Thorax ANS Flashcards
What are the three types of visceral pain stimuli?
Distension, Ischemia, Injury
What does the SNS control in terms of bodily functions?
Relaxes pre-capillary sphincters to limbs and back muscles.
Constricts pre-capillary sphincters to skin
Innervates sweat glands
Innervates smooth muscle that erects hair follicles.
What does the SNS control in terms of specific organs?
Increases rate and force of heart contraction.
Relaxes smooth muscle lining the respiratory tract.
Constricts smooth muscle sphincters that control blood flow to abdominal and pelvic organs.
Release of EPI/NE from adrenal gland.
Coordinates ejaculation.
What does the SNS control in terms of Head and Neck?
Constricts pre-capillary sphincters to skin.
Innervates sweat glands.
Innervates the smooth muscle that erects hair follicles.
Innervates pupillary dilator and superior tarsal muscle.
What does the ParaNS control in terms of the bodily functions?
Nothing.
What does the ParaNS control in terms of specific organs?
Decreases force and rate of heart contraction.
Constricts smooth muscle lining the respiratory tract.
Increases glandular secretion into respiratory tract.
Increases strength and rate of peristalsis in GI.
Increases glandular secretion in GI.
Increases tone of bladder detrusor muscle.
Relaxes smooth muscle of urinary and rectal sphincters.
Relaxes blood vessels of genitalia, allowing engorgement.
What does the ParaNS control in terms of Head and Neck?
Increases salivary and lacrimal gland secretion.
Increases glands of air sinuses and pharynx.
Innervates pupillary constrictor muscle.
Innervates ciliary body muscle, allowing acommodation.
What are the 4 key differences between sympathetic and parasympathetic systems in regards to visceromotor?
Location of PRE-ganglionic neurons
Location of POST-ganglionic neurons
Pathway of PRE to POST.
Pathway of POST to target tissue/organ.
Where do I find SNS PRE-ganglionic neurons?
Intermediolateral (IML) column of T1-L2 spinal cord
What is the pathway for SNS PRE-ganglionic neurons to get to their paravertebral ganglia?
Starting in the IML, they exit via anterior roots.
Anterior roots => spinal nerve => white rami communicans => paravertebral ganglia.
For the SNS, what options can the axon go once it has reached the paravertebral ganglia?
Synpase and exit the chain.
Ascend OR descend, synapse, and exit the chain.
Exit without synapse (abdomen and pelvis only)
Describe the pathway for the SNS beginning at the paravertebral ganglion to a somatic target in the back or limbs.
Pre-ganglionic SYNAPSES in the paravertebral ganglia.
Goes to the gray ramus, traveling in the anterior and posterior rami.
Going to:
Sweat glands (Sudomotor)
Arrector pili (Pilomotor)
Precapillary sphincter (Vasomotor)
SAP
What is hyperhidrosis?
Excessive sweating.
Nerves of Kuntz go along the pathways of T1 via the gray rami, excessively stimulating the sweat glands via their sudomotors.
What do the SNS pathways for the head look like?
Pre-ganglionic that come from T1-T3 IML will enter the sympathetic chain to ASCEND, synapsing in one of 3 locations:
Inferior cervical ganglion
Middle cervical ganglion
Superior cervical ganglion
How do the POST-ganglionic sympathetics exit their cervical ganglia?
Gray rami communicans, joining nearby cervical nerves. They innervate the same 3 as the limb and backs.
This is only for the inferior and middle cervical ganglia!!
SAP
What is unique about the superior cervical ganglia axons?
Sometimes the post-ganglionic fibers jump onto the carotid arteries to reach their target.
They also innervate the iris.
Which cervical ganglia is usually the largest?
Superior.
What is the pathway for superior cervical ganglia fibers?
They travel along the ICA, onto the ciliary body via long ciliary nerves. They are responsible for DILATING your eyes.
What 4 symptoms make up Horner’s syndrome?
Ptosis - drooping of eyelid due to de-innervation of superior tarsal (Mueller’s) muscle.
Anhydrosis - Lack of sweat on affected side of face due to de-innervation of sweat glands.
Meiosis - Persistently constricted pupil due to de-innervation of pupil dilator muscle.
Flushing/warmness - affected side of face due to de-innervation of pre-capillary sphincters in skin of face.
Damage to any of these 4 locations can cause unilateral or ipsilateral Horner’s syndrome symptoms.
Sympathetic chain in the neck
Superior cervical ganglion (less common)
IML of the upper thoracic spinal cord (rare)
Autonomic pathways from the hypothalamus => brainstem => spinal cord
Describe the pathway of the sympathetic innervation of the thoracic viscera.
Pre-ganglionic axons synapse in paravertebral ganglion OR ascend before synapsing.
Post ganglionic axons exit as the cardiopulmonary splanchnic nerve.
Joins cardiopulmonary plexus
Reaches target by traveling along bronchi or coronary arteries
Paravertebral/ascend => cardiopulmonary splanchnic nerve => cardiopulmonary plexus => bronchi/coronary arteries => target organ
Describe the pathway of the sympathetic innvervation of the abdominopelvic organs.
Pre-ganglionic axons => paravertebral ganglia (without synapsing) => exit as splanchnic => post-ganglionic neurons in prevertebral ganglia.
What are the 3 splanchnic nerves composed of?
Greater thoracic splanchnic is T5-T9 spine/paravertebral ganglia.
Lesser thoracic splanchnic is T10-T11 spine/paravertebral ganglia.
Least thoracic splanchnic is T12 spine/paravertebral ganglia.
What other splanchnic nerves are found in the abdomen besides the thoracic?
Individual lumbar splanchnic nerves. (no bundling)
