Bone Marrow and Haemotopiesis Flashcards
Why do we need blood? (9 reasons!)
- Supply of O2 to cells/tissues
- Supply of nutrients/hormones
- Removal of waste products
- Defence
- Coagulation
- Maintenance of temperature
- Hydraulic function
- Maintenance of body’s pH
- Signalling function
give 7 diseases related to blood
- Leukeima
- Anaemia
- Lymphoma
- Septicaemia
- Malaria
- Haemophilia
- Von Willebrand’s Disease
describe the anatomy of bones in relation to blood formation
Bones are not solid.
They have a hard weight-bearing calcium based outer. The inner spongy marrow which fills the shafts of the long bones and extend into the bony canals which contain the blood vessels
describe bone marrow
Bone marrow contains fat cells, fibrous tissue, blood vessels, and hematopoietic cells.It is yellow when it contains more fat cells. It is red when it contains blood forming material.It is the principal site of blood formation (hematopoiesis) in the legs, arms, ribs, sternum and vertebrae.
In newborns bone marrow is predominantly red, and more becomes yellow as you age.
what is haematopoiesis
blood formation
how do blood cells form
Most blood cells are born and mature in the bone marrow
These originate from haematopoietic cells called stem cells
These stem cells in the bone marrow continuously divide and form new cells.
what are pluripotent cells and unicommited or progenitor cells
Pluripotent cells -remain unchanged and are able to continuously self renew.
Unicommited or progenitor cells – have a limited capacity for self renewal and become committed to form one blood cell line.
what are the roles of plasma
- Hydration and maintenance of blood pressure and circulation
- Regulation of body temperature
- Albumin: stops fluid leakage and binds to and carries eg hormones and drugs
- Immunoglobulins: Defence
- Fibrinogen: Blood clotting
WBCs can be split into granulocytes and agraulocytes. What leukocytes are in each group?
Neutrophils, eosinophils and basophils are granulocytes.
Monocytes and lymphocytes are agranularcytes.
Lymphocytes can be divided into T-lymphocytes and B-Lymphocytes. what are each type?
T-lymphocytes are produced in bone marrow, mature in thymus and contribute to Cell Immunity
B-lymphocytes mature in bone marrow, become plasma cells when exposed to invading organism or on T-cell activation causing antibody production
Each type of white blood cells has a different immune response- what is it for the following: • Neutrophil • Eosinophil • Basophil • Monocyte
- Neutrophil- bacteria by phagocytosis
- Eosinophil- parasites and allergic reaction
- Basophil- ?? allergic reaction
- Monocyte- engulfs dead/damaged cells and bacteria
Describe platelets and their role in blood.
they are not a whole cell, just a fragment of a bigger cell.
they are formed in the bone marrow from large cells called megakaryocytes which break into fragments which are the platelets
they do not have a nucleus and no ability to reproduce, as they have no organelles or DNA.
they help in the clotting process by amassing at the site of injury to form platelet plug.
what is unusual about RBCs
- Biconcave shape like a shallow dish
- No nucleus or mitochondria.
- Flexible so it can squeeze through capillaries
what is the function of erythrocytes
It’s function is to carry O2 from lungs to cells/tissues via haemoglobin. Also carries CO2 out of the body.
what is erythropoiesis
red blood cell development
what 2 things are essential for the production of erythrocytes?
erythropoietin and low oxygen levels.
Iron and Vitamin B12 and Folate are essential for correct erythrocyte maturation.
why is iron?
- Erythrocytes are filled with haemoglobin
- Iron is an integral part of haemoglobin
- Erythropoiesis is an interaction between erythropoietin and iron.
Iron and Vitamin B12 and Folate are essential for correct erythrocyte maturation.
Why are vitamin B12 and folate?
• Deficiency of both lead to megaloblastic anaemia (enlarged red blood cells as the nucleus remains, which means they cannot fit through the capillaries)
• This is because vitamin B12 and folate are essential in the synthesis of DNA
• Megaloblastic anaemia results in the defective synthesis of DNA which causes a delay in the maturation of nuclei of developing erythrocytes in the bone marrow.
Results in either death of RBCs in the bone marrow or the release of erythrocytes into the peripheral blood which are enlarged and misshapen.
in what 3 ways is the unique structure of erythrocytes is adapted for function?
- Small size and biconcave shape – allows squeezing through capillaries ~5mm diameter.
- Membrane composed of flexible cytoskeleton and outer lipid bilayer –
maintains shape with maximum flexibility and hydrophobic skin. - Lack of nucleus or organelles – allows biconcave shape for maximum
surface area (exchange of gases) and flexibility. Also allows for maximum concentration of haemoglobin.
Maintenance of correct haemoglobin function requires the production of energy (ATP) from erythrocytes. what is ATP (energy) needed for?
- Maintaining haemoglobin in a reduced form and producing reducing agents NADH, NADPH and GSH
- Cytoskeletal changes for recovery of cell shape
- Maintenance osmotic pressure of the cell by driving Na2+ and Ca2+ pumps in the membrane.
why are erythrocytes are totally dependent on glucose for the production of energy
no mitochondria
Whilst anaerobic glycolysis produces the majority of energy required by the erythrocytes 4 metabolic processes are involved- what are they?
what do all of the pathways do?
- Anaerobic Glycolysis (cannot be aerobic- no mitochondria)
- Pentose Phosphate Pathway
- Methaemoglobin Reductase Pathway
- Production of 2,3-BPG (Luebering- Rapaport Pathway)
All of the pathways either produce energy or protect cells from the oxidizing environment.
why must erythrocytes produce glucose anaerobically (no oxygen)?
Erythrocytes are unable to metabolise glucose aerobically as they have no mitochondria therefore they produce energy by ANAEROBIC glycolysis which requires no oxygen.
what is anaerobic glycolysis?
Anaerobic glycolysis is a series of biochemical events which converts glucose to lactate with the production of 2xATP and 2xNADH.
