Ch. 14 Spinal Cord Flashcards
The spinal cord ends at what vertebra with the Conus Medullaris
L1
The spinal cord has 2 widened regions with a greater number of neurons… the regions supplying the upper limbs is the
Cervical Enlargement
The spinal cord has 2 widened regions with a greater number of neurons… the regions supplying the lower limbs is the
Lumbar Enlargement
Spinal cord subdivisions give rise to ______ (#) spinal nerves
31
Part of PNS, with origins of spinal nerves from conus medullaris and lumbosacral enlargement
Cauda Equine
Thin strand of pia attaching conus medullaris to coccyx
Filum Terminale
Grooves on front of spinal cord
Anterior Median Fissure
Grooves on back of spinal cord
Posterior Median Sulcus
___________ is a Meninges, a delicate layer adhering to spinal cord
Pia Mater
_____________ Is a web-like layer of the Spinal Cord Meninges
Arachnoid Mater
Area deep to arachnoid mater through which CSF flows
Subarachnoid space
Tough, outermost layer of spinal cord meninges
Dura mater
__________ space is between dura and arachnoid mater
Subdural
__________ space is between dura and vertebra
Epidural
Masses of ______ matter project from the center of the spinal cord
Grey
__________ Horns house cell bodies of somatic motor neurons
Anterior
__________ Horns house cell bodies of autonomic motor neurons
Lateral
_________ Horns house axons of sensory neurons and soma of interneurons
Posterior
This structure surrounds the central canal
Grey Commissure
Sensory nuclei in ___________ horn contain interneurons.
Posterior
___________ sensory nuclei receive signals from skin, muscle, joints
Somatic
____________ sensory nuclei receive signals from blood vessels, viscera.
Visceral
Motor Nuclei in __________ and ____________ horns contain motor neurons.
Anterior and Lateral
___________ motor nuclei (Anterior) innervate skelteal muscle.
Somatic
_______________ motor nuclei (lateral) innervate smooth muscle, heart, glands.
Autonomic
Funiculus are collectively known as “___________,” and are made of white matter.
Columns
____________ Funiculus - contains sensory tracts
Posterior
___________ & ____________ Funiculus - Contains ascending (sensory) and descending (motor) tracts
Lateral & Anterior
Ascending spinal pathways carry _________ information.
Sensory
Descending spinal pathways carry ______ information.
Motor
Cell locations of spinal pathways:
Axons are in spinal cord __________
Tracts
Cell locations of spinal pathways:
Cell bodies are in _________, spinal cord grey horns, and brain gray matter
Ganglia
Cell locations of spinal pathways:
Cell bodies are in ganglia, spinal cord grey horns, and brain ______ matter
Grey
Spinal pathways are ____________ (There is left and a right tract)
Paired
Most spinal pathway ___________: Axons cross the midline
Decussate
Contralateral means
Axons cross the midline, Information from L side of body goes to right side of brain
Ipsilateral means
Axons do not cross, Information from Left side of body goes to left side of brain
There are ____ (#) neuron sensory pathways in the spinal cord
3
There are ____ (#) neuron Motor pathways in the spinal cord
2
Each spinal nerve is formed from a merger of __________ root and _____________ root.
Anterior and Posterior
__________ Root: Axons of motor neurons whose somas are in anterior and lateral horns
Anterior
_________ Root: Axons of sensory neurons whose somas are in posterior root ganglion.
Posterior
Branches (Rami) of Spinal Nerves:
_________ Ramus - Innervates muscles and skin of back
Posterior
Branches (Rami) of Spinal Nerves:
___________ Ramus: Splits into multiple other branches, participates in plexuses.
Innervated anterior and lateral trunk, upper limb, and lower limb.
Anterior
Branches (Rami) of Spinal Nerves:
__________ ____________: Autonomic fibers that extend between spinal nerve and sympathetic trunk ganglion.
Rami Communicantes
Segment of skin supplied by a single spinal nerve
Can help localize damage to spinal nerves
Involved in referred visceral pain
Dermatomes
______________ nerves are located between ribs. Most thoracic anterior rami.
Intercostal
Network of interweaving anterior rami
Nerve Plexus
Four Main plexuses
Cervical, Brachial, Lumbar, Sacral
Branches of the Cervical plexus innervate: _________, ___________, and ________________
Neck, Head, and Shoulders
In the cervical plexus, from rami C3-C5, gives rise to __________ nerve.
Phrenic
The phrenic nerve innervates the …
Diapraghm
Brachial plexus cords give rise to __ (#) major terminal branches
5
Axillary Nerve
Median Nerve
Musculocutaneous Nerve
Radial Nerve
Ulnar Nerve
Are all part of what plexus.
Brachial
Cervical plexus is made up of _________ Rami of C1-C4, and a fw axons of C5
Anterior
Brachial Plexus is made up of _________ Rami of C5-T1, including trunks, divisions, and cords
Anterior
____________ Plexus is made up of anterior Rami of L1-L4
Lumbar
Terminal branches of _________ Plexus include:
Femoral Nerve
Obturator Nerve
Lumbosacral Trunk
Lumbar
_________ Plexus is made up of anterior Rami of L4 - S4
Sacral
Largest, and longest nerve in the body, part of Sacral Plexus
Sciatic Nerve
Sciatic Nerve splits into
- ____________ Nerve
- Common _____________ Nerve
Tibial Nerve
Common Fibular Nerve
A ___________ is required to initiate a reflex.
Stimulus
Reflex responses are preprogrammed, meaning…
Response is always the same
Neural pathway responsible for generating involuntary response to a stimulus.
Reflex Arc
Steps of a Reflex Arc:
- ________ activates receptor
- Nerve signal is propagated through sensory neuron to the spinal cord
- Nerve signal is processed in the integration center of the spinal cord by interneurons
- Nerve signal is propagated by motor neuron to effector
- Effector responds
Stimulus
Steps of a Reflex Arc:
- Stimulus activates receptor
- Nerve signal is propagated through sensory neuron to the ____________
- Nerve signal is processed in the integration center of the spinal cord by interneurons
- Nerve signal is propagated by motor neuron to effector
- Effector responds
Spinal Cord
Steps of a Reflex Arc:
- Stimulus activates receptor
- Nerve signal is propagated through sensory neuron to the spinal cord
- Nerve signal is processed in the integration center of the spinal cord by ____________
- Nerve signal is propagated by motor neuron to effector
- Effector responds
Interneurons
Steps of a Reflex Arc:
- Stimulus activates receptor
- Nerve signal is propagated through sensory neuron to the spinal cord
- Nerve signal is processed int he integration center of the spinal cord by interneurons
- Nerve signal is propagated by motor neuron to _________
- Effector responds
Effector
Different classes of spinal reflexes:
Spinal or __________
Cranial
Different classes of spinal reflexes:
Somatic or ______________
Visceral
Different classes of spinal reflexes:
Monosynaptic or ____________-
Polysynaptic
Different classes of spinal reflexes:
Ipsilateral or ______________
Contralateral
Different classes of spinal reflexes:
Innate or ___________
Acquired
_________ Reflex - Direct communication between sensory and motor neurons
Monosynaptic
______________ Reflex - Interneuron facilitates sensory-motor communication
Polysynaptic
Example of a monosynaptic reflex is…
Stretch reflex
Example of a Polysynaptic reflex is …
Withdrawal reflex
Stretch Reflex
Is classified as spinal or cranial?
Spinal
Stretch reflex is classified as:
Somatic or visceral?
Somatic
Stretch reflex is classified as:
Contralateral or Ipsilateral
Ipsilateral
Stretch reflex is classified as
Innate or Acquired
Innate
- *Steps of Stretch Reflex Activation**
1. Muscle spindle detects stretch
2. Muscle stretch stimulates _____ nerve signals to travel to the CNS
3. Sensory neuron synapses on motor neurons
4. Motor neurons transmit nerve signals to muscle fibers, resulting in contraction of the muscles
5. Interneurons synapse with motor neurons to antagonist muscles, inhibiting muscle contraction
Sensory
- *Steps of Stretch Reflex Activation**
1. Muscle spindle detects stretch
2. Muscle stretch stimulates sensory nerve signals to travel to the CNS
3. Sensory neuron synapses on _______ neurons
4. Motor neurons transmit nerve signals to muscle fibers, resulting in contraction of the muscles
5. Interneurons synapse with motor neurons to antagonist muscles, inhibiting muscle contraction
Motor
- *Steps of Stretch Reflex Activation**
1. Muscle spindle detects stretch
2. Muscle stretch stimulates sensory nerve signals to travel to the CNS
3. Sensory neuron synapses on motor neurons
4. Motor neurons transmit nerve signals to _______ fibers, resulting in contraction of the muscles
5. Interneurons synapse with motor neurons to antagonist muscles, inhibiting muscle contraction
Muscle
- *Steps of Stretch Reflex Activation**
1. Muscle spindle detects stretch
2. Muscle stretch stimulates sensory nerve signals to travel to the CNS
3. Sensory neuron synapses on motor neurons
4. Motor neurons transmit nerve signals to muscle fibers, resulting in contraction of the muscles
5. ________ synapse with motor neurons to antagonist muscles, inhibiting muscle contraction
Interneurons
- *Steps of Stretch Reflex Activation**
1. Muscle spindle detects stretch
2. Muscle stretch stimulates sensory nerve signals to travel to the CNS
3. Sensory neuron synapses on motor neurons
4. Motor neurons transmit nerve signals to muscle fibers, resulting in contraction of the muscles
5. Interneurons synapse with motor neurons to _________ muscles, inhibiting muscle contraction
Antagonist
Example of Stretch Reflex
Knee Jerk, when doctor taps your patellar tendon cause quadricep muscle to strecth
Steps of Golgi Tendon Reflex
- Muscle contraction increases tension to tendons, detected by __________ organ
- Muscle contraction stimulates sensory nerve signals that travel to the CNS
- Sensory neurons stimulate interneurons within the spinal cord
- Interneurons inhibit motor neurons to muscle, and stimulate motor neurons to antagonistic muscles
- Muscle relaxes and there is relief of tension on the tendon
Golgi Tendon
Steps of Golgi Tendon Reflex
- Muscle contraction increases tension to tendons, detected by Golgi tendon organ
- Muscle contraction stimulates _______ nerve signals that travel to the _____
- Sensory neurons stimulate interneurons within the spinal cord
- Interneurons inhibit motor neurons to muscle, and stimulate motor neurons to antagonistic muscles
- Muscle relaxes and there is relief of tension on the tendon
Sensory nerve
Travel to the CNS
Steps of Golgi Tendon Reflex
- Muscle contraction increases tension to tendons, detected by Golgi tendon organ
- Muscle contraction stimulates sensory nerve signals that travel to the CNS
- Sensory neurons stimulate interneurons within the _____________
- Interneurons inhibit motor neurons to muscle, and stimulate motor neurons to antagonistic muscles
- Muscle relaxes and there is relief of tension on the tendon
Spinal Cord
Steps of Golgi Tendon Reflex
- Muscle contraction increases tension to tendons, detected by Golgi tendon organ
- Muscle contraction stimulates sensory nerve signals that travel to the CNS
- Sensory neurons stimulate interneurons within the spinal cord
- Interneurons ______ motor neurons to muscle, and ________ motor neurons to antagonistic muscles
- Muscle relaxes and there is relief of tension on the tendon
Inhibit motor neurons to muscle
Stimulate/Excite motor neurons to antagonistic muscles
Steps of withdrawal & crossed-extensor reflex
- ________ stimulus is detected by sensory neurons
- Sensory nerve signal detected by interneurons
- Interneurons stimulate motor neurons to flexors, resulting in withdrawal of limb from painful stimulus
- Other interneurons cross to the opposite side and stimulate motor neurons to extensors on other side of the body, resulting in extensor contraction and support of body weight
Painful
Steps of withdrawal & crossed-extensor reflex
- Painful stimulus is detected by sensory neurons
- Sensory nerve signal detected by ____________
- Interneurons stimulate motor neurons to flexors, resulting in withdrawal of limb from painful stimulus
- Other interneurons cross to the opposite side and stimulate motor neurons to extensors on other side of the body, resulting in extensor contraction and support of body weight
Interneurons
Steps of withdrawal & crossed-extensor reflex
- Painful stimulus is detected by sensory neurons
- Sensory nerve signal detected by interneurons
- Interneurons stimulate motor neurons to flexors, resulting in __________ of limb from painful stimulus
- Other interneurons cross to the opposite side and stimulate motor neurons to extensors on other side of the body, resulting in extensor contraction and support of body weight
withdrawal
Steps of withdrawal & crossed-extensor reflex
- Painful stimulus is detected by sensory neurons
- Sensory nerve signal detected by interneurons
- Interneurons stimulate motor neurons to flexors, resulting in withdrawal of limb from painful stimulus
- Other interneurons cross to the opposite side and stimulate motor neurons to extensors on other side of the body, resulting in extensor___________ and support of ____________
Extensor contraction
Support of body weight
