Spinal cord conducts signals up and down the body passing through gray and white matter, respectively.
Cervical and lumbar enlargements are wide points in the cord marking the emergence of motor nerves.
Nerve fibers in a given tract in the white matter are similar in origin, destination, and function.
The tendon reflex is the inhibition of a muscle contraction that occurs when its tendon is excessively stretched.
The cross extension reflex is the contraction of the extensors on one side of the body when the flexors are contracted on the other side
the precentral gyrus of the cerebrum.
The upper motor neurons that control skeletal muscles begin with a soma in
to protect neurons in both the ascending and descending tract.
The following are all functions associated with the spinal cord except
a fracture of vertebra L4
Which of the following fractures would be the least likely to cause a spinal cord injury
posterior root of a spinal nerve
This figure shows a detail of the spinal cord, meninges and spinal nerves. What does "1" represent?
This figure shows a detail of the spinal cord, meninges and spinal nerves. What does "4" represent?
dural sheath and vertebral bones
Epidural anesthesia is introduced in the epidural space between ___ to block pain signals during pregnancy.
This figure shows the posterior aspect of spinal nerve roots and plexuses. What does "3" represent?
the cervical enlargement
This figure shows the posterior aspect of spinal nerve roots and plexuses. What does "2" represent?
the thoracic region
The ventral rami of the spinal nerves form nerve plexuses in all regions except
This figure shows a dermatome map. A patient with no sensation in the left thumb would probably have a nerve damaged in
posterior (dorsal) root
Which of the following branches of a spinal nerve have somas of solely sensory neurons?
The bundle of nerve roots that occupy the vertebral canal from L2 to S5 is called the
posterior root ganglion; gray matter
Neurosomas of the posterior root are located in the ___, whereas neurosomas of the anterior root are located in the ___.
somatic receptor afferent nerve fiber interneuron efferent nerve fiber skeletal muscle
Which one of the following best describes the order of a somatic reflex?
reflexes are spontaneous actions of the nervous system.
These are all properties of reflexes except
flexor (withdrawal) reflex.
A nurse pricks your finger to type your blood. You flinch at the pain, pulling your hand back. This is called the
parallel after-discharge circuit
The flexor (withdrawal) reflex employs a ____, which maintains a sustained contraction.
an intersegmental reflex.
If a bee sting on the right thigh causes a quick involuntary reaction of the right arm, this would be an example of
alpha motor neurons.
The fibers that carry action potentials to cause skeletal muscle to contract are
stretch (myotatic) reflex.
You go to the movies after a long day and you begin to nod off as soon as the movie starts. Your head starts to lower a little but this reflex causes your head to rise. This is called the
contract and the antagonist muscles, the hamstrings, to relax.
In the patellar tendon reflex arc, the patellar ligament is stretched, which stretches the quadriceps femoris muscle of the thigh. This reflex will cause the quadriceps femoris to
A reflex where the sensory input and motor output are on opposite sides of the spinal cord is called a(n) _____ reflex arc.