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BAMS: Cardiovascular System > Blood > Flashcards

Flashcards in Blood Deck (40)
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1

What is blood composed of?

Cells (45% of blood volume)- 'formed elements'
Red blood cells (erythrocyte)
White blood cells (leucocytes)
Platelets (thrombocytes)

Plasma (55% of blood volume) - extracellular fluid; water, electrolytes, organic molecules (glucose, fatty acids, glycerides, amino acids, etc); plasma proteins

2

Which proteins are present in the plasma?

Albumins (60%): oncotic pressure, transport of lipids
Globulins (35%): transport of ions, hormones, lipids. Immune function
Firbinogen (4%): key component of blood clot
Regulatory proteins (1%): enzymes and hormones

3

Red blood cells make up what percentage of all cells in the blood?

99%

4

What is the diameter of a red blood cell?

6-8 micrometers

5

What shape is a RBC and what does this confer?

Biconcave shape: gives large surface area relative to volume
This permits rapid gas (O2, CO2) transfer across cell membrane
Allows RBC to bend in narrow capillaries
Enables RBC to expand to accommodate fluid in hypotonic solutions

6

Where are RBCs formed?

In the red bone marrow

7

What is the average lifespan of a RBC?

120 days

8

How are old RBCs broken down?

Old RBCs are removed from circulation and broken down by MPS (monocyte/phagocyte system) - in the spleen, mainly
Breakdown products are recycled

9

What is haemoglobin made up of?

Protein - amino acid pool
Haem -> contains iron. Converted into biliverdin and bilirubin (waste products)

10

Where is bilirubin conjugated?

In the liver and excreted as bile pigment

11

What are the symptoms of excess bilirubin in the blood?

Jaundice (yellowing of skin) and itchy skin

12

What percentage of RBCs are non-functional?

10%

13

What happens to non-functional RBCs?

Broken down by haemolysis
Eliminated through urine or picked up by macrophages

14

What is transferrin?

A carrier protein made in the liver
Picks up iron and drops it off at the bone marrow -> transferrin circulates iron

15

What is anaemia caused by?

Iron deficiency in the blood

16

What is the main symptom of anaemia?

Chronic fatigue

17

How are RBCs formed?

Formed in red bone marrow, regulated by erythropoietin
Series of stages involved
During development there is a reduction in cell size and regression of nucleus
Requires folic acid and vitamin B12
Requires iron (for haemoglobin)

18

What are the stages in RBC formation?

Day 1: Proerythroblast (huge nucleus, big cell)
Day 2: Basophilic erythroblast
Day 3: Polychromatophilic erythroblast
Day 4: Normoblast
Days 5-7: Reticulocyte
Day 7: Mature RBC

19

What happens if RBC numbers are low?

Decreased oxygen delivery to cells
Decreased oxygen to kidney
Erythropoietin released
Acts on red bone marrow
Increases production of RBCs

20

Why are RBCs never 100% saturated with oxygen?

Because they also carry CO2

21

What is the molecular weight of haemoglobin?

68,000 Da

22

Describe the structure of haemoglobin

2 alpha chains and 2 beta chains
4 hame groups (porphyrin ring, iron atom)
Fe reversibly binds O2

23

What type of haemoglobin does a foetus have?

Hb-F

24

How many molecules of haemoglobin does each RBC contain?

200-300 Hb molecules per RBC

25

What percentage of cells in the blood do white blood cells make up?

1%

26

What type of cells make up the majority of white blood cells?

Neutrophils (50-70%)

27

What do neutrophils do?

Fight infections
Non-specific
General immune response
Phagocytic

28

What do neutrophils do?

Fight infections
Non-specific
General immune response
Phagocytic

29

What are eosinophils?

Immune cells involved in allergy

30

What is the precursor for macrophages?

Monocytes