introduction to structure and function of blood

Question 1

structure of blood

Answer 1

Plasma
Red cells
White cells
Platelets

Question 2

Info on red blood cells (RBC)

Answer 2

they are biconcave discs
have NO nucleus (enucleated)
don’t contain DNA, RNA or mitochondria
(erythrocytes)

Question 3

Info on WBC

Answer 3

are colourless 
the 2 most common types 
- Neutrophils : polymorphonuclear granulocyte 
- Lymphocytes
(leukocytes)

Question 4

3 types of granulocytes

Answer 4

neutrophil: most common white blood cell (weakly staining granules)
eosinophil : 1-4% of WBC (granules stain red with eosin)
basophil: <0.5% of WBC (granules stain blue/ purple with basic dyes)

Question 5

what are granulocytes?

Answer 5

A granulocyte is a type of white blood cell that has granules which contain enzymes that are released during infections, allergic reactions and asthma

Question 6

info on mononuclear cells

Answer 6

lack granules 
have large and regular nuclei 
there are 2 main types 
- Monocytes (largest type of WBC)
- Lymphocytes

Question 7

info on platelets

Answer 7

cytoplasmic fragments
no nucleus
membrane bound
contain granules

Question 8

where do blood cells come from?

Answer 8

mature blood cells are produced from stem cells in the bone marrow

Question 9

info on plasma

Answer 9

it is a fluid that contains ...  
water 
salts 
proteins 
organic molecules (metabolites, carbohydrates, lipids)

Question 10

ionic constituents of plasma

Answer 10

positive ions

• sodium
• potassium
• calcium
• magnesium
• hydrogen ions

negative ions

• chloride
• bicarbonate
• phosphate
• sulphate
• organic anions

Question 11

plasma vs serum

Answer 11

plasma is the fluid component of blood

serum is the fluid left after blood clotting - without the clotting factors

Question 12

plasma proteins

Answer 12

normal 7-9% of plasma protein
complex - thousands of different proteins
90% is albumin

Question 13

functions of blood

Answer 13

1. transport
2. defense
3. homeostasis

Question 14

info on transport of the blood

Answer 14

• carry oxygen/ nutrients to tissues
• removes CO2 / other waste products from tissues
• transport other substances (e.g. hormones) from sites of production

Question 15

erythrocytes

Answer 15

transports oxygen from lungs to the body tissues

helps in the removal of CO2 from body tissues to the lungs

Question 16

removal of CO2 from body tissues

Answer 16

• most CO2 is carried as bicarbonate in plasma
• red cell enzyme carbonic anhydrase helps CO2
• to dissolve in plasma in the tissues
• come out of solution in the lungs

Question 17

structure of RBC

Answer 17

average life span ~ 120 days
diameter ~ 8 um
thickness ~ 2 um

Question 18

info on RBC

Answer 18

• major constituent is the protein
• Hb binds oxygen
• Carries it from the lungs to the tissues

Question 19

info on haemoglobin

Answer 19

• is a protein tetramer made up of 4 polypeptide chains
  (2 alpha globin chains, 2 beta globin chains)
• each globin chain carries a haem molecule
• The haem holds a ferroud iron atom
• oxygen binds reversibly to the iron atom

Question 20

info on haemoglobin (oxygen)

Answer 20

oxyhaemoglobin is fully saturated with O2 making it bright red

deoxyhaemoglobin has lost all O2 therefore it is dark red

Question 21

pulse oximetry

Answer 21

a method to measure the oxygen saturation within the blood by measuring the colour of haemoglobin

• this can help to determine if a patient is hypoxic

Question 22

info on transport (plasma proteins)

Answer 22

plasma proteins carry substances which are poorly soluble in water (lipids, lipid soluble hormones and vitamins)

plasma proteins also carry metal ions eg Ca2+, Fe2+, Cu2+

Question 23

function of WBC

Answer 23

defence

- immunity
WBC and plasma proteins
- clotting (haemostasis)
(platlets and plasma proteins)

Question 24

types of WBC

Answer 24

neutrophil 
eosinophil 
monocyte 
lymphocyte
basophils

Question 25

neutrophils

Answer 25

phagocytose and kill bacteria & fungi

main mediators of innate immunity

Question 26

lymphocytes

Answer 26

main mediators of adaptive immunity

produce antibodies kill virus infected cells

Question 27

eosinophils

Answer 27

kill parasites

involved in allergic responses

Question 28

basophils

Answer 28

kill parasites

involved in allergic responses

involved in inflammation

Question 29

monocytes (macrophages)

Answer 29

phagocytosis of dead cells and pathogens