W5 Cardiovascular System Flashcards
What is the purpose of the CV system?
- 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
What are the four components of the CV system?
- Heart
- Arteries & arterioles
- Veins & veinules
- Capillaries
Heart Anatomy:
- The heart has 4 chambers name them.
- The heart has 4 valves name them.
- 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
Heart Anatomy:
- What is the wall separating the two sides of your heart called?
- The septum
Cardiac Cycle:
- What happens to the heart during the diastole cardiac stage?
- What happens to the heart during the Systole cardiac stage?
Diastolic stage: Relaxation or Filling phase
Systolic stage: Contraction or Ejection of blood phase
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?
"Lub" = closing the AV valves "Dub" = closing the SL valves
Cardiac Cycle: Pressure change
- What happens to the pressure in the ventricles during diastole?
- What happens to the pressure in the ventricles during systole?
- 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.
- What are the two electrical nodes of the heart?
- Sinoatrial (SA) Node
2. Atrioventricular (AV) Node
- Name the 3 tracts and 1 bundle of the SA node.
- Name the 1 bundle and 1 pathway within the AV node.
SV node: - Anterior internodal tract - Middle internodal tract - Posterior internodal tract - Bachmann's bundle AV node: - Bundle branch - Conduction pathway
Electrical Activity of the Heart:
- What are the three main recognisable waves of the heart?
- P wave
- Atrial depolarisation - QRS complex
- Ventricular depolarisation
- Hides atrial re-polarisation - T wave
- Ventricular depolarisation
There are 6 steps to depolarisation and re-polarisation.
Describe each step.
- Atrial depolarisation (initiated by SA node) causes the P wave.
- Next the impulse is delayed by the AV node.
- Ventricular depolarisation begins at apex, causing the QRS complex. Atrial re-polarisation occurs.
- Ventricular depolarisation is complete.
- Ventricular re-polarisation begins at apex causing the T wave.
- Ventricular re-polarisation is complete.
- What does Stroke Volume (SV) mean?
- How do you calculate the SV?
- Stroke volume is the volume of blood pumped out of the heart on each contraction
- End diastolic volume - End systolic volume = SV
- What does ejection fraction (EF) do?
- 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.
- What does cardiac output (Q or CO) do?
- 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
- What is blood pressure?
- What’s the difference between diastolic and systolic blood pressure?
- 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
Arterial Pulse Waveform:
- What is the Dicrotic notch?
- It is a secondary upstroke in the descending part of the pulse.
What’s the normal blood pressure for Systole and Diastole?
SBP = 120 mmHg DBP = 80 mmHg
- What is Rate-pressure product (RPP)?
- It is an estimation of myocardial workload and resulting O2 consumption
Haemodynamics (the flow of blood within the organs & tissues):
- What is vasoconstriction?
- What is vasodilation?
Vasoconstriction = Radius of the arteries decrease, Resistance to flow increases Vasodilation = Radius of the arteries increases, Resistance to flow decreases
What are the determinants of blood pressure?
- Blood volume
- Peripheral resistance
- Blood viscosity
- Heart rate
- Stroke volume
Homeostasis:
What are the 5 steps to restore blood pressure?
- Stimulus (blood pressure rises)
- Baroreceptors are stimulated
- Increased impulses from baroreceptors stimulate cardioinhabitory centre
4a. Decreases sympathetic impulses to heart
4b. Decrease rate of vasomotor impulses allows vasodilation - 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!
Name the 4 Cardiovascular Control Centre Receptors
- Baroreceptor
- Peripheral Chemoreceptors
- Mechanoreceptors/Proprioceptors
- Metaboreceptors
Give a brief description of the Baroreceptors
- Located in the carotid sinus & in the aortic arch. They sense pressure change by responding to change in the tension of the arterial wall.
Give a brief description of the Peripheral Chemoreceptors
- Regulates respiratory activity & chemical environment of arterial blood (PO2, PCO2 & pH) within appropriate physiological ranges.
Give a brief description of the Mechanoreceptors/Proprioceptors
- Responds to change in muscle length or tension
Give a brief description of the Metaboreceptors
- Found in skeletal muscle respond to increased metabolic products & stimulate an increase in blood circulation in response to exercise.
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?
- SNS & PNS regulate blood pressure and blood flow
- SNS does this via vasoconstriction & blood distribution
- PNS does this via vasodilation
What are the 3 ways of regulating Stroke Volume?
- End diastolic volume (EDV)
- The volume of blood in the ventricles at the end of diastole - Average aortic blood pressure
- Pressure the heart must pump against to eject blood - Strength of the ventricular contraction
- Altering the contraction
End Diastolic Volume (EDV):
What is the Frank Starling Mechanism?
- This states that as the left ventricles volume increases the stroke volume will increase as well.
What happens to blood flow distribution as your body goes from rest to exercise?
- 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.
