Transportation in Animals & Plants

  • The heart, an extensive network of blood vessels and blood forms circulatory system.
  • Blood is a red coloured fluid which flows in the blood vessels to every part of the body.
  • An average person has 4.5 – 5.5 litres of blood.
  • Blood consists of two components:
  • Fluid component:
    • Plasma
    • Yellowish colour
    • Contains 90% water
    • It also contains electrolytes, proteins and carbohydrates.
  • Solid Component:
    • Red Blood Cells (Erythrocytes)
    • Red in colour
    • Haemoglobin is present
    • Produced in bone marrow of bones
    • Average lifespan is about 120 days
    • Disc shaped
    • White Blood Cells (Leucocytes)
    • Colourless
    • Irregular shape
    • Lifespan is few hours to few years
    • It fights against germs that enter our body
    • Platelets (Thrombocytes)
    • Colourless
    • Round and tiny cells
    • Formed in bone marrow
    • Lifespan is about 8-14 days
    • It helps in clotting of blood
  • Blood Vessels:
  • Blood flows through a network of tubes known as ‘blood vessels’.
  • Three types of blood vessels:
    • Arteries
    • It carries blood from the heart to various parts of the body.
    • Carries oxygen rich blood except pulmonary artery
    • Thick and elastic walls
    • Lies deep under our skin
    • Veins
    • It carries blood from all the parts of the body back to our heart
    • Carries carbon dioxide rich blood except pulmonary vein
    • Thin and less elastic muscular walls
    • Less deeply situated than arteries
    • Capillaries
    • It connects arteries to veins
    • Thin walls
    • Useful substances like food and oxygen present in blood pass into the body cells through the capillaries.
  • The throbbing sensation due to the flow of blood under pressure in your arteries is called pulse.
  • The number of beats per minute is called the pulse rate.(72-80 beats per minute for a healthy person)
  • Heart
  • Pumps blood to all the parts of our body through the blood vessels.
  • Located between lungs
  • Size is roughly equal to the fist (about 12 cm in length and 9 cm in breadth)
  • It is enclosed in a double-layered membranous sac called pericardium.
  • It has 4 compartments called chambers.
  • Upper two chambers-Auricles
  • Lower two chambers-Ventricles
  • Left side of heart has oxygen rich blood
  • Right side of heart has carbon dioxide rich blood
  • Left and right side of heart are separated by a wall called septum.
  • Tricuspid valve is present between right atrium and right ventricle.
  • Bicuspid valve is present between left atrium and left ventricle.
  • The pulmonary vein brings the oxygenated blood from the lungs into the left atrium.
  • When left atrium contracts, the oxygenated blood is pushed into the left ventricle.
  • When left ventricle contracts, it pumps oxygenated blood into the main artery called aorta.
  • Oxygenated blood from arteries passes through capillaries of the body organs and gives food and oxygen to body cells.
  • Deoxygenated blood collected from the body organs enters the right atrium.
  • When right atrium contracts, the deoxygenated blood is pushed into right ventricle.
  • When right ventricle contracts, the deoxygenated blood is pumped into the lungs through pulmonary artery.
  • In the lungs, deoxygenated blood gives out carbon dioxide and absorbs fresh oxygen from the air being breathed in.
  • The contraction phase of the heart muscles is called systole.
  • The relaxed phase of the heart muscles is called diastole.
  • One complete rhythmic contraction of the heart followed by its relaxation is called a heartbeat.
  • Average heart rate is 72-80 times per minute.
  • Excretion in Animals
  • The process of removal of waste products produced in the cells of the living organisms is called excretion.
  • Excretory organs in various organisms:
  • Amoeba, Paramecium, Hydra – Through body surface by diffusion
  • Earthworms, leeches – Nephridia
  • Insects – Excretory organs
  • Vertebrates – Kidneys
  • Excretory organs in Humans:
  • Large Intestine – Undigested food is thrown out through anus in the form of faeces.
  • Lungs – Carbon dioxide is removed by exhalation
  • Skin – Sweat
  • Kidneys – Help in removal of urea, waste salts and excess water in the form of urine.
  • Excretory systems in Humans:
  • When the blood reaches the two kidneys, it contains both useful and harmful substances.
  • Useful substances are absorbed back in blood.
  • Nephron filters harmful substances.
  • Waste products dissolved in water are removed from kidney in the form of urine.
  • From kidney, urine goes into urinary bladder through ureters.
  • Urine is stored in urinary bladder and passed out from body through urethra.

Published by Priya Prakash

In the midst of winter, i found there was within me an invincible summer ~ Albert Camus

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