Chapter 13: Spinal Reflexes Flashcards
functions of white matter tracts & gray matter tracts
white matter tracts are highways for nerve impulse conduction to and from the brain
gray matter nuclei recieve and integrate incoming and outgoing info
reflex arc
the interrelationship btwn an afferent and an efferent neuron that occurs in the brain and spinal cord
5 functional components of a reflex arc
- sensory receptor
- sensory neuron
- interneuron or association neuron in the integrating center
- motor neuron
- effector
sensory receptors conducts impulse from _______ to ______
axon conducts impulses from receptor to integrating center
interneuron or association neuron in the integrating center conducts impulses from ______ to ______
relays impulses from sensory to motor neuron
motor neuron conducts impulse from ______ to ______
axon conducts impulses from integrating center to effector
effector responds to
motor nerve impulses
- any muscle or gland
reflex
rapid, predictable, automatic response to external changes to help maintain homeostasis
monosynaptic reflex arc
simplest reflex arc
- contains 1 sensory neuron
- 1 motor neuron
- 1 synapse
stretch or extensor reflex is imortant for
maintaining muscle tone and muscle coordination during exercise
patellar reflex is an example of _______ that controls _________ by causing __________
extensor reflex that controls muscle length by causing muscle contraction
reflex arc for patellar reflex
stimulant
sensory receptors
spindles
sensory neuron
integrating center
motor neuron
effectors
response
stimulant: neurological hammer
sensory receptors: muscle
spindles/proprioceptors: respond to stress
sensory neuron: enters posterior root and goes through horn
integrating center: gray matter of horn
motor neuron: impulse along anterior root
effectors: thigh entensor muscles (quad)
response: extends knee (hammies)
4 branches (rami) or spinal nerves
meningeal ramus, posterior ramus, anterior ramus, rami communicantes
meningeal ramus
- smallest
- reenters through IVF
- innervates: bertebral, meninges, blood vessels
posterior ramus
motor and sensory fibers
- innervates skin and posterior muscles of trunk
anterior ramus
- largest
- motor and sensory fibers
- innervates to extremities + lateral anterior trunk
nerve plexus
networks (interbranching) of anterior rami from several adjacent spinal nerves
- move directly to body areas
- peripheral nerves arise from plexi and then travel to body regions
intercostal/thoracic nerves
locate
innervations
anterior rami of spinal nerves T2-T12
- dont enter into formation of plexuses
- innervate at the intercostal muscles, skin of trunk, ab muscles
cervical plexus
location
innervations
nerve
injury
anterior rami of C1-C4
- innervates: muscles/skin of neck + posterior scalp
- phrenic nerve: carries fibers from C3, C4, C5
- Spinal injusry above C3=paralysis of diaphram
brachial plexus
ocation
innervations
injury (6)
anterior rami of C5-T1
- innervate: skin, muscles of arms, upper back, shoulder, chest
- injury to brachial plex=Erm Duchenne palsy (waiters tip), Klumpkes palsy, wrist drop, carpal tunnel, claw hand, winged scalpula
lumbar plexus
location
innervations
nerves (2) injury
anterior rami of L1-L4
- innervates low. ab wall, external genetalia
- largest nerves=femoral, obturator
- injury to femoral nerve=inability to extend leg, loss of sensation in skin over front thigh
injury to the sciatic nerve results in?
sciatic pain, burning, numbness, tingling, loss of sensation, muscle weakness that extends from butt down the post/ant leg
- occurs due to: herniated disc, dislocated hip, osteoarthritis, lumbosacral spin, pressure from gravid uterus
coccygeal plexus
location
innervations
nerve
anterior rami of S2-S4
- innervates at genetalia and butt
- pudendal nerve comes off coccygeal plexus
what is the skin over the entire body supplied by?
spinal nerves that carry somatic sensory nerves into the spinal cord
all spinal cords except _____ innervate specific, constant segments of the skin called ______
C1, dermatomes
how does knowledge of dermatones help doctor?
they can determine which segments of the spinal cord or which spinal nerve is malfuctioning
