Lecture # 08_Fall Flashcards
The Autonomic Nervous System regulates ___, ____, ___, and ___ function.
cardiac muscle, smooth muscle, visceral and gland function
What are the two divisions of the ANS?
Smypathetic Nervous System (the adrenergic system) and Parasympathetic Nervous System (the cholinergic system)
Which nerve transmits sensory input from the thoracic and abdominal organs?
the vagus nerve (CN X)
Most actions of the ANS are ______.
Involuntary
List the 8 things regulated by the ANS
HR, BP, GI system, temp, hunger, thirst, osmolarity, gland secretions
The peripheral ANS is the _____ component of the system.
Efferent (motor)
How do neurons of the Peripheral ANS differ from somatic neurons?
Autonomic: two-neuron unit - 1st neuron from CNS –> ganglion (myelinated) and 2nd neuron from ganglion –> target organ (unmyelinated)
Somatic: single myelinated axon with cell body in spinal cord
T or F. Both SNS and PNS are tonically active?
True. They have baseline activity that can increase or decrease - More than one way to accomplish an effect with precision
Which system is the “FIGHT OR FLIGHT” system?
Sympathetic Nervous System (SNS) = Adrenergic = “FIGHT OR FLIGHT”
Which system is know as the “REST & DIGEST” system?
Parasympathetic Nervous System (PNS) = Cholinergic = “REST & DIGEST”
Which system is also known as the cranio-sacral system? Why?
PNS because the pre-ganglionic neurons originate in brainstem or sacral segments of spinal cord
What is the Ratio of pre- : post-ganglionic fibers in the SNS?
1:20
Post-ganglionic fibers originate in sympathetic ganglion –> effector tissues - they travel within spinal nerves and outnumber pre-ganglionic fibers by 20-30:1
Concurrent stimulation of many organs at once = mass sympathetic discharge
Which system is also known as thoraco-lumbar system? Why?
SNS because their pre-ganglionic fibers (T1–L3) originate from spinal cord –> sympathetic ganglia
What are the 3 endogenous catecholamines?
Epi, NE, and Dopamine
Adrenal stimulation leads to release of what 2 catecholamines?
Epi (80%) and NE (20%)
Which catecholamine acts as a CNS neurotransmitter?
Dopamine
_____ is synthesized and stored in the adrenal medulla
Epi
T or F. Systemic catecholamines do not cross the BBB.
True.
What are sympathomimetics?
Drugs that act like catecholamines but have a different structure
Almost all endogenous ___ undergoes re-uptake into the pre-synaptic terminal and can then be metabolized by ____.
NE, Monoamine oxidase (MAO)
Where are circulating catecholamines (NE + Epi) metabolized?
in the liver and kidney
What metabolizes circulating catecholamines in the liver and kidneys? What is the metabolite?
Catechol-O-methyltransferase (COMT), Metabolite is vanillylmandelic acid
What is used in the diagnosis of a pheochromocytoma?
vanillylmandelic acid
What is the rate limiting step in the synthesis of Epi shown below?
Phenylalanine -> Tyrosine −*-> DOPA -> DA -> NE -> Epi
*Tyrosine hydroxylase = rate-limiting step
___ is synthesized and stored in post-ganglionic neurons and adrenal medulla
NE
Which catecholamine is released at the effector tissues in the PNS?
Ach
What are the two types of cholinergic receptors?
Nicotinic and Muscarinic
Where are nicotinic receptors located at?
On cell bodies of all post-ganglionic neurons, within ganglia of both SNS and PNS
Neuromuscular junction also has n-ACh-R - Blocked by non-depolarizing neuromuscular blocking agents
Where are muscarinic receptors found?
On cell membranes of effector tissues - also on pre-synaptic membrane of sympathetic (SNS) nerve terminals ( Stimulation -> inhibits release of NE)
____ is a prototype muscarinic blocker ->sympathomimetic activity
Atropine
____ is the first choice for bradyarrhythmias
atropine
T or F. Atropine can cross the BBB.
True
