ANS

What are the three divisions of the autonomic nervous system?

Sympathetic, Parasympathetic, Enteric

What characterizes the autonomic nervous system (ANS)?

It is largely involuntary.

What is the ratio of preganglionic to postganglionic fibers in the sympathetic system?

1:10

What neurotransmitter is released from preganglionic autonomic terminals?

Acetylcholine (Ach) mediated by nicotinic receptors.

Which type of muscle is innervated by the parasympathetic system?

Smooth muscle, cardiac muscle, gland cells.

What do the postganglionic sympathetic terminals release?

Norepinephrine (noradrenaline).

Identify the cranial nerves associated with the parasympathetic preganglionic cells.

Cranial nerves III, VII, IX, and X.

Where are the preganglionic sympathetic cells located?

In the intermediolateral gray of T1-L2.

What anatomical structure is formed by preganglionic sympathetic fibers exiting the spinal cord?

White rami communicantes.

What syndrome is caused by a lesion of the superior cervical ganglion?

Horner's syndrome.

Sympathetic nervous system fibers control which type of blood vessels?

Cranial blood vessels.

Preganglionic sympathetic fibers synapse with which ganglia?

Sympathetic chain ganglia.

What is the effect of the splanchnic nerves in the sympathetic supply?

They innervate abdominal and pelvic viscera.

Which ganglion does the vagus nerve synapse with?

Diffuse thoracic and abdominal ganglia.

What type of receptors do postganglionic parasympathetic terminals use?

Muscarinic receptors (M1, M2, M3).

What organ systems does the vagus nerve influence?

Heart, esophagus, lungs, stomach, liver, gall bladder, pancreas.

What role does the hypothalamus play in the ANS?

Controls temperature, heart rate, blood pressure, respiration, and endocrine release.

Which component of the autonomic nervous system governs digestive reflexes?

The enteric division.

How are visceral effector organs influenced by the ANS?

Through autonomic fibers that inform the CNS about visceral homeostasis.

What are two plexuses found in the enteric nervous system?

Myenteric (Auerbach's) and submucosal (Meissner's) plexuses.

What is the function of the enteric sensory neurons?

Respond to gut wall tension and chemical changes in the gut.

Which neurotransmitter is released by postganglionic parasympathetic fibers?

Acetylcholine (Ach).

What are the main functions of the sympathetic nervous system?

Fight or flight responses.

What is the main function of the parasympathetic nervous system?

Rest and digest activities.

What do neuropeptides in the ANS do?

Function directly on target tissues or have a modulatory role.

What is the composition of the autonomic ganglion?

Cell bodies of postganglionic fibers clustered in a ganglion outside the CNS.

Preganglionic parasympathetic fibers from which nerves innervate the salivary glands?

Facial nerve (VII) and glossopharyngeal nerve (IX).

Identify two neuropeptides mentioned that influence target tissues.

Neuropeptide Y and substance P.

From which anatomical location do postganglionic sympathetic fibers reach their targets?

Gray rami communicantes.

Which neurotransmitter is involved in the autonomic terminals but does not have specialized pre and postsynaptic structures?

Neurotransmitters diffuse over distances.

What type of muscle does the somatic motor system affect?

Skeletal muscle.

What is a major characteristic of preganglionic fibers in the ANS?

They have their cell bodies in the central nervous system.

What autonomic nervous system division is more autonomous?

The enteric division.

What is the main role of the solitary nucleus?

It reacts to sensory information affecting autonomic functions.

Where do the preganglionic parasympathetic fibers synapse in the brainstem?

Edinger-Westphal nucleus, superior salivatory nucleus, inferior salivatory nucleus, and dorsal motor nucleus.

What control does the reticular formation have related to the ANS?

Regulates breathing, blood pressure, heart rate.

What structure is associated with preganglionic sympathetic fibers besides the sympathetic ganglia?

Spinal nerve and ventral ramus.

What is the sympathetic supply to the limbs primarily responsible for?

Innervating peripheral blood vessels, sweat glands, and arrector pili muscles.

What are the types of receptors for norepinephrine in the sympathetic system?

Alpha and beta adrenergic receptors.

What is the embryonic origin of the autonomic nervous system?

Neural crest cells.

What types of fibers compose the enteric nervous system?

Sensory neurons and motor neurons.

What is the primary function of the myenteric plexus?

Regulates gastrointestinal motility.

Identify a function of postganglionic fibers in the enteric nervous system.

Innervate smooth muscle, vasculature, and secretion of the gut.

Which part of the ANS is integral for the regulation of gut function?

Enteric nervous system.

What part of the innervation does the vagus nerve primarily control?

The thoracic and abdominal viscera.

What reflexes are regulated by the hypothalamus?

Temperature control, feeding, heart rate.

Which cranial nerve is associated with taste and visceral chemosensory information?

Facial nerve.

What happens when preganglionic fibers synapse in peripheral ganglia?

They release neurotransmitters to affect smooth muscle or glands.

What is meant by visceral reflexes in the context of ANS?

Automatic responses mediated by the sympathetic and parasympathetic branches.

What type of control does the ANS have over visceral organs?

Involuntary control.