Answer:
Helper T cells stimulate B-cells to produce antibodies and killer T cells to destroy the non-self cells. Cytotoxic T cells on the other hand are direct attack cells. They can kill the micro organisms by creating pores on the invader's cell.
Explanation:
T lymphocyte mediated immunity of cell mediated immunity do not secrete antibodies but they help stimulate the B cells to produce them. Immature T cells are produced in bone marrow from where they migrate to thymus via blood. In the thymus maturation of T cells occur and then they migrate to lymphoid tissue and get differentiated into three types:
a. Helper T cells: As the name suggests, they help in activating other immune cells, in other terms they are the regulator of virtually all functions of immune system. Protein mediator called lymphokines are produced by these helper T cells in order to regulate the immune functions. Some examples of these lymphokines are: Interleukin-2 interleukin-3, interferon gamma. T helper cells stimulate the B-cells to produce antibodies.
b. Cytotoxic cells or killer T cells: The lymphokine interleukin-2 is responsible for the growth and proliferation of both cytotoxic T cells and suppressor T cells. With the help of receptor proteins on the surface of killer T cells, they bind to the specific antigen. After binding, they secrete a pore forming protein called perforins which create pores on the invaders cell membrane for water to enter into it thereby cell swells and finally lyse.
c. Suppressor T cells: They suppress the function of above two T cells.
The correct answer is the fourth option. The magnification of a specimen viewed with a compound light microscope that has an objective power of 10x and an ocular lens power of 5x is equal to 50x. Magnification is equivalent to the product of the objective power and the ocular lens. Ten times five is fifty.
Answer:
Pneumonia is an infection of the lungs caused by bacteria virus fungi or protozoa in rare condition.
no he is not right plz mark me as a brilliant
Answer:
The living organism is the organism that responds to external stimulus, moves, grows, respire, reproduce, eat and excrete.
Movement - An organism moving from place to place.
Respiration - The release of energy from glucose, occurring in every cell. we respire in order to produce energy
Sensitivity - the ability to detect and respond to stimuli. When we touch something hot, we remove our hand suddenly.
Growth - The production of new cells in an organism.
Reproduction - The process which is used to create offspring similar to parents.
Excretion - The release of harmful substances from the body. We excrete carbon dioxide when we exhale.
Nutrition - Consumption of food for energy. We get nutrition by eating three meals a day.
