Chapter Notes and Summary
• Amongst most animals blood that circulates in body distributes food and oxygen to different cells in body. It also conveys waste products to different parts of body for excretion.
• Circulatory system is made up heart and blood vessels.
• Among humans, blood flows through arteries and veins. Here heart acts as a pumping organ.
• Blood is made up of plasma, RBC, WBC and platelets. redness in blood is because of presence of a red pigment called ‘Haemoglobin’.
• Human heart beats at rate of nearly 70-80 times per a moment in a grownup being. We refer to this as ‘Heart Rate’.
• function of arteries is to carry blood from heart to other parts of body.
• Veins carry blood from all parts of body back to heart.
• Expulsion of waste product from body is known as excretion.
• Human excretory system is made up of two kidneys, two ureters, a urethra and a urinary bladder.
• Urea and salts are expelled from body with water as sweat.
• Fish excrete waste matter which gets directly dissolved in water.
• Birds, insects and lizard excrete uric acid in semi-solid from.
• Water and mineral nutrient are assimilated by roots of soil.
• Nutrients are carried along with water to whole plant through vascular tissue named ‘xylem’.
• vascular tissue for transporting food to other parts of plant is called phloem.
• Through stomata, plenty of water is lost by plants during transpiration.
• Transpiration builds up a force which draws up water absorbed by roots from soil, to reach stem and leaves.