Blood: It is an important connective tissue that circulates in a closed system of blood vessels. Total volume of blood in a human body is 5.5 litres.
Plasma: It contains 90% water and 10% other substances. It contains protein like albumin, globulin and fibrinogen. It transport carbondioxide formed during cellular respiration of the lungs.
Blood Cells:
RBC: It stands for Red Blood Corpuscles. It contains red pigment called haemoglobin. It transport oxygen and carbondioxide between the lungs and all parts of body. They are about 5million in man and 4.5 million in women.
Excess no. of RBC: Erythrocytosis
Deficiency: Anemia
WBC: It stands for White Blood Corpuscles. They are also known as leukocytes and it is about 6000-11000 per mm3 of blood. They protect the body from micro-organisms and provide immunity to the body.
Excess : Leukemia
Deficiency: Leucopenia
Platelets: They perform an important role of clot on the skin in the event of an injury and prevent excess flow of blood from the body.
Excess: Thrombocytosis
Deficiency: Thrombopenia
Functions of blood:
- It carries oxygen from lungs to the cells and tissues and carbondioxide from cells and tissues to the lungs.
- It transports harmful and waste substances like urea, uric acid to the excretory organs.
- It maintains body temperature.
- It produces antibodies which destroys harmful microbes.
The Heart:
Heart beat: The periodic contraction and relaxation of heart is called heart beat. In adults 72-80 times.
Blood Pressure: The pressure exerted by the blood on the walls of arteries is called blood pressure. Systolic b.p means blood pressure when the ventricles are contracted and diastolic when relaxed.
Sphygmomanometer: The device which is used to measure the blood pressure is called sphygmomanometer.
Pacemaker: An electronic device implanted beneath the skin for providing normal heartbeat by electrical stimulation of heart muscles, used in certain heart conditions is called pace maker.
REASONABLE FACTS
1. The wall of right ventricle is thicker than that of right auricle.
Ans- The right ventricle pumps blood into the pulmonary artery forcibly whereas right auricle does not pump the blood into arteries. Hence, the wall of right ventricle is thicker than that of right auricle.
2. Right auricle is larger than left auricle.
Ans- In the right auricle, impure blood of the whole body is poured through superior venacava and inferior venacava whereas pure blood is poured into the left auricle from lungs through pulmonary veins. Since a large volume of blood is collected in the right auricle than that of left auricle, right auricles is larger than left auricle.
3. The wall of left ventricle is thicker than that of right ventricle.
OR
There are more muscular tissues in the wall of left ventricle is thicker than that of right ventricle.
Ans-because right ventricle has to pump for a short distance i.e. from heart to the lungs. But the left ventricle has to pump blood for a very long distance inside our body, for which a great pressure is required. Due to it the wall of left ventricle is thicker than that of right ventricle.
4. WBCs are called soldiers of the body.
Ans- WBCs protects the body from the attack of disease causing germs and other harmful foreign materials. So, WBCs are called soldiers of the body.
5. The person suffering from anemia feels tired after walking short period.
Ans- The person suffering from anemia has deficiency of red blood cells or haemoglobin in his/her blood. So adequate amount of oxygen, cannot be supplied to the body to release energy. As a result, the person suffering from anemia feels tired after walking short period.
6. The wall of artery is made of thick muscles.
Ans- Inside arteries, blood flows with high speed and under high pressure. To bear the great pressure, the wall of artery is made of thick muscles.
7. Bleeding from artery is more dangerous than that from vein.
Ans- Arteries carry pure blood and blood flows with a greater pressure in arteries and wall of arteries is elastic in nature.
8. Veins have valves at intervals in their inner lining whereas the arteries do not have valves.
Ans- Inside veins, blood flows with low speed and under low pressure. So valves are present in the veins at intervals to prevent the back flow of blood. But inside the arteries, blood flows with high speed and under high pressure. So valves are absent in the arteries, as there is no chance of backflow of blood.
9. Pulse is caused by arteries.
Ans- Pulse is caused by arteries because blood flows at high pressure in arteries and wall of arteries is elastic nature.
10. Arteries are deep seated but veins are superficial.
Ans- Arteries are deep seated but veins are superficial because blood flows at high pressure in arteries and at low pressure in veins. To balance the pressure in and out of the blood vessels, they are found at different depth as mentioned above.
11. Colour of the blood is pulmonary artery is purple.
Ans- The colour of oxygenated blood is scarlet or bright red and that of deoxygenated blood is purple because the pulmonary artery carries deoxygenated blood from heart to lungs, the colour of blood in it is purple.
12. Donated blood is treated with sodium citrate.
Ans- Donated blood is treated with sodium citrate because in the donated blood fibrinogen is removed to avoid the blood cloting. Sodium citrate works as anticoagulant.
