Write Short Answers To The Questions:
- What happens when blood flow to the muscles is increased?
Increased blood flow delivers more oxygen and nutrients to the muscles and removes metabolic waste products like carbon dioxide more efficiently.
- Why is the muscular wall thicker of left vertical than that off right ventricle?
Left ventricle has thicker muscular wall because it needs to generate a much higher pressure to pump oxygenated blood to the entire body, whereas the right ventricle only needs to pump deoxygenated blood to the nearby lungs.
- Why is the heartbeat different when your body is at rest than when you are exercising?
During exercise, the body’s muscles require significantly more oxygen. The heart rate increases to pump blood faster. But at rest, the demand is lower, so the heart rate is slower.
- Describe the function of liver in circulatory system.
The liver filters blood coming from the digestive tract and passes waste product to kidneys.
- Write one main difference between venules and arterioles.
Venules are small blood vessels whose function is to collect blood from capillary. Arterioles are small subdivisions of arteries that carry blood to capillary networks.
- Why is it much easier to stop blood flow from a vein than that from an artery?
Blood in veins is under much lower pressure compared to the high pressure of blood pumping directly from the heart through arteries.
- Why is red blood cell colour red?
Red blood cells are red because they contain a protein called haemoglobin, which binds with oxygen and contains an iron-containing heme group that gives blood its distinctive red colour.
- Name two blood proteins present in human body.
Two main blood proteins are antibodies and fibrinogen.
- Name four of the materials carried by blood.
Blood carries oxygen, nutrients, hormones, and waste products.
- What work does a valve in the heart or vein do?
Valves in the heart and veins ensure unidirectional blood flow by opening to let blood through and then closing to prevent blood from flowing backward (backflow).
- Which four products constitute the blood?
Red blood cells, white blood cells, platelets, and blood plasma.
Differentiate between arteries and veins.
| Arteries | Veins |
| Carry blood from the heart | Carry blood to the heart |
| Have thick walls of muscles and elastic fibres | Have thin walls of muscles than arteries |
| Valves present only where arteries leave heart | Valves are present to prevent backflow of blood |
| Blood flows in pulses | Blood flows steadily |
| Blood is under high pressure | Blood is under low pressure |
| Blood is bright red and contains oxygen | Blood is dull red and contains carbon dioxide |
Label the given diagram of heart and write function of each part
Write a note on red blood cells.
- A red blood cell is round with both surfaces hollowed in a shape called biconcave disk.
- They do not have a nucleus and live short only for up to 100 days.
- They have an elastic cell membrane.
- They can change shape and move through narrow blood capillaries.
- They transport oxygen from lungs to all parts of the body.
Write a note on white blood cells.
- They are of different types with different shapes of nucleus.
- They are twice as big as a red blood cell.
- They are made in bone marrow and live for a long time.
- They protect the body against harmful bacteria by engulfing them.
- They produce antibodies which kill germs change poisonous chemicals into harmless substances.