Carbohydrates• Carbohydrates are good source of energy &• it supplies most of the energy that we need.• It is made up of the elements of carbon,• oxygen and hydrogen.• Carbohydrates can be divided into 3 groups: (a) Monosaccharides - glucose, fructose and galactose (b) Disaccharides - maltose, lactose and sucrose (c) Polysaccharides - starch, glycogen, cellulose
Monosaccharides are carbohydrates which cannot be broken down into simpler forms. Glucose Fructose GalactoseFound in Sugar Sweet fruits Milk
Disaccharides are created when two monosaccharides become linked. Sucrose Maltose Lactose (Glucose + (Glucose + (Glucose + Fructose) Glucose) Galactose)Found in Sugarcane, Sprouting Milk sweet fruits grains
sugar• Sugars are used to make chocolates, candies, soft drinks and cakes.• Excess carbohydrates in the body are converted by the body into fats.
Polysaccharides are long chains of monosaccharidesand are the most common carbohydrates in nature. Storage Structural Polysaccharides Polysaccharides - Stored for future - To maintain the shape use and integrity of the plant Starch Glycogen CelluloseFound Plants Animals Plants in
starch• Starch is found in food such as rice, potatoes, bread, cereals, noodles, yam, cassava, beans and grains.
OBESITY• Excess carbohydrates are turned into fats and stored under the skin which will cause someone to be overweight (obese)• This condition increases their risk of heart attack in the future.
Stroke Other complications due to obesity Blood vessel damage (arteriosclerosis) Heart attack Kidney failure
ANOREXIA• Someone who is seriously underweight is called anorexic.• This happen when they don’t eat or eat less than what they need.• They will feel weak and tired all the time because they do not have enough energy.
fats• Fats give more than twice the energy as the same amount of carbohydrates.• Functions of fats: - reserve supply of energy when we dont eat - are kept under our skin to keep us warm
• Fats are obtained from 2 main sources:(a) Animals - milk, cheese, butter and eggs.(b) Plants - peanut oil, palm oil, olive oil
Are fats bad for us? Not all fats are bad for our health. There are 2 types of fats: (a) Saturated fats - These fats are known for blocking coronary artery in the heart, which eventually leads to heart attack (b) Unsaturated fats - Some fish oils are thought to reduce the growth of fatty deposits in arteries.
Saturated fats Unsaturated fatsFound in Cheese, butter, Vegetable oil, olive animal fats, egg oilEffects blocking coronary reduce the growth artery in the heart, of fatty deposits in which leads to heart arteries. attack.
HEART ATTACK• Fats can caused someone to be obese.• Some fats can block our blood vessels in the heart and cause heart attack.• The fats can also block the blood vessels in the brain and cause stroke.
ProteinsConstituent of Diet Problems protein Excessive Deficient Gout Kwashiorkor
Proteins• It consists of long chains of amino acids which are made up of the elements carbon, hydrogen, oxygen and nitrogen.• Like carbohydrates and fats, protein can supply us with energy.• However, their main function is to build body cells, tissues, enzymes & hormones.
• They are essentials for growth and repair of worn- out parts of our bodies.• Muscles, tendons and cartilage in our bodies are made up of proteins.
Proteins can be obtained from meat, eggs, fish, milk, cheese, and beans
Normal Kwashiorkor KWASHIORKOR• This condition affects most of the children from poor countries.• Such children usually have swollen abdomens.• Their skin cracks and becomes scaly.
fibres Importance Diet ProblemsBowel movement Constipation
Fibers• Fiber is made up of cellulose which cannot be broken down by our bodies.• The right amount of fiber in our diet keeps out intestines healthy and working properly.• The lack of fibers in our diet can caused constipation.
• Vegetables, fruits, brown rice, cereals, whole wheat bread are examples of food which are rich in fiber.
Animals such as cows,sheep and goats are called ruminants. They are able to digest cellulose with the help of bacteria in their stomachs, each of which has four chambers
Vitamins Types of Vitamins Diet ProblemsWater-soluble Fat-soluble- Vitamin B - Vitamin A- Vitamin C - Vitamin D - Vitamin E - Vitamin K
vitamins• Vitamins are needed in small amounts by our bodies for health and growth.• Vitamins are classified according to: (a) Water-soluble -Vitamin B and C (b) Fat-soluble - Vitamin A,D,E,K
VITAMINS OVERDOSEVitamin pills are needed for certain groups such as youngchildren, senior citizen and pregnant women. Most of us do not need vitamin supplements because we get all of our vitamins from our diet. It can be poisonous to us!!
DEATH !!! A group of Italian explorers, who had run out of food ate the liver of a polar bear they had shot. Polar bears liver contains an enormous amount of vitamin D and these explorers suffered the effects of vitamin D poisoning, which resulted in several of them dying.
mineralsTypes of minerals Importance Diet Problems - Calcium To maintain - Iron health - Iodine - Sodium
Minerals• Minerals are substances needed by the body in tiny amounts for proper growth and development.• They are needed in some body tissues and are used in some chemical reactions of the body.
CALCIUM• Functions: - building strong bones and teeth - muscles growth and contraction - clotting of blood• Sources: - dairy products, green vegetables and eggs
IRON• Functions: - make haemoglobin (the red pigment in red blood cells)• Sources: - liver, meat, green vegetables, eggs
• Deficiency problems: - anaemia (low count of red blood cells)
IODINE• Functions: - make hormones of the thyroid gland• Sources: - seafood, seaweed, green vegetables
• Deficiency problems: - goitre (swelling of the thyroid gland in the lower neck)
SODIUM• Functions: - regulating our body fluids• Sources: - common salt (sodium chloride)• Excessive problem: - high blood pressure
water Importance Factors of intake:- to dissolve things Activity Environment- fills up the cells- helps to cool down
Water• Water plays vital roles in many life processes.• Almost 70% of our bodies are made up of water.• We can survive without food for several weeks but we would die in a few days without water
• Water is needed for: - To dissolve things so they can be carried around our bodies - Fills up the cells so they can maintain their shape - Helps to cool down when you sweat - Acts as transporting agent for digested food, wastes, hormones and antibodies
• The amount of water needed in the body depends on:• (a) The activity of the person• - people who are very active require more• water than those who are less active.
(b) The environmental conditions - people who live in hot conditions need more water than those who are in colder environment.
• Water is lost from body daily during breathing, in the urine, the feces and through sweating.• To balance out the amount of water lost daily, we need to drink about 8 glasses of water a day.
digestion• Digestion is the process of breaking down large food molecules into smaller molecules that can be readily absorb by the body.• Digestion occurs in alimentary canal, starts from the food entering our body through mouth and exit from body through anus.
Human digestive system Mouth Mouth Tongue Pharynx Esophagus Esophagus StomachSmall intestine Liver Stomach Gall bladder PancreasLarge intestine Large intestine Small Anus intestine Rectum Anus
TYPES OF DIGESTION Physical Digestion Chemical Digestion Mechanical breakdown Involves the use ofof food by chewing action enzymes to break of teeth and churning down food substances of the stomach
Enzymes• Enzymes are special types of proteins produced by our body for bringing about and speeding up chemical reactions in the body.• Enzymes that breakdown food substances are called digestive enzymes.
• Different types of digestive enzymes help to break down different nutrients into smaller and soluble molecules• Enzymes have an active site which is compatible to one specific substrate (food) Substrate Products Enzyme Active site
Substrate Products Bonds in the substrate are weakenedActive site Enzyme Enzyme-Substrate Enzyme Each type of Once the Then, the enzyme has a substrate is bound products are specific active to the active site, released & thesite, where only one the bonds in enzyme is ready to type of substrate substrate are bind with another can bind to it. weakened. substrate again.
DIGESTION IN MOUTH• Food is broken down into smaller pieces by the teeth.• Breaking up the food into smaller pieces increases the surface area of the food for the digestive enzymes to act on.• The food is then mixed with saliva, produced in the salivary gland. Salivary gland
• Saliva contains salivary amylase (an enzyme) which catalyses the breakdown of starch into maltose molecules.• However, the food is usually not kept long enough in the mouth for all the starch to be broken down into simple sugar. Amylase Digestion Starch molecule Maltose molecules
• The tongue rolls the partially digested food into small balls called bolus before swallowing.• Then the tongue pushes the bolus toward the pharynx (throat) and into the esophagus
OESOPHAGUS (GULLET)• Oesophagus is a narrow tube with strong muscles in its wall, connecting the mouth and the stomach. Oesophagus• The bolus is pushed along the Stomach esophagus to the stomach by peristalsis.
• Peristalsis is the involuntary wave-like muscular contraction and relaxation in the esophagus. Muscular contractions of• No digestive digestive tract enzymes are (peristalsis) produced here.
DIGESTION IN STOMACH• The stomach have Oesophagus Fundus sphincter muscles to Lower control the flow of esophagael food in and out of sphincter the stomach. Pyloric• Functions of sphincter stomach:– Stores food for 2 to 6 hours– Peristalsis and churning actions break apart the food substances.
• Stomach secretes gastric juices which contains hydrochloric acid and proteases• Functions of hydrochloric acid are : • Stop action of salivary amylase • Provides acidic medium for action of enzymes • Change the inactive form of enzymes into an active form. • Kills most of the microorganism in food
• The gastric enzymes are produced as inactive proteases• Proteases catalyse the breakdown of proteins into polypeptides and peptones. Proteases Proteins Polypeptides
• Mucus in the stomach protects the stomach wall from being destroyed by acid and proteases.• Food is then gradually converted to semi- fluid substance called chyme.• Chyme is pushed into the duodenum.
THE LIVER• The main function of liver in digestion is to produce bile.• Bile is a brownish- Liver green liquid which contains bile salts and bile pigments.• Bile is stored in gall bladder and Bile released into the duct duodenum through bile duct. Gall bladder
PANCREAS• Pancreas produces pancreatic juice which is released Pancreas into the duodenum Pancreatic through pancreatic duct duct.• Pancreatic juice contains enzymes such as: - Lipase Bile duct - Proteases - Amylase Duodenum
DIGESTION IN DUODENUM• The duodenum Bile from Bile from connects the gallbladder liver stomach & the small intestine. Pancreas• It receives bile from the liver Bile and pancreatic duct juice from pancreas. Duodenum
• Functions of bile: - Neutralizes acidic Lipid Bile chyme from stomach salts - Emulsify fats into oil droplets for lipase to act upon Increase surface area
Functions of pancreatic juice are: - Neutralizes acidic chyme - Contains digestive enzymes: Enzyme Action of the enzymePancreatic Starch maltose amylaseProteases Proteins Polypeptide Lipases Fats fatty acids and glycerol
DIGESTION IN SMALL INTESTINE• The small intestine consists of three sections: DUODENUM connects to the stomach JEJUNUM the longest part ILEUM attaches to the first portion of the large intestine.
• Tiny glands in small intestine produce intestinal juice which contains several types of digestive enzymes: Enzyme Action of the enzyme Maltase Maltose glucose Protease Polypeptides amino acids Lipase Fats fatty acids and glycerol
SMALL INTESTINE VILLI Veins to the liverLayers of Lumenmuscles Blood capillariesVilli Lacteal
ABSORPTION OF DIGESTED FOOD• Absorption is the movement of digested food through the wall of small intestine.• It takes place because of diffusion. Lacteal• Diffusion is the movement of the molecules from higher Blood concentration to lower capillary concentration.• The internal surface of the small intestine is covered with villi.
• The villi increase the surface in contact with the digested food, so it can absorb faster.• The walls of small Lacteal intestine are richly supplied with blood vessels to carry away the Blood digested food. capillary• The fatty acids & glycerol will diffuse into lacteal.• The glucose & amino acids will diffuse into the blood vessels.
LARGE INTESTINE• Large intestine does not secrete any enzyme. Large• Water, minerals and intestine vitamins are absorbed by large intestine.• The undigested and unabsorbed matter are discharged as faeces through anus.
• This process of discarding faeces through anus is called defecation.• If the undigested food passes through the large intestine too slowly, too much of water will be absorbed.• The faeces will become hard and dry.• This condition will leads to constipation.