Unit7

• balanced diet- eating right type of, right amount of food at a right time
• contents of balanced diet are- carbohydrates, proteins, fats, vitamins, minerals, fibre and water
• carbohydrates are from rice, bread potato and pasta

  • provides energy
  • avoid kwashiorkor
• proteins are from meat, fish and eggs

  • growth and repair
  • avoid PEM
• fibre are from cereals, fruits and vegetables

  • provides bulk(roughage) for the intestine to push food through
  • avoid bowel cancer
• calcium are from milk, cheese and eggs

  • avoid rickets
  • avoid osteoporosis later in life
• irons are from liver and red meat

  • avoid anemia
• iodine are from brain

  • avoid goitre
• vitamin A are from carrots, eggs and mango

  • avoid night blindness
• vitamin B are from green leaves, nuts and meat. avoid beriberi.
• vitamin C are from citrus fruits, strawberries and green vegetables

  • avoid scurvy
• vitamin D are from milk, eggs and oily fish

  • avoid rickets
• minerals are from fruits, vegetables and meat

  • needed in small quantities to maintain health
• water are from water, juice and milk

  • for chemical reactions to take place
  • for transport of substances in the body
  • for excretion and digestion
• label human digestion

  A) mouth

  B) salivary glands

  C) esophagus

  D) stomach

  E) liver

  F) gall bladder

  G) pancrease

  H) large intestine

  I) small intestine

  J) rectum

  K) anus

  L) pharynx

  M) appendix

  
• ingestion- taking of substances
• digestion- breakdown of food
• absorption- the movement of nutrients from intestine into blood
• assimilation- uptake and use of nutrients by cells
• egestion- the removal of undigested food from the body as faeces
• physical digestion- the breakdown of food into smaller pieces without chemical change to food molecules
• physical digestion increases surface area of food for the action of enzymes in chemical digestion
• label different types of teeth

  A) molars

  B) premolars

  C) canine

  D) incisors

  
• labels teeth structure

  A) enamel

  B) dentin

  C) pulp

  D) cementum

  E) nerve and blood vessesls

  F) root

  G) crown

  
• teeth is embedded in bone and the gums
• functions of teeth

  • incisors- cut the food
  • canine- tear the food
  • premolar- crush the food
  • molar- grind the food
• • protein digestion- stomach and small intestine
  • insulin production- pancreas
  • deamination- liver
  • partially digested food is mixed with bile- duodenum
  • most water is reabsorbed- small intestine
• The stomach's main role in physical digestion is to break down food mechanically through muscular contractions and mixing with gastric juices. This process, known as churning, helps to reduce food particles into smaller pieces, making it easier for enzymes to further break them down in the small intestine.
• emulsification- convert the large fat particles to small particles, the use is to give more surface area for chemical digestion
• chemical digestion- the breakdown of large insoluble molecules into small soluble molecules
• role of chemical digestion is to produce small molecules thta can be absorbed
• functions of enzymes

  • amylase- breakdown starch to simple reducing sugars
  • protease- break down proteins to amino acids
  • lipase- break down fats and oils to fatty acids and glycerol
  • HCL- destruction bacteria as well as other dangerous organisms
  • maltase- breakdown of sugars and assimilation in the body
• place of production of enzymes

  • amylase- mouth and pancreas
  • protease- pancreas and stomach
  • lipase, pancreas
  • HCL- stomach
  • maltase- small intestine
• HCL or hydrochloric acid in gastric juice-

  kills harmful microorganisms in food

  provides an acidic PH for optimum enzyme activity
• digestion of starch-

  • amylase breakdown starch to maltose
  • maltase breakdown maltose to glucose on the membranes of epithelium lining in small intestine
• digestion of protein by protease

  • pepsin breakdown protein in acidic conditions of stomach
  • trypsin breakdown protein in alkaline condition of small intestine
• bile is an alkaline mixture that neutralizes the acidic mixture of food and gastric juices entering duodenum from the stomach, to provide a suitable PH for enzyme action
• small intestine is the region where nutrients are absorbed
• most water is absorbed in small intestine while some are absorbed by the colon
• villi- increases the surface area for more absorption

  • thin layer wall(one cell thickness)
  • more blood supply