Lectures 67 and 68 Flashcards
The enteric nervous system of the gut is controlled primarily by what portion of the visceral motor system?
PNS
Skeletal muscle is innervated by motor neurons whose bodies are found in what horns?
anterior/ventral
Smooth muscle is innervated by
a 2 neuron chain with ganglia
SNS preganglionic neurons originate
in the lateral horns of the spinal cord
PNS preganglionic bodies originate
in cranial nerves, mostly vagus (X)
Overall control and integration of ANS function is performed by the
hypothalamus (and various brainstem nuclei)
Which division of the ANS is only activated in fight or flight?
sympathetic
The sympathetic division is often activated by
fear - this is our emergency escape system
Which division of the ANS is activated most of the time?
parasympathetic (PNS)
Which division promotes digestion and minimization of energy use?
parasympathetic (PNS)
What is the difference between the SNS and PNS in terms of branching fibers?
the SNS requires more branching in order to produce a massive, coordinated response
Preganglionic SNS cell bodies are located in the lateral horns from what levels?
thoracic T1 to Lumbar T2
The superior extension of sympathetic chain glanglia allow for innervation of
visceral effectors in the head (think salivary glands, lacrimal glands)
The SNS typically has what length of pre and postganglionic axons?
short preganglionic, long postganglionic
The PNS typically has what length of pre and postganglionic axons?
long preganglionic, short postganglionic
Which type of ganglionic axons are typically myelinated?
pre
Which type of ganglionic axons are typically unmyelinated?
post
Which type of ganglionic axons are extensively branched for fight or flight response?
both pre and post ganglionic axons of the sympathetic division
The somatic nervous system uses acetylcholine acting on what type of receptors?
nicotinic
The PNS division of the ANS uses acetylcholine acting on what kind of receptors?
principally nicotinic, but also act via muscarinic GPRs
The SNS division of the ANS uses acetylcholine acting with what?
nicotinic, but also norepinephrine (think fight or flight) via alpha or beta receptors
In the SNS division of the ANS, where is the acetylcholine acting on nicotinic receptors?
the adrenal medulla
In the SNS division of the ANS, where is NE/Epi acting via alpha or beta receptors?
in the bloodstream toward effector organ
Sympathetic innervation of sweat glands is
cholinergic
Postganglionic SNS neurons are mostly
noradrenergic (NA)
The oculomotor cranial nerve (III) serves the
eye and effects lens shape and pupil diameter
The facial nerve (VII) serves
several glands in the head including lacrimal, palantine, submandibular and sublingual
The glossopharyngeal nerve (IX) serves
the parotid salivary glands
The vagus cranial nerve (X) serves
the rest of the body - heart, lungs, liver, GI
The principal neurotransmitter at all ANS ganglia is
ACh acting on nAChRs
PNS cotransmitters include
peptides and NO
The heart acts by which cholinergic receptor type?
M2
The heart acts by which adrenergic receptor type?
Beta 1
What is the parasympathetic effect of the sinoatrial node in the heart?
decrease in heartrate
Gastric acid secretion acts by what cholinergic receptor?
M1
The sympathetic effect in the pupil is
dilatation
The sympathetic effect in the ciliary muscle is
relaxation
Basal activity of the SNS and PNS is known as
tone
When SNS is inhibited and PNS is excited, what is the effect on cardiac output?
decreased; this occurs when pressure or stretch is too great relating to blood pressure and heart rate
What kind of reflex triggers defecation?
efferent
Micturition refers to
control of urination
An erection is primarily due to activity in which division?
PNS (ejaculation is opposite)
Noredrenaline and adrenaline may only survive for
1 to 2 minutes before degradation
Synthetic sympathomimetics (acting as NE and Epi) may last for
up to 2 hours
How do amphetamines act indirectly?
by triggering NA release from SNS terminals (think ephedrine makes you hyper)
Which division do ganglion blocking drugs effect?
both the SNS and PNS - both utilize ACh acting on nicotinic receptors