W5 Cardiovascular System

Question 1

What is the purpose of the CV system?

Answer 1

• Control blood transport around the body
  (transports O2 nutrients to tissues, removes CO2 from tissues & transport of hormones)
• Regulation of body temperature
• Support of immune function

Question 2

What are the four components of the CV system?

Answer 2

1. Heart
2. Arteries & arterioles
3. Veins & veinules
4. Capillaries

Question 3

Heart Anatomy:

• The heart has 4 chambers name them.
• The heart has 4 valves name them.

Answer 3

• It has 2 Atria and 2 Ventricular chambers
• It has 2 Atrioventricular (AV) valves
  1. Mitral valve (bicuspid valve)
  2. Tricuspid valve
• Also has 2 Semilunar (SL) valve
  1. Aortic valve
  2. Pulmonary valve

Question 4

Heart Anatomy:

- What is the wall separating the two sides of your heart called?

Answer 4

• The septum

Question 5

Cardiac Cycle:

• What happens to the heart during the diastole cardiac stage?
• What happens to the heart during the Systole cardiac stage?

Answer 5

Diastolic stage: Relaxation or Filling phase

Systolic stage: Contraction or Ejection of blood phase

Question 6

Heart sounds:

• What is the heart doing when you hear your heart making the “Lub” sound?
• What is the heart doing when you hear your heart making the “Dub” sound?

Answer 6

"Lub" = closing the AV valves
"Dub" = closing the SL valves

Question 7

Cardiac Cycle: Pressure change

• What happens to the pressure in the ventricles during diastole?
• What happens to the pressure in the ventricles during systole?

Answer 7

• During diastole the pressure in the ventricles is low and it gets filled with blood from atria.
• During systole the pressure in the ventricles rises and blood is ejected into the pulmonary & systemic system.

Question 8

• What are the two electrical nodes of the heart?

Answer 8

1. Sinoatrial (SA) Node

2. Atrioventricular (AV) Node

Question 9

• Name the 3 tracts and 1 bundle of the SA node.

- Name the 1 bundle and 1 pathway within the AV node.

Answer 9

SV node:
- Anterior internodal tract
- Middle internodal tract
- Posterior internodal tract
- Bachmann's bundle 
AV node: 
- Bundle branch 
- Conduction pathway

Question 10

Electrical Activity of the Heart:

- What are the three main recognisable waves of the heart?

Answer 10

1. P wave
   - Atrial depolarisation
2. QRS complex
   - Ventricular depolarisation
   - Hides atrial re-polarisation
3. T wave
   - Ventricular depolarisation

Question 11

There are 6 steps to depolarisation and re-polarisation.

Describe each step.

Answer 11

1. Atrial depolarisation (initiated by SA node) causes the P wave.
2. Next the impulse is delayed by the AV node.
3. Ventricular depolarisation begins at apex, causing the QRS complex. Atrial re-polarisation occurs.
4. Ventricular depolarisation is complete.
5. Ventricular re-polarisation begins at apex causing the T wave.
6. Ventricular re-polarisation is complete.

Question 12

• What does Stroke Volume (SV) mean?

- How do you calculate the SV?

Answer 12

• Stroke volume is the volume of blood pumped out of the heart on each contraction
• End diastolic volume - End systolic volume = SV

Question 13

• What does ejection fraction (EF) do?

Answer 13

• The proportion of blood pumped out of the left ventricle with each beat (%)
  Or
• How much of the blood that was in the ventricle got pumped out.

Question 14

• What does cardiac output (Q or CO) do?

Answer 14

• The total volume of blood flow from the heart per minute (L/min)
• Requires interaction between heart rate and stroke volume
• The higher the better

Question 15

• What is blood pressure?

- What’s the difference between diastolic and systolic blood pressure?

Answer 15

• The force exerted by blood against the arterial walls during the cardiac cycle (mmHg)
  1. Diastolic Blood Pressure
• Force exerted during ventricular diastole
• Lowest pressure within the vascular system
  2. Systolic Blood Pressure
• Force exerted during ventricular systole
• Highest pressure within the vascular system

Question 16

Arterial Pulse Waveform:

- What is the Dicrotic notch?

Answer 16

• It is a secondary upstroke in the descending part of the pulse.

Question 17

What’s the normal blood pressure for Systole and Diastole?

Answer 17

SBP = 120 mmHg
DBP = 80 mmHg

Question 18

• What is Rate-pressure product (RPP)?

Answer 18

• It is an estimation of myocardial workload and resulting O2 consumption

Question 19

Haemodynamics (the flow of blood within the organs & tissues):

• What is vasoconstriction?
• What is vasodilation?

Answer 19

Vasoconstriction = Radius of the arteries decrease, Resistance to flow increases
Vasodilation = Radius of the arteries increases, Resistance to flow decreases

Question 20

What are the determinants of blood pressure?

Answer 20

1. Blood volume
2. Peripheral resistance
3. Blood viscosity
4. Heart rate
5. Stroke volume

Question 21

Homeostasis:

What are the 5 steps to restore blood pressure?

Answer 21

1. Stimulus (blood pressure rises)
2. Baroreceptors are stimulated
3. Increased impulses from baroreceptors stimulate cardioinhabitory centre
   4a. Decreases sympathetic impulses to heart
   4b. Decrease rate of vasomotor impulses allows vasodilation
4. Decrease CO & R return blood pressure to homeostatic range

• These 5 steps can all be done but the opposite will happen if blood pressure decreases!

Question 22

Name the 4 Cardiovascular Control Centre Receptors

Answer 22

1. Baroreceptor
2. Peripheral Chemoreceptors
3. Mechanoreceptors/Proprioceptors
4. Metaboreceptors

Question 23

Give a brief description of the Baroreceptors

Answer 23

• Located in the carotid sinus & in the aortic arch. They sense pressure change by responding to change in the tension of the arterial wall.

Question 24

Give a brief description of the Peripheral Chemoreceptors

Answer 24

• Regulates respiratory activity & chemical environment of arterial blood (PO2, PCO2 & pH) within appropriate physiological ranges.

Question 25

Give a brief description of the Mechanoreceptors/Proprioceptors

Answer 25

- Responds to change in muscle length or tension

Question 26

Give a brief description of the Metaboreceptors

Answer 26

- Found in skeletal muscle respond to increased metabolic products & stimulate an increase in blood circulation in response to exercise.

Question 27

The Sympathetic Nervous System (SNS) & Peripheral Nervous System (PNS) are part of the Autonomic Nervous System. - What are the two things they regulate? - How do each system do this?

Answer 27

- SNS & PNS regulate blood pressure and blood flow - SNS does this via vasoconstriction & blood distribution - PNS does this via vasodilation

Question 28

What are the 3 ways of regulating Stroke Volume?

Answer 28

1. End diastolic volume (EDV) - The volume of blood in the ventricles at the end of diastole 2. Average aortic blood pressure - Pressure the heart must pump against to eject blood 3. Strength of the ventricular contraction - Altering the contraction

Question 29

End Diastolic Volume (EDV): | What is the Frank Starling Mechanism?

Answer 29

- This states that as the left ventricles volume increases the stroke volume will increase as well.

Question 30

What happens to blood flow distribution as your body goes from rest to exercise?

Answer 30

- During rest, blood flow distribution it spread out throughout all tissues evenly (mostly) - During exercise, blood flow distribution has gone mainly to the muscles however, all the tissues are still getting blood.