Peripheral nervous system Flashcards
What is the mnemonic of names of the cranial nerves
Oh, oh, oh to touch and feel a girl’s very soft hands
What is the mnemonic of the type of sensory, motor, or both
Some say money matters, but my brother says big brains matter more
What are the 3 levels of neural integration in sensory systems
Receptor level
Circuit level
Perceptual level
What is the gate control theory
non-painful inputs (aB) inhibit pain transmission fibers
How do we control descending pain
release endogenous opioids, endorphins
Which System does NOT have nerve regeneration
CNS
What are the steps of nerve regeneration in PNS
- Axon becomes injured
- Macrophages clean out dead axon
- Axon sprouts regenerated by schwann cells
- Axon regenerates & a new myelin sheath forms
What is the region of skin innervated by spinal cord
dermatome
What law follows the same innervation of muscles in the joints
Hilton’s law
What keeps the diaphragm alive? what type and what nerve?
C3, C4, C5, keeps the diaphragm alive
Phrenic nerve, cervical plexus
What is the mnemonic for brachial plexus
Rugby Teams Drink Cold Bears
In Lumbar plexus, which nerve innervates adductor muscles?
Which nerve innervates anterior thigh muscles & skin of anterior/medial thigh & medial leg
- obturator nerve
- fermoral nerve
In sacral plexus, which nerve is in the skin/muscles of perineum?
Which nerve innervates hamstrings, adductor magnus?
- pudendal nerve
- Sciatic nerve
What functions do rami’s have
Sensory + motor
What are the intrafusal fibers in muscle spindles? What do they lack?
What are extrafusal fibers?
Non-contractile central regions
- Lack myofilaments
Contractile outer regions
What type of endings are in instrafusal fibres wrapped around? afferent/efferent
What are the 2 things they are wrapped around?
What do they innervate? What are they stimulated by?
Afferent endings
Primary sensory endings
- innervate spindle centre
- stimulated by rate & degree of stretch
Secondary sensory endings
- innvervate spindle ends
- stimulated by degree of stretch
What are contractile end regions of muscle spindles innervated by
- internal stretch
Gamma efferent fibers
What are extrafusal fibers innervated by?
- external stretch
Alpha efferent fibers
What types of fibers does stretch cause an increase of?
Rate of primary sensory fibers
Which motor neurons would affect muscle sensitivity?
Gamma motor neurons
Which motor neurons maintains tension & sensitivity during muscle contraction
alpha-gamma coactivation
Differentiate between inborn and learned reflexes
Inborn
- rapid, involuntary
Learned
- result from practice or repetition
What does tonically active mean
generate AP w/o additional stimuli
What are the characteristics of stretch reflexes
Monosynaptic
ipsilateral
Define reciprocal inhibition in stretch reflexes
Ex. patellar ligament is hit
- Afferent impulses travel to spinal and synapses with ALPHA motor and interneurons
- Alpha motor neurons activates quadriceps femoris to extend knee
- Interneurons make inhibitory synapses that prevent contraction of antagonist (hamstring)
What occurs in golgi tendon reflexes
What are the characteristics
reciprocal activation
- produce muscle relaxation and antagonist contracts
Polysynaptic
What are the characteristics of flexor reflexes
Polysynaptic
Ipsilateral
What do superficial reflexes depend on?
What type of reflex? monosynaptic/polysynaptic
Polysynaptic reflexes
Depend on upper motor pathways & cord-level reflex arcs
In stretch and golgi tendon reflexes, what do muscle spindles inform nervous system of?
Length of muscle
In stretch and golgi tendon reflexes, what do golgi tendon organs inform brain of?
Amount of tension in muscle and tendons
Which type of stimulus are deep?
which are superficial?
Superficial
- Meissner’s
- Merkel disc
Deep
-Pacinian corpuscle
- Ruffini endings
Which type of stimulus are fast?
Which are slow?
Fast
- Meissner’s
- Pacinian
Slow
- Ruffini
- Merkel discs
