Blood Cells: RBC WBC platelets Flashcards
What are the two major components of blood?
Cells and plasma
What percentage of blood is cells in males? females?
40-50%
35-45%
Where are the stem cells that differentiate to form different blood cell type?
Bone marrow
How many micrometres is a red blood cell?
7
Describe what is inside a red blood cell
Lacks nucleus, mitochondria, golgi, ribsomes.
Packed with haemoglobin.
Contains enzymes needed for anaerobic metabolism of glucose.
What is the name of the penultimate precursor in bone marrow?
The normoblast
Give details on the normoblast
8-10 micrometres
highly condensed nucleus
contains most of the haemoglobin
still has a few mitochondria and ribosomes
What happens when maturation of a normoblast occurs?
Nucleus ejected and remainder of cell enters the blood as a reticulocyte. It takes 1-2 days for remaining RNA and organelles to be lost. Reticulocyte count is 1% of total rbc.
What is a function of a platelet? What is it diameter?
Where are they produced?
Function = haemostasis (blood clotting) and maintenance of blood vessels. 2-3 micrometres in diameter with a bi - convex shape, no nucleus. They are produced in the bone marrow.
Where do platelets adhere to and what does this form?
They adhere to fibrin filaments and damaged endothelial cells forming a blood clot.
What is a megakaryocytes?
A giant cell with a large irregular nucleus. All the nuclear content is needed to support all the cytoplasm in the cell. Necessary for blood clotting.
What are the two types of classification of white blood cells?
- Granulocytes (neutrophils, basophil, eosinophil)
2. Mononuclear leukocytes (monocytes, lymphocytes)
What is the name for the precursor cell of granulocytes and lymphocytes?
- myeloid (bone-marrow derived)
- lymphoid (originate in bone marrow, mature in tissues such as thymus)
Give some details of neutrophils including diameter and lobe number
Neutrophils >90% 12-14um Highly lobulated nucleus with 2-5 lobes Abundant glycogen Highly phagocyte and motile 5-90 hours in circulation Attracted to sites of inflammation On activation, adhere to receptors on endothelial cells expressed in response to secretion of cytokines
What happens to a neutrophil after a single burst of activity?
They die due to limited synthetic capabilities.
What do lymphocytes do to get energy?
They rely on glycolysis meaning they have no form of new energy so the neutrophils die after a sudden release of energy.
Give details on eosinophils
12-17 micrometres diameter
bi-lobed nucleus
has specific granules
large ovular shape
major role in destruction of parasites
role in the initiation and maintenance of inflammatory responses
leave circulation within 8-12 hours of release from bone marrow
Give details on basophils
14-16 micrometre diameter bi-lobed nucleus granules containing histamine release cytokines when stimulated closely related to tissue mast cells but from a different precursor
Give details on monocytes
largest blood cell (up to 20 micrometres diameter) Nucleus which is kidney bean shaped Highly phagocytic and motile Leave blood within 2 days of release Enter tissues to become macrophages lifespan of months/years
What are 4 functions of macrophages?
- Defence against micro-organisms
- Refuse - collection for removal of tissue debris, old red blood cells
- Antigen presentation - displayed on surface and presented to T lymphocytes to tigger an immune response
- Cytokine secretion
Give details on lymphocytes including B and T ones
6-9 micrometres
condensed nucleus occupies 90% of cell
thin rim of cytoplasm
responsible for adaptive immunity
B - surface immunoglobulin for antigen receptor, respond to antigen by proliferating and maturing into plasma cells which then secrete the same immunoglobin
T - receptor for antigen, they secrete cytokines into blood stream
Outline the process of haemopoiesis
The process by which mature blood cells are generated from precursor cells.
2-2.5 weeks = earliest red cells are nucleated,
5 weeks = haemopoieses shift to liver
4-5 months = haemopoieses shits to bone marrow
Explain the origin of blood cells
All blood cells arise from a common pluripotent stem cells.
This gives rise to unipotent stem cells.
Erythropoietin is what causes the production of erythrocytes.
What is plasma composed of?
What pressure does it exert?
What are the main proteins in plasma?
- fluid component of blood
- aqueous solution of salts, nutrients and plasma proteins
Plasma proteins exert a colloid osmotic pressure to help regulate aqueous exchange between plasma and extracellular fluid.
Albumins - involved in transport of hormones, vitamins and enzymes
Globulins - include immunoglobulins
Fibrinogen - precursor or fibrin, important in blood clotting
