Autonomics Flashcards
This nucleus projects to the reticular formation, the hypothalamus, and the thalamus, forming circuits that contribute to autonomic regulation and pattern generation.
NTS
Respiratory activity is controlled by 4 integrative centers in the pons and medulla is driven mostly by low _____ levels and high ____ levels.
O2; CO2
When light is shined in the left eye of a patient, both right and left pupils constrict. When the light is moved to the right eye, neither pupil constricts. This is evidence of what kind of damage?
damage to the right optic nerve
This nucleus receives visceral afferent terminations from CN VII, IX and X
NTS (nucleus of the solitary tract)
When blood pressure increases, the NTS sends excitatory signals to the inhibitory caudal ventrolateral medulla (CVLM). What is this center inhibiting?
the CVLM inhibits the pacemaker neurons in the rostral ventrolateral medulla (RVLM), leading to reduction of heart rate and sympathetic tone
Visceral afferents in CNs IX and X provide
information on arterial (and to lesser extent venous)
pressure through high-pressure baroreceptors, located within what structures?
carotid sinus and aortic arch
medullary respiratory center that is very sensitive to
CO2 and is concerned with forced expiration via intercostals.
VRG (ventral respiratory group)
Post-ganglionic sympathetics are (excitatory or inhibitory?) to smooth muscle in blood vessels, hair follicles, iris, uterus, urethra, and vas deferens. What type of receptors mediate this?
excitatory; α1-adrenergic receptors
True or false: the vast majority of inputs to pretectal
neurons come from crossed chiasmatic fibers.
False. The vast majority come from uncrossed, ipsilateral retinal ganglia.
This brain region is often referred to as the ‘head ganglion’ of the autonomic nervous system; it controls the pattern generators in the brainstem and integrates their activity with endocrine function and behavior.
hypothalamus
What happens during lens accommodation?
Parasympathetic stimulation causes ciliary muscle to contract, releasing tension in the zonular fibers. In the absence of stretch in these fibers, internal tension causes the lens to become thicker (more spherical) and refract light for near vision.
tract that is the major descending input to pre-ganglionic neurons of the sympathetic system in the IML of the thoracolumbar spinal cord
hypothalamospinal tract
Pre-ganglionic neurons in the superior and inferior
salivatory nuclei innervate secretomotor neurons in which ganglia?
superior (CN VII) - pterygopalatine ganglion
inferior (CN IX) - otic ganglion
When blood pressure increases, baroreceptor afferent input travelling through CN IX and X stimulates excitatory neurons in the NTS, which conveys the signal to what nucleus, causing the slowing of heart rate/contractions?
nucleus ambiguus
At resting light, a patient’s right pupil is dilated. When light is shined into the left eye, the left pupil constricts but the right pupil remains dilated. This is evidence of what kind of damage?
right oculmotor nerve damage
Where are the cell bodies located for cranial nerve afferents that transmit activity from baroreceptors in the aortic arch and carotid sinus, as well as those that transmit activity from chemo/mechanoreceptors in the thoracic and abdominal viscera? Where do these afferents terminate?
inferior glossopharyngeal ganglia (CN IX) and the nodose of CN X;
terminate in the NTS
Where are the cell bodies of spinal visceral afferents located? Where do they terminate?
dorsal root ganglia;
they terminate on second order neurons in the dorsal horn, which end in the VPL (also send branches to the NTS)
Pre-ganglionic parasympathetics in this nucleus synapse in the ciliary ganglia in the orbit, and exert functional control over lens accommodation and pupil constriction
Edinger-Westphal nucleus
center that drives inspiration by exciting DRG, and is inhibited by the pneumotaxic center and by input from lung stretch receptors that serve to prevent over-inflation of the lungs
apneustic center
(fill in the missing segments of the retinal pathway of relaying information about the presence of light):
light exposure to retina –> optic nerve –> _____ –> optic tract –> branchium of superior colliculus –> ______ .
optic chiasm;
pretectal nucleus
medullary respiratory center that controls excitation of the phrenic nucleus, contracting the diaphragm, and is responsible for inspiration and respiration rhythms
dorsal respiratory group (DRG)
Individual pre-ganglionics of this branch of autonomics only innervate postganglionic neurons serving the same function.
sympathetic nervous system
pontine lesions affecting this nucleus cause urinary retention
Barrington’s nucleus
center in the upper pons that controls the rate and depth of respiration by inhibiting the DRG and apneustic center to end inspiration.
pneumotaxic center
Both pre and post ganglionic parasympathetic neurons use ______ as a neurotransmitter.
acetylcholine
Pre-ganglionic input to the _____ _____ causes chromaffin cells to release norepinephrine and epinephrine into the blood.
adrenal medulla
In humans, cold water on the face activates a loop (the diving reflex) involving what CNS components and structures?
CN V and X, spinal nucleus of V, and respiratory centers in the medulla
Most pre-ganglionic parasympathetic neurons in the medulla are located in this nucleus, which sends axons into CN X and innervate post-ganglionic neurons in the myenteric and submucosal plexuses in the walls of the GI tract from the pharynx down to the distal 1/3 of the transverse colon
the dorsal motor nucleus of the vagus (DMX)
Most pre-ganglionic sympathetic neurons use what neurotransmitter? Most post-ganglionics, with the exception of those that innervate sweat glands, use what neurotransmitter?
acetylcholine; norepinephrine
Which cranial nerves carry parasympathetic fibers? Where are they located?
CN III, VII, IX, and X. They are located in the brainstem. There are also parasympathetic preganlionics in levels S2-S4 of the spinal cord (pelvic splanchnics)
Chemoreceptors detecting pO2 are located here
carotid body
The medulla, pons and midbrain contain these structures, which reside mostly in the reticular formation, and link appropriate groups of pre-ganglionic neurons to perform a particular function (e.g., thermoregulation).
autonomic pattern generators
Axons to the contralateral Edinger Westphal nucleus cross where?
in the posterior commissure
Elicitation of the contralateral pupillary light reflex relies on the proper functioning of which cranial nerves?
CN II (optic) for the afferent limb of the reflex and CN III (oculomotor) for the efferent limb
When light is shone into one eye, the pupil of the ipsilateral eye constricts, but the pupil of the contralateral eye also constricts. This is known as what?
The consensual pupillary light reflex (CPLR)
True or false: sympathetic input to the smooth muscle in the bronchioles causes the cells to relax.
True
In addition to supplying intralaryngeal ganglia (mucus secretion) and motor to the branchiomotor muscles, the nucleus ambiguus contains preganglionic parasytmpathetic neurons that supply what tissue?
sub-pericardial tissue over the atria
True or false: spinal visceral afferents transmit information from mechano- and chemoreceptors in the pelvic viscera and also pain and temperature from all the viscera
True
Damage to the hypothalamospinal pathway above T1 causes a hemi loss of sympathetic function on the ipsilateral side, resulting in what condition?
Horner’s syndrome
nucleus that is located along the ventral midline and is the main brainstem pattern generator for thermoregulation
raphe pallidus (RPa)
Effects of this branch of autonomics are localized and last for a short time because a single preganglionic fiber may only synapse on one or two postganglionic neurons.
parasympathetic nervous system
Refers to a set of interconnected nuclei that play a crucial role in maintaining behavioral arousal and consciousness
reticular formation
The ______ is a primary regulator of the sympathetic nervous system, sending excitatory fibers to preganglionic neurons in the spinal cord via the medullary reticulospinal tract
RVLM (rostral ventrolateral medulla)
