Human Immunity and Blood

Neutrophils are granular leukocytes, containing neutral granules, in the cytoplasm. They represent 60-70%of WBC cells. The cell nucleus is 2-7 lobed. The primary functions of neutrophil are phagocytosis, ingestion and digestion of invading microorganism.

Neutrophil are granular leukocytes, containing neutral granules in the cytoplasm. They represent 60-70%of WBC cells. The cell nucleus is 2-7 lobed. In the neutrophil of human female adjacent to the nucleus, a drumstick-like hetero chromatin body is present, called Barr Body. It represents one of the two X chromosomes of female. The primary functions of neutrophil are phagocytosis, ingestion and digestion of invading microorganism.

Histamine is a natural substance produced by the body and is also present in many foods. It is released by the body during times of stress and allergy.

Mature mammalian erythrocytes (red blood cells) lack mitochondria and a nucleus to maximize space for hemoglobin. Other listed cells require mitochondria for energy production.

This option is correct. In humans, this protein is encoded by the STOM gene. It is present in membrane-protruding folds and extensions.

Blood plasma is the liquid, cell-free part of blood. Corpuscles (red blood cells, white blood cells, and platelets) are suspended in the plasma, not contained within it as a part of the plasma itself.

Platelets (thrombocytes) are cell fragments in the blood that aggregate at the site of an injury to form a clot and prevent excessive bleeding.

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

CD8 + T-cell receptor on the cytotoxic T-cell, recognize the MHC class I + peptide on the target cell surface.

Dendritic cells are potent antigen presenting cells that possess the ability to stimulate naïve T-cells. There are several types of dendritic cells, well distributed over the body.

Centroblasts are found in the dark zone and are highly mitotic cells with no surface IgD and very little surface IgM.

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.

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.

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.

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.