What does sympathetic activity do to the heart rate and stroke volume?

yes it increases it by having epinephrine and//or norepinephrine bind to beta 1 receptors on the ventricle of the heart which causes a second messanger system of cyclic AMP to phosphorylate 1) voltage gated calcium channels to stay open longer so more calcium comes inside cell from outside so more Ca can be stored in sarcoplasmic reticulm (SR) but also more interaction between actin and myosin. 2) phosphorylates calcium pump which increases its activity so more calcium can be stored in SR so there is a bigger force (bigger Stroke volume). AND also removes calcium from cytosol faster (calcium back into cisterna), which shortens the duration of refractory period which increases heart rate.