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64 terms

The Spinal Cord

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vertebral column
The spinal cord is protected by this
brain stem
the spinal cord runs from this, through the foramen magnum to L1-L2
couda equina
the spinal cord continues from L1-L2 to the coccyx, unbundled fibrous, forming this
spinal nerves
what caries sensory and motor information between the PNS and CNS?
relay station, reflex station
what are the two functions of the spinal cord?
relay station
this function of the spinal cord carries sensory information to the brain for integration and carries motor responses from the brain to the effectos
reflex station
this function of the spinal cord recieves sensory information and generates rapid, automatic motor responses that do not involve the brain.
spinal meninges
this is the combination of 3 membrane layers that surround the spinal cord. It provides shock absorption, structural support
dura arachnoid pia
what are the three membrane layers of the spinal meninges?
dura mater
this is the outermost layer of the spinal meninges that is made of tough fiberous membrane. it is separated from the vertebral column by the epidural space
epidural space
this arrea that separated the dura mater from the vertebral column contains blood vessels and adipose padding
epidural blocks
anesthetics administered in the epidural space as known as
arachnoid mater
this is the middle layer of the spinal meninges
pia mater
this is the inner layer of the spinal meninges. it is firmly bonded to the surface of the spinal cord.
subarchnoid space
this area is between the pia mater and the dura mater. it is filled with cerebrospinal fluid and contains blood vessels
spinal tap
this is the test in which scientists take samples of CSP for analysis from the subarachnoid space
dorsal ventral
what are the two types of nerve roots/
dorsal
this nerve root is incharge of sensory neurons
ventral
this nerve root is incharge of motor neurons
ganglion
this is a bundle of cell bodies in the PNS. it is only found on the dorsal nerve root.
white matter
this is the outer layer of the spinal cord. it is made of MYELINATED axons that run up (sensory) and down (motor) the spinal cord
gray matter
this is the inner layer. it is made up of UNMYELINATED axons, cell bodies, and neuroglia.
horns
masses of gray matter in the spinal cord that contain nuclei
nuclei
this is a bundle of cell bodies that make up gray matter in the CNS
sensory motor
what are the two types of nuclei
posterior
this type of horn contains sensory nuclei
somatic sensory nuclei
this type of nuclei receives information from the external environment
visceral sensory nuclei
this type of nuclei recieves information from the internal environemnt
anterior
this type of horn contains somatic motor nuclei that send comands to viseral
lateral
this type of horn contains viseral motor nuclei
gray commissures
these are axons that connect both sides of a cord
tracts
these are bundles of axons that make up white matter in the CNS
ascending
this tract sends sensory information to the brain
descending
this tract sends motor infromation from the brain
white columns
this is a collection of tracts
31
how many pairs of spinal nerves
cervical
c1-c8
thoracic
t1-t12
lumbar
l1-l5
sacral
s1-s5
coccygeal
co1
spinal nerves
each of these branch from the spinal cord to become the peripheral nerves of the PNS. each pair of this monitors a specific region of the skin (dermatone)
endoneurium
inner layer of the spinal nerve. it surrounds each neuron
perineurium
middle layer of spinal nerve. surrounds bundles of neurons called fasicles
epineurium
outer layer of spinal nerves. surrounds all of the fasicles, creatng PNS
nerve plexuses
these are adjacent spinal nerves that innervate skeletal muscles, blend to form complex networks
cervical
c1-c5. plexusthat innervated muscles and skin of the cervical and thoracic regions.
brachial
c4-t1. these are plexus innervating the pectoral girdle and upper limbs. it contains radical nerves, ulnar nerves, and median nerves
lumbar
t12-l4. these are plexuses that innnervate the abdominals, anterior and medial lower limbs.
sacral
l4-c1. this plexus innervates the gluteal and posterior and lower limbs. it contains siatic nerves.
reflexes
these are rapid, predictable, automatic responses to specific stimuli. they maintain homeostasis by making rapid adjustments to organs.
innate
reflexes that are genetically programmed. they have predictable results
aquired
these types of reflexes are learned and enhanced by repetition.
reflex arc
neural pathway a reflex follows
stimulus
actives a receptor
sensory input
activates a sensory neuron
information processing
this is processed by cord and brain
motor response
activates one or more motor neurons
effector
activates an effect
monosynaptic
type of reflex where sensory neuron synapse with only a motor neuron. involves only one spinal segment
very simple and fast
EX: stretch reflex
stretch reflex
protects skeletal muscle from over stretching. muscle spindles monitor the speed and intensity of a lengthening muscle. the motor neuron causes the stretched msucle to contract
polysynaptic
type of relfex that sensory neuron synape with more than one interneuron. it involves one or more spinal segment and it is more complex with slower reaction time.
EX: tendon reflex
Withdrawal reflex
tendon reflex
this protects skeletal muscles from over contracting. receptors called golgi tendon organs monitor the amount of tension in contracting muscle tendons. sensory neurons synapes with an inhibitory interneouron which interrupts motor neuron impulses to the contracting muscles, causing muscles to relax. this prevents damage to muscle tendon or bone (avulsion)
withdrawal reflex
reflex in which receptors (nociceptors) are triggered by painful stimuli, whichc auses the body to move away from the stimulus. it causes contractions of flexor muscles and inhibition of extensor muscles. it can involve many interneous along many segments of the spinal cord.