Week 1 - Blood and Blood Disorders

Question 1

What are the functions of blood (3)

Answer 1

• Distribution of oxygen, CO2, nutrients, hormones ect
• Regulation of Temperature, pH, fluid volume
• Protection - immune system and haemostasias

Question 2

What are the components of blood

Answer 2

• live cells surrounded by extracellular fluid
• Formed elements + liquid

Question 3

What is the composition of blood

Answer 3

55% plasma
45% erythrocytes
<1% leukocytes and platelets

Question 4

What is plasma

Answer 4

• The liquid portion of blood (55% of blood volume)
• Approx 90% water
• contains over 100 different solutes

-nutrients (glucose, AA< FS)

-proteins (fibrinogen, prothrombin, albumin (most common), Ig(anti bodies) )

-Electrolytes (Na+, K+, CL-)

-Hormones (insulin, glucagon)

-Wastes (urea, creatinine)

Question 5

What are the formed elements of blood (3)

Answer 5

• Red blood cells (erythrocytes)- major cellular components
• White blood cells (WBC, leukocytes)
• Platelets (thrombocytes) - for blood clots

Question 6

where do all formed elements of blood come from

Answer 6

bone marrow

Question 7

What are erthrocytes

Answer 7

Red blood cells

They biconcave and flexible

• for fast diffusion
• small blood vessels

Live for 90-140 days

• no organelles inside
• gets trapped in and removed from the Spleen

Question 8

What are the functions of erythrocytes

Answer 8

• Transports oxygen bound to Hb
• Facilitates CO2 transport

Question 9

How do erythrocytes transport oxygen

Answer 9

Transports oxygen bound to Hb

• Pick up O2 in lungs = oxyhaemoglobin (ruby red)
• Release O2 in tissues = deoxyhaemoglobin (dark red)

Question 10

How do erythrocytes facilitate CO2 transport

Answer 10

Facilitates CO2 transport

• CO2 binds to Hb = carbaminobaemoglobin (20%)
• Carbonic anhydrase produces bicarbonate via carbonic acid (70%) - bicarbonate helps with controlling pH (pH needs to be specific or RBC will die)
• Remaining 10% dissolves in plasma

*All passive transport based on concentration gradients

Question 11

Where do erythrocytes develop from

Answer 11

• pluripotent stem cells
• erythropoietin (EPO) develops from kidney 0 tissue hypoxia

Question 12

Explain the regulation of erythropoiesis from hypoxia

Answer 12

1. hypoxia due to decreased RBC
2. reduces O2 levels in blood
3. Kidney (and liver to a smaller extent) releases erythropoietin
4. Erythropoietin stimulates red bone marrow
5. Enhanced erythropoiesis increases RBC count
6. Increases O2 carrying ability of blood
7. Homeostasis

Question 13

What is hypoxia

Answer 13

a condition where there is an inadequate supply of oxygen to the tissues of the body despite adequate blood flow

Question 14

What are causes of hypoxia

Answer 14

• Anemia = abnormally low number of circulating erythrocytes or levels of hemoglobin or both
• low blood volume
• poor blood flow
• pulmonary disease
• high altitude - low oxygen at higher altitude

Question 15

What causes different blood types

Answer 15

Erythrocytes have proteins on their surface
different blood types are based on the different proteins on erythrocytes

Question 16

What does A and B in blood type A, AB, A+, B mean

Answer 16

A antigen or B antigen

Question 17

What does O in O blood type mean

Answer 17

neither A or B antigen

Question 18

What is the difference between positive and negative blood types

Answer 18

positive blood types has the Rh antigen
Negative blood does not have the Rh antigen

Question 19

Can Negative blood be safely given to positive blood types

Answer 19

Yes since negative blood types don’t have the Rh antigen so it won’t trigger an immune response in Rh-positive people

Question 20

Can positive blood be safely given to negative blood types

Answer 20

No,
Rh-negative people don’t have the Rh antigen on their red blood cells. So, if they receive Rh-positive blood (which does have the antigen), their immune system may recognize it as foreign and create antibodies against it.

Question 21

what are leukocytes

Answer 21

white blood cells
- key component of the immune system
- produced from pluripotent stem cells

Question 22

What are platelets/thrombocytes

Answer 22

• small disc shaped cells in the blood
• essential for blood clotting
• produced in bone marrow from pluripotent stem cells

Question 23

What is anemia

Answer 23

abnormally low number of circulating erythrocytes Or levels of hemoglobin OR both

Question 24

What are causes of anemia

Answer 24

• haemorrhage (acute, chronic) - cuts
• Haemolysis - destruction of red blood cells (not from blooding), e.g. transfusion reaction
• Deficiency in production of RBC
• Nutrient deficiencies

iron (apart of Hb)
vitamin B12 (effects DNA synthesis and the dot points below)
DNA synthesis
Abnormal fatty acids
intrinsic factor -pernicious anemia

• Acquired hemolytic anemias

Direct membrane destruction - from drugs, chemicals, toxins, mechanical heart valves

Antibody-mediated lysis - transfusion reactions, hemolytic disease of the newborn

• Aplastic anemia

-suppression of bone marrow

-all cell synthesis affected

• Infectious disease (malaria, hookworms, HIV)
• Space flights (microgravity)
• Chronic disease and inflammation (renal disease , cancers that affect bone marrow, chronic infections, autioimmune diseases)

Question 25

What are symptoms of anemia

Answer 25

Reduces oxygen carrying capacity - fatigue - labored breathing - dizziness and headaches - angina - tachycardia - paleness

Question 26

Why would tachycardia by a symptom of anemia

Answer 26

Less oxygen so the heart has to work harder to compensate tarchycardia = heart rate exceeds 100 beats per minute (bpm) in adults.

Question 27

what are hereditary disorders which can cause anemia

Answer 27

- Defective production of Hb -sickle cell anemia -thalassemia - Defective red blood cells -Spherocytosis -Glucose-6-phosphate dehydrogenase (g-6-PD) deficiency

Question 28

What are oral signs of anemia

Answer 28

- pale gums - smooth tongue - mouth ulcers - angular cheilitis - Caries - delayed tooth eruption - periodontal disease

Question 29

How do you manage patients with anemia

Answer 29

*Depends on cause of anemia May have to delay elective procedures due to haemorrhage or poor wound healing May need antimicrobial rise or antibiotic prophylaxis before invasive procedure - sickle cell anemia, aplasic anemia Some medicines may be dangerous - aspirin for G-6-PD deficient patients - can be toxic - NSAIDs for sickle cell anemia

Question 30

What is polycythemia

Answer 30

condition where there is an increased number of red blood cells in the blood leading to increased blood viscosity and a higher risk of complications like blood clots, stroke or heart problems

Question 31

What are relative causes of polycythemia

Answer 31

- Dehydration - diuretics

Question 32

What are absolute causes of polycythemia

Answer 32

- increase in cell numbers - high altitude (physiological) - genetic defect in hemocytoblasts

Question 33

What is Haemochromatosis

Answer 33

disorder in which the body absorbs and stores too much iron from the diet, leading to iron overload - genetic condition - Iron levels build up to dangerous levels - oxidative stress - Associated with severe periodontitis - bacterial pathogens use iron

Question 34

What is erythropoietin (EPO)

Answer 34

glycoprotein hormone that stimulates the production of red blood cells in the bone marrow

Question 35

where is erythropoietin (EPO) produced

Answer 35

kidney

Question 36

What triggers production of erythropoietin

Answer 36

tissue hypoxia - inadequate supply of oxygen to tissue

Question 37

what are causes of hypoxia

Answer 37

- Anemia - Low blood volume - High altitude - Hypo ventilating - Respiratory disorders Cardiovascular disorders