Quiz 3 - Autonomic Nervous System

Question 1

the ANS is the ____ portion of the nervous system

Answer 1

visceral motor (efferent)

Question 2

what do visceral motor neurons innervate?

Answer 2

smooth muscle, cardiac muscle, blood vessels, glands. also associated with hair follicles (arrector pilli muscles) and the eye

DO NOT innervate skeletal muscle!!!

Question 3

2 classifications of visceral efferent neurons

Answer 3

parasympathetic and sympathetic

Question 4

nerve

Answer 4

contains many neurons bundled together in a common epineurium

Question 5

all spinal nerves contain all four types of neurons, but branches of spinal nerves may contain ______ than four components

Answer 5

fewer

Question 6

visceral efferent component

Answer 6

• unique b/c it consists of a two-neuron chain of multipolar neurons
• synapse between the two occurs in PNS within the ganglion
• first neuron of chain: cell body in nucleus in CNS; its axon is called the preganglionic fiber
• second neuron of chain: cell body in ganglion in PNS; its axon is called the postganglionic fiber

Question 7

are there synapses in dorsal root ganglia?

Answer 7

no! they contain the cell bodies of afferent neurons

Question 8

cell bodies of the first neuron in the sympathetic system

Answer 8

• T1-L2/L3 regions of spinal cord
• axons of these neurons leave the spinal cord thru the ventral root, travel in the spinal nerve, then enter a chain of sympathetic ganglia called the sympathetic trunk/chain.
• some of the neurons synapse in the ganglia of the chain, while others travel further to synapse in ganglia in the abdomen or pelvis
• axons of second neuron go to target organ

Question 9

cell bodies of the first neuron in the parasympathetic system

Answer 9

• brainstem and S2-S4 region of spinal cord
• these neurons travel to their target and synapse in the parasympathetic ganglia that are located near or within the organ wall
• thus the second neuron of the 2-neuron chain is very short for parasympathetic neurons

Question 10

sympathetic stimulation causes:

Answer 10

• increased HR
• dilated pupils
• increased sweating
• dilated bronchial tree
• diverted blood to skeletal muscles

Question 11

cell bodies of preganglionic sympathetic neurons

Answer 11

lateral horn of T1-L2/L3; thus, sympathetic division is often called the thoracolumbar division

Question 12

cell bodies of postganglionic sympathetic neurons

Answer 12

ganglia in the PNS, which can either be in the sympathetic chain/trunk (paravertebral) or prevertebral (associated with the abdominal/pelvic plexuses in the abdominopelvic cavity)

Question 13

ganglia of the sympathetic chains

Answer 13

-located along the lateral aspects of the vertebral column, extending from the base of the skull to the coccyx

Question 14

what connects the sympathetic chain to the spinal nerves?

Answer 14

the rami communicantes

Question 15

white rami communicans

Answer 15

the branch that sympathetic neurons use to enter the sympathetic chain

Question 16

gray rami communicans

Answer 16

the branch that sympathetic neurons use to exit the sympathetic chain

Question 17

the ganglia in the sympathetic chains are typically spaced so there is ____ associated with each vertebral level

Answer 17

one

*the exception to this is the cervical region!

Question 18

sympathetic chain ganglia in the cervical region

Answer 18

-merge to form the superior, middle, and inferior cervical (stellate) ganglia

Question 19

axons of preganglionic sympathetic neurons

Answer 19

-exit spinal cord thru the ventral root, pass thru the spinal nerve, and enter the sympathetic chain thru the WRC

Question 20

sympathetic destinations can be grouped into 4 categories

Answer 20

1. limbs/body wall
2. head
3. thoracic cavity
4. abdominopelvic cavity

Question 21

route 1: limbs/body wall

Answer 21

• target: T10 spinal segment
• since there are sympathetics that arise from the T10 region of the spinal cord, the neurons do not need to travel up or down the sympathetic chain

Question 22

route 2: head

Answer 22

• preganglionic sympathetic neurons must travel up the chain from T1-L2 to reach the superior cervical ganglion
• postganglionic neurons travel on 2 nerves, called the internal and external carotid nerves, which extend from the sympathetic chain into the head by traveling with major blood vessels

Question 23

route 3: thoracic cavity

Answer 23

• some of the preganglionic neurons travel up the chain before synapsing, due to the location of the heart during development
• sympathetic chain to thoracic cavity via cardiac nerves

Question 24

route 4: abdominopelvic cavity

Answer 24

• preganglionic neurons do not synapse in the sympathetic chain, but instead in the prevertebral ganglia in the abdomen or pelvis
• nerves that connect sympathetic chain to the abdominopelvic cavity are called splanchnic nerves.
• some of the splanchnic nerves arise from the thoracic levels of the sympathetic chain, whereas others arise from lumbar and sacral levels (thus some preganglionic neurons travel down the chain)

Question 25

functions of parasympathetic division

Answer 25

• digestion, excretion, and conservation of body energy
• decreases HR, constricts pupils, constricts bronchial tree, increases peristalsis, increases secretion of digestive enzymes

Question 26

cell bodies of parasympathetic preganglionic neurons

Answer 26

found in the brainstem associated w/ certain cranial nerves (CN III, VII, IX, X) as well as in the lateral horns of the S2-S4 regions of the spinal cord

**thus parasympathetic division is sometimes called the craniosacral division

Question 27

parasympathetic preganglionic axons

Answer 27

• travel in cranial nerves and sacral splanchnic nerves

- travel out to target organ

Question 28

pelvic splanchnic nerves

Answer 28

preganglionic parasympathetic neurons that arise in the lateral horn of the S2-4 levels of spinal cord

Question 29

CN X and pelvic splanchnic nerves innervate ______

Answer 29

• structures in the thorax, abdomen, and pelvis
• ganglia associated with these nerves are typically located in the wall of the organ, or in a plexus that is near the target organ

Question 30

postganglionic neurons of parasympathetic system are

Answer 30

very short

Question 31

referred pain

Answer 31

visceral AFFERENT