nervous system 2 Flashcards
the cervical enlargement
supplies nerves to the pectoral girdle and upper limbs
the lumbar enlargement
provides innervation to structures of the pelvis and lower limbs
how many segments is the spinal cord divided into?
31
every spinal segment is associated with a pair of ____ that contain the cell bodies of sensory information
dorsal root ganglia
a dorsal root contains
the axons of the sensory neurons in the dorsal root ganglia
ventral root
leaves the spinal cord
the ventral root contains
the axons of both somatic and visceral motor neurons that control peripheral effectors
spinal nerve
distal to each dorsal root ganglion, formed by sensory and motor fibers
spinal nerves AKA
mixed nerves because they contain both afferent (sensory) and efferent (motor) fibers
the spinal cord continues to enlarge and elongate until an individual is how old?
approximately 4 years old
spinal meninges are
collevtions of specialized membranes that provide protection, physical stability, and shock absorption to the spinal cord
what are the three meningeal layers?
the dura mater, the arachnoid matter and the pia matter
the dura mater is
tough, fibrous, outermost covering of the spinal cord and brain
arachnoid mater is
the middle layer
the space the seperates the dura mater for the deeper meningeal layers is called the
subdural space
the arachnoid mater is seperated from the pia mater by the
subarachnoid space
the subarachnoid space contains what?
cerebrospinal fluid (CSF)
CSF
acts as a shock absorber as well as a diffusion medium for dissolved gases, nutrients, chemical messengers and waste products
the pia mater
innermost meningeal layer
the projection of gray matter toward the outer surface of the spinal cord are called
horns
white matter contains what?
large numbers of myelinated and unmyelinated axons organized in tracts and columns
sensory nuclei
receive and relay sensory info for peripheral receptors
motor nuclei
issue motor commands to peripheral effectors
posterior gray horns contain
somatic and visceral sensory nuclei
anterior gray horns contain
neurons concerned with somatic motor control
lateral gray horns are found
between segments and contain visceral motor neurons
the white matter can be divided into what 2 columns?
ascending tracts and descending tracts
ascending tracts
carry sensory information toward the brain
descending tracts
convey motor commands into spinal cord
each pair of spinal nerves monitors a specific region of the body surface, this area is called
a dermatome
an interwoven network of nerves is called a
nerve plexus
where do nerve plexuses exist?
where ventral rami are converging and branching to form these compound nerves
the 4 major nerve plexuses are the
cervical plexus, brachial plexus, lumbar plexus, sacral plexus
cervical plexus
innervate the muscles of the neck and extend into the thoracic cavity to control the diaphragm
the phrenic nerve is
the major nerve of this plexus, provides the entire nerve supply to the diaphragm
the brachial plexus
larger and more complex than the cervical. innervates the pectoral girdle and upper limb
what does the lateral cord form?
the musculocutaneous nerve
the lateral cord and then medial cord form?
the median nerve
the ulnar nerve is
the other major nerve of the medial cord
the posterior cord forms
the axillary nerve and the radial nerve
