NCERT Class 7 Science Chapter 11: Transportation in Animals and Plants YouTube Lecture Handouts

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NCERT Class 7 Science Chapter 11: Transportation in Plants and Animals

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BRAIN TEASERS

  • Pulmonary artery carries pure or impure blood? Reason.

  • ____ forms capillaries and these join to form _____

  • Impure blood enters which chamber of heart??

  • Who was known as “circulator”?

  • Difference between egestion and excretion..

  • Is ammonia an excretory product?

  • What is suction force and importance of root hairs?

LET’S BEGIN!!

Transport of food and waste material takes place

Circulatory System

  • Blood is the fluid which flows in blood vessels.

  • It transports substances like digested food from the small intestine to the other parts of the body.

  • It carries oxygen from the lungs to the cells of the body.

  • It also transports waste for removal from the body.

  • It is made of plasma in which various cells are suspended

  • Includes

  • RBC – red by haemoglobin. Haemoglobin binds with oxygen and transports it to all the parts of the body and ultimately to all the cells

  • WBC – fight against germs

  • Platelets: formation of clots – color changes to dark red

Blood Vessels

  • Arteries - carry oxygen-rich blood from the heart to all parts of the body (Since the blood flow is rapid and at a high pressure, the arteries have thick elastic walls and flow only in one direction even without valves)

  • Veins – carry carbon dioxide-rich blood from all parts of the body back to the heart, thin walls, have valves and allows blood to flow only towards heart

  • Capillaries – arteries divide into extremely thin tubes when reaching tissues – join to form veins that empty into heart.

  • Pulse rate - throbbing is called the pulse and it is due to the blood flowing in the arteries. Number o beats per minute is pulse rate and is between 72 & 80 beats per minute

  • Voluntary blood donation is harmless and painless and can save precious lives. Donated blood is stored in blood banks

Heart

  • Beats continuously and act as pump to transport blood

  • In chest cavity with lower tip tilted towards left – of size of fist

  • The two upper chambers are called the atria & the two lower chambers are called the ventricles – with valves

  • Chambers does not allow the pure and impure blood to mix

- Pulmonary artery

- Pulmonary Artery

- Pulmonary artery

  • Pulmonary artery (which takes oxygen-poor blood from the heart to the lungs, where it is oxygenated) - arteries carry blood away from the heart despite the fact that it carries impure blood

  • Pulmonary veins (which bring oxygen-rich blood from the lungs to the heart)

  • Coronary arteries (which supply blood to the heart muscle)

- Noemal Heart

- Noemal Heart

- Noemal Heart

Heartbeat

  • Walls made of muscles that contract and relax rhythmically

  • Measured by stethoscope – made by rubber tube, funnel and balloon

  • Each heart beat generates one pulse in the arteries and the pulse rate per minute indicates the rate of heart beat.

  • It maintains circulation of blood and transport of substances to different parts of body

  • Sponges and Hydra do not possess any circulatory system – water brings food and oxygen & carries away waste as it moves out.

  • William Harvey (A.D.1578–1657), discovered the circulation of blood. The current opinion in those days was that blood oscillates in the vessels of the body. For his views, Harvey was ridiculed and was called “circulator”.

  • Exhalation – removal of carbon dioxide from lungs

  • Egestion – removal of undigested food – large intestine and kidneys

  • Excretion – removal of waste in cells of living organisms - kidneys

  • Excretory System – parts involved in excretion

Excretory System in Humans

  • Filtration of blood by kidneys

  • Kidney – useful substance is absorbed back into blood

  • Urine – waste dissolved in water is removed

  • Adult passes 1–1.8 L of urine in 24 hours. The urine consists of 95% water, 2.5% urea and 2.5% other waste products.

  • Kidney failure due to injury or infection leads to accumulation of waste in blood – requires periodic filtering by artificial kidney - dialysis

- Excretory system in humans

- Excretory System in Humans

- Excretory system in humans

  • Sweat – contains salt and water (white patches on the clothes) – it leads to cooling (similar to water in earthen pot is cold as it evaporates from the pores of earthen pots)

  • Sweat glands are seen in armpits, palm and scalp

  • Aquatic animals like fishes, excrete cell waste as ammonia which

  • directly dissolves in water.

  • Some land animals like birds, lizards, snakes excrete a semi-solid, white colored compound (uric acid).

Transportation of Substances in Plants

  • Plants take water and mineral from soil through roots and root hairs and transport it to leaves by suction force

  • Without the root hairs the roots will not be able to absorb water and nutrients and the plant will die.

- Transportation of substances inplants

- Transportation of Substances Inplants

- Transportation of substances inplants

  • Movement of water by osmosis - Water moves from a region of lower sugar concentration to the region of higher sugar concentration across a membrane -plant absorbs water and minerals by root

  • Leaves prepare food by photosynthesis

  • Energy is released by breakdown of glucose

  • Plat absorb water and nutrient by roots – root hairs – increases surface area of roots for absorption – is in contact with water present between soil particles

  • Vascular tissue – pipe like vessels for transportation

  • A tissue is a group of cells that perform specialized function in an organism.

  • Xylem forms a continuous network of channels that connects roots to the leaves through the stem and branches and thus transports water to the entire plant

  • Phloem transport finished product or food to plant parts

  • Transpiration: Plants absorb mineral nutrients and water from the soil. Not all the water absorbed is utilized by the plant. The water evaporates through the stomata present on the surface of the leaves by the process of transpiration. Evaporation generates suction pull that pulls water to great height in trees and cools plants

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