Autonomic Nervous System

The autonomic nervous system regulates __________ functions like heart rate, digestion, and respiratory rate.

involuntary

The two main divisions of the autonomic nervous system are the __________ and __________ divisions.

sympathetic; parasympathetic

What is one key difference between the autonomic and somatic nervous systems in terms of effector targets?

The autonomic nervous system targets smooth muscle, cardiac muscle, and glands, while the somatic nervous system targets skeletal muscle.

Sympathetic preganglionic neurons originate from the __________ region of the spinal cord.

thoracolumbar

Parasympathetic preganglionic neurons originate from the __________ and __________ spinal cord regions.

brainstem; sacral

Where are sympathetic ganglia typically located, and what does this mean for pre- and postganglionic neuron lengths?

Near the spinal cord; this makes preganglionic neurons short and postganglionic neurons long.

Where are parasympathetic ganglia located, and how does this affect neuron lengths?

Near or in the effector organ; preganglionic neurons are long, postganglionic neurons are short.

All preganglionic autonomic neurons release the neurotransmitter __________.

acetylcholine

Parasympathetic postganglionic neurons release __________, while sympathetic postganglionic neurons usually release __________.

acetylcholine; norepinephrine

What is the role of muscarinic receptors in the parasympathetic nervous system?

They mediate parasympathetic effects by binding acetylcholine on target organs.

Activation of β2 adrenergic receptors in the lungs causes __________.

bronchodilation

M2 receptors in the heart cause a __________ in heart rate.

decrease

The __________ reflex involves pupil constriction in response to light.

pupillary light

If the left optic nerve is damaged, what is the pupillary response when light is shone in the left eye?

Neither pupil constricts because sensory input is blocked.

If the right oculomotor nerve is damaged, what happens when light is shone in either eye?

The right pupil remains dilated due to loss of motor function.

Parasympathetic control of the eye causes the pupils to __________.

constrict

Baroreceptor reflexes help maintain stable __________ when posture changes.

blood pressure

What happens to blood flow and pressure when someone with autonomic dysfunction performs the Valsalva maneuver?

Their heart rate and blood pressure responses may be impaired or delayed.

Why might someone feel faint when standing up quickly?

Blood pools in the lower body due to gravity, and if baroreceptor reflexes are too slow, less blood reaches the brain temporarily.

Sympathetic stimulation of the heart increases __________ and __________.

heart rate; contractility

Parasympathetic stimulation of the gastrointestinal tract increases __________ and __________.

motility; glandular secretion

What effect does sympathetic stimulation have on blood vessels in the skin?

Vasoconstriction, which redirects blood to essential organs.

Sympathetic activation causes the adrenal medulla to release __________ and __________ into the bloodstream.

epinephrine; norepinephrine

Why is the adrenal medulla considered a modified sympathetic ganglion?

It receives direct input from preganglionic neurons and acts like a postganglionic neuron by releasing hormones.