Nervous system 2 Flashcards
Where does the spinal cord extend from and to?
The spinal cord extends from the foramen magnum to the level of the first or second lumbar vertebrae (L1 or L2).
What is the function of the spinal cord?
The spinal cord facilitates two-way communication between the body and the brain, contains centers for spinal reflexes, and is responsible for initiating complex motor activities.
How many pairs of spinal nerves are there, and where do they exit?
There are 31 pairs of spinal nerves, which exit the spinal column via the intervertebral foramina.
What structures hold the spinal cord in place?
The spinal cord is held in place by the denticulate ligaments (extensions of the pia mater) and the filum terminale (a connective tissue filament extending to the coccyx).
What is the cauda equina?
The cauda equina is a bundle of spinal nerves and nerve rootlets, consisting of the second through fifth lumbar nerve pairs, all sacral nerve pairs, and the coccygeal nerve. It resembles a horse’s tail and is located in the lumbar cistern.
What divides the spinal cord into two halves?
The spinal cord is divided by the ventral (anterior) median fissure and the dorsal (posterior) median sulcus.
What is gray matter in the spinal cord made up of?
Gray matter in the spinal cord consists of multipolar neurons and is organized into paired anterior (ventral) and posterior (dorsal) horns, connected by the gray commissure.
What is the central canal in the spinal cord?
The central canal extends from the conus medullaris in the lumbar spine to the fourth ventricle, running through the center of the gray commissure.
Why are the ventral horns larger at the cervical and lumbar enlargements?
The ventral horns are larger at the cervical and lumbar enlargements because these areas correspond to the origins of nerves controlling the upper and lower limbs, which require a large number of motor neurons for precise control.
What is the role of the dorsal horns in the spinal cord?
The dorsal horns contain interneurons that receive sensory input, both somatic and visceral.
What do the lateral horns in the spinal cord contain?
The lateral horns contain sympathetic motor neurons that innervate visceral organs. These neurons exit the spinal cord via the ventral roots.
