NERVOUS SYSTEM: SPINAL NERVES Flashcards
arise along the spinal cord from the union of the dorsal roots and ventral roots
spinal nerves
all the spinal nerves contain axons of both sensory and somatic motor neurons and thus called
mixed nerves
what are the regions of the vertebral column
cervical
thoracic
lumbar
sacral
coccygleal
the area of the skin supplied with sensory innervation by a pair of spinal nerves
dermatome
what are the three major plexuses
cervical plexus
brachial plexus
lumbosacral plexus
this small plexus supplies motor innervation to the muscles of the pelvic floor and sensory cutaneous innervation to the skin over the coccyx
coccygleal plexus
originates from the spinal nerves C1 to C4 ; branches from this plexus innervate several of the muscles attached to the hyoid bone
cervical plexus
one of the most important cervical plexus is the
phrenic nerve
originates from the C5 to T1 ; five major nerves emerge from the brachial plexus to supply the upper limb and shoulder
brachial plexus
innervates two shoulder muscles and the skin over part of the shoulder
axillary nerve
innervates all muscles in the posterior arm and forearm as well as the skin over the posterior surface of the arm, forearm, and hands
radial nerve
innervates the anterior muscles of the arm and the skin over the radial surface of the forearm
musculocutaneous nerve
innervates two anterior forearm muscles and most of the intrinsic hand muscles ; also innervates the skin over the ulnar side of the hand
ulnar nerve
innervates most of the anterior forearm muscles and some of the intrinsic hand muscles ; also innervates the skin over the radial side of the hand
median nerve
what are the 5 nerves that branch from the brachial plexus
median nerve
ulnar nerve
musculocutaneous nerve
radial nerve
axillary nerve
this plexus originates form the spinal nerves L1 to S4 ; four major nerves exit this plexus
lumbosacral plexus
nerve that innervates the muscles of the medial thigh and the skin over the same region
obturator nerve
nerve that innervates the anterior thigh muscles and the skin over the anterior thigh and medial side of the leg
femoral nerve
nerve that innervates the posterior thigh muscles , the anterior and posterior leg muscles, and most of the intrinsic foot muscles
tibial nerve
nerve that innervates the muscles of the lateral thigh and leg and some intrinsic foot muscles
common fibular nerve
the tibial and common fibular nerves are bound together within a connective tissue sheath and called
sciatic nerve
what are the major regions of the brain
brainstem
cerebellum
diencephalon
cerebrum
connects the spinal cord to the remainder of the brain ; contains several nuclei involved in vital body functions, such as control of the heart, blood pressure, and breathing
brainstem
three parts of the brainstem
medulla oblongata
pons
midbrain
the most inferior portion of the brainstem and is continuous with the spinal cord ; contains ascending and descending nerve tracts which convey signals to and from other regions of the brain
medulla oblongata
on the anterior surface of the medulla oblongata are two prominent enlargements called __ ; consists of descending nerve tracts which transmit action potentials from the brain to the somatic motor neurons
pyramids
immediately superior to the medulla oblongata is the __ ; contains ascending and descending nerve tracts as well as several nuclei
pons
superior to the pons, is the smallest region of the brainstem
midbrain
the dorsal part of the midbrain consists of four mounds of tissue called
colliculi
the two _ colliculi are major relay centers for the auditory nerve pathways in the CNS
inferior
the two _ colliculi are involved in visual reflexes and receive touch and auditory inout
superior
the midbrain also contains a black nuclear mass called the __ which is part of the basal nuclei
substantia nigra
scattered throughout the brainstem is a group of nuclei called the __ ; involved in regulating cyclical motor functions such as respiration and walking
reticular formation
the reticular formation is a major component of the __ which plays an important role in arousing and maintaining consciousness and in regulating the sleep-wake cycle
reticular activating system
part of brain which is attached to the brainstem by several large connections
cerebellum
cerebellum is attached to the brainstem by several large connections called __ ; provide routes of communication
cerebellar peduncles
part of the brain between the brainstem and the cerebrum
diencephalon
3 main components of the diencephalon
thalamus
epithalamus
hypothalamus
component of the diencephalon that is by far the largest part ; consists of a cluster of nuclei and is shaped like a yoyo
thalamus
small center in the diencephalon that connects thalamus
interthalamic adhesion
component of the diencephalon that is a small area superior and posterior to the thalamus ; consists of few small nuclei involved in emotional and visceral response to odors and the pineal gland
epithalamus
an endocrine gland in the epithalamus that may influence the onset of puberty and play a role in controlling some long term cycles that are influenced by the light-dark cycle
pineal galnd
component of the diencephalon that is the most inferior part ; it contains several small nuclei that are important in maintaining homeostasis ; control of temperature, hunger, thirst etc
hypothalamus
a funnel shaped stalk that extends from the floor of the hypothalamus to the pituitary gland
infundibulum
form externally visible swellings on the posterior portion of the hypothalamus
mamillary bodies
largest part of the brain ; divided into left and right hemispheres by a longitudinal fissure
cerebrum
the most conspicuous features on the surface of each hemisphere are numerous folds called _ ; greatly increases the surface area of the cerebral cortex
gyri
the most conspicuous features on the surface of each hemisphere are intervening grooves called
sulci
each cerebral hemisphere is divided into 5 lobes:
frontal lobe
parietal lobe
occipital lobe
temporal lobe
insula
this lobe is important in the control of motor functions, motivation, aggression, mood, and olfactory
frontal lobe
this lobe is the principal center for receiving and consciously perceiving most sensory information such as touch, pain, temp, and balance
parietal lobe
the frontal and parietal lobes are separated by the
central sulcus
this lobe functions in receiving and perceiving visual input and is not distinctly separate from other lobes
occipital lobe
this lobe is involved in olfactory and auditory sensations and plays an important role in memory
temporal lobe
most of the temporal lobe is separated from the rest of the cerebrum by the
lateral fissure
this lobe is deep within the lateral fissure and involved in the perception of taste
insula
a small portion of the sensory input results in _ the conscious awareness of stimuli
perception
the spinal cord and brainstem contain a number of __ that transmit information via action potentials from the periphery to various parts of the brain
ascending tracts
two examples of ascending tracts are the
spinothalamic tract
dorsal column tract
this tract transmits action potentials dealing with sensation such as pain and temperature to the thalamus and on to the cerebral cortex
spinothalamic tract
this tract transmits action potentials dealing with sensations such as touch, pressure, and proprioception or body position
dorsal column tract
the anterior and posterior __ transmit information about proprioception to the cerebellum
spinocerebellar tract
ascending tracts project to specific regions of the cerebral cortex called the _ where sensations are perceived
primary sensory areas
this is located in the parietal lobe posterior to the central sulcus
primary somatosensory cortex
cortical areas immediately adjacent to the primary sensory areas are called
association areas
they occur without conscious thought
involuntary movements
consciously activated to achieve a specific goal such as walking or typing
voluntary movements
voluntary movements result from the stimulation of neural circuits that consists of two motor neurons
upper motor neurons
lower motor neurons
this motor neuron have cell bodies in the cerebral cortex
upper motor neurons
this motor neuron have cell bodies in the ventral horn of the spinal cord gray matter or in the cranial nerve nuclei
lower motor neurons
is located in the posterior portion of the frontal lobe directly anterior to the central sulcus
primary motor cortex
this area of the front lobe is where motor functions are organized before they are actually initiated in the primary motor cortex
premotor area
the motivation and foresight to plan and initiate movements occur in the portion of the frontal lobes called the
prefrontal area
corticospinal tracts are considered _ because they extend directly from the upper motor neurons in the cerebral cortex to lower motor neurons
direct
indirectly controlled by the cerebral cortex
indirect
especially important in controlling the speed and precision of skilled movement of the hands
lateral corticospinal tracts
group of functionally related nuclei
basal nuclei
two primary nuclei of the basal nuclei
corus striatum
substantia nigra
a primary nuclei of the basal nuclei that is located deep within the cerebrum
corus striatum
a primary nuclei of the basal nuclei that is a group of darkly pigmented cells in the midbrain
substantia nigra
attached by cerebellar peduncle to the brainstem
cerebellum
major function of cerebellum is that of a _ ; it is a sensing device that compares the data from two sources
comparator