Drugs modifying cardiac rate and force - stroke volume

Question 1

Describe the sympathetic system

Answer 1

Noradrenaline is the transmitter. Adrenaline is the hormone. beta 1 adrenoceptors are activated. Positive chronotopic effect.
increased contractility (positive inotropic effect) (phase 2)
Increased conduction velocity in AV node
Decreased duration of systole due to increased uptake of calcium into the sarcoplasmic reticulum
Decrease in cardiac efficiency with respect to oxygen consumption

Question 2

Describe the parasympathetic

Answer 2

Negative inotropic effect; atria only
Decreased conduction in the AV node
May cause dysrhythmias to occur in the atria

Question 3

stretch = increased venous return as a result of?

Answer 3

increased skeletal muscle activity. Adrenergic effects on blood vessels-increased venous tone
respiratory pump - increased death and frequency respiration