Cardiovascular System

Question 1

What percentage of blood is in the veins?

Answer 1

65%

Question 2

What are the names of the artery and vein directly below the heart?

Answer 2

Descending thoracic aorta and inferior vena cava.

Question 3

What is the superior vena cava?

Answer 3

The vein coming back into the heart from above.

Question 4

Where is the femoral artery?

Answer 4

Two - runs down each leg

Question 5

What is an end artery?

Answer 5

An artery that is the only supply of oxygenated blood to that tissue.
Prone to blood clots

Question 6

What is collateral circulation?

Answer 6

If the main artery supply breaks off, others around will supply.

Question 7

What main artery leaves the left ventricle?

Answer 7

The pulmonary artery

Question 8

What are the names of the two nodes that send electrical impulses across the heart?

Answer 8

Sinoatrial (SA) node

Atrioventricular (AV) node

Question 9

Explain how systolic and diastolic blood pressures are created.

Answer 9

The left ventricle contracts
BP in the aorta rises to 120 mm Hg (systole), stretching its wall
Aortic semilunar valve closes
The walls of the aorta recoil, pushing blood towards the heart
Pressure reduces to 70-80 mm Hg (diastole)

Question 10

What is an aneurysm?

Answer 10

The dilation of a blood vessel resulted from smooth muscle mass.

Question 11

Circling the lumen of artery, what is the name of the layer that circles it. What is in it?

Answer 11

Tunica Intima

Elastic and epithelium

Question 12

What layer circles the tunica intima in the artery? What does it contain?

Answer 12

Tunica media
Smooth muscle
Gap junctions

Question 13

What layer circles the tunica media in the artery? What does contain?

Answer 13

Tunica advertitia

Contains connective tissue, lymph vessels, nerve fibres

Question 14

How do the three layer (tunica intima, tunica media and tunica adventita) work together to cause vasoconstriction?

Answer 14

Nerve fibres in the tunica advertitia release noradrenaline into the smooth muscle of the tunica media. Depolarisation waves through the gap junction, causing vasoconstriction.

Question 15

What the three sizes of arterial passageway?

Answer 15

Artery
Arterioles
Metaarterioles

Question 16

What are precapillary sphincters?

Answer 16

Small bands that circle the muscle cells of epithelium in the metaarterioles.
When they are open, lots of blood is released into the capillaries.
When they contract and close, blood reduces.

Question 17

What do lympathetic capillaries do?

Answer 17

Drain excess extracellular fluid back to blood.

Question 18

When exercising, where would you body direct your blood?

Answer 18

Away from the digestive system and towards the skeletal muscles.

Question 19

What does the low velocity in capillaries help with?

Answer 19

More time for gas/nutrient exchange.

Question 20

What are are pericytes?

Answer 20

Contractile cells that wrap around capillary epithelium.

Can divide into fibroblasts or muscle cells - use for wound healing, cancer growth.

Question 21

Veins are capacitance vessels, what does this mean?

Answer 21

Can increase volume without increased.

Due to less elastin and muscles, can stretch.

Question 22

Explain how capillary pressure and osmotic pressure influence the changing volume between arteries and veins.

Answer 22

Filtration - capillary pressure is higher than osmotic pressure so fluid exits the artery
No net movement - pressure the same in artery and interstitial fluid.
Reabsorption - capillary pressure is less than osmotic pressure, fluid enters at veins.

Question 23

How does blood get from the legs back the heart?

Answer 23

Calf muscles pump venous blood - valves stop it flowing back