Chapter 12 Flashcards
Cranial nerve
Any of the 12 pairs of nerves that originate from the brain.
Cerebrum
The largest and most advanced portion of the brain; divided into two hemispheres.
longitudinal Fissure
The crevice that runs along the length of the brain and divides the cerebral hemispheres.
Cerebelleum
The portion of the brain that controls skeletal muscle movement.
Brainstem
Lower portion of the brain composed of the pons, midbrain, and medulla oblongata.
Vertebral Canal
Encloses and protects the spinal cord; within the vertebrae.
Three meningeal layers surround the spinal cord
the dura mater, arachnoid mater, and pia mater.
Vertebral Column
A series of 33 vertebrae that enclose the spinal cord.
White matter
is organized into columns, which are subdivided into nerve tracts, or fascicles, which carry action potentials to and from the brain.
Gray Matter - The dorsal horns
contain sensory axons that synapse with interneurons.
Gray matter - Ventral horns
The ventral horns contain the neuron cell bodies of somatic motor neurons, and the lateral horns contain the neuron cell bodies of autonomic motor neurons.
The dorsal root
conveys sensory input into the spinal cord, an
the ventral root
conveys motor output away from the spinal cord.
Muscle spindles
detect the stretch of skeletal muscles and cause the muscle to shorten reflexively.
Golgi tendon organs
respond to increased tension within tendons and cause skeletal muscles to relax.
Activation of pain receptors
causes muscles to contract and move some part of the body away from a painful stimulus.
Reciprocal innervation
causes muscles that would oppose withdrawal to relax.
Spinal nerve S5 and the coccygeal nerve
form the coccygeal plexus, which supplies the muscles of the pelvic floor and the skin over the coccyx.
In the crossed extensor reflex.
, flexion of one limb caused by the withdrawal reflex stimulates the opposite limb to extend
The obturator nerve
supplies the muscles that adduct the thigh and the skin of the medial thigh.
The femoral nerve
supplies the muscles that flex the thigh and extend the leg and the skin of the anterior and lateral thigh and the medial leg and foot.
The tibial nerve
innervates the muscles that extend the thigh and flex the leg and the foot. It also supplies the plantar muscles and the skin of the posterior leg and the sole of the foot.
The common fibular nerve
supply the short head of the biceps femoris, the muscles that dorsiflex and plantar flex the foot, and the skin of the lateral and anterior leg and the dorsum of the foot.
Other lumbosacral nerves
supply the lower abdominal muscles, the hip muscles, and the skin of the suprapubic area, external genitalia, and upper medial thigh.
In the thigh, the tibial nerve and the common fibular nerve
are combined as the sciatic nerve.