Transportation in Animals and Plants Class 7 Science Notes - Chapter 11
Transportation in Animals and Plants Class 7 Science Notes - Chapter 11
Preview of the chapter
'To convey things from one place to another' is what the verb "transport" signifies. To carry out many life processes, an organism's body needs nourishment and oxygen. Waste products created by the body's various processes also need to be transported and disposed of. As a result, the term "transport" can be used to describe a process in life in which a substance is absorbed in a part or organ of an organism and then transported to other sections of that organism's body.
These actions are carried out through the circulatory system, an internal transportation system found in animal bodies.
Introduction
Circulatory System
- Circulatory system or blood circulatory system is the main transport system in human beings and animals.
- It makes food, water and oxygen available to every parts of the body and helps in removing waste material (urea, CO2, etc).
- The circulatory system consists of blood, blood vessels and heart
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| Human Circular System |
Blood
It is a fluid tissue that flows in blood vessels. It is red in colour and it flows through a network of tubes in whole body called blood vessels.
- Blood is pumped to every part of the animal by heart.
- Blood consist of four components, i.e. plasma, Red Blood Cells (RBCs), White Blood Cells (WBCs) and platelets.
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| Blood |
Plasma
Most blood cells are suspended in plasma, the liquid portion of the blood.
- Up to 95% of it is water, and it also has dissolved nutrients, carbon dioxide, and oxygen.
RBC (Red blood cells)
RBCs are red in colour due to the presence of pigment called haemoglobin.
- Haemoglobin is a red protein that binds with oxygen and transports oxygen to all the parts of the body and ultimately to all the cells.
- It is the presence of haemoglobin which makes the blood appear red.
- It forms carboxyhaemoglobin with C02, this C02 is expelled out from the body.
WBC ( white blood cells)
The blood contains white blood cells (WBC), which are part of the immune system.
- They are like soldiers, which fight and kill germs that may enter the body
Blood Vessels
Blood travels throughout the body through tubes called blood vessels.
- Blood vessels are the collective name for arteries, veins, and capillaries.
Arteries
Arteries are blood channels that transport oxygenated blood to our body's cells and tissues.
They are responsible for transporting blood from the heart to the tissues.
Veins
Veins are blood veins that transport deoxygenated blood away from our body's cells and tissues.They transport blood from the tissues to the heart.
Capillaries
Capillaries are the tiniest blood arteries in the body.
- It performs the most critical function of the circulatory system: material exchange between circulation and cells.
- Because of the increased surface area, the fine network facilitates the process of material diffusion.
Heart
The heart is an organ that beats continually to pump blood through a system of tubes or blood arteries, carrying other substances with it. Throughout our lives, the heart continues to pump blood without resting or stopping.
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| Heart |
Valves
In veins as well as the heart, there are valves.
- They can be found in the heart at the base of large vessels leaving the heart as well as between the atria and ventricles.
- Blood flows in the body in a single path thanks to valves.
- The heart's characteristic lub-dub sound is caused by heart valves that open and close.
Pulmonary Circuit
It is the system of veins and arteries that joins the heart and lungs.
- Blood that has not been oxygenated is pumped from the body to the lungs.
- The heart receives the oxygenated blood again to pump it to the rest of the body.
Oxygenation of Blood
The alveoli of the lungs are where the blood is oxygenated.Blood is oxygenated by diffusion and is surrounded by blood vessels in the alveoli.
Pulse
The heart expands and contracts on a regular basis to pump blood into the arteries, which similarly expand and contract as blood flows through them. This is known as pulsation.
- This pulse of the arteries can be felt in several parts of the body, including the wrist.
- Pulsation is defined as the number of heartbeats per minute, also known as pulse rate.
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| Pulse |
Stethoscope
The heartbeat can be heard by an instrument called as stethoscope. It is used by doctor to amplify the sound of heart. It consists of
- a chest piece that carries a sensitive diaphragm
- two earpieces
- a tube joining both the parts
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| Stethoscope |
Excretory System
Excretion
The process of removal of waste materials produced in the cells of the living organism is called excretion.
- These are called waste materials.
- These waste material are toxic or poisonous and causes harm to the body.
- therefore, the waste material must be removed from the body so that a person may stay healthy.
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| Excretory System |
Kidneys
- These are called the magic filters.
- Kidney are bean-shaped organs present at the back of our body, just above the waist.
- It is brick red coloured about 4 inches long.
- It is richly supplied with blood vessels.
- Kidney can filter the unwanted substances from the blood.
- Each kidney consists of thousands of tiny filters called nephrons.
- When the blood containing urea and other waste salts pass through these nephrons, it filters the blood and removes urea and salts and urine are left in the kidney.
- The urine thus formed by each of the kidney is then passed through the ureter (a tube-like structure which connects the kidney to the bladder) to urinary bladder.
- The urine is stored in the urinary bladder for some times and at regular intervals it, is removed through the opening at the end of the tube called urethra.
- The process of ejection of urine is called micturition.
- The opening of urinary bladder is controlled by the ring of muscle called as bladder sphincter.
Ureters
Urine is sent from the kidneys to the urinary bladder through tubes called ureters.
Urinary Bladder
- The urinary bladder is a muscular bag where urine is accumulated and excreted from the body through the urethra.
- It can hold about 300-500 mL urine for a while before the urge to empty occurs.
Carbon Dioxide
- Carbon Dioxide It is produced as a waste product in our body cells during the process of respiration.
- The food is broken down during respiration to release energy and releases CO2 as a by-product.
- This CO2 is removed from our body by the lungs during exhalation.
- Therefore, lungs also act as the excretory organs for removing the waste product, CO2from the body.
Sweat
Sweat is the liquid waste of the body produced by the sweat glands. It contains water, salts and urea in a small amount, and is evaporated from the body during hot summer days. It helps to remove excess water, salt and urea and keep the body cool.
Dialysis
Kidney failure is a condition where the kidney stops working due to infection or injury. This can lead to the accumulation of urea in the blood, which must be removed through dialysis. The long-term solution is kidney transplantation, where the diseased or damaged kidney is removed and the matching kidney is donated by a healthy person. The donated kidney is then transplanted in its place by performing surgery.
Excretion in Other Animals
Animals also excrete waste products from their bodies, depending on the availability of water. Fishes excrete ammonia in the gaseous form, while land animals excrete uric acid pellets. Urea is the excretory product of humans, cows, goats, etc., and is eliminated as urine. Amoeba, Paramecium, etc. are unicellular organisms and their excretory products are removed by diffusion from the body of the organism into the surrounding water.
Transportation in Plants
Osmosis
Osmosis is the transport of solvent molecules through a semi-permeable membrane from an area of lower solute concentration to a region of higher solute concentration
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| Osmosis |
Root Hair
- Root hairs are elongated extensions of the roots that resemble animal hairs.
- They expand the surface area, allowing for more water and mineral exchange.
Phloem
Phloem is the plant tissue that transports the soluble organic material created during photosynthesis from the leaves to the other parts of the plant.
Xylem
Xylem is the plant tissue that transports the water and other nutrients from the roots to other parts of the plant.
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| Xylem & phloem |
Transpiration in Plants
Transpiration is the process of evaporation of water through the stomata present on the surface of leaves. This causes an upward pull, called a suction force, which pulls the water from roots upward through the stem, branches and finally to the leaves. It is necessary for plants due to its cooling effect, transport of water and minerals to the leaves for photosynthesis, and increased rate of absorption of water through the roots. In hot sunny days or in moving air, the rate of transpiration increases due to the heat from the sun or moving air causing evaporation of water at a faster rate.
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| Transpiration in Plants |
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