introduction to blood Flashcards Preview

HLTH1000 > introduction to blood > Flashcards

Flashcards in introduction to blood Deck (13):

describe blood composition

- plasma (55%) and formed elements (45% - RBC, WBC, platelets)
- buffer coat (leucocytes and platelets <1%)


what are the physical characteristic of blood

- sticky, opaque fluid, scarlet red to dark red (oxygen content)
- pH 7.35-7.45 (buffer)
38˚C (higher than body temp)
- ~8% body weight, 5-6 L = males, 4-5 L = females


what are the functions of blood

- distribution of: oxygen, nutrients (vitamins / AA), metabolic wastes and hormones
- regulation of: body temp (vasoconstriction / vasodilation), normal pH (buffer)
protection against: blood loss (platelets) and infection (WBC)


describe structure / function of plasma

- 90% water
- dissolved proteins: mainly produced by liver, 60% albumin = maintain osmotic pressure, 36% globulin = buffer / antibodies, 4% fibrinogen = clots with platelets
- nitrogenous byproducts, nutrients, electrolytes, respiratory gases and hormones


summary of formed elements

- RBC survive 100-120 days
- others survive a few days
- BC originate in red bone marrow, do not divide
- BC formation = hematopoiesis
- WBC = real / complete, biggest
- RBC = no nuclei, most abundant
- platelets: cell fragments, smallest


what are RBC

- erythrocytes (45% of blood)
- biconcave (increased SA)
- >97% haemoglobin
- no mitochondria (ATP production = anaerobic)
- dense, elastic (compressible)
- F: 2 alpha + 2 beta chains = 4x iron / heme groups = 4x oxygen molecules, heme pigment (red),


what is erythropoiesis, how is it regulated and what is hypoxia

- RBC production
- hemocytoblast (stem cells - ability to differentiate)
- transformed into pro-erythroblast and become reticulocyte (15 days)
- 2 days = erythrocyte once in blood
- regulation: hormonal control (erythropoietin - EPO) combined with adequate iron, AA and vit. B = stimulate growth
- little RBC = hypoxia (not enough O to maintain metabolism)
- too many = increase viscosity (stroke / heart attack)
- hypoxia: not enough EPO, haemorrhage, increased RBC destruction, insufficient haemoglobin (iron deficiency), high altitude (reduced availability of O)


what is anaemia and the 3 different causes

- anaemia: abnormally low O2 carrying capacity, sign of underlying disease, cannot support metabolism
- fatigue, paleness, shortness of breath, chills
- insufficient RBC: hemorrhagic (escape of blood), haemolytic (destruction of RBC), aplastic (damaged bone marrow, doesn't function normally)
- low haemoglobin: iron deficiency (follows hemorrhagic anaemia), pernicious anaemia (old people, lack vitamin B12; normal division of cells)
- abnormal haemoglobin: thalassemia (absent or faulty globin chain, thin RBC) and sickle cell (thin, fragile RBC, change in 1 of 146 AA)


what are the 4 types of WBC

- granulocytes: granules in cytoplasm
- neutrophils: most numerus, fine granules, acidic and neutral, contain hydrolytic enzymes / defensins
- eosinophils: red / crimson, lysosome like granules, fight worms, important in allergic reaction
- basophils: rare, large purplish / black, contain histamine (inflammation / vasodilator), similar to mast cells


what are lymphocytes

- present in lymphoid tissue
- few circulate in blood, crucial to immunity
- types: B (antibody), T (kill bacteria) and NK (natural killer cells, lack of MHC = invader, not phagocytic)


what are monocytes

- abundant pale-blue cytoplasm, purple nucleus
- leave circulation enter tissues and differentiate into macrophages (phagocytic, immune response)
- actively phagocytic
- activate lymphocytes


what are platelets

- small fragments of megakaryocytes, granules contain serotonin, Ca enzymes, ADP and PDGF (platelet derived GF)
- formation regulated by thrombopoietin
- involved in clotting (requires Ca and vitamin K)


what are 2 types of blood disorders

- haemophilia: x linked, absence of factor VIII (coagulation factor), women usually carriers, external bleeding episodes, bruising / internal bleeding
- malaria: plasmodium (parasite) enters blood and affects RBC, female anopheles mosquito = vector, travel to liver destroying RBC, vomiting, fever, headaches, anaemia, joint pain