Nervous System Flashcards
somatic motor division
provides conscious and subconscious control over skeletal muscles
autonomic motor division
controls visceral functions largely outside of our awareness
motor cortical homunculus
map of brain areas dedicated to motor processing for different anatomical divisions of the body
upper motor neurons
originate in the cerebral cortex and travel down to the brainstem, basal ganglia, and cerebellum
lower motor neurons
anterior grey horn cells that begin in the spinal cord and innervates muscles and glands
monosynaptic reflex
sensory neuron synapses directly with motor neuron
fast response
polysynaptic reflex
at least one interneuron between sensory neuron and motor neuron
slower response
cutaneous sense
general sense
skin
touch, temperature, pain
deep sense
general sense
muscle, tendons, joints
pain, pressure, movement, proprioception
visceral sense
general sense
internal organs
homeostasis, respiration
special senses
visual
hearing
equilibrium
smell
taste
mechanoreceptors
touch and pressure
nociceptors
pain and extreme heat/cold
thermoreceptors
temperature changes
chemoreceptors
change in chemical composition
photoreceptors
rods and cone in retina
proprioceptors
position of body in space at a given time
myelinated (L) A fibers
alpha and beta
impulses from mechanical stimuli
myelinated (S) A fibers
delta
impulses from cold receptors, nociceptors, and mechanoreceptors
unmyelinated (S) C fibers
pain, temperature, mechanoreceptors
somatotopic organization
fibers from different sections of the spinal cord are somatotopically organized in the dorsal column
sacral cord fibers
medially positioned
neurons from the foot
cervical fibers
laterally positioned
neurons from the fingers
chronic inflammatory demeylination
inflammatory demyelinating lesions (plaques) in the white matter of the CNS
multiple sclerosis (MS)
autoimmune disease affecting the brain, spinal cord, and optic nerves
targets oligodendrocytes that myelinate the cells of the CNS
fracture dislocation
loose bone stuck in dislocated bones
burst fracture
vertebral body compression
ruptured disc
protruding disc can pinch spinal nerves
ligamentous injuries
ligaments not aligned
spinal cord lacerations
tear within the spinal cord
autonomic nervous system
responsible for homeostasis
regulates body temp, fluid and electrolyte balance, and blood pressure
sympathetic division
prevails during stress
parasympathetic division
prevails during rest
direct antagonists and agonists
bind target receptor to block/mimic neurotransmitter action
indirect antagonists and agonists
alter secretion, reuptake and degradation of neurotransmitters
intracranial pressure (ICP)
pressure in the skull results in pressure gradients between compartments and a shift of brain structures
Cushing’s triad
bradycardia
shallow breathing
hypertension
due to decreased cerebral blood flow
intracranial hypertension
sustained intracranial pressure above 15mmHg
stroke
focal neurological deficit due to abnormality in cerebral circulation in the brain, retina, or spinal cord
ischemic stroke
thrombotic occlusion and embolism
neurological dysfunction
hemorrhagic stroke
arterial aneurysm
intracerebral hemorrhage
burst vessel
brain tissue death
swelling and pressure in brain
subarachnoid hemorrhage
bleeding in the subarachnoid space
transient ischemic attack (TIA)
temporary neurological dysfunction caused by ischemia without acute infarction
pain
unpleasant sensory and emotional experience
nociception
unconscious activity induced by harmful stimulus applied to a sense receptor
thinly myelinated A delta fibers
fast pain
sharp, localized sensation
terminate on L1 and L5
release glutamate
unmyelinated C fibers
slow pain
dull, intense and unpleasant
terminate on L1 and L3
release substance P
cold menthol-sensitive receptor 1 (CMR1)
respond to cold
vanilloid receptors (VR1 and VRL1)
respond to heat
acute pain
physiological sudden onset
recedes during healing
important protective mechanism
chronic pain
pathologic neuropathic pain caused by chronic progressive nerve disease
nerve injury, toxin induced nerve damage, ischemia
hyperalgesia and allodynia
hyperalgesia
exaggerated response to noxious stimuli
increases sensitivity of nociceptive afferent fibers
allodynia
pain sensation in response to innocuous stimulus
increases sensitivity of nociceptive afferent fibers
deep pain
experienced in deep, non-superficial structures
slow due to alpha delta fiber deficiency
poorly localized
joints and ligaments
reflex contraction could lead to ischemia which stimulates pain receptors to initiate spasms
visceral pain
poorly localized and unpleasant
radiates and is referred to other areas due to sparse nociceptors
severe pain
referred pain/dermatomal rule
referred to a structure that developed from the same embryonic segment or dermatome as the structure where the pain originates
convergence-projection theory
pain that is referred when somatic and visceral pain converge onto the same second-order neuron in the dorsal horn and project to the thalamus and further to the somatosensory cortex
phantom pain
associated with the removal of a limb or absence of a body part
cortical region of the neighboring digit takes the place of the amputated digit (cortical plasticity)
