Quiz 2 Flashcards
Is ANS afferent, efferent, or both?
All Efferent
What does SNS do to…
- CO
- SVR
- Lungs
- Glucose
- Pupils
- Hunger and Procreation
>CO >SVR Bronchodilation >Serum glucose Dilates pupils Inhibits eating and procreating
The is the SNS also known as?
Thoracolumbar system: all neurons are in lateral horn of gray matter from T1-L2.
What neurotransmitter is released by most postganglionic “adrenergic” fibers in the SNS?
Norepinephrine (aka noradrenaline)
What does the Parasympathetic NS do to …
- Eat and procreation
- CO and SVR
- Lungs
- Pupils
Prepares body to eat and procreate.
< CO
What is the Parasympathetic VS also known as?
Craniosacral system bc all preganglionic neurons are in the brain stem or sacral levels of the spinal cord
What neurotransmitter is associated with Parasympathetic NS?
Acetylcholine at end organ as well as at preganglionic synapse “cholinergic”
T/F The PNS is continuously active while the SNS is active only when it is activated.
False, both systems are continuously active.
Inhibition of one branch allows the other branch to dominate
What is autonomic tone?
The balance between the SNS and PNS. In adults tone is dominated by the SNS. In children under 10, tone is dominated by the PNS.
__________ neurons leave CNS to synapse with the _____________ neurons, __________ neurons extends to their target ______.
Preganglionic, Postganglionic, postganglionic, organs.
(PNS fibers)The preganglionic neurons originate in the _________ or __________ and are relatively long.
Brain stem or sacral spinal cord.
The preganglionic neurons synapse with postganglionic neurons in ganglia near the effector organ or in the wall of the effector organ.
(SNS) Where do pregangliionic neurons originate from?
Lateral horn of gray matter from T1-L2.
Where do preganglionic neurons synapse with postganglionic neurons?
Sympathetic chain, or
Sympathetic ganglia, or
Adrenal Glands.
Presynaptic neurotransmitter is what and what is its target receptor?
Acetylcholine
Nicotinic receptor
What is the postsynaptic neurotransmitter of the SNS?
Norepinephrine
What are the receptors of the target organs in the SNS?
Alpha and Beta
Autonomic innervation of the Adrenal Glands in the exception
What is the post-synaptic neurotransmitter of the PNS?
Acetylcholine
What are the receptors of the target organs in the PNS?
Muscarinic
Where does myelination occur?
Preganglionic axons of SNS and PNS
What is the captain of the Autonomic Nervous System.
Hypothalamus
SNS is found where in the CNS?
T1-L2
PNS is found where in the CNS?
Cranial nerve VII, IX, X
S2-S4
Alpha-1 Adrenergic Receptors do what?
Smooth muscle contraction Vasoconstriction Bronchoconstriction Phenylephrine NE>Epi
Alpha-2 Adrenergic Receptors do what?
Inhibits release of NE (Vasodilation)
Clonidine
Dexmetatomidine
Beta-1 Adrenergic Receptors do what?
> HR (+chronotrope) >AV node conduction (+dropotrope) >contractility (+inotrope) >diastolic relaxation (+lusitrope) Isoproterenol (Isuprel) >EPI=NE
Beta-2 Adrenergic Receptors do what?
Smooth muscle relaxation Vasodilation Bronchodilation Uterine muscle relaxation Isuprel>Epi>NE
Cholinergic Receptor (Nicotinic)
Autonomic Ganglia
Adrenal Medulla
(NMJ skeletal muscle)
Cholinergic Receptors (Muscarinic)
< HR
Spinal Cord Injury (SCI) occurs in what ways?
Injury to cord
Compression
Hemorrhage
Traumatic Vasospasm
All of there may result in ischemia/infarction
What should be avoided and contributes to secondary ischemic neurologic injury?
Systemic hypotension, and reduced spinal cord perfusion pressure.
Secondary injury may be exacerbated by hypotension due to hemorrhage or neurogenic shock, and can peak in 4-6 days.
FYI (Acute phase SCI)
Systemic vasodilation from loss of SNS tone occurs in increasingly severity with ascending levels of SCI above L2, leading to hypotension
FYI
Bradycardia complicates the picture with injuries above T6 due to compromise of SNS cardiac accelerator fibers.
FYI (Chronic Phase, Autonomic Hyperreflexia)
A neurologic disorder that occurs in association with resolution of spinal shock and a return of spinal cord reflexes.
Cutaneous or visceral stimulation (such as distention of the urinary bladder or rectum) below the level of the spinal cord transection initiates afferent impulses that are transmitted to the spinal cord at this level.
This stimulation elicits a reflex SNS response that results in intense generalized vasoconstriction and HTN.
Bradycardia occurs secondary to activation of baroreceptor reflexes.
Approximately 85% of pts w/ a spinal cord transection above the ___ dermatome will exhibits autonomic Hyperreflexia.
Incidence of AH during general anesthesia depends on the level of spinal cord transection.
T6
In contrast, it is difficult to elicit this reflex in pts with spinal cord transection below T10 dermatome.
How do you Tx Autonomic Hyperreflexia
PREVENTION: Neuralaxial block, SAB or Epidural
Direct Acting Vasodilators:
Nitroprusside
Nitroglycerine
Upper motor neuron injuries
Spastic paralysis
Not associated with muscle atrophy
Hyperreflexia
Cerebral Palsy is an example
Lower motor neuron injury (peripheral nerves)
Flaccid paralysis
Associated with muscle atrophy
Hyporeflexia
What does injury to L2 and above cause?
Lumbar injury (L1-S5)
Spastic paralysis of lower extremities
Injury causes bowel, bladder, and sexual dysfunction.
What deficits does thoracic injury (T1-T12) cause?
Same deficits as lumbar injury
T9-T12 injury causes loss of trunk of abd muscle control.
What type of injuries occur above T6?
Autonomic Dysreflexia
Neurogenic Shock: loss of vascular tone. T1-T4 are the cardiac accelerator fibers. Can cause disruption of body temperature regulation.
What type of injury occurs in cervical injuries (C1-C8)
C3-5
C1-4
C5 and above.
Same deficits as thoracic injury
C3-5: innervate diaphragm.
C1-4: quadriplegia, need for mechanical ventilation.
>C5: difficulty clearing secretions.