Block 5 Flashcards
__ fibers convey information towards the CNS
sensory
__ fibers convey information from the CNS
motor
Sensory and motor function are __ in the nervous system
separated
afferent fibers are __
sensory
efferent fibers are __
motor
axes of orientation; spatial reasoning to determine structure position; used in both brain and body
system orientation
towards the tip of the head
rostral
towards the tip of the tail
caudal
upper surface of the body
dorsal
bottom surface of the body
ventral
close to the midline
medial
farther from the midline
lateral
close
proximal
far
distal
in humans, __ is used in place of rostral
anterior
in humans, __ is used in place of caudal
posterior
How many pairs of nerves branch off from the spinal cord?
31
each nerve is split into __ and __ roots
dorsal, ventral
dorsal roots are ___
sensory
ventral roots are __
motor
DRG: cell bodies for all __ neurons entering the spinal cord
sensory
DRG cell bodies lie ___ the CNS and __ the PNS
outside, inside
each sensory and motor spinal nerve receives information from and projects information to specific body regions called ___
dermatomes
long nerves from the spinal cord that dangle down and branch off to the legs
cauda equina
epidural anesthetic is injected between __
L2 and L3
bundle of myelinated axons running up and down the spinal cord; opaque to light
white matter
unmyelinated structures in the spinal cord; translucent to light
gray matter
white matter in the CNS is called __, __, or __
tract, fasciculus, pathway
white matter in the spinal cord consists of __ and __
sensory afferent fibers and motor efferent fibers
gray matter is a collection of __ in the spinal cord
cell bodies
occupies the central region of the spinal cord, therefore is called __; 4 lobed structure home to spinal sensory and motor function
Central Gray Region
first cell in the sensory system is the ___
first order neuron
the soma of all first order neurons lie __ the CNS __ the PNS in the DRG
outside, inside
all first order neurons synapse onto a ___ in the CNS for somatosensory systems
second order neuron
nerve fibers often ___ to innervate structures on the other side of the body
cross midline
the left brain controls the __ side of the body due to __
right; decussation
when a projection crosses midline of the spinal cord
contralateral
when a projection stays on the same side of the spinal cord
ipsilateral
slow conducting fibers in the somatosensory system
nociceptors
nociceptors are activated by __ stimuli
noxious
What are noxious stimuli?
cause tissue damage
large, quick fibers in the somatosensory system
mechanoreceptors
origin for motor commands lies in the __ cortex
cerebral
final common path for motor commands is the ____ of the spinal cord
ventral horn
___ neurons project axons to contact lower motor neurons in the ventral horn of the spinal cord
upper motor neurons
___ neurons send axons that exit the CNS and innervate the skeletal muscles
lower motor neurons
lower motor neuron cell bodies lie in the ___ of the ventral horn of the spinal cord
gray matter
lower motor neuron axons exit the cord via the __ and synapse on __
ventral roots, skeletal muscle
lower motor neuron synapses exclusively use what neurotransmitter?
acetylcholine
lower motor neuron synapses are __ in nature
excitatory
upper motor neurons send two fiber bundles down either side of the spinal cord: __ and __ tracts; which activate ___ neurons
pyramidal and extrapyramidal; lower motor neurons
upper motor neurons lie in the __ of the brain
motor cortex
largest neurons in the mammalian brain
pyramidal cells
axons that leave upper motor neurons and cross the midline at the Decussation of the Pyramids (contralateral)
pyramidal tracts
pyramidal tracts descend in white matter and insert into __ of spinal cord and innervate ___ neurons
ventral horn, lower motor neurons
the __ system coordinates and gives precision to the pyramidal system
extrapyramidal
extrapyramidal neurons primarily come from ___ (basal ganglia) and ___ (celebellar) nuclei
sub-cortical, brainstem
extrapyramidal system interacts with __ neurons in the motor cortex and with ___ neurons in the spinal cord
pyramidal, lower motor
spinal cord has the capacity to integrate __ imput into appropriate __ output
afferent, motor
___ muscle fibers (bulk of muscle) do the majority of the work
extrafusal
__ muscle fibers contain a stretch receptor
intrafusal
when only one synapse is involved in a reflex, it is called a ___ reflex
monosynaptic
any stretch of a muscle is thus countered with a __ of that same muscle
contraction
muscles exist in antagonistic pairs of __ and __
flexors, extensors
forebrain has two cerebral hemispheres
subcortical and cortical
an extension of the brainstem (subcortical)
thalamus
ventral to the thalamus (subcortical)
hypothalamus
lateral to the thalamus (subcortical)
basal ganglia
olfactory bulbs and cortex, cingulate gyrus, hippocampus, and amygdala
limbic lobes
cortical includes the __, __, __, and __ lobes
frontal, parietal, temporal, occipital
includes medulla, pons, reticular formation, and cerebellum
brainstem
3 groups of cells that project to the forebrain (one term)
reticular formation
straddle midsagittal line in the brainstem; #1 source of serotonin in the brain and spinal cord; project rostrally and caudally
raphe nuclei
small nucleus on each side of dorsal brainstem; #1 source of norepinephrine in the brain; projects to cortical and subcortical regions
locus coeruleus
ventral brainstem; major source of dopamine for the brain; projects to basal ganglia (extrapyramidal motor behavior) and limbic medial forebrain (reward)
substantia nigra
contain neurons that make up the extrapyramidal motor system; part of the basal ganglia (striatum)
caudate nucleus, putamen, globus pallidus
sheet of white matter; pyramidal projection tract directly through the basal ganglia
internal capsule
midline cluster of nuclei on ventral surface of forebrain and a hanging gland
hypothalamus and pituatiary gland
hypothalamus: imput from __ and __ structures
limbic, brainstem
hypothalamus: output from the ___ via the pituitary stalk
pituitary gland
in the ___ gland, axon terminals from neurons in hypothalamus release peptides into the blood
posterior pituitary gland
in the __ gland, peptides are released into the blood and are controlled by neurons in the hypothalamus
anterior pituitary gland
___ nuclei relay visual information
lateral geniculate
__ nuclei relay auditory information
medial geniculate
___ nuclei relay somatosensory information
ventral-posterior lateral and medial
all cortex rostral to central sulcus
frontal lobe
immediately rostral to the central sulcus; primary motor cortex (not a lobe)
precentral gyrus
lobe caudal to the central sulcus
parietal lobe
immediately caudal to the central sulcus; primary somatosensory cortex
postcentral gyrus
caudal tip of the skull; primary visual cortex
occipital lobe
separated by lateral sulcus; primary auditory cortex
temporal lobe