Hematology Flashcards
General characteristics of blood
- Specialized form of connective tissue
- Enclosed in blood vessels and flows through body
- Exchange materials btwn blood and tissues
- Cooperates with nervous and endocrine systems to integrate and regulate bodily functions
Bloods 2 major components
Formed elements- RBCs/WBCs/platelets
Plasma
Proteins in plasma
Albumin Gamma globulins Fibrinogen Complement proteins Other solutes
Albumin
Major component of Plasma
- maintains osmotic pressure of blood
- role in transport of water insoluble substances
Gamma globulins
antibodies
Fibrinogen
formation of fibrin during blood clotting
Complement porteins
important in inflammation and destruction of microorganisms
Lowest layer after centrifugation
- RBCs
- About 45% of blood volume
- Hematocrit
Middle layer after centrifugation
- Buffy coat
- about 1% of blood volume
- consists of leukocytes and platelets
- -lymphocytes/monocytes/neutrophils/eosinophils/basophils
Upper layer after centrifugation
- Blood plasma
- about 50% of blood volume
Factors influencing the ability of RBCs to change shape
Geometry- biconcave shape
cytoplasmic viscosity- intracellular [Hb]
Properties of plasma membrane
Plasma membrane of RBC
Trilaminar
Membrane skeleton
Lacks- nuclei, ribosomes, mitochondria, ER, golgi and lysosomes
Membrane skeleton made up of
Spectrin actin protein 4.1 -influence deformability of membrane -stabilize membrane against shearing forces
Rouleaux
In small blood vessels rbcs often stack up in aggregates
Hemoglobin
responsible for cytoplasmic viscosity and eosinophilia
Hb globular chromoprotein
Tetramer consisting of 4 glob in polypeptide chains
-each associated with heme group
Hemoglobin A1
major form in adults
consists of 2 alpha and 2 beta polypeptide chains
Hemoglobin A2
Minor form in adults
Consists of 2 alpha and 2 delta polypeptide chains
Hemoglobin F
produced during intrauterine period
consists of 2 alpha and 2 gamma polypeptide chains
Hemoglobin S
single nucleotide mutation in DNA coding for beta
-glutamic acid–> valine
leads to sickle cell disease
-can lead to anemia and increase blood viscosity
RBCs life span and removal
120 days
removed by macrophages–spleen/liver/bone marrow
Reticulocytes
RBCs recently released from bone marrow
contain small amount of ribosomal RNA
Useful indicator of rate of erythrocyte production
Leukocytes leave vessels by means of
diapedesis
- btwn cells
- through cells
Granulocytes
Neutrophils
Eosinophils
Basophils
Agranulocytes
Lymphocytes
Monocytes
Number of leukocytes
6k-10k/microliter
Relative frequency of each leukocyte
Neutrophil- 60-70% eosinophil- 2-4% basophil- 0-1% lymphocytes- 20-30% monocytes- 3-8%
Neutrophils cytoplasmic granules
Specific granules- secondary
- very small
- 80% of granule population
Azurophilic granules- primary
- large
- stain with Azure B
- primary lysosomes
Neutrophil functions
Phagocytosis
- motile
- display chemotaxis
- pseudopodia surround bacteria forming phagosomes
- specific granules fuse with phagosome
- specific granules
- azurophilic granules
- superoxide anions formation
- netosis
- microvesicle release
- cytokine production
- neurophils die and form pus
Specific granules
discharge contents into phagosome
- lysozyme hydrolyzes glycosides in bacterial cell wall
- lactoferrin is an iron binding protein
Azurophilic granules
Fuse with phagosome forming secondary lysosome
-enzymes hydrolyze dead bacterium into its constituent small molecules
Eosinophils
2-4% of leukocytes
bilobed nucleus
granules contain hydrolytic enzymes
Eosinophil functions
Phagocytosis -kill larvae of parasites -dispose of antigen-antibody complexes -granules fuse with phagosomes enzymes digest phagocytized materal
Secretion
- release granule contents into ECS
- inactivate mediators of inflammation- histamine
- synthesize leukotriene C4 and platelet activating factor
- –role in inflammation
- –cause bronchoconstriction
- –cause mucus hypersecretion
- produce cytotokines
- –promote survival and enhance activity
Eosinophil potential role in asthma
- Airway constriction
- mucus hypersecretion
- inflammation of airway
- airway remodeling
- –increased smooth muscle
- –increased collagen in ECM
- –goblet cell metaplasia
Basophils
0-1% of leukocytes
cytoplasmic granules stain intensely with Azure B
granules rich in- heparin, histamine and SRS-A
Basophil functions
- role in inflammation
- immediate hypersensitivity reaction
- –IgE attach to cell surface
- –rapid degranulation of basophils and mast cells occurs
- —-vasodilation and sudden drop in BP
- delayed hypersensitivity reactions
- –skin reaction to contact with chemicals
- –response to tick infestation
Lymphocyte functions
20-30% of leukocytes
- B lymphocytes- humoral immunity
- –differentiate into plasma cells which produce antibodies
- –undergo mitosis in response to antigenic stimulation
- —-some plasma cells and some memory B cells
T-lymphocytes
cell mediated immunity
- T cell receptors on surface
- undergo mitosis in response to antigenic stimulation
- –memory T cells
- –cytotoxic T lymphocytes
Cytotoxic T lymphocytes
- Capable of killing foreign or viral infected cells
- Recognize other cells that have foreign antigens on their surface
- lyse these target cells (perforin)
- induce apoptosis in target cells (granzymes)
Helper T cells
- Assist B cells and T cells in their response to antigens
- produce lymphokines
- specific target for HIV
suppressor T cells
- suppress or dampen the response to foreign antigens
- suppress immune response to self molecules
- block anti-tumor responses of cytotoxic T cells
Natural Killer cells (NK)
- 5% of circulating lymphocytes
- neither B nor T cell surface molecules
- large azurophilic granules
NK cell function
- Kill virus infected cells
- kill malignant cells
- production of cytokines that influence host’s immune response
Monocytes
4% of circulating leukocytes
-contains small azurophilic granules and vacuoles
Monocytes major function
- phagocytosis of bacteria and tissue debris
- concentrate and process certain antigens for presentation to lymphocytes
- formation of osteoclasts
- formation of giant cells(inflammation)
- production of cytokines (involved in regulation of hematopoiesis
- immune surveillance
Blood platelets
small cytoplasmic fragments of megakaryocytic
normal count- 200k-400k
average lifespan 10days
contain functional repertoire of mRNAs
Platelets function
seal off small breaks in blood vessels
play role in blood coagulation
maintain competence of vascular endothelium
-thrombocytopenia- may result in leaky microvasculature
