L5 - Blood Cells Flashcards
Key facts about the blood (5)
- avg human has 5L of blood
- blood cells (45-55%)
- plasma
- human plasma proteome >10,000 proteins
- serum
Why separate the blood components?
rapid assessment of blood composition
What is the hematocrit?
% of blood volume that is composed of RBCs
What is the plasma?
blood w/o cell components
What is plasma used for? (3)
- blood substitute, to increase volume during surgery/after trauma
- controls bleeding, aids wound healing
- many drugs at therapeutic conc bind to plasma proteins
What is serum?
plasma w/o clotting factors and fibrinogen
What is serum used for? (2)
- diagnostic measurements, cosmetics
- growth media for cell culture
What are the 3 types of blood cells?
- Erythrocytes (RBC): O transport, pH buffer
- Leucocytes (WBC): Granulocytes, lymphocytes, important in host defence
- Platelets (derived from megakaryocytes) - important in blood clotting
What is bone marrow? why is it important?
- soft, spongy tissue in the centre of bones
- contains collagen and glucosamine: important for healthy bones and joints
What are the types of bone marrow?
- red - blood cells
- yellow - cartilage, fat and bone cells
What is bone marrow like in children vs adults?
children: bone marrow of most bones gen blood cells
adult: blood cell production from bones of chest, base of the skull, spinal vertebrae, upper section of limbs
What are blood cells derived from?
Hematopoietic stem cells
(undifferentiated cells capable of producing the precursors of dif blood cells)
What differentiates from hematopoietic cells?
- myeoloid progenitor cell
- lymphoid progenitor cell
What differentiates from myeloid progenitor cells? (6)
- megakaryocytes = platelets
- eosinophil
- basophil
- erythrocytes
- neutrophyl
- monocyte = dendritic cell, macrophage
What is the condition called where there is a lack in blood cells?
anemia
What are the key functions of the blood? (3)
- transport: O, CO2, nutrientrs and excretory prodcuts
- regulation: delivery or hormones, diversion of blood, temp regulation
- protection: leukocytes in infection, clotting mechanisms
Description of healthy blood vessels (in order) (6)
Heart - main circulatory pump
Arteries - v thick muscular layer, withstands high blood pressures, pumps blood around the body
Arterioles - slightly thinner walls
Capillaries - pass through tissues, one cell thick = good diffusion
Venules - smaller veins
Veins - blood back into the heart
What are erythrocytes? What do they do? (4)
RBCs
- transport O2, CO2
- contain Hb
- biconcave: high SA:vol
- membrane polysaccharides/proteins confers to blood group
What is erythropoiesis? (2)
The production of RBCs
- controlled by hormone erythropoietin (EPO)
- secreted in small amounts from kidney
What triggers EPO production?
Decreased O2 levels
- high altitude
- lung disease
- insufficient pumping of the heart
- anaemia
What is anemia?
Decrease in the total number of erythrocytes and decreased conc Hb per erythrocyte
What is anemia often caused by? (3)
- iron/vitamin B12 deficiency
- failure in BMw production - aplastic anemia
- genetic disorders - thalassemia, sicle cell anemia
What are leucocytes involved in? And which types?
Host immunity
- innate immunity
- adaptive immunity
What is innate immunity?
Myediated by meloid cells/ granulocytes
- first line of defense against pathogens
What is adaptive immunity? (3)
Mediated by lymphocytes
- 2nd line
- highly specific to particular pathogen (antigen specific)
- longer lasting protection
What are the type of myeloid cells? (3)
Monocytes (blood), macrophage (tissue), Neutrophils: phagocytic cells, innate immunity
Eosionphil: defense against parasitic infection, key mediators in asthma
Basophil/ mast cells: circulating immnue cells (histamine, pathogenesis of allergic reaction, inflammation
What are agranulocytes? What do they do? (3)
Monocytes/macrophages
- Engulf bacteria
- release inflammatory mediators (cytokines)
- antigen presenting cells (APCs) to T cells
What are granulocytes? Eg (3)
Densely stained granules in cytoplasm
(Polymorphonuclear leukocytes)
- neutrophils
- basophils
- eosinophils
What are the types of lymphocytes? (3)
- B cell, plasma cell - a/bod production
- Th cells - activation stimulus to other immune cells
- NK cells/cytotoxic Tcells - lyse virally infected cells
What are the leucocyte disorders?
Too few - patient is immunosuppressed/immunocompromised, susceptible to opportunistic infections
Too much - immune system activated inappropriately - requires immunosuppressive drugs
What are platelets? + info (3)
Known as thrombocytes
- no nucleus (anucleate)
- important in blood clotting
- progenitor cells differentiate to megakaryocytes = break off into platelets
What is platelet production controlled by?
Thrombopoeitin (from liver)
- binds to platelets
= normal = free TPO low
= low = free TPO leve high = platelet production stimulated
What are platelet disorders?
Low platelets (thrombocytopenic purpura) - excessive bleeding
Anti-platelet drugs reduce risk of blood clots in thromboembolic diseases
Treat: ischaemic stroke, myocardial infarction, deep vein thrombosis
