Spinal Cord, Spinal Nerves, and Spinal Reflexes Flashcards
Layers of tissue that protect the spinal cord
Meninges
Outer layer of meninges
Dura mater
Middle layer of meninges
Arachnoid mater
Inner layer of meninges
Pia mater
Space between dura mater and walls of vertebral canal; contains blood vessels and fat; anesthetic injection site
Epidural space
Space between arachnoid mater and pia mater filled with CSF and contains blood vessels
Subarachnoid space
Viral or bacterial infection of meninges
Meningitis
Carry sensory information towards the brain
Ascending tract
Carry outgoing motor information from the brain
Descending tract
What 2 things does white matter contain?
Ascending and descending tracts
Contains axons of sensory (afferent) neurons
Dorsal root
Contains axons of motor (efferent) neurons
Ventral root
Contains cell bodies of sensory neurons
Dorsal root ganglion
On each side of spine where dorsal and ventral roots join
Spinal nerve
Area of skin that provides sensory input via dorsal roots of one pair of spinal nerves
Dermatomes
Caused by a virus that attacks dorsal roots; produces painful rash and blisters on skin whose distribution corresponds to that of the effected sensory nerves
Shingles
Rapid automatic response to a specific stimulus
Reflex
Wiring of a single reflex
Reflex arc
What is the 1st step of a neural reflex?
Stimulus activates receptor
What is the 2nd step of a neural reflex?
Sensory neuron stimulated
What is the 3rd step of a neural reflex?
Information processing in CNS
What is the 4th step of a neural reflex?
Activation of motor neuron
What is the 5th step of a neural reflex?
Response of peripheral effector
What are the 4 classifications of a reflex?
By development, response, complexity of circuit, processing site
Control skeletal muscle contractions
Somatic reflex
Controls actions of smooth and cardiac muscles and glands
Autonomic reflex
1 synapse
Monosynaptic
More than 1 synapse
Polysynaptic
Processing site in spinal cord
Spinal reflex
Processing site in brain
Cranial reflex
Reflex that have the least delay between sensory input and motor output
Monosynaptic reflex
What is an example of a monosynaptic reflex?
Stretch reflex
Receptors in muscles that detect change in muscle fiber length
Muscle spindles
What is the 1st step in the stretch reflex?
Muscle spindle is stretched
What is the 2nd step in the stretch reflex?
Stimulus travels via afferent neurons to spinal cord
What is the 3rd step in the stretch reflex?
Synapse with efferent motor neuron which tells muscle to contract
Reflex where interneurons control more that 1 muscle group; Responses could involve stimulation of some muscles and inhibition of others
Polysynaptic reflex
What is an example of a polysynaptic reflex?
Withdrawal reflex
What are stretch reflexes controlled by?
Specific segment of the spinal cord
What does testing different reflex provide us?
Information about the status of corresponding spinal segments
What can reflexes be used to determine?
Damage to descending motor tract
Toes flare out when stimulated on the bottom of the foot
Babinski reflex
If an adult flares out their toes while doing the Babinski reflex, what can that tell us?
There might be damage to the descending motor tract
