the automatic nervous system

Question 1

compare somatic to automatic nervous system

Answer 1

Somatic systems - conscious awareness

Autonomic sensory - not consciously perceived
- Monitors internal conditions - blood gases, viscera operation, etc

Autonomic motor (controls/modulates activity of) cardiac muscle, smooth muscle & glands
- Often adjustment of internal controls in relation to whole body needs

Question 2

whats the motor pathway of somatic motor neurons

Answer 2

Somatic motor neurons go directly from spinal cord to skeletal muscle (one nerve cell in pathway)

Question 3

whats the motor pathway of automatic motor systems

Answer 3

Autonomic motor systems includes two motor neurons:

The preganglionic neuron from the CNS synapses with the postganglionic neuron in an autonomic ganglion, the postganglionic neuron ends on the effector organ.

Question 4

explain what happens in the autonomic nervous system in terms of NE or ACh

Answer 4

glands - increased or decreased secretions

smooth muscle (eg. in the urinary bladder) - contraction or relaxation

cardiac muscle (in the heart) - increased or decreased rate and force of contraction

Question 5

name and describe the 2 divisions of the automatic nervous system

Answer 5

Sympathetic division

Parasympathetic division

Both divisions often innervate the same effector

They have opposite effects

e.g. sympathetic stimulates heart rate and parasympathetic slows it down

Question 6

explain the sympathetic division of the automatic nervous system

Answer 6

Thoracolumbar division-
- outflow from thoracic & lumbar segments of spinal cord

Preganglionic fibre from lateral horns via ventral roots ->
sympathetic ganglia where they synapse with postganglionic cells in ganglia

Question 7

explain the sympathetic trunk ganglia

Answer 7

Vertical rows on either side of vertebral column

Post synaptic fibres mainly go to organs above diaphragm

Question 8

explain the sympathetic prevertebral ganglia

Answer 8

Anterior to vertebral column-

celiac, superior mesenteric & inferior mesenteric

Innervate organs below diaphragm

Question 9

explain parasympathetic neurons

Answer 9

Output at top-medulla nuclei
- Cranial nerves II, VII,IX, X (vagus nerve)
- (vasovagal attack)

Bottom of spinal cord- sacral nerves

Synapse in terminal ganglia
- Near or in the innervated organ

localised to single effector organ

Question 10

name the 2 types of neurotransmitters

Answer 10

acetylcholine

norepinephrine

Question 11

describe the neurotransmitter acetylcholine

Answer 11

All preganglionic fibre terminals

Parasympathetic postganglionic terminals

A few postganglionic sympathetic terminals

Short-lived effects

Question 12

describe the neurotransmitter norepinephrine

Answer 12

Most postganglioic sympathetic terminals

Longer effects

Amplified by adrenal release with epinephrine

Question 13

explain autonomic NS activity

Answer 13

Balance between sympathetic & parasympathetic “tone” regulated through hypothalamus

Only sympathetic to:
- Sweat glands, arrector pili muscles, kidneys, spleen, blood vessels & adrenal medulla

Question 14

explain the effects of sympathetic

Answer 14

Fight-or-Flight activities:

Dilation of pupils

Increases Heart Rate, force of heart contraction & Blood Pressure

Dilation of airways

Constricts blood vessels to non-essential organs: kidneys, GI tract

Dilates blood vessels to muscles, cardiac muscle, liver & adipose tissue

Mobilises nutrients: glucose & fats

Question 15

explain the parasympathetic affects

Answer 15

Rest-and–digest activities:
- SLUDD

Salivation

Lacrimation

Urination

Digestion

Defaecation

Decreases – Heart Rate, airway diameter, pupil diameter