CLASS X: SCIENCE

CHAPTER 6: LIFE PROCESSES

SESSION: IV

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TOPICS TO BE COVERED:

MS. REKHA CHOUDHARY , Kendriya Vidyalaya, Vikaspuri

• TRANSPORTATION IN LIVING ORGANISMS
• HUMAN HEART
• BLOOD VESSELS
• TRANSPORTATION IN PLANTS

• To learn about and appreciate life processes
• To learn about the various parts of Circulatory System.
• To enable students to understand the working of Human Heart.
• To enable students to understand the concept of Transportation in plants

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LEARNING OBJECTIVES

• Process by which food, oxygen, water, waste products are carried from one part of the body to the other parts.
• The Circulatory System consists of Blood, Blood Vessels and Heart.
• Blood – Plasma

- Red Blood Cells

- White Blood Cells

- Platelets

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TRANSPORTATION

HUMAN HEART

• The heart is a muscular organ.
• In Birds and mammals including Human , Heart has four chambers.
• The upper chambers are called atria and the lower chambers are called ventricles.
• The right and left chambers are separated by a septum. It prevents the mixing of oxygenated and deoxygenated blood.
• The atria and ventricles have valves between them to prevent blood flowing backward.

Double Circulation

• The Heart in amphibians and reptiles have three chambers and allows some mixing of oxygenated and deoxygenated blood because they do not use energy to maintain their body temperature.
• Fishes have only two chambers to their hearts, and the blood is pumped to the gills, is oxygenated there, and passes directly to the rest of the body..

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Heart In Other Organisms

BLOOD PRESSURE

• The force that blood exerts against the wall of a vessel is called Blood pressure.
• The pressure of blood inside the artery during ventricular systole (contraction) is called systolic pressure and pressure in artery during ventricular diastole (relaxation) is called diastolic pressure.
• The normal systolic pressure is about 120 mm of Hg and diastolic pressure is 80 mm of Hg.

• Arteries - Vessels which carry blood away from the heart to various organs of the body. The arteries have thick, elastic walls.
• Veins – Vessels which collect the blood from different organs and bring it back to the heart. They do not need thick walls. They have valves that ensure that the blood flows only in one direction.
• Capillaries – These are the smallest Vessels and one-cell thick. Exchange of material between the blood and surrounding cells takes place across this thin wall. On reaching an organ or tissue, the artery divides into smaller Capillaries to bring the blood in contact with all the individual cells. Then Capillaries join together to form veins that convey the blood away from the organ or tissue.

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BLOOD VESSELS

• When we are injured and start bleeding, the loss of blood from the system has to be minimised.
• Leakage in Circulatory System would lead to a loss of pressure which would reduce the efficiency of the pumping system.
• The blood has platelet cells which circulate around the body and plug these leaks by helping to clot the blood at these points of injury.
• Platelets help in Blood Clotting

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Maintenance by Platelets

LYMPH – Tissue Fluid

• Lymph is another type of fluid involved in transportation.
• Through the pores present in the walls of capillaries some amount of plasma, proteins and blood cells escape into intercellular spaces in the tissues to form the tissue fluid or lymph.
• It is similar to the plasma of blood but colourless and contains less protein.
• Lymph drains into lymphatic capillaries from the intercellular spaces, which join to form large lymph vessels that finally open into larger veins.
• Lymph carries digested and absorbed fat from intestine and drains excess fluid from extra cellular space back into the blood.

Transfer of Water in Plants

Root hair

Xylem vessels

• Xylem transports water and minerals from the roots to all parts of the plant.
• It consists of xylem vessels and tracheids.
• Water and minerals enter the roots by diffusion.
• There is steady movement of water into root xylem, creating a column of water that is steadily pushed upwards.

Transfer of Water in Plants

Root hair

Xylem vessels

• The loss of water in the form of vapour from the aerial parts of the plant through Stomata is known as transpiration.
• Evaporation of water molecules from the cells of a leaf creates a suction which pulls water from the xylem cells of roots.
• Transpiration helps in the absorption and upward movement of water and minerals dissolved in it from roots to the leaves.

• Translocation – It is the process of transports food from the leaves to the other parts of the plant.
• It is carried out by Vascular tissue – Phloem.
• The phloem consists of sieve tubes and companion cells.
• The translocation of food and other substances takes place in the sieve tubes with the help of adjacent companion cells both in upward and downward directions.
• Food from the leaves is transferred to the Phloem by the energy of ATP molecules.
• Due to osmotic pressure water enters the phloem and helps in the transport of food.

Transfer of Food in Plants

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• Transportation is the process by which food, oxygen, water, waste products are carried from one part of the body to the other parts.
• In most animals the blood that circulates in the body distributes food and oxygen to different cells of the body.
• Circulatory system consists of the Heart , Blood and Blood vessels.
• In Humans, Blood flows through arteries and veins and the Heart acts as a pumping organ.
• In highly differentiated plants, transport of water, minerals, food and other materials is a function of the vascular tissue which consists of xylem and phloem.

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A QUICK RECAP

• What are the components of the transport system in human beings? What are the functions of these components?
• Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?
• Describe double circulation in human beings. Why is it necessary?
• What would be the consequences of a deficiency of haemoglobin in our bodies?
• What are the differences between the transport of materials in xylem and phloem?

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ASSIGNMENT

• EXCRETION IN LIVING ORGANISMS
• HUMAN EXCRETORY SYSTEM
• FORMATION OF URINE
• EXCRETION IN PLANTS

TOPICS TO BE COVERED IN THE NEXT SESSION