Sympathetic Functions Overview

A system that prepares the body for stress by activating a mass discharge response, increasing heart rate and blood flow, and diverting blood to active areas.

A system that conserves energy during rest and promotes digestion, slowing heart rate and increasing gastrointestinal function.

The simultaneous activation of many sympathetic nerves throughout the body to create a widespread response.

The continuous, low-level activity of the sympathetic nervous system in a resting state, influencing organ function.

The continuous, low-level activity of the parasympathetic nervous system in a resting state, influencing organ functions and enabling balanced regulation .

The coordinated activity of these systems in maintaining homeostasis; each system adjusts activity of organs and systems providing control at rest and during exertion.

An increase in heart rate and force of contraction, triggered by the Sympathetic Nervous System, to increase blood flow and pressure to muscles during exertion.

Dilation of respiratory passages, enabled by sympathetic Nervous System, allows better ventilation to deliver more oxygen.

The temporary suppression of gastrointestinal functions like motility during stress response by sympathetic stimulation.

Keeps blood vessels partially constricted, maintaining resting blood pressure (ABP).

Maintains smooth muscle tone in intestines, and lowers heart rate to around 70-80 bpm.

Causes a rapid drop in blood pressure, potentially leading to shock.

Controlled by spinal cord centers (lateral horn cells) and brain stem nuclei, both reflexively and by higher brain centers.

Produce responses by stimulating spinal autonomic centers. Examples include micturition and defecation reflexes.

Produce responses by stimulating cranial parasympathetic centers in the brain stem. Examples include salivation and digestion.

Reflex emptying of the bladder.

Reflex emptying of the bowels.

Reflex activation triggered by food in the mouth, stimulating taste and other receptors, ultimately leading to secretions by relevant glands.

The constriction of the pupils in response to light.

A midbrain nucleus that controls pupillary constriction.

Brain stem area controlling autonomic functions like heart rate and blood pressure.

Part of the medulla oblongata that controls blood vessel diameter.

Brain area controlling heart rate slowing.

Body system increasing heart rate and blood pressure.

Brain region controlling autonomic functions and emotions.

Hypothalamic area controlling parasympathetic responses.

Hypothalamic area controlling sympathetic responses.

Outer layer of the brain controlling higher-level functions including autonomic responses, particularly in relation to emotions and thoughts.

Learned responses to stimuli; for instance, thinking of food elicits salivation.