Question

question 1
1 pts
the functions of the lymph nodes are
defense and hemostasis.
defense and diapedesis.
defense and hematopoiesis.
hematopoiesis and hemostasis.

question 2
1 pts
______ is the only antibody class with the ability to cross the placental barrier, providing passive immunity to the developing fetus during pregnancy.
ige.
igg.
igm.
iga.

question 3
1 pts
memory cells:
immediately secrete antibodies when they are formed.
are supporting cells and are not related to antibody production.
are a special type of t cell.
become plasma cells when exposed to an antigen.

Explanation:

• Question 1: Lymph nodes play a crucial role in the immune system (defense). Hematopoiesis (blood cell formation) mainly occurs in bone marrow, hemostasis (blood clotting) involves platelets and clotting factors, and diapedesis is the movement of cells through blood vessel walls. So, the main function related to lymph nodes is defense.
• Question 2: IgG is the only antibody class that can cross the placental barrier. IgE is involved in allergic reactions, IgM is the first - line antibody in the primary immune response but does not cross the placenta well, and IgA is mainly found in mucosal secretions.
• Question 3: Memory cells do not immediately secrete antibodies (plasma cells do). They are not just supporting cells. Memory B cells (not T - cells in this context) become plasma cells when re - exposed to an antigen.

Answer:

• Question 1: defense and hematopoiesis (Note: There is an error in the options. The main function of lymph nodes is defense. But if we have to choose from the given options, hematopoiesis is incorrect. However, assuming it's a mis - optioning and we consider the immune - related 'defense' part, but strictly speaking, the options are flawed).
• Question 2: IgG
• Question 3: become plasma cells when exposed to an antigen.