Question

74) The lymphatic system

A) collects fluid from around the brain and spinal cord.

B) has a pumping mechanism to move fluid.

C) is the site of B and T cell clonal deletion.

D) includes areas of high concentrations of APCs, T and B cells.

E) is very impermeable to extracellular fluid.

94) Viruses that naturally cause clumping of red blood cells can be diagnosed using a(n) ________ test.

A) both agglutination and complement fixation

B) viral neutralization

C) agglutination

D) complement fixation

E) viral hemagglutination

Answer 1

Ans.

1).

• The lymphatic system helps the immune system to remove and destroy waste toxic materials such as debris, dead blood cells, pathogens and toxins.
• The lymphatic system has it's own pumping mechanism to move fluid (lymph) across the body through it's own vessels.
• Lymphatic circulation occurs in one direction from interstitial spaces in the base of neck to the subclavian veins.
• Movement of lymphatic system depends upon the movement of muscle and joint pumps, as it lacks heart to pump it.
• During it's upward movement to the neck, lymph is filtered by lymph nodes causing removal of debris and other toxic pathogens.
• After cleaning, pure lymph flows into the subclavian vein at the base of the neck.

2).

• To diagnose certain enveloped viruses like infuenza virus, hemagglutination test is used.
• This test depends upon the unique feature of certain enveloped viruses to get adsorb on the surface of RBCs.
• This property of adsorption is imparted by an enveloped glycoprotein called hemagglutinin.
• Interaction between hemagglutinin proteins of virus and RBCs causes RBCs to clump together in the presence of virus particle, leading to the formation of a lattice.
• Thus, viral hemagglutination assay can be used to detect certain viruses that naturally causes clumping of red blood cells.