Autonomic Nervous System Overview

When body temperature rises, the sympathetic nervous system dilates blood vessels in the skin to facilitate heat loss and activates sweat glands to cool the body through evaporation.

The sympathetic nervous system stimulates the kidneys to release renin, which triggers a cascade of events leading to increased blood pressure. This is important for maintaining blood pressure during fight-or-flight.

The sympathetic nervous system increases the metabolic rate of cells, leading to increased blood glucose levels through glycogen breakdown and fat burning for energy. This provides the body with the necessary fuel for fight-or-flight.

The subconscious part of your nervous system that controls involuntary functions like heart rate, digestion, and breathing.

The 'fight or flight' part of the autonomic nervous system prepares your body for stressful situations. It increases heart rate, blood pressure, and breathing rate, while diverting blood to muscles and organs.

The 'rest and digest' part of the autonomic nervous system helps your body conserve energy and promote restorative functions. It slows down your heart rate, lowers blood pressure, and stimulates digestion.

The part of the nervous system that controls voluntary movements of skeletal muscles.

A two-neuron chain that transmits signals from the central nervous system to target organs in the autonomic nervous system.

Receptors that bind to acetylcholine (ACh), a neurotransmitter released by some autonomic neurons. They can be either nicotinic (always excitatory) or muscarinic (can be excitatory or inhibitory).

Receptors that bind to epinephrine (adrenaline) and norepinephrine, neurotransmitters released by sympathetic neurons. They come in alpha (α) and beta (β) subtypes.

The two divisions of the autonomic nervous system often act in opposition to each other (antagonistic), but sometimes they can work together (cooperatively) to achieve specific outcomes.

The overall activity level of the sympathetic nervous system. It can decrease, even without the parasympathetic system actively working, to return to homeostasis.

The sympathetic nervous system helps cool the body when it overheats by dilating blood vessels in the skin to increase heat loss and activating sweat glands to promote evaporation.

The sympathetic nervous system stimulates the release of renin from the kidneys. Renin helps raise blood pressure by activating the renin-angiotensin-aldosterone system.

The autonomic nervous system controls involuntary functions like heart rate and digestion, while the somatic nervous system controls voluntary movements.

Both the parasympathetic and sympathetic divisions of the autonomic nervous system release acetylcholine at their preganglionic synapses.

The sympathetic nervous system increases heart rate, while the parasympathetic nervous system slows it down.

Epinephrine and norepinephrine, hormones released by the sympathetic nervous system, bind to adrenergic receptors.

Certain drugs that block beta-adrenergic receptors are used to treat asthma by relaxing airway muscles and improving breathing.