Physiology

Question 1

What is blood?

Answer 1

Cells suspended in plasma

Question 2

What is the purpose of blood?

Answer 2

Fight infection
Transport Oxygen
Prevent bleeding

Question 3

Define haematopoiesis

Answer 3

Production of blood from pluripotent stem cells in bone marrow

Question 4

In an embryo where does haematopoiesis occur?

Answer 4

Yolk sac
Liver
Marrow

Question 5

In a baby/young child where does haematopoiesis occur?

Answer 5

Bone marrow

Spleen and liver

Question 6

As we mature what happens to the bone marrow?

Answer 6

The sites remain in the axial skeleton as the bones grow it decreases in size

Question 7

Describe the first three steps of the haematopoeisis tree

Answer 7

1. LT HSC
2. ST HSC
3. Multilineage progenitor

Question 8

What two precursors can the multilineage progenitor become?

Answer 8

Myeloid

Lymphoid

Question 9

Describe the fate of the myeloid precursor

Answer 9

Megakaryocyte erythrocyte precursor
- erythrocyte or platelet
Granulocyte monocyte precursor
- granulocyte or macrophage

Question 10

What is the fate of the lymphoid precursor?

Answer 10

B cell
T cell
NK cells

Question 11

What is the key difference between the precursors and mature cells?

Answer 11

Precursors - morphologically unremarkable and infrequent

Mature - specific characteristics and frequent

Question 12

What happens to the cell morphology as the cell divides?

Answer 12

It gets smaller, the nucleus condenses and eventually is removed

Question 13

Describe the characteristics of platelets

Answer 13

Lots of nuclei in one big cell, bud off to form platelets

Question 14

Name the three types of granulocyte

Answer 14

Eosinophil
Basophil
Neutrophil

Question 15

Describe neutrophils

Answer 15

Segmented nucleus with neutral staining granules
Phagocytose invaders and kill with granule contents
Attract other cells - complement and chemokine causing body stress

Question 16

What situations cause an increase in neutrophils?

Answer 16

Infection
Infarction
Trauma

Question 17

Describe eosinophils

Answer 17

Bi lobed with red staining granules

Fight parasitic infections and involved in hypersensitivity

Question 18

What type of patients often have high eosinophils?

Answer 18

Patients with allergies

Question 19

Describe basophils

Answer 19

Infrequent, purple granules with obscuring nucleus

IgE receptors and histamine - involved in hypersensitivity

Question 20

What are monocytes?

Answer 20

Single nucleated cells often with vacuoles

Circulate for a week and then enter tissues to become macrophages which phagocytose and attract other cells

Question 21

What type of immune molecule are macrophage?

Answer 21

MHC class II

Question 22

Name two methods of assessing blood constituents

Answer 22

Immunophenotyping
Bio-assays
Examination

Question 23

What is immunophenotyping?

Answer 23

Surface proteins, monoclonal antibodies with tags

Question 24

What is bio-assay?

Answer 24

Culture in vitro and show lineage of progeny in different growth conditions

Question 25

What can be examined to determine blood constituents?

Answer 25

Blood Bone marrow Special tests of bone marrow Spleen, liver, lymph nodes

Question 26

Name two methods to obtain bone marrow sample

Answer 26

Posterior iliac crest aspiration | Core biopsy

Question 27

What is the difference between the two bone marrow sampling techniques?

Answer 27

Aspiration - see individual cells | Biopsy - can see cells in context and structure of marrow

Question 28

Describe the structure and function of RBC

Answer 28

Biconcave, full of Hb No nucleus or mitochondria with a high SA to volume ratio Flexible

Question 29

What does the high SA to volume ratio allow?

Answer 29

Gas exchange

Question 30

What aspects of the RBC membrane help with its function?

Answer 30

Lipid bilayer Protein spars Protein anchor Sodium potassium pump

Question 31

Describe the structure of haemoglobin

Answer 31

Tetrameric globular protein with 2 alpha and 2 beta | Heme Fe2+ in a flat porphyrin ring - one heme per subgroup binds to one oxygen

Question 32

What is the function of haemoglobin?

Answer 32

Delivers oxygen Buffers hydrogen ions Carbon dioxide transport

Question 33

What is the name for the cellular mechanisms that generate RBC?

Answer 33

Erythron

Question 34

What are the raw materials of RBC?

Answer 34

Iron B12 folate

Question 35

What is the immediate cell before a RBC?

Answer 35

Reticulocyte

Question 36

What is the key difference between a RBC and reticulocyte?

Answer 36

There is some RNA in reticulocyte and so it acts as a marker of bone marrow function

Question 37

Name the hormone that senses hypoxia in the kidneys

Answer 37

Erythropoietin

Question 38

What is the effect of erythropoietin on bone marrow function?

Answer 38

Stimulates the erythron to increase red cell production

Question 39

State the average life span of an RBC

Answer 39

120 days

Question 40

How are red cells removed from the body?

Answer 40

Taken up by macrophage in the spleen and broken down into heme and globin

Question 41

What happens to the heme?

Answer 41

Iron can be stored as ferritin or related to transferrin for future use

Question 42

What happens to the globin?

Answer 42

recirculated

Question 43

What happens to the porphyrin ring?

Answer 43

Unconjugated bilirubin taken up in the liver and excreted in bile

Question 44

How do RBC produce energy?

Answer 44

Glycolysis

Question 45

What are the problems with glycolysis?

Answer 45

Low energy yield | Lots of free radicals produced

Question 46

State the net generation from glycolysis

Answer 46

ATP - energy | NADH - electron donor to stop oxidation

Question 47

What are reactive oxygen species?

Answer 47

Hydrogen peroxide/superoxide have unpaired free electrons that interact with DNA and proteins

Question 48

How are reactive oxygen species dealt with?

Answer 48

Glutathione reacts with hydrogen peroxide to form water and an oxidised glutathione

Question 49

How is oxidised glutathione converted back to glutathione?

Answer 49

NADPH

Question 50

What enzyme is needed to produce NADPH?

Answer 50

Glucose 6 phosphate dehydrogenase

Question 51

Name the shunt where NADPH is produced?

Answer 51

Hexose Monophosphate

Question 52

Name three ways carbon dioxide can be removed from the body

Answer 52

Dissolves Binds to haemoglobin Bicarbonate

Question 53

What ion is exchanged for bicarbonate in the red blood cell?

Answer 53

Chloride

Question 54

How is fetal haemoglobin different to adult?

Answer 54

Higher affinity - saturates more at the same oxygen concentration

Question 55

What shape is the oxygen/saturation curve?

Answer 55

Sigmoidal

Question 56

Describe the allosteric effect

Answer 56

As one oxygen binds to haem the Hb changes shape - this interacts with the adjacent globin and changes its shape and thus affinity

Question 57

Other than oxygen what else can alter the shape/position of haemoglobin?

Answer 57

Small molecules e.g 2,3 BPG

Question 58

Describe 2,3, BPG

Answer 58

Produced in glycolysis it interacts with Hb and shifts the curve to the right to allow higher release of oxygen into tissues

Question 59

What shifts the curve to the right?

Answer 59

Decreased pH, increased temp, increased CO2 (Bohr)

Question 60

What shifts the curve to the left?

Answer 60

Increased pH, reduced temp, increased oxygen (haldane)

Question 61

What would cause a reduced cell count?

Answer 61

Increased distribution e.g haemorrhage Reduced production e.g iron deficiency Redistribution e.g liver disease

Question 62

What would cause an increased cell count?

Answer 62

Stimulus e.g altitudes, hypoxia, allergy Malignancy Redistribution e.g splenic, trauma, steroids

Question 63

How do steroids cause an increased cell count?

Answer 63

Demargination - they move neutrophils away from the vessel wall