Intro to the neuroanatomy of the CNS and PNS / Overview of Pathways Flashcards
what nervous system is the cranial and spinal nerves part of?
peripheral
what nervous system is the brain and spinal cord part of?
central
what is the functional unit of the nervous system?
the neuron
where do neutrons communicate with one another at?
synapses
where does input occur at when neurons are communicating with one another?
dendrites
where does output occur at when neutrons are communicating with one another?
axon and axon terminal
what are collections of neutrons with similar structures and function called within the CNS?
nucleus
what are collections of neutrons with similar structures and functions called outside the CNS, part of the PNS?
ganglion
what are many axons covered in?
myelin
what forms myelin in the CNS?
oligodendrocytes
what forms myelin in the PNS?
Schwann cells
what is the function of myelin?
provides insulation allowing the electrical signal generated in the cell body to rapidly reach the axon terminal
what matter contains myelinated axons?
white matter
what matter contains less myelin?
gray matter
what is another term for sensory neurons?
afferents
what is another term for motor neurons?
efferents
what is the function of sensory (afferent) neurons?
to carry nerve impulses toward the CNS
what is the function of motor (efferent) neurons?
to carry nerve impulses away from the CNS
What is the function of central interneurons?
to carry nerve impulses from one part of the CNS to another
what are the somatic divisions of the PNS?
Sensory:
general somatic afferents (GSA)
special somatic afferents (SSA)
motor:
general somatic efferents (GSE)
what is the general somatic afferents division?
pain, temp, touch, muscle & joint position (proprioception)
what is the special somatic afferents division?
vision, hearing, smell, balance
where are the special somatic afferents only found?
cranial nerves I, II, VII
what is the general somatic efferent division?
innervation of skeletal muscle
what are the visceral divisions of the PNS?
Sensory:
general visceral afferent (GVA)
special visceral afferent (SVA)
Motor:
general visceral efferent (GVE)
special visceral efferent (SVE)
what is the general visceral afferent division?
pain and reflex sensations from internal organs, glands, and blood vessels
what is the special visceral afferent division?
taste
what is the general visceral efferent division?
innervation of smooth muscle (e.g gut, arteries) and glands = autonomic nervous system (sympathetic and parasympathetic subdivisions)
what is the special visceral efferent division?
innervation of skeletal muscles derived from pharyngeal arches
what are the names for convolutions on the cerebrum?
gyro and sulci
what are the names for convolutions on the cerebellum?
folia and fissures
what makes the diencephalon?
thalamus and hypothalamus
what separates the left and right hemispheres of the brain?
medial longitudinal fissure
what white matter connects the right and left hemispheres of the brain?
corpus Collosum
how many lobes is the cerebrum divided into?
6
what are the 4 classical lobes?
frontal, temporal, partial, occipital
what are the other two lobes that are named functionally?
limbic and insula
what separates the frontal and parietal lobes?
central sulcus (of Rolando)
what separates the frontal/parietal lobes from the temporal lobe?
lateral sulcus (sylvan fissure)
what separates the parietal and occipital lobes from the medial surface?
parieto-occipitaq sulcus
from what aspect can you see the limbic lobe?
from the medial surface
what structure covers the insula?
the opercula
what does the opercula consist of?
long and short gyri
what is the frontal lobe responsible for?
voluntary movement
attention
short term memory tasks
motivation
planning
speech
what is the temporal lobe responsible for?
auditory processing
further visual processing
what is the parietal lobe responsible for?
integrates sensory stimuli
language
what is the occipital lobe responsible for?
center for visual processing
what is the limbic lobe responsible for?
modulation of emotions
learning memory
visceral functions
what is the insular lobe responsible for?
taste
visceral sensation
vestibular function
what are the two sources of blood supply to the brain?
internal carotid arteries
vertebral arteries
what to the pair of vertebral arteries join together to form?
basilar artery
what is the basilar artery adjacent (inferior) to?
the pons
where does the basilar artery terminate?
the base of the circle of willis
what do the pontine arteries supply blood to?
the pons
what 3 arteries come off the basilar and vertebral arteries and supply the cerebellum?
posterior inferior cerebellar artery (PICA)
anterior inferior cerebellar arteries (AICA)
superior ceerebellar arteries (SCA)
what does the cervical spinal cord give rise to?
31pairs of spinal nerves
why are the cervical and lumbar regions of the spinal cord enlarged?
because they contain the many neurons and fibres associated with the limbs
where does the spinal cord end?
around the L1/L2
what is the area around L1/L2 called?
conus medullaris
what is the collection of roots/rootlets below the L3 level called?
cauda equina
is the grey matter in the middle or outside in a cross section of the spinal cord?
grey matter on the inside surrounded by white matter
what is white matter in the spinal cord divided into?
columns (posterior, lateral, anterior)
what is gray matter in the spinal cord divided into?
horns (posterior, lateral, anterior)
what is the posterior horn important for?
processing somatic sensory information (GSA)
what is the anterior horn involved with?
somatic motor pathway (GSE)
what is the lateral horn involved with?
sympathetic portion of the autonomic nervous system (GVE)
where can the lateral horns be found?
T1-L1/L2 regions
what forms a spinal nerve?
anterior and posterior roots
what are discriminative (fine touch)mechanoreceptors?
Meissner and Pacinian corpuscles Ruffini organs
Merkel disks
what are dorsal root ganglia (DRG)?
collections of neurons associated with each posterior spinal cord root
how many neurons are present in dorsal root ganglia at the level of C5 and C7?
C5= 60,000
C7=100,000
What are the structures of the neurons of the dorsal root ganglia?
pseudounipolar
where do dorsal root ganglia project into the spinal cord?
via the dorsal roots
where does the dorsal root ganglia travel to if it goes to the white matter?
travel up to the spinal cord
where does the dorsal root ganglia travel to if it goes to the gray matter?
posterior horn
what pathway does discriminative touch and conscious proprioception take within the CNS?
posterior column/medial lemniscus pathway
what pathway does pain, temp, crude touch take in the CNS?
spinothalamic pathway
what pathway does unconscious proprioception take within the CNS?
spinocerebellar pathways
what is the starting point for the posterior column/medial lemniscus pathway?
touch mechanoreceptors and proprioceptors in skin, muscles, and joints
where are the somata (cell bodies) of the primary sensory neurons located?
dorsal root ganglia
where do axons from the primary neurons join white matter?
posterior funiculus of the spinal cord
when both the fasciculus gracilis and fasciculus caneatus are present, which is medial?
the FG is medial relative to the FC
where is the fasciculus gracilis evident?
at every level of the spinal cord
where is the fasciculus cuneatus evident?
T6 and above (first evident at C8
where do axons in the FG and FC ascend?
ascend to the medalla
where do axons in the FG and FC terminate?
second order neurons located in the nucleus gracilis and nucleus cuneatus respectively
where do axons from the second order neurons enter after crossing?
medial lemniscus on the opposite side
where do axons in the medial lemniscus ascend?
all the way through the brainstem until reaching the thalamus and synapsing on neurons in th eventual posterolateral nucleus
what is the starting point for the spinothalamic pathway?
free nerve endings- pain, temp, and crude touch
where are primary sensory neurons located in the spinothalamic pathway?
dorsal root ganglia
where do axons from the primary sensory neurons project to for the spinothalamic pathway?
Lissauers Tract (posterolateral)
what three divisions of the trigeminal nerve carry sensory information from the face and head to pseudo-unipolar herons in the trigeminal ganglia?
opthalamic nerve (V1)
maxillary nerve (V2)
mandibular nerve (V3)
at what level do fibres project from the trigeminal ganglia and enter the brainstem?
the pons level
what are the 2 different nuclei in the brainstem?
chief sensory nucleus of CN V
spinal nucleus of CN V
which brainstem nuclei is for pain and temp?
spinal nucleus
which brainstem nuclei is for discriminative touch and proprioception?
chief sensory nucleus
what is the primary somatosensory cortex organized into?
somatic fashion creating a homunculus of body regions
what is the function of the olfactory nerve?
smell
what is the function of the optic nerve?
vision
what is the function of the facial nerve?
taste
what is the function of the vestibulocochlear nerve?
hearing and balance
what is the function of the glossopharyngeal nerve?
pharynx sensation
taste
what is the function of the vagus nerve?
taste
where does the olfactory nerves carry signals to from the nasal mucosa?
olfactory bulb
what forms the olfactory tract?
axons from neurons in the olfactory bulb
where do axons from the olfactory bulb project?
directly to the primary olfactory cortex within the piriform area of the limbic lobe
where are the optic nerves carry from and to?
from the retina to the lateral geniculate nucleus of the thalamus
how are the signals carried by the optic nerve?
via the optic tract
what forms the optic radiation?
axons from the lateral geniculate nucleus
where is the primary visual cortex located in the brain?
calcimine sulcus in the occipital lobe
where is auditory (hearing) information carried from?
the cochlea
how is auditory information carried?
by cochlear nerves
where is auditory information carried to?
cochlear nuclei (medulla)
where are neurons in the cochlear nuclei projected too?
inferior colliculus (midbrain)
where do axons from from neurons in the inferior colliculus project to?
medial geniculate nucleus (MGN) of the thalamus
where is the primary auditory cortex?
a region of the superior temporal gyrus
where is vestibular (balance) information carried from?
the vestibular apparatus (e.g semicircular canals) by the vestibular nerves
where do neurons in the vestibular nuclei project too?
numerous targets including various thalamic nuclei
what are the primary vestibular areas?
insula and temporo-parietal region
where is gustatory (tastes) information carried from?
anterior 2/3 of the tongue by the facial nerve
posterior 1/3 of the tongue by the glossopharyngeal nerve
epiglottis by the vagus nerve
where is gustatory information carried to?
solitary nucleus (medulla)
where do neurons in the solitary nucleus project to?
thalamic (VPM nucleus) which in turn project to the primary gustatory cortex
where is the primary gustatory cortex located?
insula and frontal opercula
