Which 3 structures make up the brain stem?
Medulla oblongata, pons, midbrain
Which is the most caudal region of the brain?
Brain stem
What are the functions of the brain?
Control heart rate, respiratory rate and blood pressure through ANS
Cranial nerves to innervate the head, neck, thoracic and abdominal viscera
High level tasks in cerebral cortex like thought processing and action
How many of the cranial nerves attach to the brain stem?
Which don't?
10 of the 12 cranial nerves attach to the brain stem
The only 2 that don't are the first 2, the olfactory (smell) and
optic (vision)
What is the integrating center for the auditory and visual reflexes?
The brain stem is the integrating center for the auditory and visual reflexes!
What part of the brain is responsible for the smoothing and
coordination of body movements directed by other brain regions?
The cerebellum is responsible for the smoothing and coordination of
body movements that is produced by other regions of the brain
What structures connect the cerebellum to the brain stem?
For what purpose?
The cerebellar peduncles (3-inferior, superior, middle) connect the
cerebellum to the brain stem - they are fiber tracts that carry
information to and from the cerebellum
Which of the cerebellar peduncles carries efferent information?
Which of the cerebellar peduncles carries afferent and efferent information?
The superior and middle cerebellar peduncles carry efferent
information from the cerebellum to the cerebral cortex 9 efferent
--> To brain
The inferior cerebellar peduncles carry afferent and efferent
information from spinal cord to cerebellum
Which structures divide the two cerebellar hemispheres in half and
what is the name of the ridges and grooves?
The vermis divides the two cerebellar hemispheres
The ridges on the top are called folia and the grooves that go
vertically up and down the cerebral hemispheres are fissures
What are the 3 structures of the diencephalon?
The thalamus, hypothalamus and the epithalamus are the 3 structures
of the diencephalon
What are some of the important functions of the diencephalon?
Control of ANS
Regulation of body temperature, hunger and thirst sensations
Control of endocrine system and emotional response
Formation of memory - the hypothalamus and control of motivational behavior
What is the main function of the cerebrum?
Higher though processing! Since the cerebrum has the cerebral cortex
and the two cerebral hemispheres that are involved in many of the
higher thought processing functions
What structures are found in the gray matter of the brain?
What structures are found in the white matter of the brain?
The gray matter of the brain contains short, nonmyelinated axons and
neuron cell bodies - it is colored gray because the axons are
nonmyelinated - also some brain nuclei in the gray matter
The white matter of the brain contains mostly myelinated axons
which gives it the white color - since myelin has a white shade
Is the cortex of the brain gray or white matter?
The cortex of the brain is composed of gray matter - cerebral cortex
that surrounds the cerebrum and the superficial part of the brain
What are brain nuclei and where are they found in the brain?
Brain nuclei are clusters of neuron cell bodies that are GRAY matter
and are interspersed throughout the white matter of the brain
The brain nuclei, the inner gray matter and the outside cortex are
all gray matter areas of the brain
What kind of cells line the ventricles of the brain?
Ependymal cells! This makes sense since the ventricles of the brain
are filled with cerebrospinal fluid and this is where ependymal cells exist
Which ventricles lie in the cerebral hemispheres?
Lateral ventricles and they have a horseshoe shape
What ventricle lies in the diencephalon?
The third ventricle is in the diencephalon and connects to each of
the lateral ventricles
What is the cerebral aqueduct and where does it lie?
The cerebral aqueduct is located in the midbrain and connects the
third and fourth ventricles together
What ventricle is located in the brain stem? What does it connect to?
The fourth ventricle is located in the brain stem, thus it is filled
with CSF and connects to the spinal cord
Name the structure that connects the third ventricle to the fourth
ventricle, where is this structure located?
The cerebral aqueduct connects the third ventricle to the fourth
ventricle and is located in the midbrain
What are the 3 regions of the brain stem from most caudal to most rostral?
Caudal - Medulla oblongata --> Pons --> Midbrain - Most rostral
What are the 4 general functions of the brain stem?
1) The brain stem acts as a passageway for all tracts between the
cerebrum and spinal cord
2) Brain stem is heavily involved with innervation of face and
neck, 10 of the 12 cranial nerves attach to the brain stem - only
ones that don't are I (olfactory) and II (optic)
3) Brain stem produces rigidly programmed, automatic behavior
necessary for survival
4) Brain stem integrates auditory and visual reflexes
What passes through the medulla oblongata to reach the spinal cord?
The white matter tracts pass through the medulla oblongata to connect
the rostral regions of the brain with the spinal cord
Where do the pyramidal tracts originate and what kind of information
do they carry?
The pyramidal tracts are large fiber tracts that originate from
pyramid shaped neurons in the cerebrum and descend through the brain
stem and spinal cord and carry voluntary motor output to the spinal
cord only!
Pyramidal tracts have only motor neurons!!!!
Decussation of the pyramids
The decussation of the pyramids is the crossing over of the pyramidal
tracts that carry motor output to the spinal cord, the result is the
right cerebral hemisphere controlling the left body and vice versa
The pyramidal tracts are voluntary movement only, so its the
crossing over of voluntary movement from each hemisphere to the other
side of the body
What are relay nuclei in the brain?
Relay nuclei in the brain are processing points for information
before they are relayed onto the next structure, can be found in
medulla oblongata and other places
What do the inferior cerebellar peduncles do?
The inferior cerebellar peduncles are fiber tracts that connect the
medulla oblongata to the cerebellum
- connects brain stem to cerebellum
What pairs of cranial nerves attach to the medulla oblongata?
There are 4 total cranial nerves that attach to the medulla oblongata
Cranial nerve VIII - Vestibulocochlear - hearing
Cranial nerve IX - Glossopharyngeal - swallowing
Cranial nerve X - Vagus - Regulate heart rate
Cranial nerve XII - Hypoglossal - Motor control of tongue
Describe the location of the pons with respect to the rest of the
brain stem. What two regions of the brain does the pons connect?
The pons is located rostrally to the medulla oblongata of the brain
stem, so its anterior to the medulla oblongata
The pons acts as a bridge and connects the brain stem and the
cerebellum together
What do the middle cerebellar peduncles connect?
The middle cerebellar peduncles are fiber tracts that connect the
pons to the cerebellum
What pairs of cranial nerves attach to the pons?
Cranial nerve V - Trigeminal
Cranial nerve VI - Abducens
Cranial nerve VII - Facial
All 3 connect to the pons
Describe the location of the midbrain with respect to the pons and diencephalon
The midbrain is rostral to the pons, but caudal to the diencephalon -
it literally lies in-between the pons (brain stem) and the
diencephalon (thalamus, hypothalamus, epithalamus)
Describe the substantia nigra location and what it is
The substantia nigra is located deep the midbrain - the only brown
region of the brain because of its dark melanin pigment
It is gray matter of the cerebrum and is linked to voluntary movement
Substantia nigra is brain nuclei and is gray matter!
Degeneration of the substantia nigra is linked to parkinsons disease
What is the main function of the corpora quadrigemina?
The main function of the corpora quadrigemina is the integration of
auditory and visual reflexes
Corpora quadrigemina is part of the midbrain
What pairs of cranial nerves attach to the midbrain?
Cranial nerve III - Occulomotor
Cranial nerve IV - Trochlear
Both of these nerves originate in the midbrain
Describe the location of the cerebellum with respect to the other
parts of the brain. What vegetable does it look like in midsaggital
section? What is the major function of the cerebellum?
The cerebellum is immediately inferior to the caudal end of the
cerebrum (the very back and bottom portion of the overall brain), the
cerebellum is immediately superior to the brain stem
In midsaggital section the cerebellum looks like cauliflower
Cerebellum main function is to smooth and coordinate body movements!
Describe each of these structures of the cerebellum:
Cerebellar hemispheres
Vermis
Folia
Fissures
Cerebral Cortex
Arbor Vitae
Deep cerebellar nuclei
Cerebellar hemispheres - 2 of them total
Vermis - Wormlike structure that divides but connects the two
cerebellar hemispheres together
Folia - The ridges that run atop of the cerebellum are called folia
Fissures - The long vertical grooves that are made by the folia
Cerebral cortex - the outside layer of gray matter that surrounds
the cerebellum and plays an important role in higher functions
Arbor Vitae - The tree looking thing that is composed of white
matter - brings sensory and motor information from the cerebellum
Deep cerebellar nuclei - Dark gray matter of the cerebellum that
are the only output structures of the cerebellum
What are the only output structures of the cerebellum called?
Deep cerebellar nuclei that is gray matter are the only output
structures of the cerebellum
How does the cerebellum process information? list the 3 steps
1) Cerebellum receives information from cerebrum on movements being planned
2) Cerebellum compares those planned movements to current position
of the body
3) Cerebellum sends instructions back to the cerebral cortex about
difference between planned movements and the current position of the
body - this is called FINE TUNING of the movements
Describe what regions of the brain each of the peduncles connects and
whether they carry afferent or efferent information
Superior cerebellar peduncle - connects the cerebellum to the
midbrain - carries efferent info away from cerebellum
Middle cerebellar peduncle - connects the pons to the cerebellum -
carries efferent info into cerebellum
Inferior cerebellar peduncle - connects the medulla to the
cerebellum - carries afferent info into cerebellum
Name the structure that connects the two cerebellar hemispheres
The vermis divides the cerebellum into two hemispheres, the corpus
callosum connects the two cerebellar hemispheres together
Name the 3 white fiber tracts that connect the cerebellum to the
brain stem and which tract connects to which portion
Superior Mid, Middle Pons, Inferior Medulla
The superior cerebellar peduncle connects the midbrain to the cerebellum
The middle cerebellar peduncles connects the pons to the cerebellum
The inferior cerebellar peduncles connects the medulla oblongata to
the cerebellum
What are the 3 main structures that make up the diencephalon?
The thalamus, hypothalamus and the epithalamus
Why is the thalamus considered the "gateway" to the
cerebral cortex?
Thalamus is the gateway to the cerebral cortex because every part of
the brain that communicates with the cerebral cortex must relay its
signal through a nucleus of the thalamus
-The thalamus is an important relay center for information going to
the cerebral cortex
Name some of the functions of the hypothalamus
Controls ANS Thermoregulation Thirst/hunger
regulation Circadian rhythm regulation Endocrine
system regulation Emotional response regulation
Formation of memory --> Consolidation
Describe the structure and function of the epithalamus and the pineal gland
Location?
Epithalamus located superiorly to the thalamus and most dorsal part
of diencephalon
Epithalamus consists of one tiny group of brain nuclei and a small
knob called the pineal gland
The pineal gland secretes melatonin to help us fall asleep
What structure secretes melatonin, the chemical that helps us fall asleep?
The pineal gland of the epithalamus
To which region of the brain do the thalamic neurons send their
axonal fibers?
Thalamic neurons send their axonal fibers to the cerebral cortex
What part of the diencephalon functions as the main visceral control center?
The hypothalamus is the main visceral control center, this means it
controls the regulation of the organs inside of the body like the
heart and stomach
What are the longitudinal fissure and transverse fissure and what
structures do they separate?
The longitudinal fissure separates the right and left cerebral
hemisphere from each other
The transverse fissure seperates the cerebrum from the cerebellum
What are the three regions of the cerebrum from superficial to deep?
Most superficial is the cerebral cortex which is gray matter
Deep to cerebral cortex is the cerebral white matter
Most deep is the gray matter of the cerebrum
What are the five major lobes of the cerebral cortex and what are
their functions?
Frontal lobe - Eye movement and cognitive functions - the PRIMARY
MOTOR CORTEX
Parietal lobe - Processes sensory stimuli like conscious awareness
of somatic sensation - PRIMARY MOTOR CORTEX
Occipital lobe - PRIMARY VISUAL CORTEX - processes visual information
Temporal lobe - Processes recognition of objects and faces -
AUDITORY/OLFACTORY CORTEX
Insula - Processes taste and general visceral sensation - VISCERAL
SENSORY CORTEX
Which lobe has the visceral sensory cortex?
The insula
Which lobe has the auditory and olfactory cortexes?
The temporal lobe
Which lobe has the visual cortex?
The occipital lobe
Which lobe has the primary somatosensory cortex?
The parietal lobe
Which lobe has the primary motor cortex?
The frontal lobe
Function of the:
Precentral gyrus
Postcentral gyrus
Precentral gyrus function - contains the primary motor cortex and is
responsible or initiation of motor movements - found in the frontal
lobe - frontal lobe responsible for motor function
Postcentral gyrus function - contains the primary somatosensory
cortex and is responsible for conscious awareness - found in the
parietal lobe
How are the lobes separated from one another?
Describe these:
Central sulcus
Parieto-occipital sulcus
Lateral sulcus
Central sulcus separates the frontal lobe from the parietal lobe
Parieto-occipital sulcus separates the parietal and occipital lobes
Lateral sulcus separates the parietal and temporal lobes
What are commissural fibers?
Commissural fibers are fibers of the cerebrum that connect and allow
for communication between the gray matter of the right and left
cerebral hemispheres
The largest commissure is the corpus callosum and the commissural
fibers will run through the corpus callosum to communicate both sides
of the cerebral hemispheres
What structure connects the right and left cerebral hemispheres together?
The corpus callosum
What are association fibers?
Projection fibers?
Association fibers are fibers that connect different parts of the
same hemisphere, commissural to connect the right and left and
association fibers to connect things inside of the left with things
inside of the left
Projection fibers are the fibers of the ascending and descending
tracts that carry sensory information to the cerebral cortex and motor
information away from the cerebral cortex
What structures make up the deep gray matter of the cerebrum?
What is the function of these structures?
The basal nuclei make up the deep gray matter of the cerebrum
Function of the basal nuclei is cooperation with the cerebral
cortex to modulate intensity of movement
Name the white fiber tracts that connect the cerebral cortex to more
caudal regions of the CNS
Projection fibers connect the cerebral cortex to more caudal regions
of the CNS
Limbic system is referred to as what?
Describe:
Cingulate gyrus
Hippocampal formation
Amygdaloid body
Limbic system is referred to as the emotional brain and is
responsible for out feelings on situations
Cingulate Gyrus - Mediates the emotional response to stimuli
Hippocampal formation - Contains the hippocampus and functions in
storing and retrieval of memories
Amygdaloid body - Processing of fear and the associated sympathetic
responses to fear
What structure is responsible for maintaining alertness and
consciousness and modulating overall level of conciousness?
The reticular formation is responsible for maintaining alertness and consciousness
What 3 structures serve to protect the brain?
Meninges - Outside connective tissue layer thats protects brain
CSF - Watery cushion from the ventricles of the brain
Blood brain barrier - prevents harmful molecules from getting into brain
Describe the following portions of the meninges of the brain:
Dura mater
Falx cerebri
Arachnoid mater
Subdural space
Subarachnoid space
Pia mater
Dura mater - Toughest layer and most superficial - contains 2 layers
of dense fibrous connective tissue - periosteal layer and meningeal layer
Falx cerebri - Dura mater that extends into the longitudinal
fissure between the two cerebral hemispheres
Arachnoid mater - Lies just deep to the dura mater
Subdural space - The space between the dura mater and the arachnoid mater
Subarachnoid space - Deep to the arachnoid mater, contains CSF and
blood vessels that supply brain
Pia Mater - Deepest layer of the meninges, richly vascularized with
blood vessels
Which part of the meninges contains the cerebrospinal fluid (CSF)?
Which layer of the meninges is deeply vascularized?
Subarachnoid space
Pia mater of the meninges is deeply vascularized
Explain how the choroid plexuses of the ventricles produce CSF
The choroid plexuses are capillary rich membranes located in the
roofs of the four ventricles
CSF continuously forms by filtration from the capillaries and then
passes through the ependymal cells into the ventricles
How many total cranial nerves are there?
There are 12 pairs of cranial nerves so 24 total cranial nerves
Name all of the cranial nerves by name and number
Cranial nerve I - Olfactory nerve
Cranial nerve II - Optic Nerve
Cranial nerve III - Oculomotor nerve
Cranial nerve IV - Trochlear nerve
Cranial nerve V - Trigeminal nerve
Cranial nerve VI - Abducens nerve
Cranial nerve VII - Facial nerve
Cranial nerve VIII - Vestibulocochlear nerve
Cranial nerve IX - Glossopharyngeal nerve
Cranial nerve X - Vagus nerve
Cranial nerve XI - Accessory nerve
Cranial nerve XII - Hypoglossal nerve
Where are the cell bodies of cranial nerves found?
The cell bodies for the sensory cranial nerves are found in the
receptor organs (nose for smell, eye for vision)
The cell bodies for the cranial motor nerves are found in the
ventral gray matter of the brain stem
Which of the cranial nerves is sensory only?
Which of the cranial nerves is motor only?
Which of the cranial nerves does both?
Sensory only - I, II, VIII - olfactory, optic and vestibulocochlear -
special senses so they are sensory only
Motor only - III, IV, VI, XI, XII - oculomotor, trochlear,
abducens, accessory and hypoglossal - these only function in motor nerves
Both - sensory and motor nerves - V, VII, IX, X - trigeminal,
facial, glossopharyngeal, vagus
Name the dura mater extension that lies in the longitudinal fissure
The falx cerebra is a dura mater extension that lies in the
longitudinal fissure and separates the two hemispheres
Some Say Marry Money But My Big Brother Says Big Business Makes Money
This pneumonic lines up with the order of the cranial nerves to tell
if its sensory or motor or both
Which nerves contain special somatic sensory fibers?
What is the special sense carried in each of them?
Cranial nerves II (optic - vision), VIII (vestibulocochlear -
hearing) carry the special somatic sensory fibers
What is the "great sensory nerve of the face"?
Which nerve innervates the muscles of facial expression?
The great sensory nerve of the face is the trigeminal nerve - cranial
nerve V
The nerve that innervates the muscles for facial expression is the
facial nerve
When performing brain surgery, incisions must be made through the
skull to reach the brain. What layers (in order) are cut through to
reach the brain?
Superficial - Dura mater --> Subdural space --> Arachnoid mater
--> Subarachnoid space --> Pia mater - Deep
A mans left eyelid is always drooped, what cranial nerve could be affected?
Cranial nerve III - The oculomotor nerve - since it innervates the
extrinsic eye muscles
What are the 3 functions of the spinal cord?
1) Spinal cord is involved in the sensory and motor innervation of
the entire body
2) Ascending and descending tracts travel through the white matter
of the spinal cord and provide a two way conduction pathway for
signals between the body and brain
3) Through sensory and motor integration in the spinal cords gray
matter, the spinal cord is a major center of reflexes
How many pairs of spinal nerves are there?
Where do the spinal nerves attach to the spinal cord?
Where do the spinal nerves lie?
There are 31 pairs of spinal nerves so 62 total spinal nerves
The spinal nerves attach to the spinal cord via the ventral and
dorsal nerve roots
The spinal nerves lie in the intervertebral foramina - the space
between the vertebrae
Name in order from superficial to deep the layers of the protection
of the spinal cord
Superficial - Epidural space --> Spinal dural sheath -->
Arachnoid mater --> CSF --> Pia mater - Deep
Describe these structures:
Vertebral canal
Conus Medullaris
Filum Terminale
Cauda Equina
Vertebral canal - the hole made by the vertebrae where the spinal
cord run
Conus Medullaris - The tapering end of the spinal cord, starts at
about L1
Filum Terminale - Long filaments of connective tissue that span
further than the actual spinal cord and work to hold the spinal cord
in place when we move around
Cauda Equina - The horsetail looking thing where the spinal cord
stops but the sacral and lumbar nerves run through the vertebral canal
Describe these structures:
Dorsal medial sulcus
Ventral medial fissure
Central canal
Dorsal median sulcus - a groove that separates the right side of the
spinal cord from the left side of the spinal cord on the dorsal side
of the spinal cord
Ventral median fissure - a groove located on the anterior or
ventral side of the spinal cord that separates the right side of the
spinal cord from the left side
Central canal - The hole in the middle of the gray matter in the
middle of the spinal cord where CSF is located
How many cervical spinal nerves are there?
Thoracic?
Lumbar?
Sacral?
Coccygeal?
There are 8 cervical spinal nerves
12 pairs of thoracic spinal nerves
5 pairs of lumbar spinal nerves
5 pairs of sacral spinal nerves
1 pair of coccygeal spinal nerves
Which movements would a person lose control of if they had a spinal
cord injury at the level of the T5 vertebrae?
An injury at the T5 vertebrae is below the cervical enlargement for
sure but above the lumbar enlargement - therefore this person would
still have complete control of the upper limbs but not control at all
of the lower limbs
What would happen to someone who had an injury at the level of
vertebrae C2?
If injured at C2 then the person would immediately lose all ability
to breathe as C3, C4, C5 - the phrenic nerve innervates the diaphragm
and helps the breathing motion
Anything above C3 and the person can't breathe
What makes up the white matter of the spinal cord? Describe the 3
types of fibers found in the white matter of the spinal cord
The white matter of the spinal cord is myelinated axons (thus why its
white) and contains 3 types of fibers:
1) Ascending fibers - Sensory information goes to the brain through
ascending fibers
2) Descending fibers - Motor information trav�ls from brain to
muscles through the descending fibers
3) Commissural fibers - commissural fibers allow for communication
between both sides of the spinal cord
The lateral horns have what kind of neurons and are found where?
The dorsal horns have what kind of neurons?
The ventral horns have what kind of neurons?
Lateral horns have only motor neurons - found in thoracic and
superior lumbar region
Dorsal horns have only interneurons
Ventral horns have only motor neurons
Ventral horns are largest at what points along the spinal cord?
The ventral horns are the largest at the cervical and lumbar regions
of the spinal cord
Cervical and lumbar enragements cause this since they supply the
upper and lower limbs and the ventral horns are home to the somatic
motor neurons
What section of the spinal cord contains dorsal, ventral and lateral horns?
Lateral horns are only found in the T1 to L2 regions of the spinal
cord, the lateral horns are the gray matter that relate to VM -
visceral motor function which is responsible for the motor function of
the digestive viscera and organs
What are the denticulate ligaments?
Ligaments that are lateral extensions of the pia mater that anchor
the spinal cord to the dura mater
What deficits would result if the ventral horn of the spinal cord in
the lower cervical segments is damaged?
Damage to the ventral horn of the spinal cord in the lower cervical
segments would cause a loss in the somatic motor function of the lower limbs
What kind of neurons are found in the dorsal root ganglions?
Unipolar sensory neurons since the dorsal root ganglions carry
sensory information to the spinal cord
What do the rami communicantes do?
The rami communicantes are little extensions that connect the ventral
ramus to the sympathetic trunk ganglion
What are the differences between the ventral roots and the dorsal roots?
SAME DAVE
Dorsal roots only carry sensory information in the afferent pathway
- to the spinal cord
Ventral roots only carry motor information in the efferent pathway -
away from the spinal cord
What are the differences between the dorsal rami and the ventral rami?
Ventral and dorsal rami both carry sensory and motor axons in them -
they both decussate
Dorsal rami innervate the posterior part of the trunk (back) and neck
Ventral rami innervate the anterior and lateral region of the neck
and trunk, and all regions of the limbs
What are the differences between roots and rami?
Roots (dorsal and ventral roots) are either strictly sensory or
strictly motor fibers
Strictly sensory = Dorsal roots
Strictly motor = Ventral roots
Rami are lateral branches of spinal nerves and contain both sensory
and motor fibers
Explain how dorsal rami innervate the back
Dorsal rami branch off of the spinal nerve and innervate a strip of
muscle that runs along the vertebral column, it innervates the
intrinsic muscles and skin of the back
Dorsal rami branch off to the back
What are intercostal nerves?
Intercostal nerves are ventral rami that run deep to each rib, the
ventral rami supply the intercostal muscles, the skin and anterior and
lateral areas of the thorax, and most of the abdominal wall
Ventral rami branch off to the anterior portion of the body
What spinal nerves don't form part of a nerve plexus?
The only spinal nerves that don't form part of a nerve plexus are the
T2-T12 spinal nerves - the spinal nerves in all other regions form
nerve plexuses
ONLY VENTRAL RAMI CONTRIBUTE TO NERVE PLEXUSES
What are the 4 plexuses of the body and what regions of the body do
they serve?
1) Cervical plexus - formed by the ventral rami of the first 4
cervical nerves - serve the cervical region of the body
2) Brachial plexus - formed by the ventral rami of C5-C8 and T1 -
the brachial plexus serves most of the upper limbs
3) Lumbar plexus - Innervates part of the abdominal wall, psoas
major, and anterior portion of the thigh - formed by the first four
lumbar spinal nerves L1-L4
4) Sacral plexus - innervates the butt and the lower limbs, some of
pelvis and perineum - arises from the spinal nerves L4-S4
What are the key nerves of the cervical plexus?
Key nerves of the brachial plexus?
Key nerves of the lumbar plexus?
Key nerves of the sacral plexus?
Cervical plexus - cutaneous and phrenic nerves
Brachial plexus - Musculocutaneous, median, ulnar, radial, and
axillary nerves
Lumbar plexus - Femoral and obturator nerve
Sacral plexus - Sciatic, tibial, common fibular nerve
What are cutaneous nerves?
These are sensory nerves located on the skin to allow the body to
have sensation on a specific patch of skin, carries sensory impulses
from the skin to the CNS
What is Hiltons law?
Any nerve that innervates a muscle producing movement at a joint also
innervates the joint itself (and the skin over it)
What are dermatomes?
Dermatomes are the area of the skin that is innervated by the
cutaneous branches from a single spinal nerve
Spinal nerves have cutaneous branches coming off of them, the
branches will connect to the skin via dermatomes
The only spinal nerve that doesn't attach to a dermatome is spinal
nerve C1
The ANS is the _________ of the peripheral nervous system
The ANS is the general visceral motor division of the peripheral
nervous system and the ANS innervates the digestive viscera to
modulate blood pressure, heart rate and digestion
Skeletal muscle only has what innervation?
Somatic motor nervous system innervates the skeletal muscle
Describe the somatic motor nervous system pathway and how it works
Somatic motor neurons are thick, heavily myelinated fibers that
conduct pulses rapidly
1 neuron pathway - no ganglions - only stimulatory effect on
skeletal muscle
The cell bodies of somatic motor neurons lie in the ventral horn of
the gray matter, there is one long axon that reaches from the ventral
horn of the gray matter to the skeletal muscle it innervates
Describe these:
Preganglionic neuron
Preganglionic axon
Postganglionic neuron
Autonomic ganglion
Postgagnlionic axon
Preganglionic neuron - cell bodies located in the gray matter of the
CNS, send signals to the preganglionic axon
Preganglionic axon - synapses with the second motor neuron
(postganglionic neuron) - preganglionic axons are thin, lightly
myelinated fibers
Postganglionic neuron - the second motor neuron in the autonomic
nervous system pathway, cell bodies of this neuron located in the PNS
where the synapse is close to effector organ
Autonomic ganglion - A cluster of nerve cell bodies (a ganglion) in
the ANS, can be either sympathetic or parasympathetic
Postganglionic axon - Postganglionic axon extends from the
postganglionic neuron into the visceral organ that it innervates -
unmyelinated and smaller than preganglionic axons
What types of neuron cell bodies are located in autonomic ganglia?
Autonomic ganglia are motor ganglia containing cell bodies of motor
neurons ONLY, NO sensory neurons at all
Where are the cell bodies located for the somatic motor nervous system?
What about cell bodies for the ANS?
Ventral horn of the CNS
Cell bodies of the ANS found in two locations:
Preganglionic cell bodies - Lateral horn of CNS
Postganglionic cell bodies - PNS autonomic ganglion
Describe the differences between sympathetic and parasympathetic
divisions structurally:
Origin
Length of fibers
Branching
Neurotransmitters
Sympathetic: -Originates from thoracic and superior lumbar regions of
spinal cord
-Short preganglionic fibers, long postganglionic fibers
-Lots of branching
-Releases norepinephrine at effector organ
Parasympathetic: - Originates from brain and sacral region of
spinal cord
- Long preganglionic fibers, short postganglionic fibers
-No branching in parasympathetic fibers
-Acetylcholine released at effector organs
Which part of the autonomic nervous system uses Rami communicantes?
The sympathetic division of the autonomic nervous system uses Rami communicantes
Gray RC = unmyleinated postganglionic axons
White RC = myelinated preganglionic axons
The parasympathetic division of the ANS does not use Rami
communicantes at all
What is one thing that doesn't differ between the somatic motor
system and the autonomic nervous system?
The structural type of neurons in the pathways does not differ! The
somatic motor system and the autonomic nervous system both use
multipolar neurons
Which fibers in the motor division of the PNS are not myelinated?
Postganglionic fibers of the motor division of the PNS are not myelinated
Where are sympathetic ganglia located?
Where are most parasympathetic ganglia located?
Sympathetic ganglia are located near the CNS (sympathetic trunk ganglion)
Parasympathetic ganglia are located near the target visceral organ
Are visceral sensory fibers considered part of the ANS?
Visceral sensory fibers are NOT part of the ANS - visceral sensory
fibers are part of the sensory (afferent) division
Visceral motor fibers ARE PART of the ANS
Visceral sensory --> NO
Visceral motor --> YES
What is the difference between a rami and a root?
Dorsal roots only contain sensory axons
Dorsal rami contain both sensory and motor axons
Ventral roots contain only motor axons
Ventral rami contain both sensory and motor axons
Roots can only have one type of fiber (sensory or motor) and rami
will have both sensory and motor fibers
Where is there mixing of sensory and motor axons?
The only mixing of sensory and motor axons occurs in the rami, never
mixing of the axons in the roots
Where do dorsal rami send their information out to?
Where do ventral rami send their information out to?
Dorsal rami send information out to the posterior back and the neck only
Ventral rami send info out to the limbs and anterior torso and neck
What is found inside of the sympathetic trunk ganglion?
The post-ganglionic neuron cell bodies of the sympathetic system are
found in the sympathetic trunk ganglion
The pre-ganglionic neuron cell bodies of the sympathetic system are
found in the lateral horn of the spinal cord
Where are the pre-ganglionic neuron cell bodies of the sympathetic
nervous system found?
What about the post-ganglions neuron cell bodies?
Pre-ganglionic neuron cell bodies are found in the lateral horn of
the spinal cord - since only visceral motor (autonomic) neurons are
found inside of the lateral horns of the spinal cord
The post-ganglionic cell bodies of the sympathetic nervous system
are found in the sympathetic trunk ganglion
Where are the parasympathetic neuron cell bodies found?
The parasympathetic neuron cell bodies are found close to the
visceral organ that they innervate since there are very short
post-ganglionic axons
What does craniosacral outflow mean?
What does thoracolumbar outflow mean?
The parasympathetic nervous system originates in the cranium and the
sacral and thus the outflow comes from these two areas, which is why
its called craniosacral outflow
The sympathetic nervous system originates in the thoracic and
lumbar regions of the spinal cord and thus the outflow comes from
this area, this is why its called thoracolumbar outflow
It just has to do with the origination points of the nerves
Where are the cell bodies of cranial outflow (parasympathetic)
pre-ganglionic neurons located?
Where are the cell bodies of sacral outflow (sympathetic)
pre-ganglionic neurons located?
Cell bodies of cranial outflow pre-ganglionic neurons are located in
the MOTOR CRANIAL NERVE NUCLEI IN GRAY matter of the brain stem
Cell bodies of the sacral outflow pre-ganglionic neurons are
located in the lateral horn of the gray matter
Describe the parasympathetic function these cranial nerves have on
their effectors:
Oculomotor nerve (III)
Facial nerve (VII)
Glossopharyngeal nerve (VII)
Vagus nerve (X)
Oculomotor nerve (III) - innervates the smooth muscles of the eye and
parasympathetic activity causes the pupil to constrict and the lens of
the eye to bulge - allows for focusing of the eye
Facial nerve (VII) - innervates the lacrimal gland -
parasympathetic activity stimulates secretion of lacrimal fluid
Glossopharyngeal nerve (VII) - innervates the tongue -
parasympathetic activity stimulates secretion of salivary glands
Vagus nerve (X) - Innervates the visceral organs of the thorax and
abdomen - parasympathetic activity - parasympathetic activity causes
reduction in heart rate, constriction of bronchioles, stimulates digestion
What are autonomic plexuses?
Autonomic plexuses carry fibers from both the sympathetic and
parasympathetic divisions of the ANS and combines both of these
innervations to make a plexus that serves the organs
What nerves are involved in sacral outflow of parasympathetic nervous
system? What organs do they innervate and what functions do they control?
Parasympathetic sacral outflow comes from the spinal nerves S2-S4 and
innervate organs like large intestine, bladder, uterus and stimulation
does functions like urination, defecation
What are splanchnic nerves?
Splanchnic nerves are paired visceral nerves that contribute to the
innervation of the visceral organs and they carry fibers of the ANS
system (both sympa and parasympa) as well as sensory fibers
Which spinal nerves carry parasympathetic pre-ganglionic fibers?
Spinal nerves S2, S3, and S4 carry the parasympathetic pre-ganglionic fibers
What is the result of vagal stimulation of the a) heart b) small
intestine c) salivary glands
Cranial nerve (X) vagus nerve will have the following activity:
a) decrease the activity of the heart
b) increase activity of small intestine
c) increase activity of salivary glands
Which cranial nerves will carry pre-ganglionic parasympathetic
fibers? Which cranial nerve will carry the post-ganglionic fibers to
the target organs innervated by these three nerves?
Cranial nerves (III) oculomotor, VII (facial), and
IX(glossopharyngeal) all have pre-ganglionic parasympathetic fibers
HOWEVER, cranial nerve V (trigeminal) will carry the
post-ganglionic parasympathetic fibers to the target organs
III, VII, IX pre-ganglion para fibers --> V post-ganglionic para
to the target organs
What parts of the body does the sympathetic nervous system innervate
but the parasympathetic nervous system does not?
The sympathetic nervous system has exclusive innervation in the sweat
glands, arrector pili muscles, and blood vessels
What are white rami communicantes?
What are gray rami communicantes?
What structures do these rami connect?
The rami connect the sympathetic trunk ganglia to the ventral rami of
the spinal nerves
The white rami communicantes contain the pre-ganglionic fibers that
travel INTO the sympathetic trunk ganglion - white because myelinated
The gray rami communicantes contain post-ganglionic fibers that
head away from the sympathetic trunk ganglion - gray because unmyelinated
How many sympathetic trunk ganglia in each of these regions of the
spinal cord:
Cervical region
Thoracic region
Lumbar region
Sacral region
Coccygeal region
Located in which body cavity?
Cervical - 3 cervical sympathetic trunk ganglia pairs
Thoracic - 11 thoracic sympathetic trunk ganglia pairs
Lumbar - 4 lumbar sympathetic trunk ganglia pairs
Sacral - 4 sacral sympathetic trunk ganglia pairs
Coccygeal - 1 coccygeal sympathetic trunk ganglia on each side
Total of 44-48 sympathetic trunk ganglia and 22-24 on each side
Sympathetic trunk ganglia are located in the ventral body cavity
What is the difference between dorsal root ganglia and sympathetic
trunk ganglia? Cell bodies? Location?
Dorsal root ganglia are located near the spinal cord in the dorsal
root extension off of the spinal cord and contain only sensory neurons
Sympathetic trunk ganglia are located by the ventral rami of the
spinal nerves and only contain motor neurons
Dorsal root ganglia - Sensory only --> Sympathetic trunk ganglia
- Motor ONLY
What are collateral ganglia? How do they differ from sympathetic
trunk ganglia?
Collateral ganglia are extensions from the sympathetic trunk ganglia
that receive splanchnic nerves and carry post-ganglionic sympathetic
fibers to the visceral organs
They are basically the extensions of the spinal nerves that reach
out to the visceral organs for innervation
They differ from the sympathetic trunk ganglia in that: they are
not paired and are not arranged by segment, occur only in abdomen and
pelvis, all lie anterior to vertebral column
Describe the 3 general sympathetic pathways:
1) Synapse at same level
2) Synapse at higher or lower level
3) Synapse in a collateral ganglia
1) Pre-ganglionic neuron in the lateral horn sends info through PreG
axon where it synapses with the Post-ganglionic axon in the
sympathetic trunk ganglion at the same level and exits the spinal
nerve at that level
2) Pre-ganglionic neuron in the lateral horn sends info through
PreG axon where it either ascends or descends in the sympathetic
trunk to synapse in another sympathetic trunk ganglion - PG fiber
exits the trunk at the level of the synapse
3) Pre-ganglionic neuron in the lateral horn sends info through the
PreG axon through the sympathetic trunk, into a splanchnic nerve and
synapses on a collateral ganglion. The collateral ganglion forms the
autonomic plexuses and innervates the visceral organs
Describe the sympathetic pathways to the periphery of the body and
what functions they perform
Sympathetic outflow only occurs in the thoracic and lumbar regions of
the spinal cord, so innervation of anything outside of this region
(head, legs) requires travel through the white rami communicantes and
ascend up the sympathetic trunk into the head or down into the legs
What is the function of white rami communicantes? In what region of
the spinal cord are they found?
White rami communicans function to connect the T1-L2 region of the
spinal cord with the sympathetic trunk ganglia and only carry
sympathetic pre-ganglionic axons
White because they are myelinated
They will only occur in the region of sympathetic outflow of the
spinal cord, so regions T1-L2
What kinds of axons travel through the gray rami communicantes? In
what region of the spinal cord?
Sympathetic post-ganglionic axons travel through the gray rami
communicantes, gray because unmyelinated, and occur on all of the
sympathetic trunk ganglia
White SympaPre Gray SympaPost
Sympathetic stimulation on these organs results in:
Head
Lungs and Esophagus
Heart
Abdominal Organs
Pelvic Organs
Head - sympathetic activity inhibits glands, dilates pupils, and
opens the eyelid
Lungs and esophagus - Stimulates the lungs and inhibits the esophagus
Heart - increases heart rate
Abdominal organs - inhibits digestion and stimulates adrenal medulla
Pelvic organs - inhibits urination, defecation
Explain the role of the adrenal gland and the adrenal medulla in the
sympathetic division
The adrenal gland is the main sympathetic organ, the adrenal medulla
secreted norepinephrine and epinephrine into the blood in the fight or
flight response
Innervation into the adrenal gland only contains pre-ganglionic neurons
Why are rami communicantes located only on sympathetic trunk ganglia
between T1 and L2, and gray rami communicantes branch off each
sympathetic trunk ganglion?
White rami communicantes located only on sympathetic trunk ganglia
between T1 and L2 because this is where the pre-ganglionic outflow of
the sympathetic system is located - the white rami participate in the
sympathetic outflow so can only be in the thoracic and lumbar regions
The white rami communicantes are pre-ganglionic sympathetic fibers
The gray rami communicantes are post-ganglionic sympathetic fibers
and branch off of every sympathetic trunk ganglia since they carry the
post-ganglionic fibers
Which types of autonomic fibers are located in the thoracic and
abdominal autonomic plexuses?
Sympathetic post-ganglionic fibers and parasympathetic pre-ganglionic
fibers are located in the thoracic and abdominal autonomic plexuses
SympaPost ParaPre - thoracic and abdominal plexuses
What is the function of visceral sensory neurons? Where are their
cell bodies at?
Describe the pathway that visceral sensory neurons take from an
effector to the CNS
Visceral sensory neurons detect stretch, temperature, chemical
changes within the visceral organs
Their cell bodies are found in the dorsal root ganglia and in
sensory ganglia of cranial nerves
Free nerve ending receptors detect stretch, temperature, and
chemical changes in the visceral organs and travel through the
afferent pathway to the dorsal root and into the spinal cord
What axons are found in the PNS?
What axons are found in the CNS?
What do these axons do?
PNS is composed of axons of sensory (afferent) and motor (efferent)
neurons bundled together as nerves
These nerves are information pathways to and from the periphery of
the body
Afferent respond to sensory stimuli and bring that info to CNS
Efferent transmit motor stimuli from CNS to the glands and muscles
CNS is composed of interneurons that do three steps:
Receive sensory information, direct and transport this information
to specific regions of the CNS, and initiate an appropriate motor response
CNS is interneurons, PNS is sensory and motor neurons
Where do the CNS and PNS structurally link together?
The structural link between the CNS and the PNS occurs in the gray
matter of the CNS
What is a reflex arc? describe the 5 steps of a reflex arc and give
an example
Somatic reflexes
Visceral reflexes
Reflex arcs are simple chains of neurons that cause our reflexive
behaviors - reflexes are rapid, automatic responses to stimuli
Somatic reflexes are reflexes that result in the contraction of
skeletal muscles
Visceral reflexes are reflexes the result in activation of smooth
muscle (heart), cardiac muscle or glands
5 steps to a somatic reflex arc:
1) A receptor picks up a stimuli
2) Sensory neuron -afferent pathway- transmits the stimuli
information to the CNS
3) Integration center - consists of one or more synapses in the
gray matter of the CNS - simple reflexes have 1 synapse in gray
matter, complicated reflexes have multiple synapses in gray matter
4) Motor neuron - efferent pathway - motor neuron conducts efferent
impulses from integrating center to effector
5) Effector - effector is a muscle or gland that responds to
efferent impulses by contracting or secreting
What is the difference between a monosynaptic reflex and a
polysynaptic reflex?
A monosynaptic reflex has no interneurons in the gray matter of the
CNS, the sensory axon synapses on the motor neuron - only one synapse
- monosynaptic
Ex = stretching reflex for muscle to help maintain equilibrium
A polysynaptic reflex has 1 or more interneurons in the gray matter
of the CNS - multiple synapses
Ex = withdrawal reflex - touch something hot and withdraw the hand
What is the difference between a spinal pathway and a cortical pathway?
A spinal pathway is much faster than a cortical pathway
Spinal pathways carry sensory information through gray matter of
spinal cord and sends motor output right away
Cortical pathways carry sensory info through ascending pathways to
brain, multiple interneurons involved to localize the stimulus, a
voluntary motor response is initiated and sent to the somatic motor neurons
If you touch a hot stove, you reflexively withdraw your hand. The
sensation of pain comes after your hand has moved. Why does it take
longer to feel pain than it does to move your hand?
The withdrawal reflex is attributed to the spinal pathway and occurs
much faster than the processing of pain which occurs in the cortical pathway
What is a visceral reflex arc? Describe the 5 steps of the visceral
reflex arc and give examples
A visceral reflex arc is a reflex that has to do with the visceral
organs instead of the sensory receptors and skeletal muscles
1) Stimulus on sensory receptor in visceral organ (baroreceptors)
2) Visceral sensory neuron carries impulses to integration center
3) Integration center (could be dorsal horn interneuron) integrates
the info
4) Efferent pathway out of the integration center carries info to
visceral effector (gland or organ)
5) The visceral effector receives efferent impulse and has a
response (could be secretion or other things)
THERE ARE NO INTERNEURONS IN THE VISCERAL REFLEX ARC
Compare ascending pathways to descending pathways
Ascending pathways - Sensory information only, this is an afferent
pathway meaning sensory information is traveling to the brain
Ascending pathways contain first order, second order and third
order neurons instead of upper and lower motor neurons like the descending
Descending pathways - Motor information only, this is an efferent
pathway meaning only motor information is traveling away from the
brain to the PNS
Descending pathways contain upper and lower motor neurons - upper
motor neurons are found in the gray matter of the brain and lower
motor neurons are found in the ventral horn of the spinal cord
What are 4 important summary features of the ascending and descending pathways?
1) Most of the ascending and descending pathways decussate from one
side of the CNS to the other
2) Most of the ascending and descending pathways consist of 2 or 3
linked neurons within a tract
3) Most pathways are spatially arranged in a specific way
4) All pathways occur on both sides of the spinal cord
What are ascending spinal tracts and descending spinal tracts? Where
are they found?
Ascending spinal tracts are simply the segments of the ascending
tracts that travel through the spinal cord - carries sensory
information in the afferent pathway to brain
Descending tracts are the segments of the descending tracts that
travel through the spinal cord - carries motor information in the
efferent pathway away from the brain
Ascending or descending tracts can only be found in the white
matter of the CNS
Explain first order, second order and third order neurons in
ascending pathways. What kind of impulses do they carry and where do
they synapse with each other?
1st, 2nd, 3rd order neurons in ascending pathways must be sensory
neurons since ascending pathways only have sensory information - carry
afferent sensory impulses to the brain
1st order neuron in ascending pathway extends from sensory receptor
to the spinal cord
2nd order neuron in ascending pathway synapses with first order
neuron in spinal cord and extends all the way up to the thalamus
3rd order neurons synapse with 2nd order neurons in the thalamus
and form an ascending tract that extends into the cerebral cortex
1st order: Sensory receptor --> Spinal cord
2nd order: Spinal cord --> Thalamus
3rd order: Thalamus --> Cerebral Cortex
1st and 2nd order neurons synapse with each other in the spinal cord
2nd and 3rd order neurons synapse with each other in the thalamus
Summarize the main ascending pathways:
Spinocerebellar pathway
Dorsal column-medial lemniscal pathway
Spinothalamic pathway
Spinocerebellar pathway carries proprioception from the lower limbs
and the trunk up to the cerebellum - only 2nd and 3rd order neurons
here - decussates twice so ends up on same side! Ipsilateral
Dorsal column- medial lemniscal pathway carries discriminative
senses that can be LOCALIZED precisely on the body surface (fine
touch, pressure, conscious proprioception) to the cerebellum using all
3 neurons- decussates in the medulla oblongata
Spinothalamic pathway carries pain, temp, deep pressure and
NONDISCRIMINATIVE touch to the cerebellum using all 3 neurons -
decussates in the lumbar and cervical spinal regions
Which pathway in the body decussates twice and thus has ipsilateral decussation?
The spinocerebellar pathway decussates twice and ends up on the same
side of the body as the cerebral cortex starting point
Name the location in the white matter of the spinal cord of each of
the ascending pathways:
Spinocerebellar pathway
Dorsal column-medial lemniscal pathway
Spinothalamic pathway
Spinocerebellar pathway - lateral portion of the white matter of
spinal cord
Dorsal column-medial lemniscal pathway - dorsomedially so dorsal
side and towards the middle
Spinothalamic pathway - Right below and lateral to the ventral horn
What are the termination points of the 3 main ascending pathways?
Spinocerebellar pathway - terminates in the cerebellum
Dorsal column-medial lemniscal pathway - terminates in the cerebrum
Spinothalamic pathway - terminates in the cerebrum
Which of the 3 main ascending pathways senses pain, temperature,
non-discriminative touch in the integument?
Spinothalamic pathway
Which of the 3 main ascending pathways senses fine touch, pressure,
conscious proprioception and discriminative senses?
Dorsal column - medial lemniscal pathway
Which of the 3 main ascending pathways senses proprioception from the
lower trunk?
Spinocerebellar pathway
Which pathway and its description are INCORRECTLY matched?
Spinothalamic � senses pain and pressure in the
integument Dorsal column � transmits information on fine
touch conscious proprioception from the integument
Spinocerebellar � senses temperature in the integument
Pyramidal (direct) � controls fine muscle movements
Extrapyramidal (indirect) � controls course and postural muscle
movements
Spinocerebellar does NOT sense temperature in the integument, it
senses proprioception in the lower limbs
Conscious muscle movement would be controlled by which pathway?
How about unconscious muscle movement?
Conscious muscle movement is controlled by the pyramidal (direct) pathway
Unconscious muscle movement is controlled by the extrapyramidal
(indirect) pathway
Damage to the right pyramidal pathways at the level of the pons will cause?
Paralysis of the left upper and lower limbs - since the damage is
occurring to the pyramidal (direct) pathways and this controls
conscious muscle movement of the skeletal muscles and this is
occurring above the cervical and lumbar enlargements, it will damage
the left upper and lower limbs
Left because the pyramidal tracts decussate so it will end up on
the left side of the body
Damage to the right spinothalamic pathway at the level of T5 will
cause what?
The absence of pain sensation in the left lower limb, the
spinothalamic pathway carries pain sensations and since this is
occurring at the level of T5 there will be no effect on the upper
limbs and the decussation of this pathway is at the level of the
lumbar region of the spinal cord so it will decussate still to affect
the left lower limbs pain sensation
Where do upper motor neurons originate?
Where do they synapse with the lower motor neurons?
Upper motor neurons originate in the gray matter of the brain and
send descending tracts down into the spinal cord
Upper motor neurons synapse with lower motor neurons in the ventral
horn of the spinal cord
Where do lower motor neurons originate?
Where do they exit the spinal cord?
Lower motor neurons originate in the ventral horn of the spinal cord
and exit the spinal cord in the ventral root
This makes sense because the descending pathway is carrying motor
information and the ventral root only contains motor neurons so the
lower motor neurons will exit the spinal cord via the ventral root
Where do the direct pathways decussate?
Where do the indirect pathways decussate?
Direct pathways decussate in the medulla
Indirect pathways decussate in the spinal cord
Where is the origin point of the upper motor neurons in the direct pathways?
Where is the origin point of the upper motor neurons in the
indirect pathways?
Direct pathways have origins of their upper motor neurons in the
primary motor cortex
Indirect pathways have origins of their upper motor neurons in the midbrain
Where do upper and lower motor neurons synapse?
Ventral horn of the spinal cord or directly to the motor neuron
How does the innervation of the head differ from the innervation of
the body?
Innervation of the head differs from innervation of the body in that
the tracts that are innervating originate from cranial nerves and not
from the spinal cord
Of the 3 main sensory ascending pathways, which one does not pass
through the thalamus?
The spinocerebellar pathway does not pass through the thalamus, this
is because it has only 2 neurons in its pathway - the other 2 -
spinothalamic and medial lemniscal pathways both pass through the
thalamus on their way to the cerebrum
Which protective layer of the brain is filled with CSF?
The subarachnoid space between the arachnoid mater and the pia mater
is filled with CSF
Where is the cerebrospinal fluid produced?
In the choroid plexus of the ventricles
Which cranial nerve is responsible for innervation of the anterior
2/3 of the tongue?
Which cranial nerve is responsible for innervation of the posterior
1/3 of the tongue?
The facial nerve controls the anterior 2/3 of the tongue
The glossopharyngeal nerve controls the posterior 1/3 of the tongue
Which cranial nerve innervates the superior oblique eye muscle?
Superior oblique eye muscle is innervated by the trochlear (IV)
cranial nerve
Which cranial nerve innervates the muscles responsible for mastication?
Cranial nerve V - Trigeminal nerve innervates the muscles for mastication
Which of the layers of the protection of the spinal cord is a
cushioning fat layer?
Epidural space just outside of the dura mater is a layer of
cushioning fat
Which named spinal nerve is involved in the abduction of the upper limb?
Axillary spinal nerve - serves the deltoid and the teres minor
The musculocutaneous nerve serves what compartment of the arm?
Anterior compartment of the arm is innervated by the musculocutaneous nerve
The radial nerve innervates what compartment of the arm?
The radial nerve innervates the posterior compartment of the arm
Which named nerve innervates the cutaneous lateral palm?
The cutaneous lateral palm is innervated by the median nerve
Which regions of the leg do these spinal nerves innervate?
L2-L4
L4-S2
LS-L4 is the obturator and femoral nerve
L4-S2 is the tibial and common fibular nerve
Which nerve innervates the posterior compartment of the thigh?
The posterior compartment of the thigh is innervated by the tibial
spinal nerve