NEURO LEC 12: ANS Flashcards
What is the control center of the ANS?
Hypothalamus
Sympathetic NT
epinephrine and norepinephrine
PNS NT
Ach
The ANS projects to the sympathetic NS in ________ parasympathetic ganglia in the ________
T1-L2/L3
Brainstem and S2-S4
The Afferent components of the ANS carry sensory information from _______ to the CNS
Organs/tissues
How does the ANS infleunce cardiopulm function
Regulates rate and depth of respiration
Regulates the diameter of bronchial lumen
Blood glucose and electrolytes are monitored where?
IN hypothalamus
Stretch receptors are found in the ___________
pressure receptors are found in the ________
Veins, bladder, intenstines
Aorta, carotid sinus, lungs
What are 4 kinds of receptors that the ANS uses?
Mechanoreceptors
chemoreceptors
nociceptors
thermoreceptors
How does the ANS regulate homeostasis
-Cardiopulm
-metabolism
-regulate body temp
-regulate autonomic responses
Visceral Nociceptive afferents connect with somatic efferents to cause __________
Muscle guarding in skeletal muscles
What is the fx of the solitary nucleus
viseral input (CN 7, 9, 10) converges onto solitary nucleus in medulla. (synapse point)
ANS afferents
Afferents of the ANS enter the CNS through what part of the spinal cord?
Dorsal Root
What is the area of the brainstem that controls vitals?
reticular formation - complex neural network that extends vertically throughout the brainstem
The medulla regulates vitals through autonomic efferents and the ____
Vagus N
The Medulla regulates what vitals?
Pons?
Medulla- HR, Respiration, Vasoconstrict/dilation
Pons- Only respiration
Most visceral input coming into the brainstem via cranial nerves converges in the
Solitary nucleus 7, 9, 10
Visceral information reaching the hypothalamus us used to ______. They hypothalamus does this through…
maintain equilibrium in the interior of the body (cardiorespiratory, metabolic, water resorption, digestive activity)
hypothalamus does this via acting on pituitary gland, control centers in brainstem and SC
Whats the role of the thalamus/hypothalamus/limbic system in the ANS?
Modulate autonomic brainstem control
(think, medulla and pons control, while hypothalamus, thalamus and limbic modulate!)
all preganglionic neurons in ANS release ____ (NT) and bind to what receptors?
release Ach which binds to nicotinic receptors on the post-ganglionic neuron
postganglionic neurons in PNS release ___ (NT) which binds to what receptors?
releases Ach which binds to muscarinic receptors on target tissues
most sympathetic postganglionic neurons release ____ (NT) which binds to what receptors?
release norepinephrine, which binds to adrenergic receptors (a and B receptors) on target organ
neurons that release ach are called
neurons that release norepi or epi are called
ach = cholinergic
norepi and epi = adrenergic
Norepinephrine is found inside of ___________
Whereas epinephrine is only found ____________
Most sympathetic postganglionic neurons
Only in andrenal medulla
parkinsons is degermation of dopamine-producing neurons in the substantia nigra, leading to a dopamine deficiency in the basal ganglia. what are the motor symptoms associated?
TRAP
tremors, rigidity, akinesia (bradykinesia), postural instability
**NOTE - it will also impair cognition, mood and emotions, sleep, sensory and ANS dysfxn and hyposmia
What is the enteric nervous system?
Lies within the gut for peristalsis and GI secretions
Neurons from CNS to ganglion are preganglionic, also called
Neurons from Ganglion to effector organ are called postganglionic, AKA
A-beta fibers
C fibers
Somatic efferent pathways use ______ neuron(s) in the peripheral system and autonomic efferent pathways have ______ neuron(s) with synapse outside the CNS
1
2
Preganglionic neurons of the sympathetic NS have cell bodies where?
Inside of the lateral horn in T1-L2/3
(note: they exit through ventral nerve root to spinal nerve)
where are the postganglionic SNS cell bodies?
paravertebral ganglion
Which type of fibers travel farther? Pre-ganglionic or post-ganglionic
Post ganglionic in PNS
Pre ganglionic for SNS
Travel longer vs longer physically
Where is there a 1 neuron connection within the sympathetic nervous system?
1 neuron connection directly to adrenal medulla
the rest use 2 neurons
Difference between mid/thoracic and upper lumbar vs. the upper thoracic SNS?
Midthoracic and upper lumbar nerves travel through the sympathetic trunk
upper thoracic nerves synapse inside of sympathetic trunk
SNS tracts to the periphery and thoracic viscera synapse where?
Paravertebral ganglia (sympathetic trunk)
SNS tracts to the pelvic/abdominal organs synapse where?
prevertebral ganglia (close to the organs)
Sympathetic efferents to the head originate in the ________ and synapse in the ________
Hypothalamus
Upper T Spine
What is the MAIN function of the SNS?
promote optimal circulation to organs
Increases SNS activity _______ vessels, lessened SNS activity ________ vessels
constricts
dilates
how does the SNS control body temp?
sweating
piloerection (goosebumps) to trap warm air
controls diameter of blood vessels in skinare more ventilated but dont get as much blood
How does the SNS prepare for vigorous exercise?
vasodilation to active muscles
vasoconstriction to gut and skin
How is the ANS important for a sit to stand?
Sympathetic nervous system constricts vessels to allow for adequate control of blood pressure and prevent orthostatic hypertension
T or F: Parasympathetic NS dilates blood vessels
False, it doesn’t directly control blood vessel diameter, only the sympathetic NS does this.
Which nervous system is fight or flight
which is rest and digest?
Symp- Fight or flight
Para - rest and digest
Does the PNS have an interconnected ganglia chain like the sympathetic NS?
No
Where are the 2 neuronal pathways of the PNS found?
Brainstem and Sacral cord.
Which cranial nerves are associated with the parasympathetic NS?
3, 7 , 9, 10
Basically anything with eyelid, anything with swallowing
Nucleus ambiguus is associated with what 2 cranial nerves?
9,10
From the lateral horn of the sacral SC, the axons travel in the splanchnic nerves to ____________ and _______________
Bowel/Bladder and genitalia
the parasympathetic nervous system ______ the pupils
the sympathetic nervous system ________ the pupils
constricts
dilates
the parasympathetic nervous system _______ the airways
the sympathetic nervous system ________ the airways
constricts
dilates
Which nervous system stimulates peristalsis?
Parasympathetic
What are examples of bodily systems that receive a balanced input from sympathetic and parasympathetic
Thoracic/abdominal viscera + Bowel/bladder + pupil
Sympathetic nervous system is not opposed in what systems? (Not countered by parasympathetic output)
Controlling effectors in limbs, face, bodywall, raising eye lid
Where is parasympathetic NS acting unopposed?
Increasing the convexity of the eye
Where is the breathing rhythm generator found?
Anterior medulla
Note: balances calm vs arousal
What is the Locus Coeruleus for?
arousal, alertness, anxiety
What can inhibit the locus coeruleus and decrease anxiety/arousal
slow breathing can allow subgroups of neurons from the breathing rhythm generator in the medulla to inhibit the LC
During freezing in the fight or flight response, what is activated?
Both sympathetic and parasympathetic’
note: bradycardia, immobility, combined with heightened alertness to pepare for action
What is the purpose of freezing (fight or flight)
to optimize perception of threat and select action
During freezing, first the __________ recognizes the threat and sends info to the ________ and anterior medulla to stimulate ____________
amygdala
hypothalamus
sympathetic NS
note: this is only 1 part, the Amygdala also activates the parasymp through another pathway
During freezing the amygdala activates the parasympathetic NS which communicates with the ________ causing ________ to reduce heart rate and inhibit medulla and skeletal muscle contractions
Midbrain
CN 10 (Vagus N)
Once fight/flight starts _______ decreases and ___________ increases
parasymp
symp
Horners syndrome
lesion of sympathetic pathway to face
ipsilateral ptosis (drooping eyelid)
miosis (pupil consrict)
Redness
Sweating
What can cause horner syndrome?
Damage to preganglionic nerve in upper thoracic SC, superior cervical ganglion, or cervical sympathetic trunk
horner syndrome can be a side effect due to what
stellate ganglion chemical block used to treat complex regional pain syndrome
Peripheral nerve injuries can damage sympathetic efferents causing….
problems with circulation, temp control, sweating, causing skin changes
Complete injuries in the ___________ impair B/B function and sexual function
Lumbar SC
Autonomic dysreflexia is caused by injuries above what level?
T5/T6
note: life threatening condition
What is autonomic dysreflexia?
Irritatant below level of lesion causes ascending sympathetic response that cannot be inhibited for balanced BP control.
heightened sympathetic response causes rapid BP increase
With autonomic dysreflexia you have _____ blood pressure and _______ heart rate
increased BP
Decreased HR
What should you do in the case of autonomic dysreflexia
Induce orthostatic hypotension (to reduce BP)
Check for irritant
call for help
Brainstem injuries vs cerebral injuries
Brainstem - impaired efferent control of vitals, dysfunction of CN nucei (pupil, tears, saliva, control of viscera)
Cerebral injuries- Damage to hypothalamus interferes with homeostasis with metabolic and behavioral impairments
Orthostatic hypotension definition
decrease of 20mmHG or 10mmHG diastolic during 1st 3 mins of upright posture
note: pooling of blood in lower limbs and abdomen causes decreased cardiac output and BP
How can a SCI cause orthostatic hypotension
disruption of descending signals from medulla to sympatheitc preganglionic nerves prevents vasoconstriction
autonomic degen disorders like ________ can cause orthostatic hypotension
parkinson’s
How can peripheral neuropathies cause orthostatic hypotension
damage to peripheral nerves interupt signals from SC to effectors that go to blood vessels
What is neural reflexive syncope
sympathetic overactivity caused by emotional distress, pain, pressure on carotid sinus causing strong heart contractions and activating CN10
medulla inhibits sympathetic nervous system to allow vasodilation and stimulates CN 10 to reduce HR (Vasovagal syncope)
