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Chapter – 11 Transportation in Animals andPlants
Transportation inanimals:
In most of the animals the blood that circulates in the body distributes food and oxygen to different cells of the body. It also carries waste products fromdifferent parts ofthe body forexcretion.
Circulatory system consists of the heart and blood vessels.
In humans, bloodflows through arteries and veins andthe heart actsas a pumping organ.
Blood is thefluid which flowsin blood vessels. It transport substance like digested food from the smallintestine to theother parts ofthe body.
Blood consists of plasma, RBC,WBC and platelets. Blood is reddue to thepresence of ared pigment, haemoglobin which binds with oxygen and transport oxygen to various parts.
The human heart beats about 70to 80 times per minute inan adult person. This is called heart rate.
Arteries carry blood from the heart to all parts of the body. Veins carry blood from all parts of the body back to the heart. Removal ofwaste products fromthe body iscalled excretion.
Excretory system ofhumans consists oftwo kidneys, twoureters, a urinary bladder, and urethra.
Salts and ureaare removed alongwith water assweat.
Fish excrete wastesubstances such as ammonia whichdirectly dissolve in water. Birds, insects and lizard excrete uric acidin semi-solid form.
Transportation inplants : Water and mineral nutrients are absorbed by roots fromthe soil. Nutrients aretransported along withwater to theentire plant viathe vascular tissue called xylem.
The vascular tissue for thetransport of foodto the various parts of theplant is phloem. A lotof water is lost byplants in theform of vapour through stomata during transpiration. Transpiration generates a force whichpulls up water absorbed by theroots from the soil, to reach thestem and leaves.
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