Circulatory System and Heart

Question 1

Describe the structure of haemoglobin.

Answer 1

Large quaternary protein, has four polypeptide chains each with a haem group containing an iron ion (gives blood colour).

Question 2

What reveresable reaction forms oxyghaemoglobin?

Answer 2

haemoglobin + oxygen = oxyghaemoglobin

Question 3

What is the partial pressure of O2?

Answer 3

Measure or oxygen concentration, greater the concentration the higher the partial pressure (same for carbon dioxide).

Question 4

What does oxygen affinity depend on?

Answer 4

Partial pressure of oxygen; oxygen loads onto haemoglobin when there is a high oxygen affinity and unloads when there is a lower oxygen affinity.

Question 5

Dissociation curve of oxygen affinity.

Answer 5

S shaped as when haemoglobin first combines with O2 it alters making it easier for molecules to join creating a steep bit up it eventually becomes harder so there are shallow bits at each end.

Question 6

How does CO2 concentration affect oxygen unloading?

Answer 6

Haemoglobin gives up oxygen more readily at higher partial pressures of O2 as cells need more oxygen during activity.

Question 7

Explain the Bohr effect.

Answer 7

As cells respire CO2 produced increasing its partial pressure which also increases oxygen unloading so the curve shifts right. Oxygen saturation in blood is lower for given partial pressure meaning more oxygen is being released.

Question 8

What does blood transport?

Answer 8

Respiratory gases, products of digestion, metabolic waste and hormones.

Question 9

Name the blood vessels that lead into and out of the kidneys.

Answer 9

Renal artery (in)
Renal vein (out)

Question 10

Name the blood vessels that lead into and out of the lungs.

Answer 10

Pulmonary artery (in and deoxygenated)
Pulmonary vein (out into heart and oxygenated)

Question 11

Name the blood vessels that lead into and out of the liver.

Answer 11

Hepatic artery (in from heart)
Hepatic portal vein (in from gut)
Hepatic vin (out)

Question 12

Which blood vessels provide the heart itself with blood?

Answer 12

Coronary arteries.

Question 13

Name the blood vessels that lead into and out of the heart.

Answer 13

Vena cava (in from body)
Aorta (out to body)
Pulmonary vein (in from lungs)
Pulmonary artery (out to lungs)

Question 14

Describe the features of an artery.

Answer 14

Blood from heart to rest of body:

• thick muscular walls and elastic tissue allows to stretch and recoil as heart beats allowing high pressure to be maintained
• folded inner lining/endothelium allowing artery to stretch
• all carry oxygenated blood except pulmonary artery

Question 15

Describe the features of an arteriole.

Answer 15

What arteries divide into, direct bloody to different areas of demand by muscle inside them which contract to restrict or relax to allow full flow.
- large lumen and thin muscle wall

Question 16

Describe the features of veins.

Answer 16

Veins take blood back to the heart in lower pressure, have wider lumen with very little elastic or muscle tissue.

• contain valves to prevent blood flowing backwards
• all carry deoxygenated blood except pulmonary vein

Question 17

Describe features of capillaries.

Answer 17

Branched from arterioles, found near cells in exchange tissues to create a short diffusion pathway, one cell thick walls, many creating large SA.

Question 18

What is tissue fluid?

Answer 18

Fluid surrounding cells in tissues, made of small molecules from blood plasma. It is where cells take oxygen and nutrients in from and release metabolic waste into.

Question 19

Describe pressure filtration.

Answer 19

Bob

Question 20

Which side of the heart pumps oxygenated blood to the body?

Answer 20

Left side.

Question 21

Which side of the heart pumps deoxygenated blood to the lungs?

Answer 21

Right side.

Question 22

Left hand side of heart diagram there is:

Answer 22

Pulmonary artery, superior and inferior vena cava, right atrium, semi lunar valve, right atrioventricular valve, right ventricle.

Question 23

Right side of heart diagram there is:

Answer 23

Aorta, pulmonary vein, left atrium, semi lunar valve, left atrioventricular valve, left ventricle.

Question 24

What does the left ventricle do?

Answer 24

Thicker, muscular walls as it need to contract to push blood around the body, right only needs to get to the lungs. Ventricles thicker than atria.

Question 25

What do the atrioventricular valves do?

Answer 25

Stop blood flowing be ask to the atria when ventricles contract.

Question 26

What do semi lunar valves do?

Answer 26

Links ventricles to pulmonary arteries and aorta, stop blood flowing back into heart after ventricles contract.

Question 27

What do cords do?

Answer 27

Attach atrioventricular valves to ventricles to stop them being forced into the atria as ventricles contract.

Question 28

What causes valves to open and close?

Answer 28

Higher pressure behind valve forces it open, higher pressure in front of the valve forces it shut.

Question 29

Describe the first stage of the cardiac cycle.

Answer 29

Ventricles are relaxed and atria contracts decreasing volume and increasing pressure which pushes blood into the ventricles, ventricular pressure increases with volume as ventricles receive the blood from contracting atria.

Question 30

Describe the second stage of the cardiac cycle.

Answer 30

Atria relaxes and evicted contact increasing their pressure and decreasing their volume, pressure higher in ventricles than atria forcing AV valves shut, ventricle pressure also higher than aorta and pulmonary artery pressure which forces SL valve open forcing blood out.

Question 31

Describe third stage of cardiac cycle.

Answer 31

Both ventricles and atria relax, higher pressure in arteries closes SL valves, blood returns to heart and atria fill again due to higher pressure in veins, pressure in atria increases and pressure in ventricles falls below forcing AV vales open allowing blood to flow passively.