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NERVOUS SYSTEM
PRISCILLA ROCHA, PAMELA MERCADO, ANA RUBALLOS
ANATOMY & PHYSIOLOGY PERIOD 3
ANATOMY & FUNCTION OF CLASSIC NEURON
• COMPOSED OF NEURAL TISSUE
• NERVE CELLS OR NEURONS AND NEUROLOGICAL CELLS
• NEURONS
• REACT TO PHYSICAL AND CHEMICAL CHANGES IN THEIR SURROUNDINGS
• DENDRITES RECEIVE INPUT
• LONGER PROCESS (AXON OR NERVE FIBER) CARRIES THE INFORMATION AWAY FROM THE CELL WITH
NERVE IMPULSES
ANATOMY & FUNCTION OF CLASSIC NEURON
CONTINUED…
• NERVES
• BUNDLES OF AXONS
• SYNAPSE
• SMALL SPACE BETWEEN A NEURON AND THE CELL(S) WITH WHICH IT COMMUNICATES
• DENDRITES
• SMALL CELLULAR PROCESSES THAT RECEIVE INPUT
• MYELIN SHEATHS
• AN ELECTRICAL INSULATOR THAT SPEEDS NERVE IMPULSES TO MUSCLES AND OTHER EFFECTORS
NEURON
CLASSIFICATION OF NEURONS: STRUCTURAL
DIFFERENCES
• NEURONS ARE CLASSIFIED INTO THREE
GROUPS
• EACH IS SPECIALIZED TO SEND A NERVE
IMPULSE IN ONE DIRECTION
• BIPOLAR, UNIPOLAR, PSEUDOUNIPOLAR,
PYRAMIDAL, AND MULTIPOLAR
BIPOLAR NEURONS
• 1. BIPOLAR NEURONS- A CELL BODY WITH 2
PROCESSES. ONE PROCESS SERVES AS THE
AXON AND THE OTHER LIKE A DENDRITE.
LOCATED IN SPECIALIZED PARTS OF THE
EARS, NOSE, AND EYES.
UNIPOLAR NEURONS
• 2.UNIPOLAR NEURONS- CELL BODY WITH A
SINGLE PROCESS THAT DIVIDES INTO 2
AXONAL BRANCHES. THE PERIPHERAL
PROCESS WHICH DEALS WITH PERIPHERAL
PARTS OF THE BODY, LIKE SKIN. SECONDLY,
THE CENTRAL PROCESS WHICH ENTERS THE
BRAIN AND SPINAL CORD.
PSEUDOUNIPOLAR NEURONS
• PSUEDOUNIPOLAR NEURONS IS A SENSORY
NEURON IN THE PERIPHERAL NERVOUS
SYSTEM. THE TWO PROCESSES FORM A
SINGLE PROCESS. ONE BRANCH IS
STRUCTURALLY AN AXON, HOWEVER,
FUNCTIONS AS A DENDRITE.
• AFFERENT CONDUCTION ORIGINIATING IN
A NERVE ENDING.
PYRAMIDAL NEURONS
• PYRAMIDAL NEURONS ARE LARGE
TRIANGULAR-SHAPED NEURONS IN THE
CEREBRAL CORTEX THAT TRANSMIT IMPULSES
TO VOLUNTARY MUSCLES
MULTIPOLAR NEURONS
• 3. MULTIPOLAR NEURONS- CELL BODY WITH
MANY PROCESSES, ONE AXON AND THE
REST DENDRITES. THESE ARE COMMONLY
FOUND IN THE BRAIN AND SPINAL CORD.
CLASSIFICATION OF NEURONS: FUNCTIONAL
DIFFERENCES
• THESE NEURONS ARE CLASSIFIED BY THE INFORMATION CARRIED TO THE CENTRAL NERVOUS
SYSTEM (CNS), COMPLETELY WITHIN THE CNS OR OUT OF THE CNS.
FUNCTION CONTINUED…
• SENSORY NEURONS- CONDUCT NERVE
IMPULSES FROM RECEPTORS IN PERIPHERAL
BODY PARTS INTO THE BRAIN AND SPINAL
CORD
• THEIR SPECIALIZED TO DETECT CHANGES IN
THE OUTSIDE WORLD OR WITHIN YOUR BODY
• MOST OF THE SENSORY NEURONS ARE
FOUND TO BE UNIPOLAR, BUT SOME ARE
BIPOLAR
MOTOR NEURONS
• 2. MOTOR NEURONS- TRANSMIT NERVE
IMPULSES FROM THE CNS TOWARD THE
EFFECTORS- TARGET CELLS THAT PRODUCE
RESPONSES. TYPES OF EFFECTORS ARE:
MUSCLES WHICH ARE BEING CONTRACTED
AND GLANDS THAT ARE BEING SECRETED.
THESE ARE FOUND TO MULTIPOLAR.
INTERNEURONS
• 3. INTERNEURONS- TRANSMIT IMPULSES
BETWEEN NEURONS WITHIN THE BRAIN AND
SPINAL CORD. USUALLY BETWEEN SENSORY
NEURONS WHERE THE SIGNAL IS BEING
INTERPRETED AND THE OTHER BEING SENT
TO THE MOTOR NEURONS. FOUND TO BE
MULTIPOLAR NEURONS.
INTRODUCTION TO NERVOUS SYSTEM
• THE NERVOUS SYSTEM CONSIST OF 2
MAJOR SYSTEM, THE PERIPHERAL NERVOUS
SYSTEM (PNS) AND THE CENTRAL NERVOUS
SYSTEM (CNS). THE PERIPHERAL SYSTEM IS
SUBDIVDED INTO THE STOMATIC NERVOUS
SYSTEM AND THE AUTONOMIC NERVOUS
SYSTEM.
NERVOUS SYSTEM CONTINUED…
• 1. THE PERIPHERAL NERVOUS SYSTEM
CONSIST OF THE NERVES AND GANGLIA
OUTSIDE OF THE BRAIN AND SPINAL CORD.
ITS FUNCTION IS TO CONNECT THE CNS TO
LIMBS AND ORGANS SERVING AS A
COMMUNICATION RELAY GOING BACK AND
FORTH BETWEEN YOUR BRAIN AND YOUR
EXTEREMITIES.
NERVOUS SYSTEM CONTINUED
• 2. THE AUTONOMIC NERVOUS SYSTEM IS THE SYSTEM THAT INFLUENCES THE FUNCTIONAL OF
INTERNAL ORGANS. ANS HAS 2 BRANCHES: THE SYMPATHEIC NERVOUS SYSTEM IS ONE AND
IS RESPONSIBLE FOR THE FIGHT-OR-FLIGHT RESPONSE IN THE BODY. THE SECOND IS THE
PARASYMPATHEIC WHICH IS RESPONSIBLE FOR THE REST AND DIGEST RESPONSE IN THE
BODY.
CNS AND PNS
• THE CENTRAL AND PERIPHERAL NERVOUS SYSTEMS WORK TOGETHER
• THE PNS RECEIVES INFORMATION FROM THE ENVIRONMENT AND CARRIES STIMULI VIA ACTION
POTENTIAL
• THE CNS ANALYZES THE INFORMATION AND FORMULATES A RESPONSE
• RESPONSE IS CONVEYED TO PROPER ORGAN THROUGH PNS OR MOTOR NEURONS
• CNS  BRAIN
• PNS  SPINE/NERVE ENDINGS
CENTRAL NERVOUS SYSTEM NEUROGLIA
• CNS:
• ASTROCYTES (STAR SHAPED CELLS) FOUND
BETWEEN NEURONS & BLOOD VESSELS
• OLIGODENDROCYTES (SMALLER VERSION OF
ASTROCTYES) FOUND ALONG MYELINATED
AXONS
• MICROALGIA FOUND SCATTERED
THROUGHOUT THE CNS
• EPENDYMAL (CUBOIDAL) FOUND IN THE
CENTRAL CANAL
PERIPHERAL NERVOUS SYSTEM NEUROGLIA
• SCHWANN CELLS PRODUCE MYELIN
• SATELLITE CELLS SUPPORT CLUSTERS OF
NEUROCELL BODIES CALLED GANGLIA
CLASSIFICATION OF NEUROLOGICAL CELLS CONT.
ACTION POTENTIAL
• RESTING: NERVE CELL
• SODIUM AND POTASSIUM IONS (IN NEURON
MEMBRANE) FOLLOW THE LAWS OF DIFFUSION AND
SHOW A NET MOVEMENT FROM AREAS OF HIGH
CONCENTRATION TO AREAS OF LOW
CONCENTRATION
• PUMP
• MEMBRANE MORE PERMEABLE TO POTASSIUM IONS
THAN SODIUM IONS
• CYTOPLASM OF CELLS IS NEGATIVELY CHARGED
(ANIONS SUCH AS PHOSPHATE, SULFATE AND
PROTEINS)
• OUTSIDE OF MEMBRANE GETS POSITIVELY CHARGED,
INSIDE IS NEGATIVELY CHARGED
ACTION POTENTIAL CONTINUED…
• ACTION POTENTIAL
• IF SIGNAL IS STRONG AND THE VOLTAGE REACHES A THRESHOLD, IT WILL TRIGGER THE ACTION
POTENTIAL
• PEAK VOLTAGE
• GATED SODIUM CHANNELS CLOSE AND POTASSIUM CHANNELS OPEN
• NEURON BECOMES HYPERPOLARIZED
• MORE POTASSIUM IONS ON THE OUTSIDE THAN SODIUM IONS ON THE INSIDE
REFACTORY
• REFRACTORY
• RETURNS POTASSIUM TO THE INSIDE OF THE
CELL AND SODIUM TO THE OUTSIDE OF THE
CELL
NEUROTRANSMITTERS
• NEUROTRANSMITTERS
• CARRIERS OF ELECTROCHEMICAL MESSAGES
• NEURON TO NEURON
• ACETYLCHOLINE STIMULATES SKELETAL
MUSCLE CONTRACTIONS
• MONOAMINES (MODIFIED AMINO ACIDS)
• UNMODIFIED ARE SHORT CHAINED AMINO
ACIDS
NEUROTRANSMITTERS CONTINUED…
• PEPTIDE NEUROTRANSMITTERS ARE SYNTHESIZED IN THE ROUGH ENDOPLASMIC RETICULUM
• THEY TRAVEL DOWN THE AXON TO THE NERVE TERMINAL
• OTHER NEUROTRANSMITTERS ARE SYNTHESIZED IN THE CYTOPLASM OF THE NERVE TERMINALS
AND ARE STORED IN VESICLES
• WHEN AN ACTION POTENTIAL PASSES ALONG THE MEMBRANE OF A SYNAPTIC KNOB IT INCREASES
PERMEABILITY ALLOWING CALCIUM IONS IN BY OPENING CHANNELS
• CALCIUM DIFFUSES INWARD
• THE MORE CALCIUM THAT ENTERS THE KNOB, THE MORE VESICLES RELEASE NEUROTRANSMITTERS
NEUROTRANSMITTER
BIBLIOGRAPHY
SHIER, DAVID, JACKIE BUTLER, AND RICKI LEWIS. "NERVOUS SYSTEM I: BASIC STRUCTURE AND
FUNCTION." HOLE'S HUMAN ANATOMY & PHYSIOLOGY. 11TH ED. NEW YORK: MC
GRAW HILL, 2007. 355+. PRINT.
"PSEUDOUNIPOLAR NEURON." ACADEMIC DICTIONARIES AND ENCYCLOPEDIAS. N.P., N.D. WEB.
14 APR. 2015.
"PYRAMIDAL NEURON." ACADEMIC DICTIONARIES AND ENCYCLOPEDIAS. N.P., N.D. WEB. 14 APR.
2015.