The autonomic nervous system

Refers to involuntary structures like smooth muscle, cardiac muscle, and secretory cells (i.e. glands) as they are supplied by the nervous system

visceral

Term for the autonomic nervous system, since it is the system that controls visceral structures

visceromotor

What is the main role of the autonomic nervous system?

to maintain homeostasis

Collection of nerve cell bodies in the PNS

ganglion

Refers to information coming from primary sensory neurons to the CNS that usually does not reach consciousness since it is uncontrolled

visceral afferent

Refers to information that travels via preganglionic and postganglionic neurons to effector muscles to establish motor control

visceral efferent

Visceral efferent neuron that has its cell body in the CNS in a nucleus and has myelinated axons that synapse on a neuron in an autonomic ganglion

preganglionic

Visceral efferent neuron that has its cell body in the PNS in an autonomic ganglion and has unmyelinated axons that travel to supply their targets

postganglionic

Where is the cell body of a preganglionic neuron (CNS/PNS)?

CNS

Where is the cell body of a postganglionic neuron (CNS/PNS)?

PNS

Is the axon of preganglionic neuron myelinated or unmyelinated?

myelinated

Is the axon of a postganglionic neuron myelinated or unmyelinated?

unmyelinated

Onto what does the unmyelinated axon of a postganglionic neuron synapse?

target structure

Onto what does the myelinated axon of a preganglionic neuron synapse?

autonomic ganglion

The preganglionic neurons are controlled by what other neuron that synapses on the cell bodies of preganglionic autonomic neurons?

central neurons

"Fight or flight" division of the autonomic nervous system

sympathetic

"Rest and digest" division of the autonomic nervous system

parasympathetic

The sympathetic nervous system generally has _____ (short/long) preganglionic neurons and _____ (short/long) postganglionic neurons.

short; long

The parasympathetic nervous system generally has _____ (short/long) preganglionic neurons and _____ (short/long) postganglionic neurons?

long; short

True or false: There are more postganglionic nerve fibers leaving autonomic ganglia than preganglionic fibers entering.

true

Autonomic ganglia represent a major source of divergence of the efferent pathway. In addition, there appears to be some level of integration in the autonomic ganglia evidenced by the presence of what?

interneurons

Tru or false: The autonomic nervous system is basically unilateral, meaning targets on one side of the body are supplied by autonomics from that side of the nervous system

true

Bony space that runs the length of the spine in which the spinal cord is housed

vertebral canal

How many pairs of cranial nerves attach to the brain?

12

How many bones are in the vertebral column?

26

How many cervical vertebrae are there?

7

How many thoracic vertebrae are there?

12

How many lumbar vertebrae are there?

5

How many pairs of spinal nerves are there?

31

How many total spinal nerves are there?

62

Holes between the vertebrae that the 31 pairs of spinal nerves run through and use to exit the spine

intervertebral foramina

Which division of the spine has the greatest number of associated spinal nerves?

thoracic (12)

In the cervical region, is each cervical spinal nerve named for the vertebra above or below itself (except for the C8 nerve)?

below

In the thoracic, lumbar, sacral, and coccygeal regions, is each spinal nerve named for the vertebra above or below itself?

above

Which spinal nerve root contains only motor nerve fibers?

ventral (anterior)

Which spinal nerve root contains only sensory nerve fibers?

dorsal (posterior)

Does the parasympathetic nervous system increase or decrease heart rate?

decrease

Does the parasympathetic nervous system increase or decrease digestion?

increase (opening up sphincters)

Does the parasympathetic nervous system cause bronchoconstriction or bronchodilation to happen in the lungs?

bronchoconstriction (slows breathing)

Does the parasympathetic nervous system fill up or empty the urinary bladder?

empty

Does the parasympathetic nervous system dilate or constrict the pupils?

constrict (miosis)

Does the parasympathetic nervous system contract or relax the ciliary muscles for near accommodation?

contract

Does the parasympathetic nervous system stimulate or inhibit tear production?

stimulate

What neurotransmitter is used at the synapse between the preganglionic and postganglionic neurons in the autonomic ganglia in the parasympathetic nervous system?

acetylcholine

What neurotransmitter is used at the synapse between the postganglionic neurons and their effector targets in the parasympathetic nervous system?

acetylcholine

Term for the parasympathetic nervous system since acetylcholine is the neurotransmitter used at all the synapses

cholinergic

Where are the cell bodies of preganglionic parasympathetic neurons? (2 locations)

brainstem, lateral horns of S2-4 (which is why parasympathetic is also called the craniosacral division of the autonomic nervous system)

In addition to the spinal cord levels S2-4, where else do the preganglionic parasympathetic neurons have cell bodies?

in the brainstem (in nuclei associated with some of the cranial nerves)

Is the axon of the preganglionic neuron in the parasympathetic nervous system myelinated or unmyelinated?

myelinated

After a preganglionic neuron in the parasympathetic nervous system leaves the CNS, it is called what?

cranial nerve

The parasympathetic nervous system is sometimes referred to as the craniosacral division of the autonomic nervous system. What are the 2 locations of cell bodies of preganglionic neurons that give rise to this name?

brainstem (cranial), lateral horns of S2-4 (sacral)

The neurons of the parasympathetic nervous system are called what because they have their cell bodies in the CNS and have myelinated axons that extend all the way to the synapse on the postganglionic neuron that supplies the target organ?

long preganglionic neurons

How far does the long preganglionic neuron of the parasympathetic nervous system extend from the CNS before it synapses on the postganglionic neuron that supplies the target organ?

all the way to the synapse

The postganglionic neurons of the parasympathetic nervous system are called what because they have their cell bodies in the PNS and have unmyelinated axons that synapse on the target organ (i.e. smooth muscle, cardiac muscle, gland)

short postganglionic neurons

Where is the synapse between the preganglionic and postganglionic neurons of the parasympathetic nervous system?

autonomic ganglion that is near the target organ

Where is the synapse between the postganglionic neuron and the effector target (i.e. smooth muscle, cardiac muscle, gland) of the parasympathetic nervous system?

on or very near the target

What neurotransmitter is used at the synapse between the postganglionic neuron and the effector target (i.e. smooth muscle, cardiac muscle, gland) of the parasympathetic nervous system?

acetylcholine

Term for the parasympathetic nervous system because acetylcholine is used at all the synapses, ganglionic and effector

cholinergic

Does the parasympathetic nervous system generally have short or long preganglionic neurons? Short or long postganglionic neurons?

long preganglionic, short postganglionic

What is the main role of the parasympathetic nervous system?

conserve energy and maintain normal body functions during rest

Division of the autonomic nervous system that generally has long preganglionic neurons, short postganglionic neurons, decreases heart rate, and increases digestion

parasympathetic

The parasympathetic nervous system generally has long preganglionic neurons and short postganglionic neurons. How does this affect the location of the autonomic ganglia in relation to the target organ?

ganglia are located close to or within the target organ

In the parasympathetic nervous system, do the ganglia tend to be larger or smaller than those in the sympathetic nervous system?

larger

Where do the preganglionic parasympathetic neurons synapse with postganglionic neurons in relation to the target organ?

synapse close to or within the target organ

In the parasympathetic nervous system, do the postganglionic neurons tend to be highly branched or not branched?

highly branched (because they need to innervate a broad area of the target organ)

True or false- The parasympathetic nervous system is typically more localized in its effects on target organs compared to the sympathetic nervous system.

true (due to the close proximity of ganglia to target organs and highly branched postganglionic neurons)

What are the two cranial nerves that primarily carry parasympathetic preganglionic fibers to target organs in the head and neck?

cranial nerves III (oculomotor) and VII (facial)

Which cranial nerve primarily carries parasympathetic preganglionic fibers to target organs in the thoracic and abdominal cavities?

cranial nerve X (vagus)

Does the sympathetic nervous system generally have short or long preganglionic neurons? Short or long postganglionic neurons?

short preganglionic, long postganglionic

Division of the autonomic nervous system that generally has short preganglionic neurons, long postganglionic neurons, increases heart rate, and decreases digestion

sympathetic

In the sympathetic nervous system, do the ganglia tend to be located close to or far from the spinal cord?

close to the spinal cord

In the sympathetic nervous system, are the preganglionic neurons myelinated or unmyelinated?

myelinated

After leaving the spinal cord in the sympathetic nervous system, do the preganglionic neurons synapse with postganglionic neurons close to or far from the spinal cord?

close to the spinal cord

Do the preganglionic neurons in the sympathetic nervous system synapse with postganglionic neurons on or close to the target organ?

no (they synapse in sympathetic chain ganglia near the spinal cord)

What is the term for the chain of ganglia that runs close to the spinal cord in the sympathetic nervous system?

sympathetic chain ganglia

After leaving the spinal cord, the preganglionic neurons of the sympathetic nervous system synapse with postganglionic neurons where?

in the sympathetic chain ganglia near the spinal cord

Do the postganglionic neurons in the sympathetic nervous system tend to be myelinated or unmyelinated?

unmyelinated

After leaving the sympathetic chain ganglia, the postganglionic neurons in the sympathetic nervous system innervate target organs located where?

all over the body (because they travel through spinal nerves and then to target organs)

What neurotransmitter is used at the synapse between the preganglionic and postganglionic neurons in the sympathetic nervous system?

acetylcholine

What neurotransmitter is used at the synapse between the postganglionic neurons and the effector target (i.e. smooth muscle, cardiac muscle, gland) of the sympathetic nervous system?

norepinephrine (noradrenaline)

Term for the sympathetic nervous system because norepinephrine is used at the synapse between the postganglionic neurons and the effector target (i.e. smooth muscle, cardiac muscle, gland)?

adrenergic

In the sympathetic nervous system, do the preganglionic and postganglionic neurons synapse at the target organ or near the spinal cord?

near the spinal cord (in sympathetic chain ganglia)

In the sympathetic nervous system, what is the pathway of the preganglionic neuron from the spinal cord to the postganglionic neuron?

spinal cord -> sympathetic chain ganglia -> postganglionic -> neuron

In the sympathetic nervous system, where is the synapse between the preganglionic and postganglionic neurons?

sympathetic chain ganglia

In the sympathetic nervous system, where is the synapse between the postganglionic neuron and the effector target (i.e. smooth muscle, cardiac muscle, gland)?

on or near the target

Does the sympathetic nervous system generally have short or long preganglionic neurons? Short or long postganglionic neurons?

short preganglionic, long postganglionic

What is the primary neurotransmitter used by preganglionic neurons in both the sympathetic and parasympathetic nervous systems?

acetylcholine

What is the primary neurotransmitter used by postganglionic neurons in the sympathetic nervous system?

norepinephrine (noradrenaline)

What is the primary neurotransmitter used by postganglionic neurons in the parasympathetic nervous system?

acetylcholine

The sympathetic nervous system is sometimes called the thoracolumbar division of the autonomic nervous system. What are the two locations of cell bodies of preganglionic neurons that give rise to this name?

thoracic and lumbar regions of the spinal cord

Division of the autonomic nervous system that generally has short preganglionic neurons, long postganglionic neurons, increases heart rate, and decreases digestion

sympathetic

The sympathetic nervous system generally has short preganglionic neurons and long postganglionic neurons. How does this affect the location of the autonomic ganglia in relation to the target organ?

ganglia are located close to the spinal cord, not near the target organ

In the sympathetic nervous system, do the ganglia tend to be larger or smaller than those in the parasympathetic nervous system?

smaller

Where do the preganglionic sympathetic neurons synapse with postganglionic neurons in relation to the target organ?

synapse close to the spinal cord, not on or near the target organ

In the sympathetic nervous system, do the postganglionic neurons tend to be highly branched or not branched?

not branched (because they don't need to innervate a broad area of the target organ)

True or false- The sympathetic nervous system typically has more widespread effects on target organs compared to the parasympathetic nervous system.

true (due to ganglia being located near the spinal cord and non-branched postganglionic neurons)

What is the role of the sympathetic nervous system in terms of blood flow to skeletal muscles?

increases blood flow (to prepare for physical activity)

What is the role of the sympathetic nervous system in terms of blood flow to the digestive organs?

decreases blood flow (to conserve resources for physical activity)

What is the role of the sympathetic nervous system in terms of the pupils of the eyes?

dilates the pupils (to improve vision for physical activity)

What is the role of the sympathetic nervous system in terms of bronchioles in the lungs?

dilates bronchioles (to increase oxygen intake for physical activity)