AP PSYCHOLOGY

Detailed explanation-1: -The sympathetic nervous system releases norepinephrine (NE) while the parasympathetic nervous system releases acetylcholine (ACh). Sympathetic stimulation increases heart rate and myocardial contractility.

Detailed explanation-2: -The sympathetic nervous system increases heart rate, whereas the parasympathetic nervous system suppresses it. Heart rate variability (HRV) can be analyzed using electrocardiography (ECG) to assess the activity of the autonomic nervous system (Kimura et al., 1996).

Detailed explanation-3: -The heart rate goes down when activity in the sympathetic nervous system decreases. Conversely, the heart rate goes up when parasympathetic nervous system activity (which controls the body’s involuntary responses at rest) decreases (because there is less inhibition).

Detailed explanation-4: -Heart Rate and Outcomes The higher the vagus nerve activity is, the slower the heart rate is, the greater the increase in the parasympathetic component of heart rate variability is, and the better the outcome is. In HF, heart rate is less regulated by parasympathetic activation.

Detailed explanation-5: -Cardiac sympathetic innervation of the heart includes innervation of the sinoatrial (SA) node, which allows sympathetic nerves to increase heart rate by increasing the slope of diastolic depolarization during the spontaneous SA node action potential.