Specialized Connective Tissue: Blood Flashcards
What is the composition of blood? (2)
o Plasma- an aqueous solution with
proteins
o Cells
What are the types of blood cells? (3)
- Erythrocytes (red blood cells)
- Leukocytes (white blood cells)
- Thrombocytes (platelets)
What are the staining types? (4)
o Modified Romanovsky-type stain
o Methylene blue (basic dye)
o Azures (basic dye)
o Eosin (acidic dye)
What are the features of thrombocytes? (4)
What is the function of thrombocytes? (3)
o Surveillance of blood vessels
o Clot formation
o Repair of injured tissue
What are the features of erythrocytes? (8)
- An anucleate, biconcave disc devoid of organelles
- Derived from proerythroblasts in bone marrow
- Structure maximizes surface area
- Diameter of 7.8 μm is used as a histologic ruler
- Has a lifespan of ~120 days
- Erythrocytes can fold over themselves to pass freely
through capillaries - Shape is maintained by integral and peripheral membrane proteins
- Contains haemoglobin
What diseases affected erythrocytes? (2)
o Malaria
- Plasmodium falciparum
- Integrity of cytoskeleton is lost and leads to cell death
o Sickle cell anaemia
- Genetic mutation results in the formation of sickle haemoglobin (HbS)
- RBCs become sickle-shaped
- These cells are more rigid and adhere more readily to endothelial surfaces
What is the classification of leukocytes?
What are the granulocytes? (3)
- Neutrophils
- Eosinophils
- Basophils
What are neutrophils? (6)
- Most numerous leukocytes and most common granulocytes
- 10-12 μm in diameter
- Has a polymorphonuclear nucleus (multilobed)
- Barr body present in females
- Motile cells- extravasate out of blood vessels and into connective tissue
- Short-lived and inactive in circulation- only activate in connective tissue
What are the neutrophil granules? (3)
Granules:
o Azurophilic granules (primary)- lysosomes
o Specific granules (secondary)- enzymes, complement activators, antimicrobial peptides
o Tertiary granules- phosphatases and metalloproteinases
What are the functions of neutrophils? (2)
Functions:
o Phagocytosis of bacteria
o Modulation of other immune cells
What are eosinophils? (2)
- Same size as neutrophils
- Bilobed nucleus
What are the eosinophil granules? (2)
- Granules:
o Azurophilic granules (primary)- lysosomes
o Eosinophilic granules- large refractile specific granules
What are the functions of eosinophil granules? (2)
Functions:
o Associated with allergic reactions, parasite infections and chronic inflammation
o Phagocytose antigen-antibody complexes
What are basophils? (3)
- Same size as neutrophils
- Least numerous leukocyte
- Lobed nucleus is obscured by granules
What are basophil granules? (2)
- Granules:
o Azurophilic granules (primary)- lysosomes
o Basophilic granules- heparin, histamine, heparan sulfate, leukotrienes, interleukin-4 and -13
What are the functions of basophils?
(similar to mast cells)
o Involved in hypersensitivity reactions
What are the types of agranulocytes? (2)
- Lymphocytes
- Monocytes
What are lymphocytes? (3)
- Main functional cells of the immune system
- Most common agranulocytes
- Slightly indented spherical nucleus and scant cytoplasm
How are lymphocytes divided? (3)
- Natural Killer cells (innate immune cell)
- T cells (long lifespan)
- B cells (variable lifespan)
What are Natural Killer cells (innate immune cell)? (2)
- 15 μm diameter with kidney-shaped nucleus
- Release granzymes and perforins to lyse virus infected or cancer cells
What are T cells (long lifespan)?
- Differentiate in the thymus and have T cell receptors
What are B cells (variable lifespan)? (3)
- Differentiate in bone marrow
- Involved in producing circulating antibodies
- Differentiate into plasma cells
What are monocytes? (6)
- Precursor of macrophages and osteoclasts
- 18 μm diameter- largest leukocyte
- Kidney-shaped nucleus
- Travel from bone marrow to body tissue where they differentiate
- Remain in blood for only ~3 days
- Macrophages phagocytose bacteria/cells/debris and are antigen-presenting
