structure of heart

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Review questions-circulatory system

REVIEW QUESTIONS
Give one word for the following:
1. A blood vessel that transports oxygenated blood from lungs to heart.
2. A blood vessel that poured blood into right atrium.
3. Covering of heart.
4. The thinnest blood vessel
5. The cells of blood responsible for clotting of blood.
6. The blood vessel which carry blood back to the heart from lungs
7. The largest artery of the heart.
8. The blood vessels which connect arteries to veins
9. A non nucleated cell present in human blood.
10.
Differentiate between the following:
1. Artery and vein
2. Red blood cell an White blood cell
3. Blood and lymph
Short answer questions
1. What is the meaning of double circulation?
2. Draw the human heart and label its parts.
3. Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?
4. How many chambers are there in the heart of (1).an amphibian, (2).mammal, and (3) a fish?
5. Describe the circulatory system in a fish.
6. How do amphibians tolerate mixing of blood?
7. List three differences between an artery and vein.
8. What is lymph? Why it is called extra cellular fluid?
9. Why is lymph important for the body?
10. How is lymph returns back to the blood?
Long answer questions:
1. Explain various types of blood cells.
2. Explain how oxygenated blood from lungs is sent to all parts the body
3. Explain the structure of heart with the help of well labeled diagram.

Blood vessels

BLOOD VESSELS

• Arteries and veins are the main blood vessels.

1. Have thick walls to withstand the pressure of the blood and a small lumen
2. Carry blood from heart to different organs.
3. Do not have valves
4. Carry oxygenated blood to the whole body except pulmonary artery.
5. Situated deeper in the tissues

Veins:

1. Have thinner walls and a large lumen.
2. Carry blood from organs towards the heart.
3. Have valves to prevent the back flow of blood.
4. Carry deoxygenated blood to the lungs except pulmonary vein.
5. Situated superficially.

Capillaries: Have extremely thin walled and very narrow lumen. They do not have valves Blood flows with low pressure. Allow exchange of gases food materials and waste. Capillaries join together to form venules then they join to form veins.

Lymphatic system

Lymphatic system is an open circulatory system. It consists of lymphatic capillaries Lymphatic vessels, lymph nodes and lymphatic organs. Lymph flows in one direction only i.e. from tissue to heart.

Capillaries have very fine pores through which blood plasma filters out and starts flowing into the inter cellular spaces. This fluid is called extracellular fluid. A part of this fluid enters into the lymph capillaries. The fluid inside the lymph capillaries is called lymph. Lymph is yellow fluid which contains blood plasma minus blood proteins.

Lymph enters into lymph capillaries which join together to form large lymph vessels The lymph vessels finally drains lymph into large veins.

Functions of lymph

1. It takes up excess fluid that has diffused out from the blood capillaries and puts it into blood.
2. It has lymphocytes which fight against germs and bacteria and produce antibodies to fight against infections.
3. It absorbs and carries digested fats from the intestine.
   

ciculatory system

Circulatory system

Blood circulatory system of man consists of following components:
Blood
Blood vessels
Heart

BLOOD
Functions of Blood
1. Transport of nutrients
2. Transport of respiratory gases
3. Transport of waste products
4. Transport of hormones
5. Transport of water, inorganic ions and elements.
6. Regulation of body temperature
7. Protection from diseases

Composition of blood
i) IT is red coloured fluid connective tissue that circulates in the body.
ii) It looks red in colour due to pigment hemoglobin present in red blood cells.
iii) It has two components:
a. Plasma
b. Cells

Blood plasma: It is a pale yellow fluid that forms 55% of blood. It contains water, plasma proteins, inorganic compounds, food waste, hormones, enzymes and other compounds.

Blood Cells: There are three types of blood cells.
i. Red blood cells or erythrocytes i. White blood cells or leucocytes
ii. Blood platelets or thrombocytes

All blood cells together form about 45% of blood and float in the blood plasma.


Red blood cells :

1. Circular and biconcave shape


2. Without nucleus


3. Cytoplasm has hemoglobin, a red pigment that gives red colour to these cells.


4. Transport oxygen from lungs to tissues and help in transport of carbon dioxide from tissues to lungs. Protect the body against diseases and infections.


5. Number varies from 4.5-5 million /cubic mm.

White blood cells :

• Round or irregular shape


• Distinct nucleus


• 3.Cytoplasm is colourless without hemoglobin.


• Protects the body against diseases and infections.


• Number is much less than red blood cells. Varies from 7000-10,000/cubic mm.




• 
  Blood platelets
  1. Irregularly shape, fragments of cells
  2. Without nucleus
  3. Cytoplasm is colouless
  4. Help in clotting of blood.
  5. Number is around 2,50,000/cubic mm.
  
  In infants red blood cells are formed in the red bone marrow of stem cells. In adults red blood cells are formed in the red bone marrow of stem cells of the bones of skull, ribs, sternum, vertebrae and pelvic bones. Life span of red blood cells is about120 days after which they are destroyed in spleen or liver.