Haemotology

Question 0

Describe the composition of blood

Answer 0

Adults have 4-6L of blood

• 55% - Plasma (nutrients, gases, electrolytes, hormones, plasma proteins and waste products)
• 45% - Cells (RBCs/WBCs and platelets)

Question 1

List the functions of blood

Answer 1

• Transports heat, O2, CO2, nutrients, H2O, waste products and hormones.
• Protects - WBC’s to aid clotting, immunity and defence (inflammation)
• Regulates fluid, pH, temperature and others (such as hormones)

Question 2

Describe the composition of plasma proteins

Answer 2

• Albumin - produced by be liver, it influences blood pressure, flow and fluid balance
• Fibrinogens/Clotting factors - produced by liver and aids injuries
• Globulins - produced by plasma cells and helps immunity/antibodies

Question 3

Describe the structure and function of red blood cells

Answer 3

• Function - gas transport (O2 and CO2)
• Structure - disc shaped with thick rim and an increased surface area/volume ratio. No nucleus or organelles (cannot multiply). Contains heamoglobin and carbonic anhydrase enzyme (carbonic acid from CO2 and H2O)

Question 4

Describe the production and life cycle of red blood cells

Answer 4

• RBCs have a short lifespan - about 120 days
• Produced by a process named ‘erythropoiesis’
• Developed from committed stem cells to mature erythrocytes in about 7 days
• Produced in the red bone marrow at a rate of 2 million cells a second.
• Stimulated by EPO hormone.
• Eryptosis - programmes cell death, same rate as erythropoietin balancing circulation.

Question 5

Define anaemia and discuss the associated signs and symptoms

Answer 5

• A medical condition in which the capacity of the blood to transport oxygen to the tissue is reduced, either because of too few RBCs or too little haemoglobin
• Can be a result of - inadequate nutrition, blood loss periods, RBC destruction or something wrong with the cells.

Question 6

What are the 3 main classes of anaemia?

Answer 6

• Excessive blood loss (haemorrhage)
• Excessive RBC destruction (haemolysis)
• Deficient RBC production (in affective erythropoesis)

Question 7

What are the other types of anaemia (apart from the 3 main classes)

Answer 7

• Diet induced - iron, vitamin b12, folks acid and cells become small (microcytic anaemia)
• Pernicious - damage to stomach lining, no absorption and cells become big (macrocytic anaemia)
• Aplastic - problems with bone marrow

Question 8

Classify erythrocytes according to their size and structure/number

Answer 8

Erythrocytes size:
- Microcytic - small in size (iron deficiency)
- Macrocytic - larger in size (folate or b12 deficiency)
- Normacytic - normal in size (splenic anaemia caused by enlargement of spleen)
Structure/Number
- Hypochromic - paler than normal, less haemoglobin (iron deficiency)
- Hyperchromic - darker than normal, increased haemoglobin and reduction in number (pernicious anaemia)
- Normochronic - normal haemoglobin concentration, not enough cells produced (aplastic, haemolytic anaemias)

Question 9

Categorise white blood cells based on appearance and function

Answer 9

GRANULOCYTES

• Membrane bound enzymes with granules, digest endocytosed parties
• Neutrophils, Eosinophils, Basophils

AGRANULOCYTES

• No granules, contain lysosomes to break down foreign matter endocytosed by cells.
• Lymphocytes, Monocytes and Macrophages

Question 10

Describe the functions of platelets and their role in haemostatis

Answer 10

• Secrete chemicals such as clotting factors, factors for endothelial repair and vasoconstrictors in broken cells.
• Form temporary ‘platelet plug’
• Dissolve old blood clots
• Attract leukocytes to sites of inflammation to phagocytose bacteria.

Question 11

Describe how the body balances iron, input and output, find to deplete and replenish stores.

Answer 11

• Iron carries O2 to the tissues from lungs to RBCs in the form of haemoglobin.
• Balance - recycles iron from catabolised erythrocytes. Ferretin (a protein) can store and release iron to meet noida needs. Regulation of absorption of iron from intestines when it’s needed.
• Iron input - dietary iron, medication/vitamin pill and absorbic acid.
• Iron output - lost from the skin and interior surfaces of body and menstruation.

Question 12

Define the terms: thrombosis and fibrinolysis.

Answer 12

• Thrombosis - the formation of a thrombus (clot) within a vessel. Initiated by pooling of blood in veins due to sluggish flow
• Fibrinolysis - a process that breaks down clots in order to prevent them from growing back or becoming problematic. Uses plasmin (an enzyme that breaks down fibrin)

Question 13

How do you calculate Haemoglobin Concentration (Hb Conc)

Answer 13

• tests the amount of Haemoglobin within RBC’s
• males = 4.5-6.6 x 10(12) per litre
• females = 3.8-5.8 x 10(12) per litre

Question 14

What is a haematocrit?

Answer 14

• take a blood sample and putting it in a centrifuge - separates cells from plasma to calculate the % of total volume made up of RCB/WBC’s
• Normal range -
  Female = 37-47%
  Male = 40-54%

Question 15

What is Mean Cell Volume (MCV)

Answer 15

Measures the average size of RBC’s

Question 16

What is Mean Cell Haemoglobin (MCH)

Answer 16

Average amount of Haemoglobin in RBC’s

Question 17

What is Mean Cell Haemoglobin Concentration

Answer 17

Average concentration of Haemoglobin in RBC’s

Question 18

What is a differential white cell count?

Answer 18

Used as part of a complete blood count to determine high/low WBC levels to help diagnose random immune responses

Question 19

Why is iron important?

Answer 19

It carries oxygen to the tissues from the lungs in RBC’s as Haemoglobin.
It is recycled from catabolised mature RBC’s

Question 20

Haemolysis occurs when a blood cell is placed into:

Answer 20

A hypotonic solution