lecture 9: spinal cord Flashcards
the brainstem begins and ends where
Begins at medulla oblongata (brain stem) down to the level of
L2
what is the end point of the spinal cord called
CONUS MEDULLARIS
how many enlargements are there on the spinal cord
2
what are the 2 enlargements of the spinal cord
cervical and lumbar ellargemnts
what is formed from the cervical enlrgements
brachial plexus
the cervical englargement innervates what
the upper extremityies (c5-t1)
the 2 enlargements lead to waht
lead to the 2 plexus
what is formed from the lumbar enlargements
lumbar plexus
the lumbar enlargements innervates what
lower extremeity (L!-S4)
the divided into R/L halves by
depressions called the what
1) anterior/ventral median fissure
2) posterior (dorsal) median sulcus
the anterior depression of the spinal cord is called a fissure or sulcus
fissure
the posterior depression of the spinal cord is called a fissure or sulcus
sulcus
If we transect the spinal cord we find what
basic H-form in the
center - Grey Commissures
the H form is comprised by
nuclei (grey matter)
what is the center or grey matter called
central canal
true or false; The central canal is continuous/discontinuous the length of the spinal cord
continuous
the central canal is continous with what ventricle
the 4th ventricle
what is the central canal filled with
CSF
surroundingthe H form of the grey matter is what
areas of white matter
what is the white matter comprised of
bundles of myelinated nerve fibers
what are the myelinated nerve fibers/what cells make up the white matter in the CNS
oligodendrocytes
what is each bundle of myelinated nerve fibers called
tract
what do tracts do
1) send signals to simular locations
2) carry motor and sensory info
what are the 2 types of tracts
ascending/sensory
descinding/motor
ascending tracts carry what info
sensory
desciding trcts carry what info
motor
ascending tracts relay info from what
Relay impulses from the periphery or spinal levels to the
brain
descending tracts relay into from where
Relay impulses from the brain to different spinal levels and
the periphery`
what are the pairs of horns of the grey comissure
2 atnerior (ventrial) horns 2 posterior (dorsal) horns
the lateral hones of the spinal cord are ony found where
in T spine and upper L spone
=ANS
The groups of nerve fibers which enter the Dorsal Horn are
called
Dorsal roots
The groups of nerve fibers which enter the Ventral Horn are
called
Ventral roots
dorsal roots carry sensory or motor into
sensory
ventral roots carry motor or sneosry info
motor
where do the dorsal root cell bodies lie
lie outside the s.c. in the intervertebral
foramen and are called,
what are the cell bodies of dorsal roots called
dorsal root ganglia/spinal ganglia
ventral roors contain axos of ./
motor neurons
where are the cell bodies of ventral roots contained
Cell bodies are contained within the anterior and lateral
horns
the dorsal and ventral roots come together to form what
spinal nerve
T/F the spinal nerve contains only motor info?
false motor and seosry
where does the spinal nerve exit
intervertebral foramen
the spinal nerve is made from the joining of….
dorsal roots and ventral roots
once outside of the intervertebral formamen. the spinal cord divides into
dorsal and ventral rami
the dorsal rami supply what
supply the deep vertebral muscles and skin of
the back
the ventral rami supply
supply all the ventral and lateral musculature
true or false: spinal nerves are mixed?
true
how many pairs of spinal nerves
31 pairs
explain the divisions of the spinal nerve
8 cervical 12 thoracir 5 lumbar 5 sacrum 1 coccyx
what is the function of meninges
Protect the brain and spinal cord
the meninges form the supporting framework for…
arteries, veins and venous sinuses
what do meninges enclose and why
Encloses the subarachnoid space for the circulation of CSF
what are the 3 meninges
dura mater
arachnoid
pia mater
the dura mater is associated with
Diaphragm Sellae (covers pituitary gland)
the arachnoid contains what
Subarachnoid space: contains CSF
pia mater contains what ligmanets
Denticulate ligaments
are denticulate ligaments found only in the spinal cord
yes
what do all three laters of the meninges cover
• All three layers cover the spinal nerves until they exit through
the intervertebral foramina
what are denticulate ligmanets
extensions of pia mater that help acnhor the spinal to the dura mater
free nerve endings are what kind of dendrites
bare dendrites
what aare the 2 types of specialized nerve endings
free nerve endings
encapsulated sensory endins
where do free nerve endings branch
branch between epithelial cells, connective cells, muscle
cells,
free nerve endings act as what type of receptors
Are thought to act primarily as pain receptors of the body
• Also act as tickle, itch and thermal, and touch receptors
encapsulated sensory endings are what types of dendrites
enclsosed
what are encapsulated sensory ends surrounded bt
by connecttive tissuec apsules
how many encpasulate nerve endngs are here
6
what are the 6 encapsulated sensory endings
Meissner Corpuscles • Pacinian Corpuscles • End bulbs of Krause • Ruffini Corpuscles • Muscle Spindles • Golgi Tendon Organs
where do meissner corpuscles surround
spinal ending of a dendrite
true or false: messiner corupuscles are superfical
true
what are meissners corpuscles sensite to
light touch, pressure, and slow vibrations
true or false: meissner corpuscles are slowly adapting
false, rapidly
where are meissners corpusles foundn
Skin (dermis) - especially the finger tips
• Mucous membrane of the tongue
• Other sensitive regions of the body (ex: eyelids)
where are pacinian corpuscles located
Located in the dermis and subcutaneous tissue, submucosa,
joints, periosteum, and some viscera
pacianian or meissners are deep
pacinian
pacinnian corpuscles are slow or rapid adaptiingn
rapidly adaptinng
what are pacinian corpuscles stimulated by
Stimulated by heavy pressure, fast vibrations, tickling
where are end bulbs of krause located
Located in the mucous of the lips, tongue, conjunctiva,
external genitalia
end bulbs of krause are common where
throughout the body (dermis of the skin)
what do end bulbs of krause sevre as
cold recptors
where are ruffinni corps located
Located in sub-cutaneous tissue, ligaments, tendons
ruffinis are slow or fast adapting
Slow-adapting
what do ruffinis respond to and why is that imporantn
Respond to stretching of the skin
• Contribute to the kinesthetic sense of, and control of, joint position and
movement
where are muscle spindles founnd
in skeletal muscel
what do muscle spinles react to changes in
muscle length
true or fales: msucle spindles are contained in a capsule
true
within the capsule of muscle spindles what are the sksletal muscle fibers called
intrafusal fibers
muscle spindles are supplied by what type of neurons
sensory neurons
epxlain the msucle spindles
When the muscle is stretched so are the intrafusal fibers which
send afferent nerve impulses back to the spinal nerve
• In response, there is stimulation of the efferent (motor) neurons
to the same muscle that contracts it
• Therefore stretch is reflexively resisted
why does the muscle contract in response to stim muscle spindles
contract to prvent overstretching
muscle spindles are important for stiumlation or inhbitory
stim
GTO are important for stimulation or inhibitory
inhibitory
what are GTO composed of
Composed of dendrites that have many branches on the
muscle tendon junction
what do GTO raect to
msucle tension
explain the gto
React to muscle tension
• The stimulus will go back to the s.c. where the motor neurons
to the same muscles are inhibited, thus relaxing the muscle
• Principle of PNF stretching and hold/relax stretch
what is the princicle of PNF strengthcinng based on
GTO
all spinal nerves except CI are what
cuteanous (innervate the skin)
all spinal nerves except BLANK are cutenous
c1
each spinal nerve innervates a segmental field of skin called a…
dermatome
in dermatones there is a specfic area for each but there is never any overlap
falsem there is considerable overlap
what a dermatomes imporant for
imporant for diagnostic technique
reflexes are made from what 3 systems
cranial reflexes
somatic relfexses
autonomic reflexes
what is the reflex arc made up of
Sensory Receptor • Sensory Neuron • Integrating center • Motor Neuron • Effector
