CENTRAL NERVOUS SYSTEM

• is the part of the nervous system consisting of the brain and spinal cord.

• This system controls the other system of the body. Its afflictions are reflected in the other systems of the body, and affliction in the other system are reflected in the nervous system.

NEURON

• Is the structural unit. It has body in which the nucleus is placed and processes that extend out from this body. The processes are DENDRITES which transmit nerve impulses towards the body and the AXON which transmit nerve impulses away from the body.

• Circuit are formed in the nervous system by interconnections between Neurons and theses connection are called synapses

THE BRAINis an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals

• Gray matter- composed of nerve cell bodies• White matter- compose of myelinated nerve

fibers.• Nucleus- a mass of gray matter in any part of the

brain and spinal cord• Commissure- a band of fibers joining

corresponding opposite parts of the brain and spinal cord

DIVISION OF THE BRAIN

• 1. FOREBRAIN (PROSENCEPHALON)– TELENCEPHALON (CEREBRUM)– DIENCEPHALON (thalamus, epithalamus, hypothalamus)

• 2. MIDBRAIN (MESENCEPHALON)– CORPORA QUADRIGEMINA– CEREBRAL PEDUNCLES

• 3. HINDBRAIN (RHOMBENCEPHALON)– CEREBELLUM,PONS– MEDULLA OBLONGATA

FOREBRAIN

TELENCEPHALON

TELENCEPHALON (cerebrum)

• the largest portion of the brain.• holds the instructions for everything you do in

your daily life

Parts of the cerebrum

• Gyri- They help to separate the lobes based on its functional roles and increase the overall size of the cerebrum.

• Sulcus- a groove or furrow, especially one on the surface of the brain. Also called fissure

GYRI

• he specific gyrus used for motor functions in the frontal lobe is called the pre-central gyrus;

• the gyrus used for sensory function in the parietal lobe is called the post-central gyrus.

SULCUS

• the central sulcus is a deepened groove used to separate the frontal lobe from the parietal lobe.

• Longitudinal fissure: which divides the cerebrum into the two hemispheres.

• Collateral fissure: found in the inferior temporal lobe of the brain

SULCUS (FISSURE)• HIPPOCAMPAL SULCUS: a sulcus that extends from the

brain's corpus callosum to the tip of the temporal lobe.• Transverse fissure: found between the cerebrum and the

cerebellum. Note that a "transverse fissure" can also be found in the liver and lungs.

• Occipitoparietal fissure: found between the occipital and parietal lobes of the brain.

• Fissure of Sylvius: separates the frontal and parietal lobes of the brain from the temporal lobe.

• Wernicke's fissure: separates the brain's temporal and parietal lobes from the occipital lobe.

Frontal Lobe

Movement of the body Personality Concentration, planning, problem solving Meaning of words Emotional reactions Speech Smell

FOUR LOBE OF THE BRAIN

Parietal Lobe Touch and pressure Taste Body awareness

Temporal Lobe Hearing Recognizing faces Emotion Long-term memory

Occipital Lobe Sight

DIENCEPHALON

• THALAMUS– It helps to control the attention span, sensing pain

and monitors input that moves in and out of the brain to keep track of the sensations the body is feeling.

– The thalamus has been thought of as a "relay" that simply forwards signals to the cerebral cortex.

DIENCEPHALON

• Epithalamus– a part of the dorsal forebrain– to connect the limbic system to other parts of the

brain

DIENCEPHALON

• HYPOTHALAMUS– A releasing hormones or hypothalamic hormones– controls mood, thirst, hunger and temperature.

MIDBRAIN

• Central aqueduct of Sylvius – Canal wich connects the 3rd and 4th ventricles of

the brain

MIDBRAIN

• Corpora quadrigemina– Four rounded nuclear masse consisting of:

• Superior colliculli- upper 2 for visual reflexes• Inferior colliculli- lower 2 for auditory reflexes

MIDBRAIN

• CEREBRAL PEDUNCLE– A pair of cylindrical bodies made up of nerve fiber

tracts which connect to the forebrain with the hindbrain

HINDBRAIN

• CEREBELLUM– the little brain– essential body functions such as processing

procedural memories, balance, posture and coordination, allowing humans to move properly and maintain their structure.

HINDBRAIN

• PONS– the pons Varolii ("bridge of Varolius")– It interprets information that is used in sensory

analysis or motor control. The pons also creates the level of consciousness necessary for sleep.

HINDBRAIN

• MEDULLA OBLONGATA– A Cone-shaped– maintains vital body functions such as the heart

rate and breathing.

SUPPORTING STRUCTURES

• SKULL• MEANINGES• CORPUS CALLOSUM• BRAINSTEM

BRAINSTEM

• the central trunk of the mammalian brain• connecting the brain with the spinal cord and

the rest of the body

CORPUS CALLOSUM

• a broad band of nerve fibers joining the two hemispheres of the brain.

• is a thick band of nerve fibers

SKULL

• is a bony structure in the head of most vertebrates (in particular, craniates) that supports the structures of the face and forms a protective cavity for the brain.

• The skull forms the anterior most portion of the skeleton and is a product of encephalization, housing the brain, many sensory structures (eyes, ears, nasal cavity), and the feeding system.

MENINGES

• Are compose of the membranes that cover the brain and spinal cord

• There 3 major layer– Dura mater– Arachnoid mater– Pia mater

DURA MATER

• Consist of 2 layer dense fibrous tissue containing many blood vessels.

ARACHNOID MATER

• Is a delicate serous membrane situated between the dura and pia mater. It is separated from the dura by a potential space know as the subdural space, and from the pia mater by a definite space, the subarachnoid space where the cerebrospinal fluid flow.

PIA MATER

• A fine vascular membrane consisting mainly of minute blood vessels that are supported by fine connective tissues. It closely invests the brain completely covering the convolution and dipping down into each fissure.

CSF

• This formed and secreted within the ventricle of the brain by the choroid plexus. It is a clear, slightly alkaline fluid consisting of water, protein, some glucose, lymphocytes and hormones.

• The averages amount of CSF is 80-200 mL.

PATHWAY OF THE CSF

PATHWAY OF CSF

• Choroid plexuslateral ventriclesInterventricular foramen of monroethird ventricle aqueduct of sylvies or iter fourth ventriclelateral foramina of lushca and median foramen of magendie subarachnoid spaceabsorbed through the arachnoid villi and drained into the superior sagittal sinusback to the circulation

Blood supply

• Internal carotid canal – form the common carotid, enters the cranial cavity through the carotid canal

• Ventral cana – form the subclavian artery ascends by passing through the vertebral foramina of the cervical vertebra. It enters the foramen magnum and unites to form basiller artery.

Blood drainage of the brain

• The blood drainage is through the large venous sinuses derived from the dura maer and into the internal jugular vein at either side of the neck

CRANIAL NERVES

The cranial nerves are 12 paired sets of nerves that arise from the brain/brainstem and leave the Central Nervous System through cranial foramina

There are 2 general categories of cranial nerve function:

1. Sensory functions • Special senses – Vision• General senses – Touch and pain in the face

2. Motor functions• Somatic motor cranial nerves – innervate

skeletal muscles in the head and neck• Parasympathetic cranial nerves – innervate

glands, smooth muscle, and cardiac muscle

I Olfactory (Sensory)

• Located in olfactory bulb of brain and has olfactory receptors for sense of smell

II Optic (Sensory)• This sensory cranial nerve leads from eyes to

thalamus• Vision

III Oculomotor (Motor, Parasympathetic)

• Arise from midbrain and leads to eye muscles (including eyelids & lens) and pupil

• Eyelid and eyeball movement; constricts pupils, thickens lens

IV Trochlear (Motor)• It work with the oculomotor nerve to

produce the eye movements

V Trigeminal (Motor & Sensory)• Largest cranial nerve• Muscles of mastication• Sensory for head/neck, meninges, sinuses, &

external surface of tympanic membrane• Divided into three branches consisting of the

ophthalmic, maxillary and mandibular nerves.

VI Abducens (Motor)

• Eye movement (laterally)

VII Facial (Sensory, Motor, Parasympathetic)

• Sensory: Taste• Motor: Muscles of facial expression• Parasympathetic: Salivary and tear

glands

VIII Vestibulocochlear (Sensory)

• Vestibular nerve – Balance• Cochlear nerve - Hearing

IX Glossopharyngeal (Sensory, Motor, Parasympathetic)

• Swallowing, sense of taste, and saliva secretion

X Vagus (Sensory, Motor, Parasympathetic)

• Smooth muscle sensory and motor control in throat, lungs, heart, and digestive tract

XI Accessory (Motor)

• Movement of neck and shoulders

XII Hypoglossal (Motor)

• Movement of tongue, swallowing, and speech

CEREBRUM (Telencephalon & Diencephalon)

• The Olfactory and Optic nerves arise from the anterior portion of the brain

MIDBRAIN• The Oculomotor and Trochlear nerves stem from the

midbrainPONS

• The Trigeminal, Abducens, and Facial nerves arise in the pons

• Vestibulocochlear nerve arises in the inner ears & goes to the pons

MEDULLA OBLONGATA

• The Glossopharyngeal, Vagus, Accessory, and Hypoglossal nerves are attached to the medulla oblongata

SPINAL NERVES

Spinal nerves

• is a mixed nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body. In the human there are 31 pairs of spinal nerves, one on each side of the vertebral column.

• The spinal nerves are part of the peripheral nervous system.

Regional nervesNERVES ORIGIN

CRANIAL NERVES are the spinal nerves from the cervical vertebrae

THORACIC NERVES originates from below each corresponding thoracic vertebra

LUMBAR NERVES are the five spinal nerves emerging from the lumbar vertebrae.SACRAL NERVES arising through the sacrum

COCCYGEAL NERVES It arises from the conus medullaris

C1-c6 Neck flexorsC1–T1 Neck extensorsC3, C4, C5 Supply diaphragm (mostly C4)C5, C6 Move shoulder, raise arm(deltoid); flex elbow (biceps)C6 externally rotate (supinate) the armC6, C7 Extend elbow and wrist(triceps and wrist extensors);pronate wristC7, T1 Flex wrist; supply small muscles of the handT1–T6 Intercostals and trunk above the waistT7–L1 Abdominal musclesL1–L4 Flex thighL2, L3, L4 Adduct thigh; Extend leg at theknee (quadriceps femoris)

L4, L5, S1 abduct thigh; Flex leg at the knee (hamstrings); Dorsiflexfoot (tibialis anterior); Extendtoes

L5, S1, S2 Extend leg at the hip (gluteus maximus); Plantar flex foot and flex toes

SPINAL NERVES FUCNTIONS

CLINICAL MANIFESTATION

TRIGEMINAL NEURALGIA

• Also called tic doulourex• Is a form of neuropathic pain• Is a chronic pain condition that affects the 5th

cranial nerve

CAUSE AND PREVENTION

• CAUSE– Most of trigeminal

neuralgia are believed to be caused by blood vessel pressing on the root of the trigeminal nerve

• PREVENTION– EAT SOFT FOODS– Make sure your drinks

and food are not too cold or hot when you consume them

– Wash your face with lukewarm water