Somatic Nervous System flash card
What are multipolar neurons?
motor (efferent) nerves that convey neural impulses from the CNS to distant targets
What are pseudounipolar neurons?
sensory (afferent) nerves that convey neural impulses from sensory receptors to the CNS
What does the nervous system allow us to do?
enables our body to react to continuous changes in our internal and external environments
How can the nervous system be divided structurally?
CNS (brain and spinal cord) and PNS (cranial and spinal nerves)
How can the nervous system be divided functionally?
somatic (voluntary) nervous system and autonomic (involuntary) nervous system
What are the functions of the central nervous system?
integrates and coordinate incoming and outgoing signals and carries out higher order “cognitive” functions such as learning & memory
What is gray matter?
consists of regions within the CNS which contain a high density of nerve cell bodies
How are the H-shaped regions of horns subdivided?
dorsal horns and ventral horns
What is white matter?
consists of bundles of nerve axons (referred to as tracts) which are traveling to and from the brain
What is the function of the PNS?
conducts impulses to or away from the CNS
What are ganglion?
collection of nerve cell bodies in the PNS
What is a peripheral nerve?
bundle of nerve axons in the PNS
How are peripheral nerves classified?
cranial nerves or spinal nerves
What are the 32 pairs if spinal nerves
8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygcal
Where do the spinal nerves arise?
from the spinal cord
How do spinal nerves arise?
from the spinal cord by rootlets
What do the rootlet of the spinal cord converge to form?
the dorsal root and ventral root
What do the dorsal and ventral roots unite to form?
the spinal nerve
What do spinal nerves divide into?
dorsal and ventral ramus
What are peripheral nerves?
spinal nerves and their branches (dorsal and ventral rami)
What does the dorsal ramus do?
convey nerve fibers to/from:
back muscles and skin overlying the back
What does the ventral ramus do?
conveys nerve fibers to/from a much larger area of the body:
the anterior and lateral regions of the torso/trunk
the arms and legs
What different types of nerves do peripheral nerves carry?
somatic motor, general sensory, visceral motor, visceral sensor
What do somatic motor nerves do?
convey impulses from the CNS to skeletal (voluntary) muscles
What are somatic motor nerves?
What do general sensory nerves do?
convey sensations from the body to the CNS such as pain, touch, temperature
What are general sensory neurons?
Where do cell bodies of the somatic motor nerves reside?
Where do the axons of the somatic motor nerves exit?
via the ventral root and ultimately innervate skeletal muscles
Where do cell bodies of the general sensory nerve axons reside?
dorsal root ganglion
a swelling located along the dorsal root of all spinal nerves
Where do the general sensory nerve axons project?
into the dorsal horn of the spinal cord via the dorsal root
Identify the functional nerve components
Where does the somatic nervous system provide general sensory and motor innervation?
to all parts of the body except: organs int eh body cavities, smooth and cardiac muscle, glands (seat and salivary)