Introduction to Neuroscience

* Sensory Input
* Integration
* Motor Output

functions of the nervous system.

Sensory Input

\- gathering information

\- to monitor changes occurring inside and outside the body

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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.

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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.

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Schwann Cells

produces myelin sheath in the PNS.

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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

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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

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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.