BIOLOGY CHAPTER # 09
TRANSPORT CLASS IX
Define the following terms
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Blood
The fluid that circulates in the heart, arteries, capillaries, and veins of a vertebrate animal carrying nourishment and oxygen to and bringing away waste products from all parts of the body.
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Water potential
Water potential is the potential energy of water in a system compared to pure water, when both temperature and pressure are kept the same.
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Diffusion
Diffusion is the process of movement of molecules under a concentration gradient. It is an important process occurring in all living beings. Diffusion helps in the movement of substances in and out of the cells.
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Stomata
Stomata are the tiny openings present on the epidermis of leaves.it is surrounded by two guard cell.
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Bifacial leaves
Leaves that have stomata at lower epidermis called bifacial leaves.
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Humidity
Humidity is the concentration of water vapour present in the air. Water vapor, the gaseous state of water.
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Sieve plates
A perforated wall or part of a wall at the end of one of the individual cells making up a sieve tube First Known Use of sieve plate.
(viii) Granulocytes
A type of white blood cells in the immune system, granulocytes are differentiated by the presence of a particular granule in their cytoplasm.
(ix) Heart beat
Pumping of blood by rhythmic pulsation of heart throughout the body is called heartbeat.
Distinguish between the following in tabulated form
- Pulmonary circuit and systematic circuit
| PULMONARY CIRCUIT | SYSTEMATIC CIRCUIT |
| The circuit through which blood flows from the heart to lungs and back is called pulmonary circuit, | The circuit through which blood flows from the heart to body tissues and back is called systemic circuit. |
| The arteries of pulmonary circuit carry deoxygenated blood, | Systemic circuit carry oxygenated blood. |
| Pulmonary circuit receives blood from body tissues and circulates it through lungs | Systemic circuit receives blood from pulmonary veins and pumps to the aorta, which spreads the oxygenated blood thought out the body. |
| Pulmonary circuit’s components are found mainly in the abdominal cavity, associated with lungs | Systemic circuit’s components are found in all over the body.
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- Open type circulatory system and close type circulatory system
| Open Circulatory System | Closed Circulatory System |
| The hemolymph directly bathes the organs and tissues. | The blood circulates within closed vessels. |
| The blood and interstitial fluid cannot be distinguished. | Blood and interstitial fluid are distinct. |
| Present in molluscs and arthropods. | Present in annelids and vertebrates. |
| Blood is pumped into the body cavity. | Blood is pumped through the vessels by the heart. |
| Capillary system is absent. | Capillary system is present. |
| Blood is in direct contact with the surrounding tissues. | Blood is not in direct contact with the tissues. |
- Xylem and Phloem
| Xylem | Phloem |
| Xylem tissues are the tubular-shaped structure, with the absence of cross walls. This tissue resembles the shape of a star. | Phloem tissues are tubular-shaped, elongated, structures with the presence of walls with thin sieve tubes. |
| It is located in the centre of the vascular bundle. | It is located on the outer side of the vascular bundle. |
| Xylem fibres are smaller. | Phloem fibres are larger. |
| They are present in roots, stems and leaves. | They are present in stems and leaves, which later transports and grow in roots, fruits and seeds. |
| These tissues move in a Unidirectional. (only in one direction – upward direction) | These tissues move in a Bidirectional. (both ways – up and down) |
| They live with hollow dead cells. | They live with cytoplasm without the nucleus. |
Arteries and Veins
| ARTERIES | VEINS |
| Involved in carrying oxygenated blood except for pulmonary arteries | Involved in carrying deoxygenated blood except for pulmonary veins |
| Consists of three distinct layers, which are rigid, thicker and highly muscular. | Consists of three distinct layers, which are thinner and less muscular. |
| Located deep within the body. | Peripherally located closer to the skin. |
| Red in colour. | Blue in colour. |
| Carry blood away from the heart to various parts of the body. | Carry blood towards the heart from the various parts of the body. |
| High pressure, as the blood flows by the pumping pressure of the heart. | Low pressure, as the blood flows by the capillary action of the veins. |
| Comparatively higher oxygen level. | Comparatively low oxygen level. |
B.Cs and R.B.Cs
| RBC – Red Blood Cells | WBC – White Blood Cells |
| Red blood cells are called Erythrocytes. | White Blood Cells are called Leucocytes or Leukocytes. |
| RBCs have a bi-concave disc shape | WBCs have an irregular shape. |
| Size varies from 6 – 8 µm in diameter. | Size varies from 12 – 17 µm in diameter. |
| The lifespan of RBC is about 120 days. | The lifespan of WBC is around 12-20 days after which they are destroyed in the lymphatic system |
| Red blood cells do not have a nucleus on maturity. | WBCs are characterized by the presence of a large central nucleus. |
| Due to the presence of hemoglobin, these cells appear red in color. | These cells are colorless, as they do not have any pigment. |
Write short answers of following questions
- Why capillaries are made up of single layer of endothelium?
Capillaries are smallest of all blood vessels and their wall is made up of single layer of epithelial cells known as endothelium. They help to enable the exchange of water, oxygen, carbon dioxide, and many other nutrients and waste substances between the blood and the tissues.
- How water flow through xylem?
The tension created by transpiration “pulls” water in the plant xylem, drawing the water upward in much the same way that you draw water upward when you suck on a straw. Cohesion (water sticking to each other) causes more water molecules to fill the gap in the xylem as the top-most water is pulled toward the stomata.
- Why veins contain semilunar valves in it?
Right at the very start of the aorta is the aortic valve and at the very start of the pulmonary artery is the pulmonary valve, each of which are semilunar. In the heart there are two semilunar valves that lead to blood vessels. The pulmonary semilunar valve leads to the pulmonary trunk, and the Aortic semilunar valve leads to the Aorta.
- Why atherosclerosis cause myocardial infraction and stroke?
Causes of myocardial infarction can be divided in to non-modifiable factors (which we cannot change) and modifiable factors (which we can change). Non-modifiable factor
| Non-modifiable factors | Modifiable factors |
| Sex (More in males)
Age ( More in old age) Race (More in blacks) Family history |
Stationary life (no exercise)
Smoking Stress Heavy alcohol consumption High fat diet |