Sensory Input
Integration
Motor Output
functions of the nervous system.
Sensory Input
- gathering information
- to monitor changes occurring inside and outside the body
Integration
to process and interpret sensory input and decide if action is needed.
Motor Output
- a response to integrated stimuli
- the response activates muscles or glands
Central Nervous System
composed of the brain and spinal cord.
Peripheral Nervous System
composed of nerves outside the brain and spinal cord.
Sensory Division
- afferent; ascending
- nerve fibers that carry information to the central nervous system
Ruffini Endings
for perception of touch and pressure, signaling continuous state of skin deformation and heat perception.
Krause's End-Bulb
for touch, pressure, and cold perception.
Pacinian Corpuscle
- deeper part of the skin
- responsible for perception of deep touch and vibration
Free Nerve Endings
- for pain, temperature, touch, pressure, tickle, and itch sensations
- found throughout the body
Hair Follicle Endings
- mechanical movement and touch
- found at the base of each hair follicle
Merkel's Disk
for low intensity touch, velocity of touch, ability to perceive continuous contact of object with skin, 2 point discrimination and localization of touch.
Meissner's Corpuscle
for discriminative touch and texture recognition
increase concentration in the fingertips and toes
Motor Division
- efferent; descending
- nerve fibers that carry impulses away from the central nervous system
Somatic Nervous System (Voluntary)
Autonomic Nervous System (Involuntary)
two subdivisions of motor division.
Neurons
cells specialized to transmit messages.
Soma (Cell Body)
Dendrites
Axon
Axonal Terminal
components of the neurons.
Cell Body
nucleus and metabolic center of the cell.
Axons
transfers information from the cell body to the outside.
Dendrites
receives information towards the cell body.
Astrocytes
brace neurons together
act as a chemical mediator among the ions that penetrates your brain
maintain chemical activity in the brain
forms the blood-brain barrier
Oligodendrocytes
produces myelin sheath in the CNS.
Schwann Cells
produces myelin sheath in the PNS.
Ependymal Cells
circulate the flow of CSF in the brain.
Microglia
acts as macrophages of the cell.
Spinal Cord
- situated within the vertebral canal of the vertebral column and is surrounded by three meninges
- cylindrical and begins superiorly at the foramen magnum in the skull and terminates at the conus medullaris
- it has 31 pairs of spinal nerves by the anterior or motor roots and the posterior or sensory roots
Filum Terminale
a prolongation of the pia mater.
Gray Matter
is seen on cross section as an H-shaped pillar with anterior and posterior gray columns, or horns, united by a thin gray commissure.
White Matter
may be divided into anterior, lateral, and posterior white columns.
Posterior Root
consists of bundles of afferent fibers that carry nervous impulses to the CNS
Posterior Root Ganglion
swelling on the posterior root where
Anterior Root
consists of bundles of nerve fibers carrying nerve impulses away from the CNS (efferent fibers).
Brain
it lies in the cranial cavity and is continuous with the spinal cord through the foramen magnum.
Dura Mater
Arachnoid Mater
Pia Mater
three meninges of the brain.
Medulla Oblongata
Pons
Cerebellum
parts of the hindbrain.
Medulla Oblongata
- is conical in shape and connects in shape and connects the pons superiorly to the spinal cord inferiorly
- for auto-rhythmicity
- serves as pathway for sensory and motor information
- has connection with the other parts of the brain stem
Pons
is situated on the anterior surface of the cerebellum, inferior to the midbrain and superior to the medulla oblongata.
Cerebellum
- lies within the posterior cranial fossa of the skull
- for coordination, balance, and equilibrium
Vermis
median portion that connects the hemispheres of the cerebellum.
Cerebellar Peduncles
- composed of large bundles of nerve fibers connecting the cerebellum to the remainder of the nervous system
- has superior (midbrain) , middle (pons), and inferior parts (medulla oblongata
Cerebellar Cortex
- surface layer of each cerebellar hemisphere
- is composed of gray matter
- is thrown into folds, or folia, separated by closely set transverse fissures
Dentate Nucleus
the largest mass of gray matter that is found in the interior of the cerebellum, embedded in the white matter.
Fourth Ventricle
cavity filled with CSF and is connected superiorly to the third ventricle by the cerebral aqueduct; inferiorly, it is continuous with the central canal of the spinal cord.
Midbrain
- is the narrow part of the brain that connects the forebrain to the hindbrain
- contains many nuclei and bundles of ascending and descending nerve fibers
Cerebral Aqueduct
which connects the third and fourth ventricles.
Forebrain
comprises the diencephalon and the cerebrum.
Diencephalon
- is almost completely hidden from the surface of the brain
- consists of a dorsal thalamus and a ventral hypothalamus
Thalamus
is a large, egg-shaped mass of gray matter that lies on either side of the third ventricle.
Interventricular Foramen
- formed by the anterior end of the thalamus
- the opening between the third and lateral ventricles
Hypothalamus
- forms the lower part of the lateral wall and floor of the third ventricle
- for thermoregulation
- for secretion of hormones
- center for hunger and satiety
- responsible for regulating emotions
Cerebrum
largest part of the brain, consists of two cerebral hemispheres, which are connected by a mass of white matter called the corpus callosum.
Fissures
- deep grooves
- separate major regions of the brain
Transverse Fissure
separates cerebrum and cerebellum.
Longitudinal Fissure
separates cerebral hemispheres.
Sulci
grooves on the surface of the cerebral hemispheres.
Gyri
twisted ridges between sulci.
Commissures
- composed of commissural fibers
- allows communication between cerebral hemispheres
Corpus Callosum
the largest commissure.
Association Fibers
connect different parts of the same hemisphere.
Projection Fibers
connect higher and lower structures of the brain.
White Matter
lies deep to the gray matter of the cortex.
Cerebral/Basal Nuclei
- discrete innermost clusters of gray matter within the masses of white matter
- are oval, spherical, or sometimes irregularly shaped clusters of neuron cell bodies
Corona Radiata
- fan-shaped collection of nerve fibers
- passes in the white matter to and from the cerebral cortex to the brain stem
- converges on the basal nuclei and passes between them as the internal capsule
Caudate Nucleus
tailed nucleus situated in the medial side of the internal capsule.
Lentiform Nucleus
lens-shaped nucleus on the lateral side of the internal capsule.
Peripheral Nervous System
consists of spinal nerves, cranial nerves, and their associated ganglia.
Efferent Fibers
are involved in motor functions, such as the contraction of muscles or secretion of glands.
Afferent Fibers
usually convey sensory stimuli from the skin, mucous membranes, and deeper structures.
31 pairs
how many pairs of spinal nerves?
12 pairs
how many pairs of cranial nerves?
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
spinal nerves associated with regions of the spinal cord
Cauda Equina
lower nerve roots that form a vertical leash of nerves around the filum terminale.
Posterior Ramus
passes posteriorly around the vertebral column to supply the muscles and skin of the back.
Anterior Ramus
- continues anteriorly to supply the muscles and skin over the anterolateral body wall and all the muscles and skin of the limbs
- they join one another at the root of the limbs to form complicated nerve plexuses
Sensory Ganglia of Spinal Nerves
Cranial Nerves and Autonomic Ganglia
division of ganglia
Sensory Ganglia
- are fusiform swelling on the posterior root of each spinal nerve just proximal to the root’s junction with a corresponding anterior root
- posterior root ganglia
Autonomic Ganglia
- are often irregular in shape and are situated along the course of efferent nerve fibers of the ANS
- are found in the paravertebral sympathetic chains around the roots of the great visceral arteries in the abdomen and close to, or embedded within, the wall of various viscera
Falx Cerebri
separates left and right cerebral hemisphere.
Tentorium Cerebelli
separates cerebrum and cerebellum.
Diaphragma Sellae
seperates pituitary gland.
Falx Cerebelli
separates the left and right cerebellar hemisphere.