#11. Autonomic NS

Question 1

What does the PNS divide into?

Answer 1

• the somatic nervous system
• autonomic nervous system
• enteric nervous system

Question 2

Describe the somatic nervous system

Answer 2

• consciously controlled
• voluntary
• sensory receptors and motor neurons to skeletal muscles

Question 3

Describe the enteric nervous system

Answer 3

• involuntary
• sensory from chemical changes in GI tract and stretching it
• motor to GI smooth muscle
• actual muscles that move food through the GI tract

Question 4

Describe the autonomic nervous system

Answer 4

• involuntary
• sensory from visceral organs
• motor to smooth muscles, cardiac muscles and glands

Question 5

What does the ANS divide into?

Answer 5

sympathetic and parasympathetic

Question 6

describe the sympathetic nervous system

Answer 6

“fight or flight”

–increased alertness and metabolic activities in order to prepare the body for an emergency situation

Question 7

Describe the parasympathetic nervous system

Answer 7

“rest and digest”

• activites conserve and restore body energy
• most output is to smooth mm and glands of GI tract and respiratory tract
• dilating vessels to GI tract which speeds processes.

Question 8

Explain autonomic tone

Answer 8

typically the two divisions of the ANS work in opposition to one another. Despite this fact most organs receive innervation from both. autonomic tone is the balance between the sympathetic and parasympathetic activity in one structure

Question 9

What regulates autonomic tone?

Answer 9

the hypothalamus

Question 10

Which structures only receive innervation from the sympathetic system?

Answer 10

• sweat glands
• arrector pili mm
• kidneys
• spleen
• most blood vessels
• adrenal medullae

Question 11

How do the organs that do not receive parasympathetic innervation still have a range in responses?

Answer 11

by increasing or decreasing the sympathetic tone. an increase in sympathetic tone has one effect while a decrease in symp tone would do the opposite

Question 12

What happens in a sympathetic response?

Answer 12

• pupils dilate
• HR, force of heart contraction and BP increase
• airways dilate (faster mvmt of air in and out of lungs)
• BV to skeletal mm dilates
• BV to cardiac mm dilates
• BV to GI tract constrict
• BV to kidneys constrict
• BV to liver dilate (for glycogenolysis)
• BV to adipose tissue dilate (for lypolysis)

Question 13

What happens in a parasympathetic response?

Answer 13

• Salivation
• Lacrimation
• Urination
• Digestion
• Defication
• decreased HR, diameter of airways (aka. bronchoconstriction), and pupil diameter

Question 14

Where does the somatic NS get its sensory input?

Answer 14

• from receptors for somatic senses (tactile, thermal, pain, proprioceptive sensations) and from receptors for special senses (sight, hearing, taste, smell, equilibrium)
• these are consciously perceived

Question 15

Where does the autonomic NS get its sensory input?

Answer 15

• from interoreceptors (sensory receptors located in BVs, visceral organs, mm and nn that monitor conditions in the internal environment)
• not usually consciously perceived

Question 16

Where does control of motor output for the somatic NS come from?

Answer 16

-primary motor area of cerebral cortex
-voluntary
(with contributions from basal nuclei, cerebellum, brainstem and SC)

Question 17

Where does control of motor output for the autonomic NS come from?

Answer 17

-involuntary control from the hypothalamus

Question 18

Describe the motor neuron pathway for the somatic NS

Answer 18

• one neuron pathway
• somatic motor neuron goes from CNS to skeletal muscle
• type A fiber

Question 19

Describe the motor neuron pathway for the autonomic NS

Answer 19

• two types:
• one is a two neuron pathway with an aunomic ganglion and the first neuron is a type B fiber and the second is a type C fiber.
• the other is only to chromaffin cells in the adrenal medulla which then release hormones that affect BV diameter. this is a one neuron pathway and is a type B fiber.

Question 20

What neurotransmitter is involved in the somatic NS?

Answer 20

only ACh

Question 21

What neurotransmitters are involved in the autonomic NS?

Answer 21

ACh and norepinephrine

Question 22

What hormones are involved in the autonomic NS?

Answer 22

norephinephrine and epinephrine

Question 23

What are the effectors of the somatic NS?

Answer 23

skeletal mm

Question 24

What are the effectors of the autonomic NS?

Answer 24

• smooth mm
• cardiac mm
• glands

Question 25

What is the response from the somatic NS?

Answer 25

contraction of skeletal mm

Question 26

What are the responses from the autonomic NS?

Answer 26

• contraction or relaxation of smooth mm
• increase or decrease in rate and force of contraction of cardiac muscle
• increase or decrease in secretions by glands

Question 27

What are the main parts of the autonomic motor pathway?

Answer 27

1. preganglionic neuron
2. postganglionic neuron
3. autonomic ganglia

Question 28

Describe the preganglionic neuron

Answer 28

• first neuron in the pathway
• cell body is in the CNS
• axon is a type B fiber
• usually goes to autonomic ganglion and synapses with postganglionic neuron

Question 29

What is the thorocolumbar division/sympathetic division?

Answer 29

-in the sympathetic division, preganglionic neurons have their cell bodies in the lateral horns of gray matter in T1 to L2 (sometimes L3)

Question 30

What is the craniosacral division/parasympathetic division?

Answer 30

-in the parasympathetic division, cell bodies of preganglionic neurons are in the nuclei of 4 cranial nerves (X, XI, VII, III) and in the lateral gray matter of S2 to S4

Question 31

Describe the postganglionic neuron

Answer 31

• the second neuron in an autonomic motor pathway
• in the PNS
• cell body is in an autonomic ganglion
• type C fiber
• terminates in a visceral effector