Organization and Function of the Nervous System Flashcards
The nervous system is made up of
three subsystems
○ Central Nervous System (CNS)
○ Peripheral Nervous System (PNS)
○ Autonomic Nervous System (ANS)
The CNS consists of the brain and the spinal
cord, which are both surrounded by the
____ and float in _____
meninges; cerebrospinal fluid
The PNS includes
○ Cranial Nerves
○ Spinal Nerve Roots and branches
○ Peripheral Nerves
○ Neuromuscular Junction
In the mid-sagittal plane, the dura
creates the _____ and then forms the _____, which divides the hemispheres
superior sagittal sinus; Falx Cerebri
Between the cerebrum and the cerebellum, the dura creates the _____ and then forms the _____, dividing the cerebellum from cerebrum
transverse sinuses; Tentorium Cerebelli
Other than neurons, neural cells are called
____, and are supporting in nature
glial cells
A type of glial cell is the _____, which have long arm projections and wrap the axons of CNS neurons in layers, which we call the Myelin Sheath
Oligodendrocyte
There are many types of _____ in the brain, all of which have different supporting roles, including structure support or creating transport of nutrients from capillaries
to the neuron
Astrocytes
____ are simple cuboidal epithelium that lines the ventricular system and help create CSF and the BBB
Ependymal cells
____ are the cell type that creates the myelin sheath in the peripheral nervous system
Schwann Cells
Several (4) different segments of the brain
○ Brainstem: Medulla Oblongata, Pons, Midbrain
○ Cerebellum
○ Diencephalon: The Core- Thalamus & hypothalamus
○ Telencephalon: The cerebral hemispheres / lobes
The Telencephalon, more commonly called the Cerebrum, is divided into four main lobes:
○ Frontal Lobe
○ Parietal Lobe
○ Temporal Lobe
○ Occipital Lobe
What the Fronal lobe is responsible for
reward, attention, planning, motivation, inhibition, etc. Also the home of the motor cortex (most posterior part of the frontal lobe).
Function of the parietal lobe
This lobe integrates a large amount of sensory information from various modalities, including spatial sense, navigation (proprioception), and the sensation of touch (in the somatosensory cortex)
“recieving and experiencing”
Function of the occipital lobe
Being the smallest of the four lobes, this lobe is mainly responsible for the processing of visual sensory information. It includes primary visual cortex, as well as deeper visual integration areas
What is the smallest lobe of the brain
Occipital
Temporal lobe funciton
This complex lobe has many important known functions, including the processing of sensory input into derived meanings, retention of information (memories), facial
recognition, emotional association,
language comprehension, etc.
Two main areas involved with speech and
language capabilities
○ Broca’s Area
○ Wernicke’s Area (temporal lobe)
Broca’s and Wernicke’s area are interconnected and integrated with a major highway of axons called the ____
Arcuate Fasciculus
T/F These two areas, Broca’s and Wernicke’s, are bilateral structures
F - they are not bilateral (commonly located in the dominant hemisphere)
Where is broca’s area located?
posterior lateral region of the dominant frontal lobe
Broca’s vs. Wernicke’s area function
Broca’s - language production
Wernicke’s - language comprehension
Damage to this area results in “expressive
aphasia,” or difficulty forming speech
Broca’s area
Damage to this area results in “receptive aphasia,” or difficulty understanding speech or written language.
Wernicke’s area
This area does not initiate movement, but
helps to coordinate movements, adjusting motor impulses coming from the cerebrum to facilitate precision and accurate timing
Cerebellum
Damage here produces Ataxia.
Cerebellum
CSF is actually formed by ependymal cells that line the ventricles, a structure called the
_____.
Choroid Plexus
Gray Matter vs White matter
○ Gray Matter consists of aggregations of
neuronal cell bodies, such as the outer
layer of the cerebral cortex.
○ White Matter consists of neuronal axons
that are coated with myelin sheath
Deep gray matter structures
Basal ganglia
Thalamus
Hypothalamus
_______- Multiple structures that are involved in the management of motor function and other higher level brain function
Basal Ganglia
_____- Processes incoming sensory
information and relays to cortex.
Thalamus
As sensory information is coming in from the periphery, this structure relays it to where it needs to go
_____- Maintains physiologic homeostasis and plays a major role in endocrine function and the pituitary
Hypothalamus
The ______ is a major highway of axons that connects one hemisphere to the other, which is an important interaction necessary for consciousness and awareness.
Corpus Callosum
The _____ is a white matter highway of entering and exiting axons
Internal Capsule
Deep white matter structures:
Corpus callosum
Internal Capsule
The ______ is most commonly involved in strokes.
Middle Cerebral Artery (MCA)
Trace the pass for venous blood return through the sinuses
Slide 31
_____ of the twelve cranial nerves exit
from one of these brainstem three structures
Ten
CN I
The Olfactory Nerve
○ Responsible for the sense of
smell and receives sensory
information through the
cribriform plate inferior to the
frontal lobes
CN II
The Optic Nerve-
○ Responsible for vision by transporting sensory information from the retina to the optic chiasm, where it becomes the optic tracts, then the optic radiations, and then into the occipital lobes.
CN III
The Oculomotor Nerve-
○ Responsible for pupillary constriction, eyelid elevation (opening the eye), and most extraocular movements (all but out and down-and-in).
CN IV
The Trochlear Nerve-
○ Responsible for downward and internal rotation of the eye due to innervation of the Superior Oblique Muscle.
CN V
The Trigeminal Nerve-
○ Motor function- Muscles of Mastication- Temporalis and Masseter muscles (jaw clenching) and Lateral Pterygoids (lateral jaw movements).
○ Sensory function- Facial sensation in three divisions- Ophthalmic (V1), Maxillary (V2), and Mandibular (V3)
CN VI
The Abducens Nerve-
○ Lateral deviation (abduction) of the eyeball via Lateral Rectus.
CN VII
The Facial Nerve-
○ Motor function- Muscles of Facial Movements- Including those for facial
expression, closing the eyes, and closing the mouth.
○ Sensory Function- Taste on the anterior ⅔ of the tongue
CN VIII
The Acoustic or Vestibulocochlear Nerve-
○ Responsible for hearing (cochlear division) and balance (vestibular)
CN IX
The Glossopharyngeal Nerve-
○ Motor function- Muscles of the pharynx involved with swallowing.
○ Sensory function- Eardrum, ear canal, the pharynx, and taste from the posterior ⅓
of the tongue
CN X
The Vagus Nerve-
○ Motor function of the palate, pharynx, and larynx. Sensory function of the pharynx
and larynx. Major parasympathetic functions
CN XI
The Accessory Nerve-
○ Responsible for motor innervation of sternocleidomastoid and trapezius
CN XII
The Hypoglossal Nerve-
○ Responsible for motor function of the tongue.
The spinal cord ends at about the level of the ___ or ___vertebrae (the Conus Medullaris)
L1 or L2
Below the conus medullaris, the lower lumbar and sacral spinal nerves extend down through the CSF of the thecal sac, forming the _____
Cauda Equina
To minimize the possibility of injury to neural
tissue, lumbar punctures are generally performed at the level of _____
L3-4 or L4-5.
The neuron cell bodies located in the posterior or dorsal gray horns are ____ neurons that have axons that extend superiorly
sensory
The neuron cell bodies in the anterior or ventral horns are _____ neurons that innervate muscle groups.
lower motor
T/F Most peripheral nerves that extend out of the vertebral column contain both sensory and motor fibers, which join together outside of the spinal cord.
T
Spinal segments that correlate with large muscles groups are often capable of
the _____, which occurs solely in the spinal cord when a muscle is rapidly and suddenly stretched.
Reflex arch
Voluntary movement is _____ in the _____ of the frontal lobe contralateral to the muscles to be moved (neuron fires).
initiated; Premotor Cortex
The Premotor Cortex neuron synapses
on neurons in the corresponding
______
Primary Motor Cortex
The _____ Motor Cortex often call the SMA, helps to coordinate and facilitate appropriate Primary Motor Neuron excitation
Supplementary
Body parts that require finer motor control have _____ regions of dedicated cortex
larger
Voluntary movement from the cortex is adjusted and fine-tuned by the ____ and cerebellar systems as it moves through the brain and spinal cord.
basal ganglia
Voluntary movements are communicated
via the _____Tract.
Corticospinal (Pyramidal)
In the lower portion of the medulla, almost
all of the fibers _____
decussate to the contralateral side
motor neurons will eventually synapse on a
Lower Motor Neuron in the _____ of
the gray matter
ventral horn
Motor neuron tracts that come from the
cortex and synapse on the motor nuclei of
cranial nerves are called the _____
Corticobulbar Tract
The axon moves through the ____ Root before joining _____ Root (sensory) to form
the Spinal Nerve Root.
Ventral; Dorsal
The Neuromuscular Junction (NMJ) is an important anatomic and physiologic
structure where the _____ synapse on
the membrane of muscle cells.
LMNs
The olfactory (smell) cortex (and auditory cortex) is located in the superior medial portion of the _____, most commonly adjacent to the gustatory (taste) cortex
temporal lobe
Tactile (touch) sensation is processed in
the _____
somatosensory cortex
How is Pain, temperature, and crude touch information processed differently?
This sensory information decussates immediately once it enters the spinal cord and travels through the Spinothalamic
Tract through the cord and brainstem, straight to the Thalamus where it is
processed and relayed to the cortex.
Position, vibration, and fine touch pathways
This sensory information does not decussate
immediately, but instead the primary sensory neuron extends all the way to the ipsilateral lower medulla through the Posterior (Dorsal) Column.
A Dermatome is the band of skin that is innervated by the _____
sensory fibers of a single spinal nerve root.
____ are the muscle groups innervated by motor fibers of a single spinal nerve root and follow a similar distribution as dermatomes
Myotomes
