Spinal cord Flashcards
Where does the spinal cord begin and end?
medulla oblongata to conus medullaris (L1-L2)
Where does the spinal cord extend from?
foramen magnum of the occipital bone
if the cranial meninges encircles the brain, what surrounds the spinal cord?
spinal meninges
What are the layers of the spiral meninges?
dura mater, arachnoid mater, pia mater
Which layer of the meninges forms a sac from the level of the foramen magnum to the second sacral vertebrae?
dura mater
what is the space between the dura mater and the wall of the vertebral canal and what does it contain?
epidural space; contains a cushion of fat and connective tissue
what is the space btw the dura mater and arachnoid mater and what does it contain?
subdural; contains interstitial fluid
which layer of meninges contains blood vessels that supply oxygen and nutrients to the spinal cord?
pia mater
Which space in the spinal meninges is filled with cerebrospinal fluid?
subarachnoid space
Which component fuses all layers of the meninges and protects against sudden displacement?
denticulate ligaments
which strands of tissue connects the arachnoid mater and pia mater?
arachnoid trabeculae
Where is the inferior end of the spinal cord in adults?
adults? second lumbar vertebra
the cervical enlargement and lumbar enlargement accommodate nerves from ____ to ____?
from lower to upper limbs
It is an extension of the pia mater that arises form the conus medularis to anchor the spinal cord to the coccyx. What it it?
filum terminale
Where does the conus medullaris end in adults?
ends at the level IV disc btw L1 and L2
The inferior portion of the lumbar enlargement where the spinal cord tapers to a conical shaped portion is known as?
conus medullaris
the fine strand of nerves that rather continue in the vertebral canal instead of leaving the vertebral column is known as?
cauda equina (horse’s tail)
What is the lumbar puncture or spinal tap?
administration of local anesthetics with a long needle into the subarachnoid space
How is the vertebral column flexed?
laying in a fetal position
Which vertebrae is spinal tap normally performed in adults?
L3 and L4 or L4 and L5
What is the acronym for the uses of spinal tap?
MAWIII Withdrwaw CSF, measure CSF pressure, administer chemotherapy, Introduce antibiotics, contrast media, and anesthetics
What connects the spinal nerve to a segment of the spinal cord?
two bundles of axons
what are rootlets?
a smaller buundle of axons
what is a root?
1 bundle of axons
The posterior and anterior root are also known as?
dorsal and ventral root
What does the posterior root ganglion contain?
cell bodies of sensory neurons
what does the ventral root contain?
motor neurons
What cross bar of the H shape of spinal grar matter is made up of ____?
gray commissure
the central canal is continuous with which ventricle of the medulla oblongata?
fourth ventricle
what does the white commissure connect in the spinal cord?
left and right sides
What do lateral gray horns contain?
cell bodies of autonomic motor neurons
what is the overall function of the spinal cord gray matter?
receive and integrate incoming and outgoing information
the viruses of this infection destroy cell bodies of motor neurons in the anterior horn of the spinal cord and nuclei of cranial nerves. what is the name of this virus?
polio
what are the divisions of the white matter?
posterior (dorsal), anterior (ventral), and lateral white columns
bundles of myelinated axons that have a common origin and carry similar information are known as ____?
tracts
what are the clear distinctions btw sensory and motor tracts?
sensory tracts are ascending (towards the brain) and motor tracts are descending (down the spinal cord)
Which nerves connect the CNS to sensory receptors, muscles and glands?
spinal nerves
How many pairs of spinal nerves are there?
31 pairs
Where does the first cervical pair of spinal nerves emerge from?
occipital bone and atlas
spinal nerves are named according to the region and level of the vertebral column they emerge from. T or F?
T
How many pairs of cervical, thoracic, lumbar, sacral, and coccygeal sinal nerves are there?
C1-C8, T1-T12, L1-L5, S1-S5, Co1
Spinal nerves exit inferior to the vertebra of the same number except which one?
cranial nerves
While vertebral column growth continues, what age does the spinal cord elongation stop?
4 or 5
The spinal cord extends the entire length of the vertebral column. T or F?
F
cauda equina comprises the roots of which spinal nerves?
lumbar, sacral, and coccygeal nerves
The dorsal and ventral roots of the spinal cord unite to form ____?
the spinal nerve
The spinal nerve divides to form _____?
dorsal primary ramus and ventral primary ramus
A group of axons is known as?
a fascicle
if the entire nerve is covered by the epineurium, what covers the fascicle?
perineurium
What is a common covering found on a myelinated or unmylinated axon?
endoneurium
Which ramus innervates the deep muscles and skin of the dorsal surface of the trunk?
posterior ramus
Which ramus innervates the muscles and structures of the upper and lower limbs and the skin of the lateral and ventrical of the trunk?
anterior ramus
Which structures do the meningeal branch of each spinal nerve supply?
vertebrae canal and associated structures
rami communicantes contributes to which component?
trunk ganglia of the autonomic nervous system
With the exception of most thoracic nerves, anterior rami of spinal nerves form a network of axons known as?
plexus (braid)
Instead of forming plexuses, what do thoracic nerves form?
intercoastal nerves
which muscles do intercostal nerves supply?
intercostal and abdominal muscles
Plexuses contain both sensory and motor neurons. T or F?
T
What are the trunks formed by union of roots in the brachial plexus?
Superior, inferior, and middle trunk
Which plexus supplies the skin and muscle of the head, neck, superior portion of the shoulder and chest, and the diaphragm?
cervical plexus
Which nerves arise from the cervical plexuses and supply motor fibers to the diaphragm?
phrenic nerves
What causes the stoppage of breathing during respiratory arrest?
spinal cord above C3, C4, and C5 origin are severed and phrenic nerve are severed and no longer sending impulses
which part of the body does the brachial plexus supply?
shoulders and upper limbs
Which nerve arises from the brachial plexus and supplies the muscles of the posterior aspect of the arm and forearm?
radial nerve
the inability to extend fingers and wrist known as wrist drop is a result of which nerve damage?
radial nerve
Improperly administering intramuscular injections into the deltoid muscle or applying casts too tightly aroud the humerus can lead to which injury?
radial nerve injury
Which plexus supplies the anterolateral abdominal wall, external genitals, and part of the lower limbs?
lumbar plexus
The largest nerve in the body that arrises from sacral plexus is known as?
sciatic nerve
Pain in the legs, foot, and toes may be due to which nerve injury?
sciatic nerve injury (sciatica)
Herniated disc, dislocated hip, uterus pressure during pregnancy, or improperly administered gluteal intramuscular injection can all lead to ____?
sciatica
Sensations that arise in the skin such as tactile sensations (touch, vibration) or thermal sensation are known as?
cutaneous innervation
What are the 2 types of afferent nerves that convey cutaneous sensations towards the CNS?
dermatomes and cutaneous nerves (peripheral nerve fields)
The area of the skin that provides sensory input to the CNS via one pair of spinal nerves or cranial nerve V is known as?
dermatomes
adjacent dermatomes typically overlap except at _____?
the axial line
herpes zoster, the virus that causes chicken pox also causes?
shingles
When herpes zoster leaves the posterior root ganglion for the sensory neuron of the skin, what are the resulting symptoms?
pain, blisters and skin discoloration
What are the principal functions of the spinal cord?
nerve impulse propagation and information integration
While the gray matter receive and integrate information, what does white matter do?
carries sensory impulses towards the brain and motor impulses from the brain towards effectors
What information can be derived from the name of a tract such as lateral corticospinal tract?
lateral white column; starts at the cortex and ends at the spinal cord; motor neuron because it carrying information away from the brain
What is the ability to feel exactly what part of the body is touched?
discriminative touch
The precise control and voluntary muscular movement is controlled by ____?
the cerebral cortex
what are the types of descending pathways?
direct and indirect pathways
Which descending pathway causes voluntary movement and which causes autonomic movement of skeletal muscles?
direct pathways causes voluntary movement and indirect pathways causes autonomic movement
what are the types of direct pathways?
LAC; lateral corticospinal, anterior corticospinal, and corticobulbar tract
direct pathways originate in the cerebral cortex, while indirect pathways originate in the ____?
brain stem
What are the types of the indirect pathways?
RTV ML; Rubrosipnal, tectospinal tract, vestibulospinal tract, lateral reticulospinal tract, and medial reticulospinal tract
A fast, involuntary sequence of actions that occurs in response to a particular stimulus is known as ____?
reflex
Reflexes may be innate or learned or they may be ___ or ___?
spinal reflex or cranial refex
What is the difference btw somatic and visceral reflexes?
somatic reflexes contract skeletal muscles while visceral reflexes are for glands, smooth, cardiac muscles (ANS)
The specific pathways that nerve impulses follow into the CNS are known as?
reflex arcs
What are the reflex arc components?
MISES; sensory receptor, sensory neuron, integrating center, effector, motor neuron
When a generator/graded potential of a sensory receptor reaches threshold, what occurs?
nerve impluse(s) are triggered.
what are polysynaptic reflex arc?
arcs with integrating center comprising of more than one synapse and more than two neurons
which feature of the muscles prevents over-stretching by causing contraction?
patellar reflex (stretch reflex)
What is the clinical correlation for the absence of patellar reflex?
westphal’s sign
It is the opposite of stretch reflex because it causes muscle relaxation when the muscle tension is too high. What is it?
tendon reflex
What is the difference btw flexor reflex and crossed extensor reflex?
flexor reflex helps to contract flexor muscles to avoid pain or injury while crossed extensor reflex helps to maintain balance.
the gentle stroking of the lateral outer margin of the sole is known as?
platar flexion stroke
What is the dosiflexion of the the great toe with/without lateral fanning of the other toe under the age of 1(1/2)?
babinski sign
The presence of babinski sign after age 1(1/2) instead of toe curling is an interruption of which tract?
corticospinal tract
A reflex indicating a damage to a pyramidal tract where there is a rapid decrease in resistance when flexing a joint is known as?
clasp knife reflex
Unlike somatic reflexes that can be tested by tapping, all autonomic reflexes are not practical diagnostic tools except which one?
pupillary light reflexes
What is the major difference btw hyperactive reflexes and decreased reflexes?
hyperactive reflexes indicates CNS disease while decrease reflexes is usually found outside the CNS
