L5 - Blood Cells

Question 1

Key facts about the blood

Answer 1

• avg human has 5L of blood
• blood cells (45-55%)
• plasma
• human plasma proteome >10,000 proteins
• serum

Question 2

Why separate the blood components?

Answer 2

rapid assessment of blood composition

Question 3

What is the hematocrit?

Answer 3

% of blood volume that is composed of RBCs

Question 4

What is the plasma?

Answer 4

blood w/o cell components

Question 5

What is plasma used for?

Answer 5

• blood substitute, to increase volume during surgery/after trauma
• controls bleeding, aids wound healing
• many drugs at therapeutic conc bind to plasma proteins

Question 6

What is serum?

Answer 6

plasma w/o clotting factors and fibrinogen

Question 7

What is serum used for?

Answer 7

• diagnostic measurements, cosmetics
• growth media for cell culture

Question 8

What are the 3 types of blood cells?

Answer 8

• Erythrocytes (RBC): O transport, pH buffer
• Leucocytes (WBC): Granulocytes, lymphocytes, important in host defence
• Platelets (derived from megakaryocytes) - important in blood clotting

Question 9

What is bone marrow? why is it important?

Answer 9

• soft, spongy tissue in the centre of bones
• contains collagen and glucosamine: important for healthy bones and joints

Question 10

What are the types of bone marrow?

Answer 10

• red - blood cells
• yellow - cartilage, fat and bone cells

Question 11

What is bone marrow like in children vs adults?

Answer 11

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

Question 12

What are blood cells derived from?

Answer 12

Hematopoietic stem cells
(undifferentiated cells capable of producing the precursors of dif blood cells)

Question 13

What differentiates from hematopoietic cells?

Answer 13

• myeoloid progenitor cell
• lymphoid progenitor cell

Question 14

What differentiates from myeloid progenitor cells?

Answer 14

• megakaryocytes = platelets
• eosinophil
• basophil
• erythrocytes
• neutrophyl
• monocyte = dendritic cell, macrophage

Question 15

What is the condition called where there is a lack in blood cells?

Answer 15

anemia

Question 16

What are the key functions of the blood?

Answer 16

• transport: O, CO2, nutrientrs and excretory prodcuts
• regulation: delivery or hormones, diversion of blood, temp regulation
• protection: leukocytes in infection, clotting mechanisms

Question 17

Description of healthy blood vessels (in order)

Answer 17

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

Question 18

What are erythrocytes?

Answer 18

RBCs
- transport O2, CO2
- contain Hb
- biconcave: high SA:vol
- membrane polysaccharides/proteins confers to blood group

Question 19

What is erythropoiesis?

Answer 19

The production of RBCs
- controlled by hormone erythropoietin (EPO)
- secreted in small amounts from kidney

Question 20

What triggers EPO production?

Answer 20

Decreased O2 levels
- high altitude
- lung disease
- insufficient pumping of the heart
- anaemia

Question 21

What is anemia?

Answer 21

Decrease in the total number of erythrocytes and decreased conc Hb per erythrocyte

Question 22

What is anemia often caused by?

Answer 22

• iron/vitamin B12 deficiency
• failure in BMw production - aplastic anemia
• genetic disorders - thalassemia, sicle cell anemia

Question 23

What are leucocytes involved in? And which types

Answer 23

Host immunity
- innate immunity
- adaptive immunity

Question 24

What is innate immunity?

Answer 24

Myediated by meloid cells/ granulocytes
- first line of defense against pathogens

Question 25

What is adaptive immunity?

Answer 25

Mediated by lymphocytes
- 2nd line
- highly specific to particular pathogen (antigen specific)
- longer lasting protection

Question 26

What are the type of myeloid cells?

Answer 26

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

Question 27

What are agranulocytes?

Answer 27

Monocytes/macrophages

• Engulf bacteria
• release inflammatory mediators (cytokines)
• antigen presenting cells (APCs) to T cells

Question 28

What are granulocytes?

Answer 28

Densely stained granules in cytoplasm
(Polymorphonuclear leukocytes)

• neutrophils
• basophils
• eosinophils

Question 29

What are the types of lymphocytes?

Answer 29

• B cell, plasma cell - a/bod production
• Th cells - activation stimulus to other immune cells
• NK cells/cytotoxic Tcells - lyse virally infected cells

Question 30

What are the leucocyte disorders?

Answer 30

Too few - patient is immunosuppressed/immunocompromised, susceptible to opportunistic infections

Too much - immune system activated inappropriately - requires immunosuppressive drugs

Question 31

What are platelets?

Answer 31

Known as thrombocytes

• no nucleus (anucleate)
• important in blood clotting
• progenitor cells differentiate to megakaryocytes = break off into platelets

Question 32

What is platelet production controlled by?

Answer 32

Thrombopoeitin (from liver)

• binds to platelets
  = normal = free TPO low
  = low = free TPO leve high = platelet production stimulated

Question 33

What are platelet disorders?

Answer 33

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