Assalamualaikum.

Biology attack! Hari isnin dah subject critical. Biology and Sejarah. Kena belajar nih weh. Dah nak SPM. Kenalah sedar sikit diri awak tuh. Dan harini saya nak share sikit pasal apa yang saya dah baca :)

• The three components of circulatory system in human and animals are the blood (medium), blood vessels (vessels) and the heart (pump).

• The human blood consists of plasma and blood cells.

• There are three types of blood cells: erythrocytes, leucocytes and platelets.

• Plasma contains water and dissolved substances such as minerals, plasma protein, vitamins, digested food materials, nitrogenous waste products, hormones and dissolved gases.

• Blood is the medium of transport.

• Oxygen is transported to all the body cells in the form of oxyhaemoglobin.

• Carbon dioxide is transported in the form of bicarbonate ions in the plasma and carbaminohaemoglobin in the erythrocytes.

• Humans have a closed, double and complete circulatory system.

• Amphibians have a closed, double and incomplete circulatory system.

• Fish has a closed and single circulatory system, while insects have an open circulatory system.

• Blood clotting prevents serious blood loss, prevents the entry of microorganisms and foreign particles into the body, maintains blood pressure and flow of blood in a closed circulatory system.

• The mechanism of blood clotting involves thrombokinase, prothrombin, vitamin K, calcium ions, thrombin and fibrinogen.

• High hidrostatic pressure of the blood capillary forces certain materials in the plasma to filter out of the blood capillary and fill up the spaces between the body cells. The fluid formed is called interstitial fluid or tissue fluid.

• The lymphatic system complements the circulatory system in the function of transport by transporting substances in the lymph, especially fatty acids, glycerol and vitamins A, D, E and K back to the circulatory system.

• The lymph nodes produce antibodies to act against the antigens.

• There are three lines of the body’s defence mechanism: a) The first line of the defence (skin, mucous membrane) b) The second line of defence (phagocytes) c) The third line of defence (lymphocytes)

• Immunity is the ability of the body to resist the infection pf pathogen by producing a specific antibody.

• Immunisation is the process of acquiring an immunity through innoculation.

• Active immunity involves the production of antibodied by lymphocytes, while passive immunity involves the administration of antibodies into the body from other sources.

• Natural active immunity is acquired when a person recovered from an infection.

• Artificial active immunity is acquired through the injection of vaccine.

• Natural passive immunity is acquired by the offspring from the mother through the placenta of the foetus or the breast milk.

• Artificial passive immunity is acquired through the injection of serum which contains antibodies.

• A healthy cardiovascular system depends on the nutrition and lifestyle of an individual.

• The transport system in plants is the vascular system, which consists of vascular tissue such as xylem tissue and phloem tissue.

• Xylem tissue transport water and minerals from the roots to the leaves and provide mechanical support for the plant.

• The phloem tissue is to transport organic substances from the leaves to all parts of the plants.

• Xylem tissue consists of two types of cells called xylem vessels and tracheids.

• Phloem tissue consists of two types of cells for transport, namely sieve tubes and companion cells.

• Sieve tubes of the phloem tissue transport the product of photosynthesis through a process called translocation.

• Transpiration is the process where water is lost from the leaves in the form of water vapour through the stomata in the leaf.

• Transpiration enables the roots to absorb and transport w

• ater and dissolved minerals from the roots to all parts of the plant. Transpiration gives a cooling effect to the plants.

• Environmental factors that affect the rate of transpiration are temperature, light intensity, relative humidity and air movement.

• The movement of water in the xylem tissue of the plant is due to transpirational pull (suction force), root pressure and capillary action (as a result of cohesion and adhesion of water).

• The movement of water from the soil into the root hairs and through the cortex cells in the root is by osmosis.

• The movement of water through the mesophyll cells in the leaf is also by osmosis.