PNS/VNS Flashcards
How do sensory receptors work?
They transduce a stimulus into a receptor potential, which changes firing frequency of AP’s, enabling the signal to get transmitted along the entire nerve length
What is receptor adaptation?
Receptor loses its sensitivity over time
Slowly adapting receptors vs. fast adapting receptors
- slow adapting receptors remain responsive to unchanging stimuli like P
- fast adapting receptors detect onset of changing stimuli, like vibration
Skin sensing modalities
fine touch crude touch vibration temperature pain
Meckel’s receptors
nonencapsulated, slowly adapting receptors
- low frequency vibration and P
Meissner’s receptors
encapsulated, rapidly adapting receptors
- light touch
Pacinian receptors
located deeper in the skin, encapsulated, very rapidly adapting
Ruffini recpetors
detect skin stretching and P
Nociceptors
free nerve endings that detect tissue damage –> pain receptors
Specialized receptor that detects muscle length
Muscle spindle
Specialized receptor that detects muscle strength
Golgi tendon organ
Pregang parasympathetics
- Edinger Westphal nucleus - CN III - pupil constriction
- Superior/Inferior salivatory nucleus - CN VII to ptery and submandib ganglion, CN IX to otic (parotid) gang
- Dorsal motor nucleus of vagus of nucleus ambiguous
Where do the pre gang sympathetics synapse?
lateral horn of gray matter
Common NT of enteric system
ACh
Where do incoming signals to ANS get interpreted?
Nucleus of solitary tract
Horner’s Syndrome
- caused by lesion anywhere from hypothalamic to ciliary nerve on ipsilateral side
- ptsosis and meiosis
- if lesion was central (brainstem or spinal cord), would get loss of sympathetic function over entire ipsilateral side of body
Bladder fullness vs. “very fullness”
- fullness: detected in body –> spinothalamic tract
- very fullness: detected in trigone –> posterior columns
Where is voluntary control of bladder emptying begun?
- medial side of superior frontal gyrus
- before it develops (3yo), pontine micturition central reflexively empties
GVA
part of ANS only from core, not periphery
GVE vs GSE
GVE is ANS motor system, has 2 neurons vs. GSE which has 1
Sympathetic/parasymp effect on coronary arteries
parasymp dilates, symp dilates (beta) and constricts (alpha)
