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1. To distribute nutrients.
2. To remove waste products.
3. To transport respiratory gases.
4. Transportation of hormones.

It is the movement of molecules from the area of higher concentration towards the area of lower concentration or where they are absent.

If some carbon dioxide is released from a cylinder placed on one corner of the room the gas molecules will move about at random in the air after some time they will become evenly distributed throughout the room.

Exchange of respiratory gases across the cell membrane take place through diffusion.

Osmosis is the movement of solvent molecules from the area of higher concentration towards the area of lower concentration through the semipermeable membrane.

Membrane which allows both solvent and solute molecules to pass through it. E.g., filter paper, cell wall in plant cell.

Membrane which allows only small (solvent) molecules to pass through it is called semipermeable membrane. E.g., cell membrane.

Membrane which doesn't allow any molecules to pass through it is called impermeable membrane.

Take a beaker. Fill it with water. Take a thistle funnel lined with semipermeable membrane. Fill 35% sugar solution in thistle funnel and place it in a beaker. Fix the thistle funnel with iron stand. Mark the level of solution in the stem of thistle funnel. Leave the apparatus for some time.

After some time it will be noticed that the level of sugar solution will rise in the stem of thistle funnel.

The rise in level of sugar solution in thistle funnel is due to the movement of water molecules from beaker into the thistle funnel by the process of osmosis.

Movement of solvent molecules from outside to inside of the cell is called endosmosis.

Movement of molecules from inside to outside the cell is called exosmosis.

1. Root absorb water molecules from soil by the process of osmosis.
2. Water molecules pass from the cell to another by osmosis.

The swelling of cell of plant due to excess of water is called turgor. Inside the cell wall there is a cell membrane which is semipermeable membrane. When concentration of water around cell is high endosmosis take place and cell become turgid. In this condition vacuole and protoplasmic concents exerts pressure on cell wall. This pressure is called turgor pressure.

1. This pressure keep the stem of young plants upright.
2. Rapid increase in length and elongation in roots is due to turgor.

Absorption of water takes place through the root hairs. Root hairs are microscopic outgrowths of epidermal layer of root. Water is absorbed by root hairs and brought to the epidermal layer. From epidermal layer it is carried to the cortex and from here it is brought to the xylem vessels. Through xylem vessels it is brought to the stem and leaves.

Conduction of water and mineral salts from root to the arial parts of the plant is called ascent of sap.

Ascent of sap takes place through xylem vessels.

Pressure exerted by the cortical cells of the root on sap. It is weak force and contribute weak force for ascent of sap.

as the result of loss of water molecules from stomata spongy mesophyll become less saturated as the result vacuum is created this contribute for a suction pressure and water molecules move from xylem to the spongy mesophyll. In this way water molecules move from root to the leaves in a form of chain of water molecules. Transpiration pull is strongest known force responsible for the ascent of sap.

Loss of water vapours from the arial parts i.e. (leaves) of the plant is called transpiration.

1. Plants loose excess of water molecules through the process of transpiration.
2. The process of transpiration keeps the plant cool during hot days.
3. It provides strongest force responsible for the ascent of sap.

Rate of transpiration is directly proportional to the temperature of surroundings.

Rate of transpiration is directly proportional to the light.

Rate of transpiration is inversely proportional to the humidity.

Rate of transpiration is directly proportional to the velocity of wind.

Translocation is the process by which synthesized food is transported from leaves to the different parts of the plant body. This process takes place through the phloem tissues.

Synthesized food is transported in the form of glucose and amino acids. This food is stored in different parts of the plant like root, stem, leaf and fruits. In addition this food is used in assimilation and cellular respiration.

Plants manufacture excess amount of food and store it in the different parts of the plant body. Examples,

In turnip, radish, carrot and beet plants excess food is stored in roots.

In potato and ginger food is stored in stem.

Food is also stored in seeds of plant which is used by embryo during development.

Stored food is utilized by plants during autumn as leaves fall in autumn and food cannot be prepared by plants.

Following are some points in significance of transport system.

1. Transport of O₂.
2. Transport of CO₂.
3. Transport of waste products.
4. Transport of hormones.
5. Transport of nutrients.

Heart is muscular organ. It is located in thoracic cavity between two lungs. It is enclosed in a membrane called pericardium. Between the two layers of pericardium there is a fluid called fiencardial fluid.

Human heart consist of four chambers.

1. Right atrium
2. Left atrium
3. Right ventrical
4. Left ventrical

Two atria are separated by interatrial septum, and two ventricals are separated by interventricular septum.

Valves are special arrangement in heart which allows unidirectional blood flow and prevent back flow of the blood. Right atrioventricular valve incurpid valve lies between right atrium and right ventrical. Left atrioventricular valve is situated between left atrium and left ventrical. Aortic valve situated at the junction of left ventrical and aorta. Pulmonary valve is situated at the junction of right ventrical and pulmonary trunk.

Contraction of chamber of heart.

Relaxation of chambers of the heart.

Blood from all parts of the body is collected in right atrium. At same time left atrium receive oxygenated blood from lungs through pulmonary veins. This is diastolic phase of atria. After this both atria contract and blood is pumped to the respective ventricles through biaspid and triaspid valves. This is systolic phase of atria.

After this both ventricles contract and blood is pumped to lungs from right ventrical and to all parts of the body from left ventrical. This is ventricular systole.

These are vessels which bring blood from heart to the different parts of the body.

These are blood vessels which bring blood from organs to the heart.

These are microscopic vessels lined by single layer of epithelium. Exchange of different substances can easily take place through capillaries.

When blood is forced in aorta during ventricular systole it expand arterial walls this expansion is called pulse. The normal pulse rate is 72 per minute.

Pressure exerted by blood on blood vessels. During ventricular systole its value is 120 mm Hg and during ventricular diastole its value is 80 mm Hg. The pulse pressure is 120- 80 = 40 mm Hg.

Blood is composed of plasma and formed elements.

It consist of water, electrolytes, enzymes, hormones, vitamins, nutrients, fibrinogen, etc.

Formed elements consists of following parts.

They are biconcave disc like cells. They are non nucleated cells. RBCs are formed in bone marrow. They contain a pigment called haemoglobin which carry oxygen.

They are found in different sizes. They are nucleated. WBCs provide protection to our body from disease causing factors like bacteria, virus etc.

These are fragments of cells. They are smaller in size. They play important role in blood clotting.

In ABO system there are four blood groups.

1. A
2. B
3. AB
4. O

Person having blood group A has antigen A and antibody B.

Person having blood group B has antigen B and antibody A.

Person having blood group AB has antigen AB and no antibody.

Person having blood group O has no antigen but has antibody AB.

Determination of blood group is essential for blood transfusion.

Antigens are found on the surface of RBC. They stimulate the formation of antibodies. They are protein in nature.

They are found in plasma. They provide defense to our body against foreign antigen.

It is tendency or ability of body to resist against diseases.

Incolation of certain antigen (virus and bacteria) to induce production of antibodies to increase immunity against disease.

Watery fluid separated from clotted blood and free from blood cells and fibrin.