Chapter 15: ANS, Sympathetic and Parasympathetic Nervous System

Question 1

Somatic Efferent Innervation

Answer 1

goes to skeletal muscle, is controlled voluntarily and is always excitatory,

Question 2

Autonomic Efferent Innervation

Answer 2

goes to viscera, is under involuntary control of brainstem, may be inhibitory or excitatory

Preganglionic neurons have their soma in lateral horn and axon leaves through ventral root to synapse on post-ganglionic neuron in the ANS ganglia.

Question 3

What are Similarities and Differences between Sympathetic and Parasympathetic?

Answer 3

Similarities

Both branches have preganglionic neurons that synapse at a ganglion with a postganglionic neuron,
Both preganglionic neurons secrete ACh,

Differences
Sympathetic Postganglionic secrete Norepinephrine and Epinephrine (NE, E)
Parasympathetic Postganglionic neurons secreted Acetylcholine (ACh)

Question 4

Sympathetic Branch

Answer 4

Preganglionic neurons – are cholinergic neurons because they secrete ACh onto the sympathetic ganglion

Postganglionic neurons – have cholinergic nicotinic receptors and MOST of them are adrenergic neurons because they secrete norepinephrine onto the organ

Respiratory rate increases,
Heart rate increases
Amount of blood leaving ventricles (stroke volume) increases,
Blood pressure increases,
Pupils dilate,
Glucose levels increase in blood,
Blood flow to skeletal muscle increases,
Blood flow to gastrointestinal system and kidney decreases.

Question 5

Parasympathetic Branch

Answer 5

Preganglionic neurons – are cholinergic neurons because they secrete ACh onto the terminal ganglion

Postganglionic neurons – have cholinergic nicotinic receptors and are cholinergic neurons because they secrete ACh onto the organ innervated

Respiratory rate decreases,
Heart rate decreases
Amount of blood leaving ventricles (stroke volume) decreases,
Blood pressure decreases,
Pupils constrict,
Glucose levels decrease in blood,
Blood flow to skeletal muscle decreases,
Blood flow to gastrointestinal system and kidney increases.

Question 6

Cholinergic

Answer 6

Secretes ACh, Parasympathetic

Question 7

Adrenergic

Answer 7

Secretes NE, E. Sympathetic

Question 8

Sympathetic Chain Ganglia

Answer 8

Sympathetic pre-synaptic neurons release ACh in ganglion, ACh binds to cholinergic receptors on sympathetic post-ganglionic neurons.

Question 9

Adrenal Medulla is stimulated by

Answer 9

The Sympathetic system to secrete Epinephrine (neurohormone) directly into blood to sustain the effects of sympathetic system

Question 10

Acetylcholine (ACh)

Answer 10

found in neuromuscular junction, pre-ganglionic sympathetic and parasympathetic, and post-ganglionic parasympathetic fibers, retina, and others,
EXCITES skeletal muscle, INHIBITS cardiac muscle.

Question 11

Excitatory Amino Acids

Answer 11

induce neuronal depolarization.

Glutamate - Found in Central Nervous System, involved in learning and memory.

Aspartate - Found in spinal cord.

Question 12

Inhibitory Amino Acids

Answer 12

induce neuronal repolarization

Glycine - most common in spinal cord, retina and brain.

GABA (γ-Aminobutyric Acid) - most common in brain, found in thalamus, hypothalamus, cerebellum, occipital lobes.

Question 13

Catecholamines

Answer 13

effects depend on postsynaptic receptor,
Norepinephrine (nor-adrenalin):
Involved in dreaming, awake states,
Can excite cardiac muscle can excite or inhibit smooth muscle.
Epinephrine (adrenaline):
Involved in excitation of cardiac muscle, and excitation or inhibition of smooth muscle.

Question 14

Dopamine

Answer 14

Highly concentrated in Substantia Nigra of Midbrain,

Involved in elevation of mood and control of skeletal muscle (missing - results in Parkinson’s disease)

Question 15

Neurotransmitters that affect ‘mood’

Answer 15

Serotonin
Norepinephrine (noradrenaline)
Epineprhine (adrenaline)
Endorphins

Question 16

Serotonin

Answer 16

Involved in sleepiness, alertness, thermoregulation and mood.
Many mood-altering medications (for clinical depression) work to prevent serotonin uptake (serotonin-uptake inhibitors).

Question 17

Histamine

Answer 17

Secreted from hypothalamus as neurotransmitter and many tissue in response to injury,
Potent vasodilator in nervous system and other tissues.

Question 18

Ionotropic Synapse

Answer 18

‘message’ to postsynaptic cell results in ‘ions’ moving through receptor (similar to neuromuscular junction).

1. ) Presynaptic neuron receives action potential,
2. ) results in Ca+2 entry to depolarize presynaptic neuron,
3. ) neurotransmitter is released and binds to,
4. ) an inotropic receptor on postsynaptic cell,
5. ) Depending on the ion, the postsynaptic cell depolarizes or repolarizes.

Question 19

Metabotropic

Answer 19

uses protein-messages to postsynaptic cell,
results in activation of other enzymes (proteins),
and activation of a 2nd messenger system

1.) Presynaptic neuron receives action potential,

2.) results in Ca+2 entry to depolarize presynaptic neuron,
neurotransmitter is released and binds to,

3. ) a metabotropic receptor on postsynaptic cell,
4. ) the receptor activates membrane proteins such as G-proteins,
5. ) A 2nd messenger is produced.

Question 20

Re-uptake by presynaptic neuron after neurotransmitter break down

Answer 20

Example - Acetyl cholinesterase (Neuromuscular junction)

Exanple - Monoamine oxidase (MAO)

Question 21

If you give a patient an adrenergic blocker (beta blocker for example), what side effects do you expect (in the respiratory system for example)?

Answer 21

HR decreases, Parasympathetic