A person can catch a cold several times in a year because there are many different strains of the cold virus and the body's immune system is not able to build up long-lasting immunity to all of them. This means that even if a person has had a cold before, they can still catch a different strain of the virus.
On the other hand, a person only catches measles once in their lifetime because the measles virus stimulates the immune system to produce long-lasting immunity. Once a person has had measles, their body develops antibodies that can recognize and fight off the virus if they are exposed to it again. Therefore, the person becomes immune to future measles infections.
Explain why a person can catch a cold several times in a year but only catches measles once in his or her lifetime
3 answers
Distinguish between blood, plasma, serum, tissue fluid and lymph
Blood is a fluid connective tissue that circulates throughout the body, delivering oxygen and nutrients to the tissues and carrying away waste products from the cells.
Plasma is the liquid component of blood that contains water, electrolytes, hormones, clotting factors, and proteins such as albumin, globulin, and fibrinogen.
Serum is the clear, yellowish fluid that remains after blood has clotted and the clot has been removed. It contains the same components as plasma, except that it lacks the clotting factors.
Tissue fluid, also known as interstitial fluid, is the fluid that surrounds the cells in the body's tissues. It is formed from plasma that has leaked out of the capillaries and contains water, electrolytes, nutrients, and waste products.
Lymph is a fluid that is similar in composition to tissue fluid but is found in the lymphatic vessels and lymph nodes. It is formed from tissue fluid that has been absorbed into the lymphatic vessels and contains immune cells and lymphocytes that help to fight infections and diseases.
Plasma is the liquid component of blood that contains water, electrolytes, hormones, clotting factors, and proteins such as albumin, globulin, and fibrinogen.
Serum is the clear, yellowish fluid that remains after blood has clotted and the clot has been removed. It contains the same components as plasma, except that it lacks the clotting factors.
Tissue fluid, also known as interstitial fluid, is the fluid that surrounds the cells in the body's tissues. It is formed from plasma that has leaked out of the capillaries and contains water, electrolytes, nutrients, and waste products.
Lymph is a fluid that is similar in composition to tissue fluid but is found in the lymphatic vessels and lymph nodes. It is formed from tissue fluid that has been absorbed into the lymphatic vessels and contains immune cells and lymphocytes that help to fight infections and diseases.
1 answer