NERVOUS SYSTEM

Nervous System

Responsible for the regulatory functions and coordinating

functions of the body.

CNS

it contains the brain and spinal cord

brain

Process information and control most of the body

functions.

spinal cord

A long, cylindrical structure that runs down the vertebral

column and is segmented into regions that correspond to

different parts of the body.

PNS

Consists of all the structures and nerves outside the CNS.

SPINAL NERVES

● It is located in the spine.

● 31 pairs

CRANIAL NERVES

● Located in the brain.

● 12 pairs

SOMATIC PNS

Controls voluntary movements by connecting the CNS

to the muscles.

AUTONOMIC PNS

Controls involuntary actions such as the heart rate.

SYMPATHETIC PNS

flight or fight response.

PARASYMPATHETIC PNS

rest or digest.

NEUROGLIA

● These types of cells protect, nourish, and support

neurons.

● Not capable of transmitting electrical impulses.

ASTROCYTES

● The blood-brain barrier regulates what substances can

enter your brain.

OLIGODENDROCYTES

Forms part of the myelin sheaths of several axons within

the CNS.

Myelin sheaths

protect, nourish, and electrically insulate

the axons. When the axons are electrically insulated, the

sending and transmitting impulse rate is faster.

EPENDYMAL CELLS

Secrete cerebrospinal fluid.

MICROGLIA

Acts as an immune cell by removing the pathogens and

the dead cell by the process of phagocytosis.

SCHWANN CELLS

● wraps around axons.

● Forms the myelin sheaths in the PNS.

SATELLITE CELLS

Protect neurons from heavy metal poison, specifically lead

and mercury.

NEURONS

specialized in transmitting electrical

impulse.

● The functional units in the nervous system.

● Receive stimuli and transmit action potentials to other

neurons or to effector organs.

DENDRITES

Part of the neuron that receives signals.

CELL BODY (SOMA)

Processes the information received from dendrites.

AXONS (NERVE FIBER)

Transmits action potentials away from the cell body to

other neurons.

NODES OF RANVIER (NEUROFIBRIL NODES)

● Area where myelin sheaths of adjacent cells dip toward

the axon but do not cover it.

● Nodes that are located in between the myelin sheaths.

NISSL BODIES

These are just rough endoplasmic reticulums that

synthesize proteins.

AXON HILLOCK

A cone-shaped area of the neuron cell body where a

single axon arises from.

SYNAPSE

Gaps or spaces between two axon terminals that trigger

neurotransmitter signals.

NEUROTRANSMITTER

● Chemicals that carry signals across the synapses.

● Any specific chemical agents released by a presynaptic

cell on excitation that cross the synaptic cleft and

stimulate or inhibit the postsynaptic cell.

Glutamate

Most common neurotransmitter in the CNS

Excitatory

- propagates nerve impulses

- promotes firing of action potential

Excitatory

Acetylcholine, Glutamate, Epinephrine

Inhibitory

- inhibit nerve impulses

- prevents the firing of action potential

Inhibitory

GABA, Glycine, Serotonin

Excitatory and Inhibitory

They can be both excitatory and inhibitory

but the effect differs on what type of

receptors they interact with.

(mainly inhibitory)

Dopamine

(mainly excitatory)

Norepinephrine

Conus medullaris

a cone-like region with its tip as the

inferior end of the spinal cord and extends to the level of

the second lumbar vertebra

Cauda equina

the numerous roots of spinal nerves

extending inferiorly resemble a horse’s tail

meninges.

The spinal cord and brain are surrounded by connective

tissue membranes called

DURA MATER

● Outer layer

● Thickest and tough

ARACHNOID MATER

● Middle layer

● Thin and resembles a spider web

PIA MATER

● Inner layer

● The thin, delicate layer that adheres to the spinal cord and

cranial structures

SUBARACHNOID SPACE

● Between the arachnoid mater and the pia mater.

● Where CSF flows.

EPIDURAL SPACE

● Space between the vertebral column and dura mater.

● Where the anesthesia is administered during labor.

SUBDURAL SPACE

● Area between the dura mater and the arachnoid mater.

● Contains serous fluid.

Plexus

organization produced by the intermingling of the

nerve.

BRAINSTEM

● Responsible for many essential functions: Controls

breathing, heartbeat rates and reactions to auditory and

visual stimuli.

● Most important part since it contains the limbic system

and reflex center.

MEDULLA OBLONGATA

Reflex centers: regulating heart rate, blood vessel

diameter, respiration, swallowing, vomiting, hiccuping,

coughing, and sneezing.

PONS

● Initiates rapid eye movement sleep or Sleep-wake cycle

● Assist in controlling respiratory functions

MIDBRAIN

● Serves as visual reflex center

● Part of auditory pathway

● Involved in maintaining muscle tone and coordinating

movements

RETICULAR FORMATION

● It is a diffuse system consisting of several loosely packed

nuclei scattered throughout the length of the brainstem.

● Controls, arouses, and maintains consciousness, including

the sleep-wake cycle.

● Coordinates the rhythmic activities of swallowing,

breathing and the heart rate.

DIENCEPHALON

Part of the brain between the brainstem and cerebrum.

THALAMUS

● Largest part of the diencephalon, constituting about

four-fifths of its weight.

● Relay station for sensory impulses EXCEPT olfactory.

● Interpretation center for pain, temperature, and touch.

HYPOTHALAMUS

● Central controller of the endocrine system.

● Functions: CATEES (Circadian rhythm, Appetite,

Thermoregulations, Emotions, Endocrine, Sexual drive)

CEREBRUM

● Controls intellectual processes and emotions

● Contains the frontal lobe, parietal lobe, temporal lobe, and

occipital lobe.

● Responsible for thoughts, emotions and voluntary

movements.

Cerebral cortex

gray matter surface

GYRI

folds

SULCI

grooves

Corpus callosum

bridge connecting two hemispheres

Frontal lobe

muscle movement, moods,

aggression, smell, motivation

Parietal lobe

touch, pain, balance, taste,

temperature

Temporal lobe

hearing, smell, memory,

abstract thought, judgment

Occipital lobe

vision

CEREBRAL MEDULLA

Transmits signals between the different areas of the brain.

Association fibers

connect areas of the cerebral

cortex within the same hemisphere.

Commissural fibers

connect one cerebral hemisphere

to the other (corpus callosum)

Projection fibers

connect the cerebrum to other parts

of the brain and spinal cord

BASAL GANGLIA

● Group of functional related nucleus in the brain.

● Involved in controlling motor functions.

Caudate nucleus

plays a major role in

learning and memory.

Substantia nigra

– midbrain that is part of controlling

the movement coordination: “nigra” from the dark

pigmented nucleus in the brain.

CEREBELLUM

● Little brain

● Maintains body posture and balance.

LIMBIC SYSTEM

● Plays a central role in basic survival functions, such as

memory, reproduction, and nutrition

● Involved in interpreting sensory input and emotions in

general.

Hippocampus

long term memories

Amygdala

processes emotions

Cerebrospinal fluid (CSF)

a clear fluid similar to blood

serum with most of the proteins removed.

Choroid plexus

produces CSF

Arachnoid villi

absorbs CSF and reabsorbed into blood

“Come Lets Formally Take Sylvia For Lunch Mamaya

Sa Aristocrat”

Choroid plexus, Lateral ventricle, Foramen of

Monro, Third Ventricle, Sylvian Aqueduct,

Fourth Ventricle, Lushka (2), Magendie,

Subarachnoid space, Arachnoid Villi

(I) OLFACTORY

● Smell

● Sensory

(II) OPTIC

● Sight

● Sensory

(III) OCULOMOTOR

● Movement of eyeball, constriction of pupil

● Motor

(IV) TROCHLEAR

● Movement of eyeball (superior oblique)

● Motor

(V) TRIGEMINAL

● Chewing, sensations in teeth and face

● Both

(VI) ABDUCENS

● Movement of eyeball (lateral rectus)

● Motor

(VII) FASCIAL

● Facial expression, taste, tear and salivary glands

● Both

(VIII) VESTIBULOCOCHLEAR

● Equilibrium, hearing

● Sensory

(IX) GLOSSOPHARYNGEAL

● Swallowing, taste, salivary gland

● Both

(X) VAGUS

● Certain muscle movements, sensory impulse

● Both(XI) ACCESSORY

(XI) ACCESSORY

● Swallowing, head movement

● Motor

(XII) HYPOGLOSSAL

● Swallowing, speech

● Motor

SOMATIC SENSATION

Specialized or capable of responding to different stimuli in

the body.

MECHANORECEPTORS

Respond to mechanical stimuli such as bending or

stretching receptors.

NOCIRECEPTORS

Responds to stimuli that result in pain.

THERMORECEPTORS

Responds to temperature change.

CHEMORECEPTORS

Responds to chemicals such as odor molecules.

PHOTORECEPTORS

Respond to light.

SENSE OF SMELL (OLFACTION)

Occurs in response to odors that stimulate sensory

receptors in the extreme superior region of the nasal

cavity, called the olfactory region.

TASTE BUDS

The sensory structures that detect taste

TASTANTS

dissolved in saliva, enter

the taste pores

Carbohydrates

produces sugar