ANS 1&2

What directly controls the autonomic nervous system?

Medulla & hypothalamus

What indirectly influences it?

Limbic system

Why is the hypothalamus called the "head ganglion"?

It’s the main regulator of autonomic functions

Where does the sympathetic division originate?

Spinal nerves T1–L2 (thoracolumbar outflow)

Choose the incorrect choice:
Where does the parasympathetic division originate?

Cranial nerves IV & VI

How many neurons are involved in the autonomic pathway?

Two: preganglionic & postganglionic neurons

Where do the preganglionic & postganglionic neurons synapse?

In a ganglion

Which is shorter in the sympathetic system: preganglionic or postganglionic?

Preganglionic neuron

Which is longer in the parasympathetic system: preganglionic or postganglionic?

Preganglionic neuron

Where do sympathetic preganglionic axons exit the spinal cord?

With ventral roots of T1 to L3/L4 spinal nerves

Through which structure do sympathetic preganglionic axons pass to reach ganglia?

White rami communicantes

Where do sympathetic preganglionic axons synapse?

Paravertebral sympathetic ganglion chain

Which cranial nerves carry parasympathetic fibers to visceral structures in the head?

Oculomotor, facial, and glossopharyngeal nerves.

Which cranial nerve carries parasympathetic fibers to the thorax and upper abdomen?

Vagus nerve.

Which spinal nerves contribute to the sacral outflow of the parasympathetic division?

The second to fourth sacral spinal nerves (S2–S4).

What visceral structures are supplied by the sacral outflow of the parasympathetic system?

Pelvic viscera.

Where do parasympathetic preganglionic fibers synapse?

On short postganglionic neurons located on or near the target

Which of the following is not an autonomic neurotransmitter?

Epinephrine

What two molecules are needed to synthesize acetylcholine?

Choline and acetyl-coenzyme A.

Which enzyme catalyzes the synthesis of acetylcholine?

Choline acetyltransferase.

Where is choline acetyltransferase found in high concentration?

In the cytoplasm of cholinergic nerve endings.

How is acetylcholine removed from the synaptic cleft?

By hydrolysis into choline and acetate.

Which enzyme breaks down acetylcholine in the synapse?

Acetylcholinesterase.

Which neurotransmitter is released by all preganglionic autonomic neurons?

Acetylcholine.

Which postganglionic parasympathetic neurons release acetylcholine?

All of them.

Which sympathetic postganglionic neurons release acetylcholine?

Those that innervate sweat glands and blood vessels in skeletal muscles.

What is the precursor amino acid for norepinephrine synthesis?

Tyrosine.

Where is norepinephrine synthesized?

In noradrenergic neurons and adrenal medullary cells.

How is norepinephrine removed from the synaptic cleft?

By reuptake into presynaptic neurons or enzymatic breakdown.

Which enzymes do NOT break down norepinephrine?

Hydroxylase

Which neurons release noradrenaline in the autonomic nervous system?

Sympathetic postganglionic neurons, except those that release acetylcholine.

Which endocrine structure releases noradrenaline directly into the bloodstream?

The adrenal medulla.

What type of neurotransmitter is dopamine in the sympathetic ganglia?

An inhibitory neurotransmitter.

Where is dopamine released in the

By interneurons in the sympathetic ganglia.