Class 10 Science Transportation Exam Notes

Transporation

This Class 10 Science exam notes page on Transportation covers the need for transport in living organisms, the human circulatory system with blood and its components, blood groups and the Rh factor, blood clotting, the structure of the human heart, double circulation, and transport of water and food in plants through xylem and phloem, along with transpiration.

TRANSPORTATION

Transportation is the movement of materials from one part to another, usually from the region of their availability to the region of their use, storage or elimination.

FUNCTION OF TRANSPORTATION

Food:
Food is available at particular points, for example leaves in plants and the alimentary canal in animals. Food has to be transported to every living cell of the body for extraction of energy and materials.

Metabolic Gases:
Oxygen and carbon dioxide are the two metabolic gases. Oxygen is required by every living cell for cellular respiration. It has to be transported from the outside environment first to the respiratory surfaces, and then to individual cells in animals or directly to the cells in plants. Carbon dioxide is formed as a by-product and is passed out for elimination.

Waste Products:
Toxic waste products are produced during metabolism and must be excreted. For this, they are first taken to the kidneys for separation, translocated to the urinary bladder for storage, and then carried from the urinary bladder to the region of elimination.

Water:
Plants absorb water from the soil with the help of their roots. It is transported to all parts of the plant.

Hormones:
Hormones are formed in particular regions and are transported to the areas where they function.

TRANSPORTATION IN HUMAN BEINGS

In humans, the transport of oxygen, nutrients, hormones and other substances to the tissues, of CO₂ to the lungs, and of waste products to the kidneys is carried out by a well-defined circulatory system. In lower organisms, materials are transported by diffusion.

Circulatory System:
The circulatory system comprises the heart, blood vessels, blood, lymphatic vessels and lymph, which together serve to transport materials throughout the body.

The components of the circulatory system in higher animals are:
1. Blood
2. Pumping organ, the heart
3. A system of blood vessels for distribution and collection of blood, consisting of arteries, veins and capillaries.

[Figure: Flow diagram titled BLOOD. Blood divides into Plasma and Blood cells. Plasma divides into Serum and Protein. Blood cells divide into Erythrocytes (Red blood corpuscles), W.B.C and Platelets]

BLOOD CORPUSCLES

I. Red Blood Corpuscles (RBC) or Erythrocytes:
These are minute, circular, biconcave discs having no nucleus. They look red due to the presence of the red coloured pigment haemoglobin. Red blood cells have a life span of about 120 days. They are produced in the bone marrow. The number is 4.5 to 5.5 million per cubic mm.

Function:
Haemoglobin transports oxygen from the lungs to the body tissues.

II. White Blood Cells (WBC) or White Blood Corpuscles:
These are large, nucleated, colourless cells and are less numerous than erythrocytes. There are about 5000 WBC per millilitre of blood.

[Figure: DIFFERENT TYPES OF BLOOD CELLS IN MAN. Granulocytes are Neutrophil, Eosinophil and Basophil. Agranulocytes are Lymphocyte and Monocyte. Also shown are the surface and side views of an erythrocyte (RBC) and platelets]

WBC are mainly of two types:
(i) Granulocytes: their cytoplasm has granules and the nucleus is lobed.
(ii) Agranulocytes: their cytoplasm does not contain granules and the nucleus is a single large spherical nucleus.

III. Blood Platelets:
Platelets are rounded, colourless, biconvex and non-nucleated blood cells which help in the coagulation of blood. They are also called thrombocytes.

KINDS OF BLOOD VESSELS

There are three types of blood vessels in the human circulatory system.

(A) Arteries:
Arteries carry blood from the heart and supply it to the organs. They have thick muscular walls and are deep seated. All arteries carry oxygenated blood except the pulmonary arteries, which carry deoxygenated blood to the lungs for purification. They do not have valves.

(B) Veins:
Veins collect blood from the tissues of the organs and bring it to the heart through two big veins, the superior and inferior venae cavae. Veins carry deoxygenated blood except the pulmonary veins. They have thin walls, are placed more superficially, and contain valves.

(C) Capillaries:
Capillaries are extremely thin-walled and narrow vessels. They lie closely placed with the cells of the tissue in an organ. Oxygen and food pass into the cells, and carbon dioxide and other wastes pass into the capillaries from the cells.

IMPORTANT TERMS

The following terms should be understood clearly before studying blood groups.

(A) Antigen:
An antigen is a substance capable of stimulating the formation of an antibody. It is any substance, such as a bacterium or virus, that the body regards as foreign. It may be formed in or introduced into the body, and it is capable of causing disease. Antigens are present on the red blood cells of the donor.

(B) Antibody:
An antibody is a specialised protein produced by certain white blood cells (lymphocytes) in response to the entry of a foreign substance, that is an antigen, into the body, in order to render it harmless.

BLOOD GROUPS

Landsteiner discovered four blood groups in human beings, based on the mutual compatibility of antigens and antibodies. They are A, B, AB and O.

A person with blood group O can give blood to all the groups, and hence is called the universal donor. Similarly, a person with blood group AB can receive blood from all the other groups, and hence is called the universal recipient.

Blood group O does not contain any antigen on the surface of its red blood cells, so no reaction occurs with the blood of the recipient.

The plasma of blood group AB does not contain antibodies, so no reaction occurs with the antigens of the donor's blood.

Rh Factor (Rhesus Factor):
The Rh factor is a kind of antigen in the blood. It was first found in the Rhesus monkey. On the basis of the presence or absence of the Rh factor, human beings are divided into Rh positive (Rh⁺) and Rh negative (Rh^-).

The Rh factor is important in childbirth. If the blood of the baby (embryo) is Rh⁺ and the mother is Rh^-, she may lose her baby, as antibodies will attack the baby. Nowadays this condition is medically not considered as serious, and certain techniques and procedures are available to save the baby.

Table of Blood Groups:

FUNCTIONS OF BLOOD

Blood performs the following functions:

Transport of Oxygen and Carbon Dioxide:
Blood transports oxygen from the respiratory surfaces (the lungs and buccal cavity) to the body tissues, and carbon dioxide from the tissues to the respiratory surfaces.

Transport of Food:
Blood transports digested food to the different cells of the body.

Transport of Waste Products:
Blood transports the waste products of cells and organs to the kidneys, lungs, skin and intestine, so that they may be eliminated.

Chemical Coordination:
Hormones produced by endocrine glands are distributed to the vital tissues by the blood.

Defence Against Infection:
When bacteria or any other disease-causing pathogen enters the body, it is destroyed by WBCs. One type of WBC, called lymphocytes, produces antibodies against a specific pathogen, and so immunity against the disease is created in the body.

Clotting of Blood:
To prevent excess bleeding, blood platelets and some proteins form a clot, which prevents further bleeding.

Water Balance:
Blood maintains a constant body temperature, and distributes and exchanges water between the cytoplasm of cells.

Temperature Regulation:
Heat produced by the deeper tissues is taken to the body surface, so that it may be given out, and the body temperature is maintained.

Maintenance of Body pH:
In RBC, some carbon dioxide combines with water to form carbonic acid (H₂CO₃), which dissociates into H⁺ and HCO₃^-. These ions combine with the ions of plasma to maintain a constant pH.

Maintenance of Pressure:
Arteries maintain a proper blood pressure, which helps to balance the atmospheric pressure.

BLOOD CLOTTING

Sequence of events during clotting of blood:

[Figure: Flow chart showing clotting of blood. Injured tissue and blood platelets release Thromboplastin, with Vitamin K from the Liver and Ca⁺² acting on Prothrombin (inactive, in blood) to form Thrombin (active). Thrombin converts Fibrinogen (soluble) into Fibrin (insoluble). Fibrin, together with dead RBCs, dead bacteria and dead WBCs, forms the clot]

THE HUMAN HEART

The heart is a pumping organ that receives blood from the veins and pumps it into the arteries. It is made up of cardiac muscles. It is situated in the thoracic cavity, above the diaphragm and between the two lungs. It is enclosed in a double-walled membranous covering called the pericardium.

Chambers of the Heart:
The interior of the heart is divided into four chambers, which receive the circulating blood.

The Auricles:
The two upper chambers are called the right and left auricles. They are separated by a partition called the inter-atrial septum. The sinoatrial node (SAN), or the pacemaker, is located in the upper wall of the right atrium.

The Ventricles:
The two lower chambers of the heart are the right and left ventricles. They are separated from each other by an inter-ventricular septum.

Valves of the Heart:
Valves are muscular flaps which prevent the blood from flowing back. Two types of heart valves are distinguished:

The Atrio-Ventricular Valves:
These valves separate the atria from the ventricles. The right side of the heart has the tricuspid valve, and the left side has the bicuspid valve, also called the mitral valve. They prevent the backward flow of blood into the atria.

Semilunar Valves:
These are located in the arteries leaving the heart.

Blood Flow Through the Heart:
The path of blood flow can be shown as under:

[Figure: Flow diagram of blood through the heart. Deoxygenated blood from the body enters the Vena cavae and then the Right Auricle, then the Right Ventricle. From the Right Ventricle, deoxygenated blood goes through the Pulmonary artery to the Lungs. Oxygenated blood returns through the Pulmonary veins to the Left Auricle, then the Left Ventricle, then the Systemic aorta, and then to the Body. The pulmonary circulation runs between the right ventricle and the left auricle, and the systemic circulation runs between the left ventricle and the right auricle through the body]

DOUBLE CIRCULATION

Double circulation has two components: pulmonary circulation and systemic circulation.

[Figure: Showing double circulation and function of blood to provide oxygen. Pulmonary circulation has lung capillaries, pulmonary artery to lungs and pulmonary vein from lungs. Systemic circulation has vena cava from the body, deoxygenated blood, aorta to the body, oxygenated blood, and capillaries in body organs apart from the lungs. The heart lies in the middle]

Pulmonary Circulation:
Pulmonary circulation is the movement of blood from the heart to the lungs and back. Deoxygenated blood of the body enters the right auricle, passes into the right ventricle, which pumps it into the pulmonary arch. With the help of two separate pulmonary arteries, the blood passes into the lungs.

Systemic Circulation:
Systemic circulation is the circulation of blood between the heart and the different parts of the body except the lungs. Oxygenated blood received by the left auricle passes into the left ventricle. The left ventricle pumps it into the aorta, for supply to the different body parts, including the walls of the heart, with the help of arteries.

Double circulation is an improvement over single circulation, as the heart pumps both oxygenated and deoxygenated blood forcefully through the body. In amphibians and reptiles, double circulation is incomplete due to the mixing of blood. It is complete in birds and mammals.

TRANSPORTATION IN PLANTS

Some materials (gases) pass in and out of plants through diffusion. Other materials required for building the plant body, such as nitrogen, phosphorus, other minerals and water, are obtained from the soil. They have to be transported over long distances, depending upon the size of the plant. There are two independent pathways having conducting tubes. One is xylem, which moves water and minerals from the soil to the aerial parts. The other is phloem, which carries food from the region of availability (for example leaves and storage organs) to the areas of utilisation.

Xylem (Wood):
Xylem is a complex tissue which transports sap (water and minerals). It has four types of cells: xylem fibres, xylem parenchyma, tracheids and vessels. Vessels and tracheids are called tracheary elements, because they take part in the transport of sap. Both tracheary elements have lignified walls.

Phloem:
Phloem is a complex tissue which takes part in the transport of food. It has four types of cells: sieve tubes, companion cells, phloem parenchyma and phloem fibres. Only phloem fibres are dead cells; the others are living cells.

TRANSPIRATION

Transpiration is the loss of water in vapour form from the exposed parts of a plant. There are three types of transpiration: lenticular, cuticular and stomatal.

Lenticular Transpiration:
This is the loss of water in vapour form from the lenticels present in the bark of stems. It is only 0.1% of the total.

Cuticular Transpiration:
This is the loss of water in vapour form through the cuticle covering the leaves and other aerial parts. The amount of cuticular transpiration depends upon the thickness of the cuticle.

Stomatal Transpiration:
This is the loss of water vapour through the stomata present over the leaves and other soft aerial parts. It always occurs whenever the stomata are open for gaseous exchange.

[Figure: Transpiration or evaporation of water from aerial surfaces, causing absorption and ascent of sap]

•Pumping organ- 'Heart'  

• Similarly a person with AB blood group is called Universal Recipient as he can receive blood of all other groups.

• The plasma of blood having blood group AB do not have antibodies therefore reaction will not occur with the antigen of the donars blood.

 The Atrio-Venticular Valves :

FUNCTION OF BLOOD OF PROVIDE OXYGEN.