Cardiovascular System Flashcards Preview

Body Logistics > Cardiovascular System > Flashcards

Flashcards in Cardiovascular System Deck (39):
1

Which two 'loops' of the circulatory system exist?

Pulmonary circuit
Systemic circuit

2

What is meant by a closed cardiovascular system?

Blood never leaves vessels

3

The average adult has how much how much circulating blood? What does this consist of?

5 litres

3 litres of plasma
2 litres of red blood cells

4

Where does most of our blood lie in our blood vessels at any one time?

In peripheral veins (65%)

5

What is the valve between the right atrium and right ventricle called?

Tricuspid valve

6

What is the valve between the left atrium and left ventricle called? How many cusps does this have?

Mitral valve

2

7

What is the valve between the pulmonary artery and the right ventricle called?

Pulmonic valve

8

What is the valve between the aorta and left ventricle called?

Aortic valve

9

Why are the structures of the right side of the heart generally more fragile?

Deals with blood which is at lower pressures

10

What are the two main arteries supplying the heart? Where do they stem from?

Left and right coronary arteries

Stem from the aorta

11

What are end arteries? What occurs in blockage of end arteries?

Terminal artery supplying all or most of the blood to a part of the body

So blockage ---> insufficient blood supply to tissue

12

Give two examples of end arteries? What is the only example of an absolute end artery in the body?

Coronary arteries
Cerebral arteries

Central artery to the retina

13

What is stenosis?

Narrowing of an artery

14

What is meant by collateral circulation?

More than 1 artery supplies blood to a particular part of the body

15

What happens at the SA node?

Wave of excitation results in atrial systole

16

What happens at the AV node?

Wave of excitation down the left and right bundle branches to the Purkinje fibres ----> ventricular systole

17

Why is the wave of excitation paused at the AV node?

To avoid simultaneous contraction, allows all the blood to enter the ventricle

18

The elasticity of arteries allows them to respond to changes in blood _____ to keep blood flowing

Pressure

19

What is the systolic pressure?

Typically 120mmHg - the blood pressure in the aorta during systole

20

What is the diastolic pressure?

Typically 70-80mmHg

21

What are the 3 layers present in the walls of most blood vessels?

Tunica Intima - endothelium next to lumen
Tunica Media
Tunic Adventitia

22

What is the difference between the tunic media found in arteries and veins?

Much thicker in arteries

23

What is an aneurysm?

Dilation of a blood vessel

24

What is the tunica adventitia?

A thin layer of fibroelastic connective tissue on the outer layer of blood vessels

25

What is the thickness of the tunic media in arteries? How are the smooth muscle cells in this layer connected?

40 layers of smooth muscle

By gap junctions

26

What are arterioles? What is the structure of its tunica media?

Arteries with a diameter of less than 0.1mm

Only 1-3 layers of smooth muscle in the tunica media

27

What is the wall structure of capillaries?

A single layer of endothelium and a basement membrane

28

Is there a high or low blood velocity through capillaries? Why?

Low - around 0.3 mm/s
Allows gas/nutrient exchange to take place

29

Where are pericytes found?

In capillaries and venules - form a branching network on outer surface of endothelium

30

What is the structure of the wall of postcapillary venules?

Same as capillaries (endothelium + pericytes)

31

What is the wall structure of venules?

Endothelium + pericytes OR thin smooth muscle cells

32

What do veins and venules contain to prevent the back flow of blood?

Valves

33

What is the largest diameter blood vessel?

Veins

34

What is the structure of the wall of a vein?

More connective tissue
Less muscle fibres

Tunica media = 2-3 smooth muscle cell layers

35

What is the meaning of capacitance vessels?

Can stretch to hold more blood (or recoil to hold less) with no pressure changes

36

Blood flows in which order through vessels starting with muscular arteries?

Muscular arteries
Arterioles
(Precapillary sphincters)
Capillaries
Post capillary venules
Venules
Veins

37

How does blood flow in veins? (2)

With the help of contraction of skeletal muscle

Thoracic pump when breathing

38

What is the major vein of the heart?

Coronary sinus

39

What does failure of the calf muscle pump result in?

Venous hypertension ----> venous ulceration