Autonomic Flashcards
Peripheral nervous system is divided into which two sections
Motor and sensory
The motor division of the PNS is subdivided into
Autonomic and somatic
Autonomic nervous system regulates
homeostasis
Circulation, respiration, digestion, metabolism, secretions, body temperature reproduction
afferent pathway in the ANS comes from
From the viscera
The efferent pathway flows to
Motor to smooth muscle, cardiac muscle glands
Sympathetic and parasympathetic
Mechanoreceptors
Pressure- baroreceptors aorta and carotid sinus and lungs
stretch- veins, bladder, intestines
chemo receptors
carotid and aortic bodies
Medulla, hypothalamus, taste buds, olfactory bulbs
chemo receptors in the medulla respond to
Hydrogen ions and carbon dioxide
chemo receptors in the hypothalamus response to
Blood glucose levels
nociceptors
Pick up on noxious stimuli in the viscera and arterial walls
respond to stretch and ischemia and respond to any indication of a threat to the tissue
Thermoreceptors
respond to changes in temperature
hypothalamus blood temperature
Cutaneous external temperature
there are two routes for the afferent pathways from visceral receptors to access CNS
spinal cord via the dorsal roots
Brainstem via cranial nerves
Which is the main visceral sensory nucleus?
Solitary nucleus
Cranial nerves send visceral info to the solitary nucleus
solitary nucleus sends info to
pons and medulla, which is the visceral control
Hypothalamus thalamus and limbic systems which is the modulatory control
Limbic system influences respiratory by
Activating respiratory control areas in the pons and in the medulla rather than directly controlling respiration
Visceral afferents synapse with
visceral efferents (autonomic reflexes)
Neurons that ascend to the brainstem hypothalamus and thalamus
visceral nociceptive afferents also connect to
somatosensory, nociceptive tract neurons (referred pain)
Somatic efferents (muscle guarding)
medulla visceral control…
Heart rate
Respiration
vasoconstriction and vasodilation
pons
Respiration
hypothalamus, thalamus, limbic system are going to modulate
brainstem autonomic control
hypothalamus brainstem modulation
Regulation of homeostasis and internal equilibrium
Affects heart and respiration rate metabolism, water balance, digestion, and body temperature
Thalamus brainstem modulation
Projected to limbic system
Limbic system brainstem modulation
Emotions, moods, motivation
Induce autonomic responses like anxiety increasing heart rate
efferent pathways are what type of pathway
two neuron pathway
Preganglionic and postganglionic
Sympathetic
fight or flight
target structures are in body wall and body cavity
parasympathetic
Rest and digest
Target structures are in body cavities, head, and external genitalia
Preganglionic cell bodies are located
In the lateral gray matter of the thoracic/lumbar spinal cord
T1-L2
Postganglionic cell bodies are located
In sympathetic chain ganglia
Or
Collateral ganglia
sympathetic chain explanation
The neurons are coming from the lateral gray matter between the segments of T1 to L2
then through the spinal nerves
then come out the paravertebral sympathetic ganglia
Collateral ganglia explanation (Accessory ganglion)
unpaired prevertebral ganglia because they positioned anterior to the column
The axons are going to exit the sympathetic chain ganglia in four routes
- spinal nerves
- sympathetic nerves
- splanchnic nerves
- Splanchnic nerve to adrenal gland
The preganglionic cell bodies of the parasympathetic system are in
cranial nerves 3,7,9 and 10 ( brainstem)
pelvic splanchnic nerves (lateral parts of the gray matter in the sacral spinal cord S2 three or four)
postganglionic cell bodies of the parasympathetic system located
in Terminal ganglia
pre-ganglionic nerves versus postganglionic nerves
pre
run between CNS and the ganglion
cholinergic (acetylcholine)
May be myelinated
post
Between the ganglion and the organ
parasympathetic - cholinergic
Sympathetic - adrenergic (epinephrine)
Preganglionic cell bodies of a sympathetic system
thoracolumbar outflow
T1-L2
Preganglionic cell bodies of the parasympathetic system
Craniosacral outflow
either in the brainstem or in the sacral spinal cord
Postganglionic cell bodies of the sympathetic nervous system
Paravertebral- sympathetic chain or trunk , alongside the vertebral column
prevertebral- unpaired collateral or accessory ganglia
Postganglionic cell bodies of the parasympathetic system
Terminal ganglia that are in or near the walls of the organs that they’re going to innervate
Head
Organ wall
pathway sympathetic trunk including rami
from the lateral horn, ventral root, the spinal nerve through the white ramus to the sympathetic chain, then synapses with the post ganglionic neuron is back to the spinal nerve via the gray ramus, then out the spinal nerve towards the effector
exit sympathetic chain via spinal nerves
spinal nerves- synapsing with postganglionic neurons in the sympathetic chain ganglia * at the same level or go to a different level and then exit. exit out through the grey ramus communicants. re-enter nerve and proceeded to the effector. these Go to the skin the blood vessels, the muscles.
exit sympathetic chain via sympathetic nerves
sympathetic nerves- pre-ganglionic axons enter the sympathetic chain, and then either synapse at the same level or different level and then the postganglionic axons form on the sympathetic nerves from the sympathetic chain and then they go to the organs and the thoracic cavity, the heart
Sympathetic chain via splanchnic nerves
splanchnic nerves- preganglionic-axons coming out of the ventral root to the sympathetic chain ganglia and without synapsing they exit to form the splanchnic nerves then it’s synapses with the postganglionic neuron cellbody in the collateral or prevertebral gangia.
exit sympathetic chain via splanchnic nerve to adrenal gland
Splanchnic nerve to adrenal gland- Pre-ganglionic axon comes out of the ventral root and goes to the sympathetic chain And passes through it into the splanchnic nerve then the collateral ganglia And then directly to the adrenal gland synapses In the cells of the adrenal gland
