Unit 7: Human Nutrition

Balanced diet

Getting all the right nutrients in correct proportions

Factors affecting diet

Age, gender, activity, pregnancy

Malnutrition

A condition caused by eating an unbalanced diet

Over-nutrition

Balanced diet but eating too much

Under-nutrition

Having too little food

Coronary heart disease

Eating too much fats which are rich in cholesterol

Constipation

Lack of fibre in food because fibers are indigestible and forms bulks. Friction between bulk and walks of intestine stimulate the peristalsis.

Obesity

Eating too much fats and carbohydrates leads to their storage in the body and increase in body weight

Carbohydrates

Energy

Fats

Energy, building materials, energy store, insulation, buoyancy, making hormones

Proteins

Energy, building materials, enzymes, hemoglobin, structural material, hormones, antibodies

Vitamin C

Protect cells from aging, immune system, prevent scurvy

Vitamin D

Absorption of calcium

Calcium

Development and maintenance of strong bones and teeth

Iron

Making hemoglobin

Fibre

Provides bulk for feces, promotes peristalsis

Water

Chemical reaction, solvent

Lack of Vitamin C

Pale skin and sunken eyes, Scurvy

Lack of Vitamin D

Rickets, weak bones and teeth

Lack of Calcium

Rickets, weak bones and teeth, poor clotting of blood

Lack of Iron

Anaemia

Ingestion

The taking in of substances into the body

Digestion

The breakdown of food

Absorption

The movement of nutrients from the intestines into the blood

Assimilation

Uptake and use of nutrients by cells

Egestion

The removal of undigested food from the body and feces

Incisors

Rectangular shape, sharp for cutting and biting

Canine

Sharp-pointed for holding and cutting

Premolar

Blunt for chewing and crushing

Molar

Chewing and crushing, two roots

Enamel

Strongest tissue in the body made from calcium salts

Root Canal

Help to anchor teeth

Pulp cavity

Contains tooth#producing cells, blood vessels and nerve endings which detect pain

Dentine

Calcium salts deposited on a framework of collagen fibre

Neck

In between crown and root, it is the gums

Tooth decay

Coating of bacteria and food on teeth

Emulsification

Breaking down large fats droplets into small oil droplets

Physical digestion

Breakdown of large particles to small particles

Chemical digestion

Breakdown chemical bonding between molecules

Mouth

pH: 7. Contains teeth used for physical digestion

Stomach

pH: 1. Kill bacteria. Elastic wall

Duodenum

pH: 10. Liver produces bile salt → stores in gall bladder → bile salt emulsifies fat globules

Stomach Acid

HCL: Kill bacteria, provide optimum pH for enzymes and to denature salivary amylase.

Absorption

Movement of digested food molecules through wall of the intestine into the blood or lymph

Ileum

Where absorption takes place. The small intestine is folded into many villi which increase surface area for absorption

Epithelium

Only one cell thick for faster transport

Capillary

Transport glucose and amino acids

Hepatic portal vein

Delivers absorbed products to the liver

Lacteal

Absorbs fatty acids and glycerol

Colon

Part of the large intestine that absorbs minerals and vitamins. Also reabsorbing water from waste to maintain body’s water levels

Rectum

Part of the large intestine where feces temporarily stored