ANS Part 1 Flashcards by Paige Hamay

What’s the difference between the somatic vs autonomic nervous system?

Somatic: conscious, voluntary motor control of skeletal muscles
Autonomic: involuntary motor control of primarily visceral organs

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Describe where the preganglionic neurons originate in the sympathetic vs parasympathetic nervous system AND their lengths

sympathetic: thoracolumbar spinal cord (T1-L3)/ SHORT
Parasympathetic: brain stem & sacral spinal cord (S2-S4)/LONG

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What neurotransmitter does the sympathetic NS release from preganglionic neurons and what receptor is this NT activating?

ACh and nicotinic 2

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What neurotransmitter does the parasympathetic NS release from preganglionic neurons and what receptor is this NT activating?

ACh and nicotinic 2

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What NT does adrenergic neurons release?

Norepinephrine

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What NT does cholinergic neurons release?

ACh

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What NTs activate adrenoreceptors?

Norepinephrine AND epinephrine

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What NT activates cholinoreceptors?

ACh

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How does epinephrine get into circulation?

Adrenal medulla secretes it

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What is the junction between the post-ganglionic neuron and effectors (target tissues) called?

Neuroeffector junction

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What is the length of the sympathetic VS parasympathetic post-ganglionic neurons?

Sympathetic: LONG
Parasympathetic: SHORT

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Where does the cell body of each preganglionic neuron reside?

CNS

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Where do axons of pre-ganglionic neurons synapse on?

cell bodies of post-ganglionic neurons in an autonomic ganglia OUTSIDE CNS

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Where is the sympathetic autonomic ganglia located?

Paravertebral ganglia (sympathetic chain) and prevertebral ganglia

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Where is the parasympathetic autonomic ganglia located?

in or near effector organs

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What are the two main types of effector organs the sympathetic NS has impact on?

1) . Smooth muscle/glands

2) . Thermoregulatory Sweat glands

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What is the main type of effector organ the parasympathetic NS has impact on?

Smooth muscle/glands

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What NT does the parasympathetic postganglionic neuron release? What type of receptor does this activate?

ACh

Muscarinic (cholinergic influence)

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What NT does the sympathetic postganglionic neuron release on smooth muscle/glands?

Norepinephrine

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What NT does the sympathetic postganglionic neuron release on sweat glands? What receptor does this activate?

ACh

Muscarinic (cholinergic influence)

What are the four types of receptors on sympathetic smooth muscles/glands activated by norepinephrine or epinephrine?

Alpha 1
Alpha 2
Beta 1
Beta 2

What is the receptor type on somatic skeletal muscle end plate?

N1- nicotinic receptor

What action does the sympathetic NS have on the Heart (SA node, HR/AV nodal conduction/Contractility)

Increases all

B1 receptor

What action does the parasympathetic NS have on the Heart (SA node, HR/AV nodal conduction/Contractility)

Decreases all

Muscarinic receptor

What is the action on the bronchioles for sympathetic VS parasympathetic innervation?

sympathetic- dilates (B2 receptor) | parasympathetic- constricts (muscarinic receptor)

What are the actions on GI tract smooth muscle walls vs smooth muscle sphincters by sympathetic innervation?

walls- relaxation (a2, b2 receptors) | sphincters- contraction (a1 receptors)

What are the actions on GI tract smooth muscle walls vs smooth muscle sphincters by parasympathetic innervation?

walls- contraction sphincters- relaxation **Both muscarinic receptors

What are the actions on bladder detrusor muscle (wall) vs sphincter by sympathetic innervation?

BLADDER FILLING wall- relaxes (b2 receptor) sphincter- contracts (a1 receptor)

What are the actions on bladder detrusor muscle (wall) vs sphincter by parasympathetic innervation?

BLADDER EMPTYING wall- contraction sphincter- relaxation **both muscarinic receptors

What are the male genitalia actions when innervated by sympathetic vs parasympathetic NS?

Sympathetic: ejaculation (a receptors) parasympathetic: erection (m receptor)

What are the actions on the iris radial muscle vs ciliary eye muscle by sympathetic innervation?

radial muscle- dilates pupil (a1 receptor) | ciliary muscle- dilates for far vision (b receptor)

What are the actions on the iris circular sphincter muscle vs ciliary eye muscle by parasympathetic innervation?

Circular sphincter- constricts pupil ciliary- contracts for near vision **Muscarinic receptor

During bladder filling, what is the action of the external sphincter and what NS controls its?

External sphincter is control by somatic NS | contracted (voluntary)

During bladder emptying, what is the action of the external sphincter and what NS controls its?

Controlled by somatic NS | relaxed (voluntary)

What is the action on thermoregulatory sweat glands in skin by sympathetic innervation?

increase in action (MUSCARINIC receptor)

What is the action on thermoregulatory sweat glands in skin by parasympathetic innervation?

Non existent; only sympathetic has innervation

What are the four target tissues for A1 receptors?

GI sphincters Bladder internal sphincter Radial muscle, iris Vascular smooth muscle, skin, renal, splanchnic

What is the target tissue for A2 receptors?

GI tract wall

What is the main target tissue for B1 receptors?

HEART | also salivary glands, adipose tissue, kidney

What are the three main target tissue for B2 receptors?

GI tract wall Bladder wall BRONCHIOLES

Where are the three locations for nicotinic receptors?

1) . Skeletal muscle, motor end plate (N1) 2) . Post ganglionic neuron cell bodies PNS & SNS (N2) 3) . Adrenal medulla (N2)

Where are the two main locations for muscarinic receptors?

1) . All effector organs in PNS | 2) . Sweat glands in SNS

What is the important NT and receptor type when we think of treating severe hypotension/shock?

Norepinephrine | A1 agonist

What condition do we think about in regards to epinephrine and B2 receptor?

Hypotension

If a patient has asthma but needs to control high BP, what beta blocker should be used?

B1 blocker ONLY (metoprolol) | **B2 blockers would constrict bronchioles

If a patient has a migraine and high BP, what beta blocker should be used?

Propranolol Because non selective BBs can cross the blood brain barrier into CNS **also make sure pt doesn't have asthma

What action does the parasympathetic NS have on saliva secretion?

Increase by muscarinic receptor

Explain what NTs the adrenal medulla has influence on: talk about preganglionic neuron and what is released into circulation

``` Preganglionic neuron (located in thoracic spinal cord) is releasing ACh on Nicotinic 2 receptor on adrenal medulla chromaffin cells chromaffin cells then secrete epinephrine (80%) & norepinephrine (20%) into general circulation ```

What are the side effects of using scopolamine for motion sickness? Explain process & why side effects occur

- Medication blocks muscarinic receptors in target tissues - Usually muscarinic receptor activation increases saliva, constricts pupils, decreases HR, and contracts bladder wall to pee - Therefore, blocking this receptor gives symptoms of dry mouth, dilates pupils, increases HR, and slow voiding of urine