Granulocytic cells

The granulocytes are classified as Neutrophils, Eosinophils and Basophils on the basis of cellular morphology and cytoplasmic staining characteristics.granulocytes

a) Neutrophils:

  • It has a multi-lobed nucleus & granulated cytoplasm that stains with both acid & basic dyes.
  • It is often called a "Poly-morphonuclear leukocyte'(PMN)
  • These are produced by hematopoiesis in the bone marrow, which are released into the tissues, where they have a life span of only a few days.
  • Movement of circulating neutrophils into tissues called "Extravasation".
  • The neutrophils contains primary & Secondary granules:

Larger, denser primary granules

Peroxidase, Lysozyme, Various hydrolytic enzymes

Smaller, secondary granules

Collagenase, Lactofemn & Lysozyme

  • Both primary & secondary granules are fuse with phagosomes.
  • The cells exhibit a larger "Respiratory Burst" than macrophages & express higher levels of "defensins" than macrophages do.

b) Eosinophils:

  • The cells are motile phagocytic cells that can migrate from the blood into the tissue spaces.
  • It has a bi-lobes nucleus & a granulated cytoplasm that stains with the acid dye "Eosin" red (hence its name).
  • Play a significant role like phagocytic role like macrophages.
  • The secreted contents of eosinophilic granules may damage the parasite membrane.

c) Basophils:

  • It has a lobed nucleus and heavily granulated cytoplasm that stains with the basic dye "methylene Blue".
  • These are nonophagocytic granulocytes, which release pharmacologically active substances from their cytoplasmic granules. These substances play a major role in certain "Allergic responses".

Popular posts from this blog

B-Lymphocytes

Image
The letter "B" designate from its site of maturation, in the "Bursa of fabricius" in the birds; and " Bone marrow " in the mammalian species, including humans & mice. B-Lymphocytes carries out " Humoral-immune response " by producing antibodies. B-Lymphocytes is stimulated by "T h -lymphocytes". When the antigen stimulate, the B-cell divides repeatedly & differentiate over a 4 to 5 day period, generating a population of Plasma cells & M emory cells. Plasma cells lack membrane-bound antibody, synthesize and secrete one of the five classes of antibody. Each of the approximately 1.5X10 5 molecules of antibody on the membrane of a single B- cell has an identical binding site for antigen. Development of B-Lymphocytes: B-cell differentiation as assessed by membrane immunoglobulin expression can be divided into antigen-independent and antigen-dependent phases. Surrounding microenvironment influences of the bone...
Read more

Elements of Immunity

The term immunity is defined as the resistance shown by the host against the adverse effects caused by microbes and their toxic products. In vertebrates two types of defense mechanisms work together to contact infection. 1. Innate Immunity (or) Non-Specific resistance 2. Acquired immunity or Specific resistance I) Innate Immunity: a) It is a non-specific immunity. b) This mechanism of immunity is similar for most types of infections, hence its name. c) Its resistance to infection is by blocking the entry of pathogens into the body or by destroying the microbes through means other then antibodies. d) Thus no-specific defense mechanism provides innate immunity which operates through many factors. 1) First line Defense (External Defense):             First line defenses are physical barriers like SKIN, MUCUS MEMBRANE, Vaginal Bacterias 2) Second line Defense (Internal Defense):       ...
Read more

Macrophages antimicrobial and cytotoxic activities

Antimicrobicia! & cytotoxic substances produced by activated macrophages can destroy phagocytosed microorganisms. Mediators of antimicrobial and cytotoxic activity of macrophages and neutrophils Oxygen-dependent killing Oxygen-independent killing Reactive oxygen intermediates O 2 .- (Superoxide anion) OH - (Hydroxide radicals) H 2 O 2 (Hydrogm peroxide) ClO - (Hypochlorite anion) Defensins Tumor necrosis factor -alpha (macrophage only) Lysozyme Hydrolytie enzymes Reactive nitrogen intermediates NO (nitric oxide) NO 2 (nitrogen dioxide) HNO 2 (nitrous oxide)   Others NH 2 Cl (monochloramine)   A) Oxygen-dependent killing mechanism: Activated phagocytes produce a number of " Reactive Oxygen Intermediates (ROIs) " & "reactive nitrogen intermediates" that have potent antimicrobial activity.  During phagocytosis, a metabolic process known as the " Respiratory Burst " occurs in activated macrophages. D...
Read more