Flashcards Dr. Alegre created to help with chapter 13: The Spinal Cord, Spinal Nerves, and Spinal Reflexes
Sensory nuclei receive and relax sensory information from ______.
Motor nuclei issue motor commands to ______ ______.
The _____ gray horns contain somatic and visceral nuclei.
The _____ gray horns contain somatic motor nuclei.
The lateral gray horns are located only in the ____ and _____ segments that contain _____ motor nuclei.
Thoracic and lumbar
Posterior and Anterior to the central canal, ______ contains axons that cross from one side of the cord to the other before they reach a destination in the gray matter.
The gray commissures (a joining together)
This acts as a shock absorber and a diffusion medium for dissolved gases, nutrients, chemical messengers, and waste products.
This procedure introduces radiopaque dyes into the CSF of the subarachnoid space.
The projections of gray matter toward the outer surface of the spinal cord are called _______.
A tract or ______ is a bundle of axons in the CNS that all relax the same type of information (sensory and motor) in the _______ direction.
________ _____ carry information toward the brain (sensory).
Convey motor commands to the spinal cord
This plexus innervates the pectoral girdle and upper limbs and ventral rami of C5-T1.
The nerves arising from this plexus innervate the pelvic girdle and lower limbs. It contains axons from the ventral rami T12-L4.
Lumbar and sacral plexus
_______ consists of the ventral rami of spinal nerves C1-C5. It innervates the muscles of the neck and extends into the thoracic cavity where they control the diaphragm muscles.
The major nerve of this plexus, the ______ nerve provides the entire nerve supply to the diaphragm.
When you step on a tack, a dramatic _____ reflex is produced in the affected leg. With pain receptors in your foot stimulated, the sensory neurons activate _____ in the spinal cord that stimulate motor neurons in the _______ gray horns.
In theory, the contraction of a flexor muscle should trigger a stretch reflex in the _____ that would cause them to contract, opposing the movement.
Interneurons in the _____ ______ prevent this competition through ______ _______.
When the flexors contract, the extensors _______.
Name the 4 major nerve plexuses formed by the ventral rami.
Every spinal segment is associated with a pair of dorsal ______ ______. They contain the cell bodies of ______ neurons.
______ roots bring sensory information into the spinal cord.
_____ roots contain the axons of motor neurons that extend into the peripheny to control ______ and ______ effectors.
somatic and visceral
The ______ surface bears a shallow, longitudinal groove called the posterior median sulcus.
Posterior or dorsal surface
The _____ _____ ______ is a deeper groove along the anterior (ventral) surface.
Anterior median fissure
A slender strand of fibrous tissue, that extends from the inferior tip of the conus medullaris and continues along the length of the vertebral canal as far as the 2nd sacral vertebra.
Filum terminale (terminal thread)
It provides longitudinal support to the spinal cord as a component of the _____ ligament.
The entire spinal cord can be divided into ____ segments on the basis of the origins of the spinal nerves.
The dorsal ramus of each spinal nerve contains ______ motor and ______ motor fibers that innervate the skin and skeletal muscles of the back.
The axons in the relatively large ______ _____ supply the ventro-lateral body surface, structures in the body wall, and the limbs.
Distal to each dorsal root ganglion, the sensory and motor roots are bound together into a simple ____ _____, which are classified as mixed nerves meaning they contain both _____ and _____ fibers.
The spinal cord continues to enlarge and elongate until approx. age _____.
In adults, the spinal cord extends only to the level of ____ or _____.
L1 or L2
This consists of a meshwork of elastic and collagen fibers that is firmly bound to the underlying neural tissue.
Blood vessels servicing the spinal cord run ____ ____ ____ of the spinal pia mater, within the subarachnoid space.
along the surface
______ ligaments prevent lateral movement of the spinal cord.
A collection of neuron cell bodies with a common function is called a ______.
A center with a discrete anatomical boundary is a ______.
Bundles of axons in the white matter of the CNS are called ______. They form larger groups in the spinal cord called ______.
Tracts form larger groups in the spinal cord called
Centers and tracts that link the brain and the rest of the body are called ______.
______ distribute information from peripheral receptors to processing centers in the brain.
_______ begins at the CNS centers that are concerned with motor control and end at the effectors they control.
Step 1 in the reflex arc is the arrival of a stimulus and activation of a ________.
Step 2 is the activation of a ______ neuron.
Step 3 is the ________ processing.
Step 4 is the activation of a ________ neuron.
Step 5 is the response of a ______ ______.
The crossed extensor reflex is called a _____ reflex arc because the motor response occurs on the opposite side of the stimuli.
When you step on a tack, the _____ reflex pulls the affected foot away. The ____ _____ reflex straightens the other leg to support your body weight.
The two occur ______.
Results from the connections that form between neurons during development are _____ ______.
More complex, learned motor patterns are called _____ ______.
What is the neural tissue that protects the spinal cord from the vertebral column. It also provides physical stability and shock absorption?
This forms the tough, outer layer or covering of the spinal cord.
Between the dura mater and the walls of the vertebral canal lies the _____ space. It contains loose connective tissue, blood vessels and a protective padding of adipose tissue.
A delicate network of collagen fibers and elastic fibers that extend between the arachnoid membrane and the outer surface of the pia mater.
Many stretch reflexes are _____ reflexes that help maintain a normal upright posture.
_______ is the central portion of the intrafusal fiber that distorts the dendrites and stimulates the sensory neuron, increasing the frequency of the action potential generation.
_____ is the central portion of the intrafusal fibers that inhibits the sensory neuron, decreasing the frequency of action potential generation.
This moves affected parts of the body away from a source of stimulation.
The strongest reflexes are triggered by ______ stimuli.