Peripheral Blood constituents, components and functions Flashcards
What does blood carry to the body?
nourishment eg. glucose - electrolytes e.g Na, K, Cl – hormones – vitamins – antibodies – heat – oxygen – WBC - defense
What does blood carry away from the body?
- waste matter e.g urea
– carbon dioxide
What is blood made up of?
Plasma
Red blood cells (erythrocytes)
Platelets
White blood cells (leukocytes)
What are the types of leukocytes present in blood?
lymphocytes monocytes eosinophils (granulocyte) Basophils (granulocyte) neutrophils (granulocyte)
What are the functions of red blood cells (erythrocytes)
Transport O2 from lungs to tissues
Transport CO2 from tissues to lungs
RBC - shape, avg diameter, volume
Shape-biconcave disc
Avg diameter- 7.2um
Volume - 88fl
How does the shape of the RBC related to its function?
The biconcave shape -
- allows for flexibility to be able to flow through very small blood vessels
- maximises surface area to volume ratio for gaseous exchange
The description of RBC containing haemoglobin
Tetramer - 4 polypeptide (globin) chains
Contains 4 heme groups
Heme group - protoporphyrin and Fe 2+ (ferrous)
What are the functions of Haemoglobin in RBC?
- transport O2 from lungs to tissues
- transport CO2 from tissues to lungs
CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3-
(CA-carbonic annhydrase)
Buffers H+
What are the abnormalities in Haemoglobin?
- synthesis of abnormal haemoglobin eg. sickle cell anaemia
- reduced rate of synthesis of normal chains - alpha and beta thalassemias
The Neutrophils (a leukocyte)
- nucleus has 2 to 5 lobes
- cytoplasm contains fine pink-ble or grey-blue granules
- spend 8 to 10 hours in circulation and then to tissues
- non specific defence- especially against bacteria
- variety of granules - antimicrobial proteins(lysozomes, defensins), proteases, myloperoxidase
- mediators of inflammation
- engulf microorganisms via phagocytosis
The Eosinophils ( leukocyte)
- the nucleus has lobes (often no more than 3)
- deeply staining red to orange cytoplasmic granules
- circulates in blood for four to five hours and then migrate to tissues
- has 3 types of granules(specific, primary, small dense)
The Specific Granules of Eosinophils
- potent cytotoxic proteins-major basic protein, eosinophil peroxidase
- predominant type of granule in eosinophils
What do Eosinophils do ?
- defense against parasitic infections
- modulation of type 1 hypersensitivity rxns
- potential to damage to host tissue
- limited phagocytic and bactericidal capabilities
The Basophils (leukocyte)
. the nucleus usually has 2 lobes
. contains many cytoplasmic granules that stain light to dark purple
. modulation of hypersensitivity/ immune mediated inflammatory rxns-via release of mediators
. type 1 hypersensitivity rxns, tumour cytotoxicity, rejection of parasites
. granule contents - histamine, serotonin, prostaglandins, leukotrienes
The lymphocyte (leukocyte)
. round or slightly indented nucleus; thin rim of light blue cytoplasm
. role in specific/acquired immunity
. 2 main types - T and B lymphocytes
The T lymphocyte
- 40-80% of blood lymphocytes
- several subsets eg CD4 TH1 helper T cells
CD4 TH2 helper T cells
cytotoxic CD8 + T cells (CTLs)
The B lymphocyte
role in humoral immunity (antibody mediated)
differentiate into plasma cells
The Monocyte (leukocyte)
- circulate up to 2 days in blood then tissue then mature then actively phagocytic macrophages
- usually the largest leukocytes in blood
- variable shape of nucleus
- abundant cytoplasm that stains bluish-grey
- sometimes the cytoplasm contains vacuoles that cause foamy/ground glass appearance to cytoplasm
The Monocyte
Marophage function
- Major role in phagocytosis
- removal and processing of aged red blood cells, dead/necrotic tissue, foreign material
- defence and elimination of microorganisms - especially fungi and intracellular organisms such as Mycobacterium
- involved in the immune response - take part in antigen processing and presentation
- initiation of inflammatory process
The Platelets
thrombocytes
- small anuclear cytoplasmic fragments derived from megakaryocytes
- very small, discoid in shape, fine reddish granules
- primary role: hemostasis (arrest of bleeding) and repair of vascular damage
- Optimal hemostasis - adequate numbers of functionally normal platelets
- Issue - bleeding problems - cause (decrease in blood platelet count thrombocytopenia, abnormality in platelet function thrombopathy)
The Plasma
What is plasma
- fluid component of unclotted blood
- pale yellow solution containing electrolytes, proteins, small inorganic molecules
The Serum
Clear yellow liquid obtained after blood clots
contains some substances found in plasma except coagulation factors
Plasma Electrolytes
- Na+ (major cation)
- K+ Ca2+ Mg2+ Fe2+ (in lower conc)
- Cl- and HCO3- (major anions)
The plasma proteins
- large number of different properties
- 4 distinct families
. proteins involved in hemostasis
. Immunoglobins
. complement system
carrier/transport proteins
The Proteins involved in hemostasis
- coagulation factors- involved in formation of solid fibrin clot
- natural inhibitors of blood coagulation
- prevent inappropriate clot formation or excessive
coagulation - deficiencies- thromboembolic disease
- antithrombin III, protein C&S, tissue factor pathway
inhibitor, heparin cofactor II
- prevent inappropriate clot formation or excessive
- proteins of fibrinolytic system (involved in degradation and dissolution of formed fibrin)
- T-PA ( tissue plasminogen activator), plasminogen, plasmin-stimulate fibrinolysis
- fibrinolytic inhibitors eg alpha2 - antiplasmin, plasminogen activator inhibitor (PAI-1)- control/inhibit fibrinolysis
Plasma Proteins
The Immunoglobulins
- antibody molecules
- 5 different classes - IgA, IgD, IgE, IgG, IgM
The Plasma Proteins
Complement System
- family of plasma proteins
- inflammation and immunity against microbial infections
- circulate as zymogens
- 9 major components : C1 to C9
- lysis of bacteria or infected cells (C5 - C9)
- opsonise (coat) bacteria or cells then phagocytosis (C3b)
- chemoattractants (C3a, C4a, C5a)
The Plasma Proteins
Carrier/Transport Proteins
- transport system for nutrients and waste products
- eg. transferrin - iron
haptoglobin - Hgb
albumin - non specific binder
Blood Banking
- collection, separation and storage of blood
- obtained from blood donations
- blood separated into various components and used according to needs of the patient
- great need for blood/ blood components in hospitals and emergency treatment facilities
