Organization of the Autonomic Nervous System

Question 1

What is the autonomic nervous system motor to?

Answer 1

smooth muscle, cardiac muscle, and some glands

Question 2

two components of the autonomic nervous system

Answer 2

sympathetic and parasympathetic

Question 3

sympathetic nervous system

Answer 3

prepares the body for exertion:

• raises blood pressure
• increases heart rate
• dilates the airway
• dilates the pupils

primary action is the control of arterial blood flow

Question 4

parasympathetic nervous system

Answer 4

mainly involved with digestion, brings body back to a resting state:

• lowers blood pressure
• decreases heart rate
• constricts the airway
• constricts the pupils
• constricts GI smooth muscle (peristalsis)
• glandular secretion

only found in the head, neck, and body cavities

Question 5

thoracolumbar outflow

Answer 5

the sympathetics, so called because sympathetic neurons exit the spinal cord only in the spinal roots from T1 to L2

also called the adrenergic system because its transmitter is noradrenaline/norepinephrine

Question 6

locations of the first and second cell bodies of the thoracolumbar outflow

Answer 6

first cell body: lateral horn

second cell body: sympathetic trunk, collateral or prevertebral ganglia, or adrenal medulla cells

presynaptic sympathetics travel to collateral ganglia from the sympathetic trunk via thoracic and lumbar splanchnic nerves

Question 7

white rami

Answer 7

the places where all presynaptics enter the sympathetic trunk

Question 8

gray rami

Answer 8

the location where postsynaptics rejoin spinal nerves

Question 9

splanchnic nerves

Answer 9

nerves that form after the symapse in the sympathetic trunk, travel directly to the heart and other splanchnopleure derivatives

Question 10

stellate ganglion

Answer 10

inferior cervical/ T1 sympathetic trunk ganglia for heart/lungs

Question 11

collateral ganglia

Answer 11

clustered by big arteries coming off the aorta

located on the aorta because their job is to innervate the arterties, follow them to the target organs

Question 12

craniosacral outflow

Answer 12

parasympathetic neurons only exit the CNS with cranial nerves and sacral spinal nerve roots

Question 13

location of the first and second cell body of the craniosacral outflow

Answer 13

first cell body - the brain and the lateral horn region of the spinal cord at levels S2-S4

second cell body - within the wall of the organs they innervate

Question 14

What is the primary neurotransmitters for parasympathetic nerves?

Answer 14

acetylcholine - parasympathetics are called the cholinergic system

Question 15

vagus nerve

Answer 15

parasympathetic - destined for all thoracic viscera plus abdominal viscera of the foregut and midgut

Question 16

pelvic splanchnic nerves

Answer 16

parasympathetic - for the viscera of the pelvis and hindgut

Question 17

general sensory

Answer 17

neurons provide intense innervation of the body wall, they are the neurons in the spinal nerve branches

Question 18

visceral sensroy

Answer 18

neurons that innervate the visceral organs dirived form the splanchnoete

they generally provide very dull sensation

travel with ALL autonomic nerves

cell bodies in the dorsal root ganglia

Question 19

referred sensation

Answer 19

originates from a visceral location and is sensed by the same spinal segment in the body wall

ex. heart pain in the arm

Question 20

components of every autonomic plexus

Answer 20

visceral sensory fibers, presynaptic parasympathetics, sympathetics

Question 21

How do visceral sensory neurons get from organs to the spinal cord?

Answer 21

through plexuses

into splanchnic nerves

into sympathetic trunk

into spinal nerves via communicating rami at every vertebral level

into the spinal cord via dorsal roots

cell bodies are in dorsal root ganglia with the general sensory cell bodies

Question 22

motor vs. sensory areas in the neural plate

Answer 22

if the dorsal spinal cord is sensory and the ventral part motor, then the lateral part of the neural plate (altar plate) must be sensory and the medial part (basal plate) motor, with the autonomic components at the interface

Question 23

neural crest derivatives

Answer 23

dorsal root ganglia

sympathetic chain ganglia

collateral ganglia

adrenal medulla cells

postsynaptic parasympathetics

melanocytes of skin

Question 24

embryonic basis of the somatic and autonomic nervous systems

Answer 24

somatic nervous system invades the somatopleure

autonomic nervous system invades the splanchnopleure

Question 25

alpha and beta receptors

Answer 25

determine whether a cell is stimulated or inhibited by sympathetic action

Question 26

nitric oxide

Answer 26

among a series of vasoactive molecules that act to inhibit smooth muscle contraction to help dilate arteries

Question 27

What are the two plexuses that parasympathetic neurons feed into?

Answer 27

enteric plexus and a plexus on the abdominal aorta