Overview Of The CVS

Question 1

Main function of the CVS

Answer 1

Transport from external to internal environment, between cells and materials leaving the body

Question 2

Arrangement of the CVS

Answer 2

Pulmonary exchange leaves the pulmonary vein into the left atrium then ventricle then pumped out of the aorta into the arterial system. Blood flows through the systemic circulation through the venous system into the right atrium then ventricle out of the pulmonary artery into the pulmonary circulation.

Question 3

Why are vascular beds arranged in parallel?

Answer 3

So all the beds get the same level of oxygenation and prevents changes in blood flow in one organ affecting flow in other organs.

Question 4

Systole?

Answer 4

Phase of ventricular contraction and ejection

Question 5

Diastole?

Answer 5

Phase of ventricular relaxation and filling

Question 6

Blood pressure entering the heart?

Answer 6

0mmHg. It is said to be atmospheric pressure

Question 7

Blood pressure out of the heart to the lungs?

Answer 7

25 mmHg

Question 8

Blood leaving the aorta?

Answer 8

90mHg

Question 9

Cardiac output?

Answer 9

Volume of blood pumper / min. = 5L/min

Question 10

What is CO determined by?

Answer 10

Stroke volume (volume ejected per contraction.
Heart rate (HR)

Question 11

Diastole is what % of the cardiac cycle?

Answer 11

60%

Question 12

Pulse pressure?

Answer 12

Systolic pressure - diastolic pressure

Question 13

Ambulatory blood pressure equation

Answer 13

SP - DP / 3 + DP

Question 14

Why does pressure drop as it moves through the system?

Answer 14

There is resistance to the flow

Question 15

What determines pressure in the arterial system?

Answer 15

Resistance to blood flow and blood volume in the arterial system

Question 16

Pressure equation (Ohms law)

Answer 16

Flow x resistance

Question 17

ABP equation

Answer 17

CO x TRP (total peripheral resistance)

Question 18

How is blood flow altered in arterioles

Answer 18

Vasodilation and vasoconstriction

Question 19

How are veins suited to their function

Answer 19

Thin walls
Carry blood at low pressure
Muscle under control of ANS
Wide lumen to accommodate large volumes 
Reservoirs used to adjust ventricular filling

Question 20

How are arteries suited to their function?

Answer 20

Carry blood at high pressure
Thick, muscular walls
Elastic layers
Relatively small lumen 
High pressure conduits

Question 21

How are venues suited to their function?

Answer 21

Low pressure
Resemble capillaries
Low pressure conduits

Question 22

How are smaller arteries, arterioles suited to their function?

Answer 22

Carry blood at modest pressure
Thick, muscular walls
Muscle under influence of local factors and ANS
Function to control flow to tissues

Question 23

How are capillaries suited to their function?

Answer 23

Carry blood at low pressure
Single endothelial cell wall
Gets blood to the call via diffusion
Maximise exchange between blood and tissue

Question 24

What % of body weight is blood?

Answer 24

Around 7%

Question 25

How is ABP maintained?

Answer 25

ABP = CO X TRP

It is maintained by negative feedback control