Introduction to CVS

Question 1

Why do we need a CVS?

Answer 1

• Temperature regulation
• Pump blood through the lungs and carry oxygen
• Transport nutrients to muscles and organs
• Circulates hormones and immune mediators
• Connection to the lymphatic system
• Human reproduction

Question 2

What is passive diffusion?

Answer 2

Is the random undirected thermal movement of molecules

Question 3

the relation between time of diffusion and distance

Answer 3

t ∝d^2

Question 4

What does the CVS use

Answer 4

CVS uses convection to provide fast and directional transport

Question 5

What does the heart create and using what in convection formation?

Answer 5

The heart creates a pressure gradient using metabolic energy

Question 6

What does output of blood from the heart create?

Answer 6

The output of blood at high pressure creates a pressure difference with distant blood vessels

Question 7

Average pressure in aorta

Answer 7

> 100 mmHg

Question 8

Average pressure in vein

Answer 8

5-10 mmHg

Question 9

What does pressure difference drive?

Answer 9

Pressure difference drives blood flow

Question 10

Systole

Answer 10

Contraction

Question 11

Diastole

Answer 11

Relaxation

Question 12

What are the brain and myocardium usually regarding cardiac output?

Answer 12

Myocardium and brain are relatively under perfused

Question 13

Why does the under perfusion of myocardium and brain lead to clinical problems?

Answer 13

Can lead to angina, stroke

Question 14

Equation of cardiac output

Answer 14

Cardiac output=Heart rate x stroke volume

Question 15

What is the cardiac output?

Answer 15

Volume of blood expelled from the left ventricle per minute

Question 16

What factors affect cardiac output?

Answer 16

Filling pressure
Sympathetic and parasympathetic nerves
Chemical factors and hormones

Question 17

Why is blood flow and blood pressure so critical?

Answer 17

Critical for correct bodily function

Question 18

Equation for blood flow

Answer 18

Pressure difference/Resistance

Question 19

Systemic circualtion

Answer 19

120/80 mmHg

Question 20

Pulmonary circulation

Answer 20

25/15 mmHg

Question 21

Sequence of aortic blood vessels

Answer 21

Aorta–>Arteries–>Arterioles

Question 22

Sequence of vena blood vessels

Answer 22

Veina–>Venules–>Vena cava

Question 23

Equation for blood velocity?

Answer 23

Blood flow/(cross sectional area x nr^2)

Question 24

What are capillaries made up of and what advantage does it give them

Answer 24

Capillaries made up millions of small vessels giving a very large cross section

Question 25

What is the aorta and comment on CSA?

Answer 25

Aorta is one large artery and has a low cross sectional area

Question 26

Why is velocity much slower in capillaries?

Answer 26

Velocity much slower in capillaries allowing gaseous/nutrients exchange to occur

Question 27

Comment on circulation in series

Answer 27

Same blood supply between organs Lower perfusion pressures Medically significant if first organ perfused

Question 28

Comment on circulation in parallel

Answer 28

Safeguard O2 supply in organs Most organs supplied this way

Question 29

What are the three layers of the blood vessels?

Answer 29

Inner layer-Endothelium Middle layer-Smooth muscle External layer-External elastic membrane

Question 30

What are the four functional groups of blood vessels?

Answer 30

Arteries Arterioles Capillaries Venules and veins

Question 31

What do arteries accommodate and convert?

Answer 31

Large arteries accommodate and convert intermittent ejection into continuous flow

Question 32

What do arterioles control?

Answer 32

Control BP and regulate blood flow

Question 33

What is the function of capillaries?

Answer 33

Nutrients delivery to cell tissue water and lymph formation removal of metabolic waste

Question 34

What do venules and veins control?

Answer 34

Control filling pressure and provide reservoir of blood