Introduction to Structure & Function of Blood

Question 1

what are the components of blood?

Answer 1

plasma and cells

Question 2

describe erythrocytes

Answer 2

• have no nucleus, mitochondria, DNA or RNA

- biconcave shape

Question 3

what are the different types of leukocytes?

Answer 3

neutrophils, eosinophils, basophils, monocytes and lymphocytes

Question 4

describe neutrophils

Answer 4

• polymorphonuclear: irregular, multi lobed nucleus

- are granulocytes: prominent cytoplasmic granules

Question 5

describe eosinophils and basophils

Answer 5

are granulocytes: have prominent cytoplasmic granules

Question 6

describe monocytes and lymphocytes

Answer 6

• monocytes are the largest leukocyte
• both lack granules
• have regular nuclei

Question 7

what are platelets?

Answer 7

membrane bound cytoplasmic fragments with no nucleus and contain granules

Question 8

where are mature blood cells produced?

Answer 8

from stem cells in the bone marrow

Question 9

what is plasma?

Answer 9

the fluid component of blood containing H2O, salts, proteins an d organic molecules such as metabolites and carbohydrates

Question 10

what are the ionic constituents of blood?

Answer 10

cations: Na+, K+, Ca2+, Mg2+, H+
anions: Cl-, HCO3-, PO3²- , SO4² -

Question 11

what is serum?

Answer 11

the fluid left after blood clotting

Question 12

what percentage of blood plasma do proteins make up?

Answer 12

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

Question 13

what does blood carry?

Answer 13

• O2/nutrients to tissues
• removes CO2/waste products from tissues
• transports hormones from site of production to its site of action

Question 14

what do erythrocytes carry?

Answer 14

• O2 from lungs to body tissues

- helps removal of CO2 from body tissues to lungs

Question 15

how is CO2 removed from the body?

Answer 15

• carried as HCO3- in the plasma

- carbonic anhydrase helps CO2 by allowing it to dissolve in the plasma

Question 16

what is the main constituent protein of RBCs?

Answer 16

-Haemoglobin, Hb

Question 17

what does Hb do?

Answer 17

• binds to O2
• each globin carries a haem molecule
• each haem carried a Fe2+ which binds reversibly to O2

Question 18

what are the different forms of Hb and how can you distinguish them?

Answer 18

• oxyhaemoglobin:fully saturated w O2 and is bright red

- deoxyhaemoglobin: lost all O2 and is dark red

Question 19

how many Hb molecules are there per RBC?

Answer 19

300,000,000

Question 20

what do the plasma proteins transport?

Answer 20

• carries substances w poor solubility

- lipids, lipid soluble hormones, metal ions

Question 21

how does the blood have a defensive role?

Answer 21

• immunity: WBC, plasma proteins

- clotting (haemostasis): platelets and plasma proteins

Question 22

how do neutrophils have a defensive role?

Answer 22

• phagocytosis: kills bacteria and fungi

- main mediators of innate immunity

Question 23

how do lymphocytes defend the body?

Answer 23

• main mediators of adaptive (acquired) immunity

- produces antibodies and kills infected cells

Question 24

what do eosinophils and basophils do to defend the body?

Answer 24

• kills parasites, involved in allergic reactions

- basophils cause inflammation

Question 25

what is the role of monocytes in the defensive mechanism?

Answer 25

macrophages are responsible for phagocytosis of dead cells and pathogens

Question 26

what is the role of plasma in immunity?

Answer 26

- 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

Question 27

what is the main role of platelets?

Answer 27

- major role in primary homeostasis - recognise damage at blood vessel wall - forms platelet plugs to stop bleeding

Question 28

what is homeostasis?

Answer 28

- keeping the internal environment of the body constant | - maintaining the pH 7.4, controlling distribution of H2O and solutes, distributing heat

Question 29

what is the plasma's role in homeostasis?

Answer 29

- 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

Question 30

what is haemocrit (Ht) and how is it measured?

Answer 30

- it is the packed cell volume | - volume of cells/ total volume

Question 31

what are common blood tests and what do they measure?

Answer 31

- [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

Question 32

why are blood tests important?

Answer 32

-they are used to diagnose infection