CVS Calculations

Question 1

What are the three values related to the cardiovascular system?

Answer 1

Heart rate stroke volume and cardiac output

Question 2

What are the two cardiac mechanisms?

Answer 2

Vascular shunt mechanism
Venus return mechanism

Question 3

What is the equation for cardiac output?

Answer 3

Cardiac output = stroke volume times heart rate

Question 4

What is the distribution of cardiac output at West compared to during exercise?

Answer 4

Rest about 20% of the bodies blood will be delivered to each organ however at exercise about 85% of the bodies blood will be delivered to the muscles

Question 5

What three receptors are there to tell that the body has started exercising?

Answer 5

Chemo receptors
Proprio receptors
Barrow receptors

Question 6

What do chemo receptors do?

Answer 6

Monitor chemical changes in the body during exercise and during recovery

Question 7

What is the function of Proprio receptors?

Answer 7

Monitor the increase in muscle activity during exercise and decreased during recovery.

Question 8

What is the function of brow receptors?

Answer 8

Monitor blood pressure increases during exercise and decreases during recovery

Question 9

What happens during the vascular shunt mechanism?

Answer 9

The detection of the increased intensity of exercise is detected by the receptors.

The receptors relay the messages to the VCC VCC. Send a message via the sympathetic nervous system to increase or decrease sympathetic stimulation to the arterials and pre-capillary sphincters.

The VC decreases stimulation of arterials and pre-capillaries sphincters at the muscles. Vasodilatation happens and blood rushes through the opposite happens at the organs.

Question 10

At rest, what does the capillaries look like in the vascular centre mechanism on an organ?

Answer 10

Pre-capillary sphincter open and Vezzo dilate therefore blood coming through the arterials can easily get in.

Whilst at the muscles the pre-capillary sphincter are closed and the arterials vasoconstrict

Question 11

What is meant by venous return?

Answer 11

The return of blood to the heart during the cardiac cycle

Question 12

Why do we need to keep VR high?

Answer 12

To keep stroke volume high something that is essential for the delivery of oxygen during exercise the more blood returning the more the heart is stretching to deal with the blood. This increases the stimulation of the SA node which intern increases heart rate and stroke volume.

Question 13

What are the two problems that might slow down VR?

Answer 13

The blood pressure in the veins is very low
Most of the blood has been distributed lower than the heart and therefore has a fight against gravity to make its way back to the heart

Question 14

What are the five solutions to overcoming the delaying problems of VR?

Answer 14

Respiratory pump
Gravity
Pocket valves
Skeletal muscle pump
Smooth muscle

Question 15

What is the function of pocket valves?

Answer 15

Veins have valves to stop the backflow of blood. This means once the blood reaches a certain point it cannot return.

Question 16

What is the function of a skeletal muscle pump?

Answer 16

When the muscles in the lower leg contract, they squeeze the surrounding veins and force the blood back to the heart this links with the pocket valves to keep the blood moving.

Question 17

What is the function of smooth muscle?

Answer 17

Rain is aligned with smooth muscle that can vino constrict and force the blood back to the heart. It cannot constrict as much as an artery.

Question 18

What is the function of the respiratory pump?

Answer 18

As the diagram flattens and we inhale the pressure of thoracic cavity is increased forces blood back to the heart. This happens more the higher our breathing rate is.

Question 19

What is the function of gravity?

Answer 19

Blood from above the heart returns via gravity

Question 20

How is the heart regulated during exercise?

Answer 20

Intrinsic factors:
Increased temperature – causes increased speed of nerve transmission which intern increases stimulation of the essay node which intern increases HR.
Increased venous return – increased volume of blood returning stretches the walls of the heart which increases stimulation of SA node which intern increases HR.

Question 21

What are the hormonal factors regulating heart during exercise?

Answer 21

Adrenaline

Adrenaline is released prior to exercise which stimulates the sympathetic nervous system which increases stimulation of the essay node which intern increases heart rate. It is also increasing the force of cardiac contractions.