6. Blood Flashcards
What is plasma?
Blood minus the cells
What does plasma comprise?
- Water
- Salts and minerals
- Plasma proteins
- Hormones (signal molecules)
- Other clotting factors
What is serum?
Plasma minus clotting factors
Erythrocytes have a lifespan of how long?
120 days
Where are erythrocytes produced?
In the liver in the foetus and bone marrow in adults
What is the major erythrocyte protein?
Haemoglobin
Where are erythrocytes destoryed?
In the liver and spleen
What is the erythrocyte cell membrane major protein?
Spectrin
What are the 2 different types of leukocytes?
Granulocytes and agranulocytes
What are the 3 different types of granulocytes?
- Neutrophils
- Eosinophils
- Basophils
What are the 2 different types of agranulocytes?
- Lymphocytes
- Monocytes
Describe neutrophils.
- Commonest white blood cell
- Multi-lobed nucleus
- Granular cytoplasm
- 12-14 um diameter
What is the function of neutrophils?
Phagocytic- engulf and destroy bacteria and other foreign macromolecules
What are the 3 types of cytoplasmic granule in neutrophils?
- Primary granules
- Secondary granules
- Tertiary granules
Name 2 examples of primary granules.
Lyzosomes- myeloperoxidase and acid hydrolases
What are secondary granules?
Specific granules that secrete substances that mobilise inflammatory factors
What are tertiary granules?
Gelatinases and adhesion molecules
Describe eosinophils?
- 1% total white blood cells
- 12-17 um diameter
- Bi-lobed nucleus
- Distinctive large red cytoplasmic granules with crystalline inclusions
What is the action of eosinophils? (5)
- Antagonistic in action to basophils
- Phacocytic with particular affinity for antigen/antibody complexes
- Receptors for IgE
- Inhibit mast cell secretion
- Neutralise histamine and restricts the inflammatory response
Describe basophils.
- 0.5% white blood cells
- 14-16 um diameter
- Bi-lobed nucleus and prominent dark blue-staining cytoplasmic granules containing histamine
What are the functions of basophils? (4)
- Involved in inflammatory reactions and prevent coagulation and afflutination
- Circulating form of tissue mast cells
- Receptors for IgE
- Release histamine and other vasoreactivve agents in response to allergens
- Results in immediate hypersensitivity reaction
What are the 2 functional subtypes of lymphocytes?
B cells and T cells
What do B cells become?
Plasma cells which secrete antibodies
What are T cells involved in?
Cell-mediated immunity
What do T helper cells do?
Help B cells and activate macrophages
What do T cytotoxic cells do?
Kill previously marked target cells
What do T suppressor cells do?
Suppress TH cells and supress the immune response
What do natural killer cells do?
Kill virus infected cells
Describe monocytes.
- Characteristic reniform nucleus
- 15-20 um diameter
What are the functions of monocytes? (3)
- Differentiate into several cell types within tissue
- Major phagocytic and defensive role
- Some become antigen presenting cells, passing antigen fragments to lymphocytes
What do monocytes differentiate into?
- Tissue macrophages
- Kupffer cells
- Osteoclasts
- Antigen presenting cells
- Alveolar macrophages
What are platelets?
Fragments of cells derived from large multi-nucleated megakaryocytes in the bone marrow
Describe platelets.
- 1-3 um diameter
- Surrounded by cell membrane
- Contain vesicles with coagulation factors
What are platelets responsible for?
Clotting of blood especially when the endothelium lining of blood vessels is breached
Where do all blood cells form in adults?
In the haematopoeitic bone marrow
What does the myelon series give rise to?
White blood cells
What does the erythron series give rise to?
Erythrocytes
What do megakaryocytes give rise to?
Platelets
What happens in erythropoeisis?
- Reducing cell size
- Haemoglobin production
- Reduction and loss of organelles
- Basophilia in early precurosrs change to eosinophilia in late prescursors
- Loss of nucleus
What is erythropoeisis mediated by?
Erythropoeitin (EPO)
What happens in granulopoeisis?
- Increasing number of granules
- Increasingly complex shape of the nucleus
- Large pool of stored mature neutrophils in marrow
