Introduction to Structure & Function of Blood Flashcards
what are the components of blood?
plasma and cells
describe erythrocytes
- have no nucleus, mitochondria, DNA or RNA
- biconcave shape
what are the different types of leukocytes?
neutrophils, eosinophils, basophils, monocytes and lymphocytes
describe neutrophils
- polymorphonuclear: irregular, multi lobed nucleus
- are granulocytes: prominent cytoplasmic granules
describe eosinophils and basophils
are granulocytes: have prominent cytoplasmic granules
describe monocytes and lymphocytes
- monocytes are the largest leukocyte
- both lack granules
- have regular nuclei
what are platelets?
membrane bound cytoplasmic fragments with no nucleus and contain granules
where are mature blood cells produced?
from stem cells in the bone marrow
what is plasma?
the fluid component of blood containing H2O, salts, proteins an d organic molecules such as metabolites and carbohydrates
what are the ionic constituents of blood?
cations: Na+, K+, Ca2+, Mg2+, H+
anions: Cl-, HCO3-, PO3²- , SO4² -
what is serum?
the fluid left after blood clotting
what percentage of blood plasma do proteins make up?
7-9% = 90% of that is albumin, a protein made in liver and helps keeps the fluid in bloodstream so there is no leakage into other tissues
what does blood carry?
- O2/nutrients to tissues
- removes CO2/waste products from tissues
- transports hormones from site of production to its site of action
what do erythrocytes carry?
- O2 from lungs to body tissues
- helps removal of CO2 from body tissues to lungs
how is CO2 removed from the body?
- carried as HCO3- in the plasma
- carbonic anhydrase helps CO2 by allowing it to dissolve in the plasma
what is the main constituent protein of RBCs?
-Haemoglobin, Hb
what does Hb do?
- binds to O2
- each globin carries a haem molecule
- each haem carried a Fe2+ which binds reversibly to O2
what are the different forms of Hb and how can you distinguish them?
- oxyhaemoglobin:fully saturated w O2 and is bright red
- deoxyhaemoglobin: lost all O2 and is dark red
how many Hb molecules are there per RBC?
300,000,000
what do the plasma proteins transport?
- carries substances w poor solubility
- lipids, lipid soluble hormones, metal ions
how does the blood have a defensive role?
- immunity: WBC, plasma proteins
- clotting (haemostasis): platelets and plasma proteins
how do neutrophils have a defensive role?
- phagocytosis: kills bacteria and fungi
- main mediators of innate immunity
how do lymphocytes defend the body?
- main mediators of adaptive (acquired) immunity
- produces antibodies and kills infected cells
what do eosinophils and basophils do to defend the body?
- kills parasites, involved in allergic reactions
- basophils cause inflammation
what is the role of monocytes in the defensive mechanism?
macrophages are responsible for phagocytosis of dead cells and pathogens
what is the role of plasma in immunity?
- immunoglobins (Ig) are made of B lymphocytes
- they acts as antibodies against pathogens
- complement proteins in plasma kill bacteria and pathogens
- they cooperate w Ig and WBCs
what is the main role of platelets?
- major role in primary homeostasis
- recognise damage at blood vessel wall
- forms platelet plugs to stop bleeding
what is homeostasis?
- keeping the internal environment of the body constant
- maintaining the pH 7.4, controlling distribution of H2O and solutes, distributing heat
what is the plasma’s role in homeostasis?
- plasma pH, [ion] and [protein] must be kept within same limits
- this can be disturbed by disorders of the kidney, liver, lungs, CV system and endocrine system
what is haemocrit (Ht) and how is it measured?
- it is the packed cell volume
- volume of cells/ total volume
what are common blood tests and what do they measure?
- [Hb] (Hb in g/l): overall [Hb] of blood, used to diagnose anaemia
- mean RBC volume (MCV): side of red cells
- mean (red) cell Hb content (MCHC): how much Hb is in each cell
- haemocrit (Ht or Hc): diagnose the type of anaemia
- total WBC count: neutrophil + lymphocyte count
why are blood tests important?
-they are used to diagnose infection
