Ch 17 Control Of Cardiovascular Function

Question 0

Normal range of Cardiac output

Effects of changes in preload and Afterload

Answer 0

Cardiac output is the amount of blood pumped out of the left ventricle each minute range is 4-8L/min formula: heart rate x stroke volume

Preload is the stretching of the ventricle End-Diastolic Volume how much the actin and myosin sites stretch

Afterload is the Arterial Pressure the pressure the heart must generate to move blood into the aorta to the rest of the body

Question 1

Role of parasympathetic and sympathetic modulation of Cardiovascular function

Answer 1

SNS sympathetic nervous system signals (norepinephrine/ adrenergic) the veins to contract due to fight or flight response, hypoxia or low pH. Increases (tachycardia) heart rate due to increase depolarization and shortens the repolarization.

Parasympathetic nervous system slower activities maintenance event occurs ACH released opens k+ channels slows depolarization
Decrease HR control the SA node
Can completely stop SA
Vagus nerve lowering BP

Question 2

Stroke Volume and Ejection Fraction

Answer 2

Stroke volume : amount of blood pumped per each contraction of the heart 65- 70mL
Ventricle Vol. - Residual Vol. = Stroke Vol.

Ejection Fraction: Give you the % of blood pumped out of the heart. Normal range:55-65%
Formula: stroke Vol. / End-Diastolic Vol.

Frank Starling Law of heart end-diastolic volume vs. cardiac output

Question 3

Cardiac Cycle

Answer 3

Cardiac cycle is the he complete heart beat all steps involved

Atrial contraction :Systole period: when the heart start pumping then av valve closes 1st heart sound

Isovolumetric contraction:ISO means same so it means same volume . LV is contracting but the mitral valve is closed and the aortic valve is closed

Rapid ejection : the LV has contracted so much that blood is ejected out and flows to the rest of the body high volume flow

Reduced ejection: still ejecting blood but it’s not as much as it was before

Isovolumetric relaxation:(diastole) same volume the valve are closed but the the ventricles are relaxing to prepare for next contraction

Rapid ventricular filling; blood from the LA flows down and fills the LV until it’s almost filled

Reduced ventilation filling:

E

Question 4

Electrocardiography

Answer 4

Recording the electrical activity of the heart monitors left ventricle function cardiac rumors and congenital defects

Question 5

Basic waveforms in ECG

Answer 5

Basic waveforms are P-wave , QRS, S-T segment, T-wave,

P-Wave is tracking the atrial depolarization
QRS- ventricular depolarization (atrial repolarization lost on ECG current not strong enough) .12s

S-T no net current no large conduction

T-Wave ventricles repolarization.16s

Question 6

Depolarization

Answer 6

Going from a negative potential to a more positive action potential