The heart Flashcards

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1
Q

What are the 4 components of blood?

A
  1. Red blood cells
  2. Platelets
  3. Plasma
  4. White blood cells
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2
Q

What are the 2 adaptations of red blood cells?

A
  1. Large SA for faster diffusion
  2. No nucleus so more space for haemoglobin
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3
Q

What is haemoglobin?

A

A quaternary protein with a haem group at the centre of each polypeptide chain containing Fe2+

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4
Q

What do haem groups contain?

A

One Fe2+ which one oxygen molecule binds to

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5
Q

What is the term used to describe the attraction between haemoglobin and oxygen?

A

Affinity

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6
Q

Where does haemoglobin load/associate with oxygen?

A

Lungs

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7
Q

Where does haemoglobin unload/dissociate with oxygen?

A

Respiring tissues

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8
Q

What is % saturation of haemoglobin?

A

A measure of how oxygenated blood is

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9
Q

What is partial pressure of oxygen?

A

A measure of concentration of oxygen not attached to the haemoglobin molecule

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10
Q

Why does the second oxygen molecule attach easier?

A

Each time a molecule of oxygen attaches the whole haemoglobin changes shape which exposes more of the next O2 binding site and makes it easier for the next O2 molecule to attach

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11
Q

What is the advantage of the sigmoid shape of an oxygen dissociation curve?

A

Shows that O2 isn’t unloaded until it reaches the respiring tissues

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12
Q

What does the Bohr effect curve shifting right mean?

A

More respiration so higher partial pressure of O2 and Hb has lower affinity for O2 so more O2 unloaded at respiring tissues

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13
Q

What does the Bohr effect curve shifting left mean?

A

Lower partial pressure of O2 and Hb has higher affinity for O2 so more O2 loaded at the lungs

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14
Q

What is systole?

A

Contraction (occurs separately in atria and ventricles)

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15
Q

What is diastole?

A

Relaxing

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16
Q

What are the valves called between atria and ventricles?

A

Atrioventricular valves

17
Q

What are the valves called between ventricles and arteries?

A

Semi-lunar valves

18
Q

Which direction should blood flow?

A

From atria –> ventricles –> arteries

19
Q

What happens if there is higher pressure in the ventricles than the atria?

A

The atrioventricular valves close

20
Q

What happens if there is higher pressure in the arteries than the ventricles?

A

The semi-lunar valves close

21
Q

Define cardiac output

A

Mean volume of blood leaving the left ventricle per minute

22
Q

Define stroke volume

A

Mean volume of blood leaving the left ventricle during each contraction

23
Q

How does blood flow around the body?

A

Vena Cava –> right atrium –> right ventricle –> lungs –> left atrium –> left ventricle –> Aorta

24
Q

How are arteries/arterioles adapted to their function?

A
  1. More muscular tissue constricts width to control blood flow (thickest in arterioles)
  2. More elastic tissue allows elastic recoil due to pressure of systole (thickest in arteries)
  3. Narrow lumen maintains high pressure
25
Q

How are veins adapted to their function?

A
  1. Less muscular tissue - blood is returning to heart so less need to control flow to tissues
  2. Less elastic tissue - blood under less pressure returning to heart
  3. Less overall thickness - pressure too low to burst walls (allows flattening, allowing compression by muscles)
  4. Valves prevent backflow of blood due to low pressure
26
Q

How are capillaries adapted to their function?

A
  1. One squamous epithelial cell thick for short diffusion distance
  2. Many and highly branched for large SA
  3. Narrow lumen so red blood cells are squeezed flat (reduces diffusion distance for O2)
  4. Spaces between cells allow white blood cells to leave blood and enter cells
27
Q

What is coronary heart disease?

A

Coronary arteries become narrower so less blood supplied to heart muscle and less O2 + glucose for respiring cells

28
Q

What is myocardial infarction (heart attack)?

A

Coronary artery becomes completely blocked so no O2/glucose so no respiration so cell and tissue death