Слайд 1DIGESTIVE
SYSTEM
Boarding Schools of Tatarstan R.F.
Слайд 2FOOD
A nutrient is a substance required by the body for energy,
growth, repair, and maintenance. Nutrients in food and beverages include carbohydrates, lipids, proteins, vitamins, and minerals.
Слайд 4Energy and Building Materials
Each nutrient plays a different role in maintaining
a healthy body.
Carbohydrates, proteins, and lipids are involved in providing both energy and building materials to the cells.
Слайд 6Carbohydrates
Carbohydrates that exist as single sugar molecules are called monosaccharides or
simple carbohydrates. Carbohydrates made of two or many sugar molecules linked together by chemical bonds are called complex carbohydrates.
Complex carbohydrates must be broken down into simple sugars before cells can use their energy.
Слайд 7Proteins
Amino acids from proteins are used by the body for making
additional proteins. Extra amino acids in the diet are used for energy or converted to fat.
The body needs 20 different amino acids to function. Ten amino acids (called essential amino acids) must be obtained directly from food.
Слайд 8Lipids
The body uses lipids to make steroid hormones and cell membranes
and to store energy.
Fats are lipids that store energy in plants and animals. Fats are also stored around organs and act as padding and insulation.
Слайд 10Vitamins, Minerals, and Water
Vitamins are organic substances that occur in foods
in small amounts. They are necessary in trace amounts for the normal metabolic functioning of the body.
Minerals are naturally occurring inorganic substances that re used to make certain body structures and substances. They are also needed for normal nerve and muscle function.
Слайд 14DIGESTION
Organisms must break down their foodstuffs into their
components for passing through
the cell membrane.
This process is
called digestion.
Слайд 15 There are two types of digestion. These
are;
Mechanical digestion
Chemical digestion
TYPES OF DIGESTION
Слайд 16MECHANICAL DIGESTION
Pieces of food are firstly cut, crushed, or broken into
smaller particles without being changed chemically. This process is called mechanical digestion.
Mechanical breakdown increases the surface area of the food particles.
. Protein Protein
Слайд 18Chemical digestion is series of reactions in which foods are hydrolyzed,
aided by water and enzymes. Food split into its monomers by means of chemical digestion.
CHEMICAL DIGESTION
STARCH + WATER
n GLUCOSE
Слайд 20TYPES OF DIGESTION ACCORDING TO
THE THEIR MEDIUM
There are two types digestion according to the their medium.These are
EXTRACELLULAR DIGESTION
INTRACELLULAR DIGESTION
Слайд 21INTRACELLULAR DIGESTION
In unicellular organisms foodstuffs are digested within food vacuoles in
the cytoplasm. They are taken into cell by pinocytosis or phagositosis.
Слайд 22EXTRACELLULAR DIGESTION
In this process, digestion of food takes
place within an area external to the organism by the secretion of digestive enzymes.
Extracellular digestion is seen in protista, invertebrates and all vertebrates.
Слайд 24HUMAN DIGESTIVE SYSTEM
The digestive system is made up of highly specialized
digestive tube and several organs.
Human Digestive System includes;
Mouth
Eusophagus
Stomach
Small Intestine
Large Intestine
Слайд 29MOUTH
Food enters the body through the mouth.
Mechanical and chemical digestion
occur in mouth. Teeth help in mechanical digestion.
There are three pairs of salivary glands in the lining of the mouth. Salivary glands secrete saliva into the mouth. They help in chemical digestion
Слайд 31TEETH
Teeth are adapted for mechanical digestion of food.
Each tooth
is composed of crown and root
The crown is covered with enamel. It is hardest material of our body.
Слайд 36TYPES OF TEETH
There are 4 types of teeth. These are
1- Molars
12
2- Pre molars 8
3- Canines 4
4- Incisors 8
TOTAL 32
Слайд 41ESOPHAGUS
After chewing of food, it is pushed by the tongue to
the esophagus. The esophagus connects mouth with the stomach.
Peristalsis begins in the esophagus. Peristalsis is the series rhythmic muscles contraction and relaxations. Food moves through the digestion system by peristalsis.
Слайд 45STOMACH
Food is stored temporarily in the stomach. Mechanical and chemical digestion
occur in mouth. Food is broken down mechanically into smaller particles by the contractions of the muscles.
Stomach secretes enzymes for chemical digestion
Слайд 50Most digestion and absorption occur in small intestine. Most chemical digestion
and all absorption occur in ileum. All digestion is completed in the small intestine.
The small intestine has three parts. They are duodenum jejunum and ileum.
SMALL INTESTINE
Слайд 56Undigested materials pass from the small intestine into the large intestine.
There is no digestion in this part.
The large intestine contains many bacteria. They produce vitamins such as vitamin K.
Large intestine opens to the outside of the body through the anus.
LARGE INTESTINE
Слайд 57FUNCTIONS OF LARGE INTESTINE
Reabsorption of water
Absoption of vitamins
Eliminations of undigested materials
Слайд 59DIGESTION OF CARBOHYDRATES IN THE MOUTH
Chemical digestion of carbohydrate starts in
mouth. Salivary glands secrete saliva into the mouth. Saliva is juice which contain digestive enzyme is called ptyalin or amylase.
Amylase breaks down starch into dextrin and maltose.
Starch + Water
Amylase
Dextrin + Maltose
Слайд 60Stomach is an acidic area. Amylase can not work in acidic
region.
Therefore chemical digestion of carbohydrates stop in stomach.
DIGESTION OF CARBOHYDRATES IN THE STOMACH
Слайд 61 When food passes into the small intestine from
stomach, it stimulates cells of small intestine. Than small intestine secretes two hormones into the blood. These hormones are secretin and cholecystokinin.
DIGESTION OF CARBOHYDRATES IN THE SMALL INTESTINE
Слайд 62They stimulate pancreas and it secretes pancreatic enzymes to small intestine.
Enzymes act on every types of carbohydrates. Pancreatic juice includes amylase, maltase, lactase and sucrase.
Слайд 64 Digestion of carbohydrates is completed in small
intestine.
Dextrin + H2O
Glucose + Glucose +……
Amylase
Maltose + H2O
Maltase
Glucose + Glucose
Sucrose + H2O
Sucrase
Glucose + Fructose
Lactose + H2O
Lactase
Glucose + Galactose
Слайд 66DIGESTION OF PROTEINS
Digestion of protein starts in stomach and complete in
small intestine.
When food enter the stomach, it stimulates some stomach cells.These cells secretes GASTRINE hormone. This hormone stimulates gastric gland and it produces gastric juice.
Gastric Juice is composed of;
Mucus, HCl and Pepsinogen
Слайд 67REACTIONS IN THE STOMACH
Pepsinogen + HCl
Pepsin
Protein + H2O
Peptones
Pepsin
Milk + H2O
Casein
Rennin
Casein+ H2O
Peptones + a.a….
Pepsin
Слайд 68DIGESTION OF PROTEINS IN THE INTESTINE
Tripsinogen and Chymotripsinogen take role in
the digestion of proteins that are secreted by pancreas.
Enterocinase and Erepsin are secreted by intestinal glands to digest proteins.
Слайд 69DIGESTION OF PROTEINS IN THE SMALL INTESTINE
Tripsinogen + Enterocinase
Tripsin
Peptones+H2O
Peptides + Amino acids
Tripsin
Peptides+ H2O
Erepsin
aa + aa + aa + aa +…
Слайд 71DIGESTION OF LIPIDS
Digestion of lipid occurs only in small intestine. The
cells of the liver produce bile. Than it is stored in gall bladder. When food enters to small intestine it secretes cholecystokinin hormone. This hormone causes removing of bile from gall bladder to small intestine.
Слайд 72
Bile does not contain enzyme but it aids mechanical digestion of
lipid. This process is called emulsification.
Слайд 75 Lipase is secreted from pancreas. Lipase breaks down lipid molecules into
fatty acids and glycerol.
Lipid
Small lipid particles
Bile
Lipid + H2O
3 Fatty acid + Glycerol
Lipase
Слайд 77ABSORBTION
There are many finger like projections in lining of small intestine.They
are called VILLI.
Villi increas the absorption surface of small intestine.
Passing of digested materials from small intestine to blood is called absorption.
Vitamins and inorganic materials pass into the blood without digestion.
Слайд 79
The digestive products of carbohydrates, aminoacids and vitamins pass from the
microvilli to the venules (the small branches of the veins).
Fatty acids and glycerol pass from the microvilli to the lymph circulation.