

Holozoic nutrition Holozoic nutrition: feeding on ready- made complex organic matter.

What is Nutrition? The taking in of food (chemical energy) by the body & converting it into living matter

5 processes in digestion INGESTION Taking in food Breakdown of complex food substances into smaller soluble food substances DIGESTION ABSORPTION Digested food is absorbed Into body cells Absorbed food is use to provide energy or form new protoplasm ASSIMILATION EGESTION Removal of undigested food

Feeding/ Ingestion Feeding/ Ingestion – intake of food into the mouth.

Digestion Digestion – large food molecules are broken down into small, soluble and diffusible molecules. 2 types: Physical and chemical digestions

2 types of digestions Physical digestion refers to the mechanical break up of food into small particles which increases its surface area for chemical digestion. (E.g. Chewing, stomach churning). It also mix the digestive enzymes with the food particles

2 types of digestions Chemical digestions – breaking of biomolecules like proteins, starch and fats into small soluble molecules which can be absorbed by the cells. It involves digestive enzymes and chemical reactions like hyrolysis.

Why must food molecules be broken down into smaller, simpler forms before it can be absorbed by the cells for other uses? Cell membranes are partially permeable and only allow small molecules to pass through. e.g. glucose must pass through the cell membrane to reach the mitochondria so as to release energy in tissue respiration e.g. amino acids must pass through the cell membrane to reach the ribosomes to synthesise proteins.

Absorption Absorption – digested food materials are taken into the body cells.

Assimilation Assimilation – absorbed food materials are converted into new protoplasm or used to provide energy.

Do not confuse Ingestion with Egestion!!! Egestion – elimination of undigested food materials (faeces) Do not confuse Ingestion with Egestion!!!

Digestive enzymes Starch Proteins Lipids/ Fats maltose amino acids AMYLASE Starch maltose PROTEASE Proteins amino acids LIPASE Lipids/ Fats fatty acids & glycerol

Alimentary canal

The Digestive System Consists of: 1) The gut or alimentary canal (9 m) from mouth to anus. 2) Glands (A cell, tissue, or organ that secretes a chemical substance). 3) Associated organs.

Mouth and buccal cavity The Alimentary Canal Mouth and buccal cavity Oesophagus Stomach Small intestines Large intestine Anus

Mouth & Buccal Cavity

The Mouth & Buccal Cavity

The Mouth & Buccal Cavity Food enters through the mouth. This process is called ingestion. Teeth cuts food into small pieces. This increases surface area to volume ratio for enzyme to act more efficiently.

The Mouth & Buccal Cavity Salivary glands produce saliva to moisten food. Saliva also contains salivary amylase to break down starch to maltose. pH of saliva is neutral (around pH 7).

The Mouth & Buccal Cavity Salivary Glands

The Mouth & Buccal Cavity Salivary Amylase Starch Maltose Salivary amylase is active at pH 7.

The Mouth & Buccal Cavity Tongue rolls food into boli. Food is swallowed and enters the pharynx.

Human Alimentary Canal Made up of a tubular gut called the alimentary canal. Food travels through our body along the alimentary canal which is a continuous tube beginning at the mouth and ending at the anus. The parts of the gut includes: mouth, pharynx, oesophagus, stomach, small intestine, large intestine and anus. mouth stomach oesophagus small intestine pharynx large intestine anus Rectum

The Alimentary Canal & Associated Organs Mouth & salivary glands Pharynx, Oesophagus Stomach Small intestine- duodenum & ileum Associated organs-liver, gall bladder, pancreas Large intestine- colon, rectum Anus

Alimentary Canal & Associated Organs mouth stomach oesophagus duodenum pharynx colon/ large intestine anus salivary gland liver gall bladder pancreas jejunum ileum rectum

What we learn today. Nutrition (Definition) 5 Processes of Nutrition Digestive Enzymes Alimentary Canal Alimentary Canal & Accessory Organs

Alimentary Canal & Associated Organs duodenum pharynx gall bladder jejunum liver salivary gland ileum oesophagus anus stomach colon/ large intestine rectum mouth pancreas