Chapter 18 Autonomic Nervous System

What are the sympathetic division pathways?

1) Spinal nerve pathway 2) Postganglionic sympathetic nerve pathway 3) Splanchnic nerve pathway 4) Adrenal Medulla pathway

What does the spinal cord influence in the ANS?

ANS reflex centers for defecation and urination

What are the neurons that synthesize and release norepinephrine (NE) called?

Adrenergic neurons

What are the neurons that bind NE called?

Adrenergic receptors

How can the adrenergic receptors be grouped by?

All postganglionic neurons with exception of those that innervate the sweat glands of the skin and blood vessels

What is neuronal convergence?

Axons from numerous preganglionic neurons synapse with and influence a single ganglionic cell

What is neuronal divergence?

Axons from one preganglionic cell synapse with and influence numerous ganglion cells

Why does the two-neuron pathway of the ANS has a distinctive advantage in increased communication and control?

Because of neuronal convergence and neuronal divergence.

What cranial nerves are associated with the parasympathetic division?

CN III - Oculomotor CN VII - Facial CN IX - Glossopharyngeal CN X - Vagus

What are the several major plexuses associated with the ANS?

Cardiac plexus Pulmonary plexus Esophageal plexus Abdominal aortic plexus - celiac, superior mesenteric, inferior mesenteric Hypogastric

What are the different types of prevertebral ganglia in the sympathetic division?

Celiac ganglia, superior mesenteric ganglion, and the inferior mesenteric ganglion

Which regions influence autonomic function?

Cerebrum Hypothalamus Brainstem Spinal cord

What are the neurons that synthesize and release acetylcholine (ACh) called?

Cholinergic neurons

What are the neurons that bind (ACh) called?

Cholinergic receptors

What are the autonomic plexuses?

Collections of sympathetic postganglionic axons and parasympathetic preganglionic axons, as well as some visceral sensory axons.

What is the parasympathetic nervous system concerned with?

Conservation of energy and replenishing nutrient stores. "Rest and digest"

What are some antagonistic effects of dual innervation examples?

Control of the heart rate - parasympathetic division slows the heart rate down but the sympathetic speeds it up. Control of muscular activity in the GI tract - parasympathetic (smooth muscles) increase work but the sympathetic division slows it down. Control of the pupil diameter in the eye.

What is the parasympathetic division also called?

Craniosacral division

What are the two neurons in an ANS pathway?

First is the preganglionic neuron which is found in the brainstem or spinal cord. It extends from this cell body and exits the CNS in either a cranial nerve or spinal nerve. Second is the ganglionic neuron which lies in an autonomic ganglion. A postganglionic axon extends from the cell body to the effector.

Where are the ganglionic neurons found in?

Found in either the terminal ganglia, which are close to the target organ or intramural ganglia, which are located within the wall of the target organ.

How many CNS regions influence the autonomic function?

Four

The neurotransmitters released in the SNS and ANS are different. What are they?

In the SNS acetylcholine (ACh) is released. In the ANS, preganglionic axons release ACh, while the postganglionic axons release either ACh or Norepinephrine (NE).

What is there difference of the SNS and ANS relating to neural pathways?

In the SNS there is only one neuron pathway which extends from the CNS straight to the effector. In the ANS, there are two neurons in a pathway.

Where are the cell bodies housed in the sympathetic division?

In the lateral horns of the spinal cord

What does the hypothalamus influence in the ANS?

Integration and command center four autonomic functions which is involved with our emotions

What does dual innervation mean?

It means that visceral effectors that are innervated by postganglionic axons from both parasympathetic and sympathetic divisions. These actions can be antagonistic or cooperative

Which ones of the three sympathetic trunk ganglia house neuron cell bodies that extend postganglionic axons to the thoracic viscera?

Middle and inferior ganglia

What are the two types of cholinergic receptors?

Nicotinic and muscarinic

In CN X, what is the parasympathetic outflow?

Origin - Medulla Oblongata Autonomic ganglia - Multiple terminals and intramural ganglia Effectors - Thoracic viscera and most abdominal viscera

In CN IX, what is the parasympathetic outflow?

Origin - Medulla Oblongata Autonomic ganglia - Otic ganglion Effectors - Parotid salivary gland

In CN III, what is the parasympathetic outflow?

Origin - Pons Autonomic Ganglia - Ciliary Ganglia Effectors - ciliary muscles to control lens accomondations

In CN VII, what is the parasympathetic outflow?

Origin - Pons Autonomic Ganglia - Pterygopalatine ganglion and Submandibular ganglion Effectors - Lacrimal glands, glands of the nasal cavity, palate, and oral cavity (salivary glands)

In the Pelvic Splanchnic Nerves, what is the parasympathetic outflow?

Origin - S2, S3, S4 (Spinal nerves) Autonomic ganglia - Terminal and intramural ganglia Effectors - some abdominal viscera and most pelvic viscera

Which division of the ANS works constantly? Why not the other one?

Parasympathetic division works all the time. If it was sympathetic works all the time, we would stress out and die.

Summary of the two way neuron in the ANS.

Preganglionic Neuron (brain stem) -> Preganglionic axons (exits CNS via cranial/spinal nerve) -> ganglionic neuron -> postganglionic axon -> effector

What is the sympathetic nervous system concerned with?

Preparing the body for emergencies. "Fight or Flight" response.

What does the somatic nervous system (SNS) include?

Processes that are perceived or controlled consciously.

How does the CNS control the ANS?

Several layers of the CNS coordinate and regulate the ANS.

Which one of the three sympathetic trunk ganglia contain postganglionic sympathetic bodies whose axons are distributed to structures of the head and neck?

Superior cervical

What are the three sympathetic trunk ganglia?

Superior cervical Middle ganglia Inferior ganglia

What is the difference between the ANS and the SNS?

The ANS includes processes that are regulated without our awareness.

What are the divisions in the ANS?

The Parasympathetic and the Sympathetic division.

Which division of the somatic nervous system initiate and transmit nerve impulses from the CNS to the skeletal muscles?

The Somatic MOTOR Division

This division of the ANS is much more complex. Which is it?

The Sympathetic Division

Which part of the ANS includes the components that initiate and transmit nerve impulses from the CNS to cardiac muscle, smooth muscle, and glands.

The autonomic motor division

Which components of the ANS have receptors that detect stimuli associated with blood vessels, internal organs, and viscera?

The autonomic sensory division

What components are there in the ANS?

The autonomic sensory division and the autonomic motor division

Part of the two neuron pathway in the ANS that is found an autonomic ganglion. And the axon that extends from the cell body to the effector.

The ganglionic neuron then to the postganglionic axon which extends from the cell body to the effector.

What is immediately anterior to the paired spinal nerves that are lateral to the vertebral column?

The left and right sympathetic trunks

Which division is more discrete and localized?

The parasympathetic division

What are the differences in the sympathetic and parasympathetic axons?

The parasympathetic has longer preganglionic axons and shorter postganglionic axons. The sympathetic has shorter preganglionic axons but longer postganglionic axons.

What is the similarities between preganglionic axons and postganglionic axons in both divisions?

The preganglionic axons of both divisions are myelinated and the postganglionic axons of both divisions are unmyelinated.

Part of the two neuron pathway in the ANS that is found in the brainstem or spinal cord.

The preganglionic neuron

What connects the spinal nerves to each sympathetic trunk?

The rami communicantes

Which division of the somatic nervous system detects stimuli and transmission of nerve impulses from special senses, skin, and proprioceptors to the CNS.

The somatic SENSORY division

What divisions does the somatic nervous system have?

The somatic sensory and somatic motor division.

What are the different rami communicantes?

The white rami communicates, which carry preganglionic sympathetic axons. And the gray rami commmunicantes carry postganglionic sympathetic axons.

How are the neurons that bind (ACh) grouped?

They are grouped by: All the sympathetic and parasympathetic preganglionic neurons, all parasympathetic postganglionic neurons, and sympathetic postganglionic neurons that innervate the sweat glands of the skin and blood vessels

Where does the sympathetic preganglionic neurons originate from?

They originate from in the lateral horns of T1-L2

Where do the parasympathetic preganglionic neurons originate from?

They originate from the brainstem or in the lateral gray matter of S2-S4

What is the sympathetic division also known as? Why?

Thoracolumbar, because the preganglionic neuron bodies originate and are housed between T1 and L2.

How many sympathetic trunk ganglia is the cervical portion partitioned into?

Three

What is the function of the ANS?

To maintain homeostasis

What are some examples of special senses that can be detected by the sensory system?

Vision, Hearing, Equilibrium, Smell, and Taste

What does the cerebrum influence in the ANS?

conscious activities in the cerebrum that affect the hypothalamus

What does the brainstem influence in the ANS?

major ANS reflex centers