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56 Cards in this Set
- Front
- Back
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What are the 7 types of cells in blood?
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-Red blood cells (erythrocytes)
-Platelets (thrombocytes) -5 types of white blood cells (leukocytes) |
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What is the function and composition of plasma?
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-Cells are suspended in plasma
-Comprised mainly of water -Contains proteins, clotting factors, ions, hormones and CO2 |
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What are the 2 main functions of blood?
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- Transport through the body; O2, CO2, glucose, lipids, amino acids, Ions, wastes (urea), hormones & heat
-Defence; against infections, injury and malignancy |
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How many red blood cells are in the normal human?
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-Women average 4.8x10^6per microlitre of blood
-Men average 5.4x10^6per microlitre -Varies depending on health, altitude etc |
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Where do RBC precursors mature?
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Bone marrow
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What processes occur in bone marrow during RBC maturation?
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-Manufacture haemoglobin until it accounts for 90% of dry weight
-The nucleus is squeezed out of cell -Nearby macrophages ingest the extruded nuclei and break down their DNA |
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What are the stages of RBC maturation?
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Pronormoblast-->Basophilic Normoblast-->Polychromatic Normoblast-->Orthochromatic Normoblast-->Polychromatic erythrocyte-->Erythrocyte
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Describe the shape of RBC's
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Bi-concave disk with central region of pallor
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What is the structure of haemoglobin?
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-Consists of 4 polypeptides; alpha and beta
-each polypeptide is attached to the prosthetic group heme -there is one iron atom at the centre of each heme |
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What is the function of haemoglobin?
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loads, transports and offloads oxygen
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What is 2,3 DPG and its function?
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Produced in glycolysis of RBC's, shifts O2 dissociation curve to right
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How can oxygen be transported in the blood?
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One molecule of oxygen can bind to each haeme group
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How is CO2 transported in blood?
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-Half is directly bound to haemoglobin (at a different site to O2)
-Most converted to to HCO3- and transported in plasma -Small amount diffused into plasma |
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Can RBC differentiate once created?
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No, no DNA or nucleus for replication
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What is the life span of RBC's?
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~120days
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How are RBC's broken down? and which parts are reused?
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-Most of the iron from haemoglobin is reclaimed for reuse
-Remainder of the heme portion of the molecule is degraded into bile pigments and excreted by the liver |
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What is hematocrit?
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-The fraction of blood occupied by RBC's
-Normally 45% -Lower in anaemia |
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What are platlets?
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Cell fragments produced from megakaryotypes
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What is normal value of platelets in blood?
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-150,000 to 450,000platelets per microlitre
-<50,000 there is danger of uncontrolled bleeding |
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What is the function of platelets?
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Solidification of blood via a process of coagulation or clotting at site of vascular injury
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What are the components of a blood clot?
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-A plug of platelets enmeshed in a network of insoluble fibrin molecules
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Describe white blood cells?
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-Much less numerous than RBC's
-~5x10^3/microlitre -Have nuclei Participate in protecting the body from insults |
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What are the different types of WBC's?
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-Granulocytes; neutrophils, eosinophils, basophils
-Agranulocytes; lymphocytes, monocytes |
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What are the most abundant type of WBC?
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Neutrophils (polymorphs)
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Where are precursors for neutrophils visible?
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Bone marrow
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What is the lifespan of neutrophils in the blood?
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6-10hrs
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How do neutrophils efffect an action?
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-Neutrophils squeeze through the capillary walls and into infected tissue by a chemotactic process where they phagocytise the invaders (eg microbes)
-They die after this process |
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Where are neutrophils always acting?
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Keep bacteria in throat, nasal passages and colon commensal
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What can cause dysfunction of neutrophils?
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-Heavy doses of radiation
-Chemotherapy -Stress -Allows usually harmless bacteria to proliferate |
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Are eosinophils abundant in blood?
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-Normally quite low (0-450/microlitre)
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What is the main organism eosinophils act against?
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Parasitic worms
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How do eosinophils act?
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-Cytotoxic action
-Release contents of eosinophilic granules on the invaders -Granules are basic (high pH) in nature |
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Where do basophils accumulate?
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At the site of infection or inflammation
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How do basophils function against invaders?
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-They discharge the content of their basophilic granules
-Acidic contents |
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What mediators are contained in the basophil granules? and what is their function?
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-Histamine, serotonin, prostaglandins, leukotrienes
-increases blood flow to area -Can add to the inflammatory process |
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What other process do the mediators from basophils play a role in?
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allergic responses
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What are the 2 common types of lymphocytes?
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B-lymphocytes and T-lymphocytes
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What is the function of B-lymphocytes?
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-Responsible for making antibodies
-Differentiate into plasma cells |
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What are the subsets of T-cells?
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Helper t-cell, Cytotoxic t-cells and regulatory t-cells
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What is the function of helper t-cells?
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-Enhance the production of antibodies by B-cells
-Produce lymphokines that recruit macrophages and neutrophils to the site of infection or other tissue damage |
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What is the function of cytotoxic t-cells?
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Kill virus infected and tumour cells
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What is the function of regulatory t-cells?
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-Required for immunological tolerance, they shut down the t-mediated immunity towards the end of a reaction
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Where are lymphocytes created and mature to T-cells?
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-Bone marrow ultimate source of lymphocytes
-Those that are going to become t-cells migrate to the thymus where they mature |
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Where do you find both B and T-cells?
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Lymph nodes, spleen and other tissues
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What is the function of B and T-cells?
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-Encounter antigens
-Continue to divide by mitosis -Mature into fully functional cells |
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What is the difference between a monocyte and macrophage?
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Monocytes become macrophages when they leave the blood
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What is the function of macrophages?
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-Phagocytose foreign material (antigens) that enter the body as well as dead and dying cells of the body
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What is haemopoiesis?
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Blood cell development, ongoing process
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What are the 3 phases in life which haemopoiesis occurs?
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-Yolk sac blood islands
-Fetal liver -bone marrow and spleen |
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What is the role of stem cells in haemopoiesis?
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-Initially pluripotent, stem cell becomes committed to either lymphoid, myeloid, or erythroid/megakaryocytic lineages
-8 Major lineages possible |
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Why are stem cells unique?
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They have the ability to both self renew to produce more stem cells or differentiate along a specific developmental lineage
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Where are adult haemopoietic stem cells (HSC's)found and characterised?
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-Very rare, mixed up with connective tissue and stromal cells in bone marrow.
-Characterised by specific surface antigens (CD34) -Generally in quiescent state(G0) |
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What controls balance between self renewal and lineage commitment of stem cells?
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Stochastic & external factors such as growth factors
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What cells are involved in innate immunity (rapid response)?
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Dendritic cell
Macrophage Mast cell Natural killer cell Granulocytes |
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What cells are involved in adaptive immunity (slow response)?
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Tcells and Bcells
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What cells are involved in both innate and adaptive immunity?
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Natural killer t cells and another form of T cell
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