Biology

Human Immunity and Blood

2,051 Questions

Human immunity and blood questions cover the physiological mechanisms protecting the body against diseases and the components of blood. Topics include blood groups, cell mediated immunity, monoclonal antibodies, and blood coagulation. These biology topics frequently appear in general science sections of competitive exams.

Blood groupsCell mediated immunityMonoclonal antibodiesBlood coagulationCancer immunology

Human Immunity and Blood Questions

Multiple choice

Thrombocytes is another name for _________.

  1. red blood corpuscles

  2. platelets

  3. plasma

  4. white blood corpuscles

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Thrombocytes is the technical medical term for platelets, the blood components involved in clotting.

Multiple choice

Which among the following changes takes place when an antigen reaches a lymph node in an equipped animal?

  1. There is an increase in the output of cells in the efferent lymphatics over the following 24 h.

  2. There is a decrease in the output of cells in the efferent lymphatics over the following 24 h.

  3. There is an immediate output of activated blast cells.

  4. It is transported to the spleen.

  5. It is all immediately destroyed by macrophages.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Antigen-reactive cells are depleted from the circulating pool of lymphocytes within 24 h of antigen first localizing in the lymph nodes or spleen, and there is a dramatic fall in the output of cells in the efferent lymphatics.

Multiple choice

Which among the following specialized cells are involved in the entry of lymphocytes into lymph node within a tissue?

  1. M-cells

  2. Mesangial cells

  3. PALS

  4. HEV endothelial cells

  5. Selectins
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The high-walled endothelium of the post-capillary venules (HEV) in lymph nodes express vascular addressins which are recognized by homing receptors on lymphocytes passing through the afferent lymphatics and which mediate entry of the lymphocytes into the lymph nodes.

Multiple choice

The tactile bodies inside germinal center macrophages are _____________.

  1. the VLA molecules

  2. the Phagocytosed foreign antigen

  3. a sign of macrophage apoptosis

  4. bacterial cell wall components resistant to degradation

  5. the DNA fragments
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

There is very extensive apoptotic cell death amongst light zone centrocytes and the resultant DNA fragments are visible as 'tingible bodies' within the macrophages, which have phagocytosed the apoptotic lymphocytes.

Multiple choice

The paracortical area of a lymph node accomodates significantly

  1. follicular dendritic cells

  2. plasma cells

  3. macrophages

  4. T-cells

  5. B-cells
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

T-cells are mainly confined to the paracortical (thymus-dependent) area of lymph nodes and in nodes taken from children with selective T-cell deficiency. The paracortical region is virtually devoid of lymphocytes.

Multiple choice

S3 stands for pneumococcus polysaccharide SIII. In a lymph node, the antigen pneumococcus polysaccharide SIII causes

  1. lymphocyte proliferation in the paracortex

  2. PALS development

  3. proliferation in cortical lymphoid follicles

  4. development of cellular hypersensitivity

  5. the absence of germinal centers
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Stimulation of antibody-formation by this thymus-independent antigen leads to proliferation in this location with development of germinal centers while the paracortical region remains inactive, reflecting the inability to develop cellular hypersensitivity to the polysaccharide.

Multiple choice

Expression of a CD8 alpha-alpha homodimer is characteristic feature of ____________.

  1. follicular dendritic cells

  2. intraepithelial lymphocytes

  3. eosinophils

  4. classical cytotoxic T-lymphocytes

  5. classical helper T-lymphocytes
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

CD8 alpha-alpha homodimers are almost exclusively found on intraepithelial lymphocytes and may restrict these cells to recognition of certain nonclassical MHC molecules, perhaps including TL and Qa1.

Multiple choice

Fibroblastsare the principal active cells of connective tissue. Which among the following occurs when a resting native T-cell activates its specific MHC/peptide complex on the edge of a fibroblast?

  1. It undergoes blast cell formation.

  2. It produces IL-2.

  3. It becomes anergic.

  4. It moves from Go to G1 of the cell cycle.

  5. It secretes IL-1.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In the absence of costimulator, a cell becomes anergic and incapable of subsequent response to the specific antigen.

Multiple choice

Which among the following is a distinctive feature of B cells?

  1. Class I MHC

  2. CD3

  3. Measles virus receptor

  4. Polyclonal activation by concanavalin A

  5. Surface immunoglobulin
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

B-cells express surface immunoglobulin of a specificity created by that cell's particular immunoglobulin gene recombination. A totally different gene set encodes the T-cell receptor for antigen.

Multiple choice

Which of the following cells do not have nuclei?

  1. White blood cells

  2. Red blood cells

  3. Platelets

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Mature mammalian red blood cells (erythrocytes) lose their nuclei and other organelles to maximize space for hemoglobin, which carries oxygen.