Lecture 31: Cardiac physiology (reading 3)

What are the three things do the Sympathetic nerves innervate

SA node, AV node, Ventricular myocardium

What are the two things do the parasympathetic nerve innervates

SA node and AV node.

What are the three things do the Sympathetic nerves innervate

SA node, AV node, Ventricular myocardium

What are the two things do the parasympathetic nerve innervates

SA node and AV node.

How does the sympathetic Nervous system increase the force of the ventricular contraction

Epi/ NE binds to B1 adrenergic Receptors on ventricular myocardium

What are the 4 cAMP pathways

ATPase on SR, VG L-type Ca, Ryanodine, myosin

Systole=

Ventricular contraction

Diastole=

ventricular relaxation

How are heart sound created

By turbulent blood flow through the closing valves

What are the 2 heart sounds

Lub & Dub

Which is the second heart sound

Dub

How is Lub created

Turbulent blood flow through closing AV valves

How is Dub created

Turbulent blood flow through closing SL valves.

Flow of ventricular filing

Atrial contraction (blood leaves atria) → Isovolumetric contraction →ventricular ejection→ Isovolumetric relaxation→ Ventricular filling

Cardiac Output

The volume of blood pumped by ventricles per minute

What is the equation of Cardiac Output

HR x SV

What is the similar equation of Cardiac output

HR x (EDV -ESV)

Stroke volume

Volume of blood pumped/ ejected per beat or stroke

Equation of stroke volume

EDV-ESV

End diastolic volume

the amount of blood in the ventricle just before the heart contracts

End systolic volume

Amount of blood in ventricles at the end of systole after contraction

What are the factors stroke volume controls

Heart size, fitness level, ventricular contractility, and end diastolic volume

What is ventricular contractility influenced by

Sympathetic NS and hormones

What is End diastolic volume influenced by

Starling’s law

Starlings law

rate at which blood fills the heart determines the strength of its contraction.

Intrinsic control of stroke volume

Control from heart stretch (Starling’s law)

Extrinsic control of stroke volume

Control by nerves and hormones (e.g. adrenaline)