Nervous System Galena Park High School A&P Instructor: Terry E. Jones

Nervous System

Galena Park High SchoolA&

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Instructor: Terry E. Jones

A. Coordination 1. Controls senses and stimuli between all systems. 2. Coordinates muscle movement


P I. Function

B. Protection 1. Senses danger and responds 2. Maintains electrical signals through out the body 3. Stimulates glandular secretions


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C. Higher Level Thinking 1. Analyzes and formulates 2. Repository for vast amounts of knowledge


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A. Central Nervous System 1. Brain and spinal cord 2. Acts as a sensory processing and command center


PII. Physical Organization

B. Peripheral Nervous System 1. Nerves leaving the spinal cord 2. Location of sensory neurons 3. Transmits impulses to organs and glands


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A. Afferent Division 1. Moves impulses from sensory cells to the brain a. Somatic Sensors-from skin, skeletal and joints b. Visceral Sensors from organs


PIII. Functional Organization Peripheral Nervous System

B. Efferent Division (motor) 1. Carries impulses from brain to the organs and muscles 2. The impulse creates a response or a motor response


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C. Sub-divisions of the Motor Division 1. Voluntary system a. Mostly skeletal Muscle b. Can be controlled by our actions


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2. Involuntary system a. Cardiac Muscle b. Smooth Muscle c. We do not control them. They are controlled by the brain


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3. Parts of the Involuntary system a. Sympathetic –generally maintains activities of systems at rest or doing natural tasks b. Parasympathetic – generally reacts to stress when systems out of balance c. Both work in opposition to each other


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A. Neuroglia (all types of nerve cells) 1. Astrocyte Cells

a. Link capillaries to neurons b. Attached to neurons


PIV. Anatomy-Nervous Tissue

A. Neuroglia (all types of nerve cells) 1. Astrocyte Cells

a. Link capillaries to neurons b. Attached to neurons


PIV. Anatomy-Nervous Tissue

2. Microglia Cellsa. Spider-like appearance

b. Dispose of debris and bacteria in the brain


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3. Ependymal Cellsa. Attached to cavities of the

brain and spinal cord b. Their beating cilia moves fluid around the brain and spinal cord


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4. Oligodendrocyte Cellsa. Wrap around neurons in brain

b. Forms the myelin sheath that insulates neurons c. Brain tumors effect these cells since they can divide


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5. Schwann Cellsa. Wrap around neurons in the

periphery neurons b. Forms the myelin sheath that insulates neurons


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6. Neuron a. Impulse transmitting cells of the

nervous system b. Cell Body- main sections of the cell which has the organelles c. Dendrites – branched appendages that carry the impulse toward the cell body


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d. Axon – Branched appendage that carries the impulse away from the cell body nervous system e. Axon Terminal – End of an axon filled with neurotransmitters f. Synapse – Gap between neurons over which the impulse is carried by neurotransmitter


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A. Resting Membrane 1. Waiting for stmuli

2. Outside of membrane- positive 3. Inside of membrane - negative


PIV. Generating an Impulse

B. Depolarization 1. Stimuli changes permeability of membrane

2. Positive ions rush in 3. Inside becomes more positive; outside becomes more negative


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C. Generation of Active Potential 1. If stimulus is strong, entire membrane switches polarity

2. This causes a flow of electricity


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D. Propagation of Action Potential 1. After first spot on membrane changes polarity

2. The change moves down the entire length of the membrane


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E. Repolarization 1. Stimulus disappears and membrane permeability return to normal

2. Positive ions flow out and original positive and negative condition is restored


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F. End of the Line 1. When action potential reaches end of the axon, a neurotransmitter is released into the synaptic cleft

2. Neurotransmitter diffuses across cleft and attaches to receptors on the next nerve 3. Impulse process starts again for next nerve cell


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A. Five Parts of a Reflex Arc 1. Receptor-Senses the Stimulus

2. Sensory Neuron-Takes impulse to spinal cord 3. Integration Center – Transfers impulse into a response


P V. Reflex Arcs

4. Motor Neuron – Takes impulse from spinal cord to a muscle

5. Effector – Muscle or organ receiving impulse


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A. Cerebrum - Anatomy 1. Two hemispheres

2. Largest part of the brain 3. Superior to the other brain areas


P VI. The Brain

4. Gyri –raised ridges of tissue 5. Sulcus – Shallow grooves

separating the gyri 6. Fissures – deep grooves separating lobes of the cerebrum


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7. Lobes – large portions of the cerebrum which generally have special functionsB. Lobes of the Cerebrum Parietal Lobe, Frontal, Occipital,

and Frontal


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1. Parietal a. Orientation b. Consciousness of Senses c. Recognition d. Movement


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2. Occipital Lobe a. Sight Sensation b. Sight Interpretation3. Temporal Lobe a. Hearing

b. Sense of Smell c. Speech


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4. Frontal Lobe a. Reasoning, Planning b. Parts of Speech c. Movement d. Emotions e. Problem solving


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C. Diencephalon Areas 1. Thalamus a. Relay station for sensory input b. Can sense good or bad c. Final interpretation is done in the sensory cortex


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2. Hypothalamus a. Regulates body temperature, water balance and metabolism b. Emotional drives centered here C. Control the pituitary gland


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3. Epithalamus a. Contains the pineal gland b. Forms the cerebospinal fluids important to the central nervous system


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D. Brain Stem Areas 1. Midbrain a. Reflex centers for hearing and vision 2. Pons a. Fiber tracts pass through the pons b. Involved in breathing


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3. Medulla Oblongata a. Connects with the spinal cord b. Involved in heart rate, blood pressure, breathing, swallowing and vomiting 4. Reticular Formation-controls motor

activity – Found in all of the brain stem


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E. Cerebellum 1. Located under and behind the cerebrum 2. Provides homeostasis involving our balance and equilibrium 3. Monitors body performance and sends out

adjustments when needed.


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A. Ataxia 1. Loss of muscle coordination due to cerebellum damage from stroke or head injury 2. Appearance of stumbling or drunk


P VII. Homeostasis

B. Encephalitis 1. Pressure on the brain 2. Caused by bacteria or virus 3. Meningitis occurs with it many times 4. Headache, fever, convulsions


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C. Hydrocephalus 1. Fluid is obstructed 2. Causes pressure on the brain 3. Babies heads grow larger because bones are flexible. 4. Adults suffer brain damage 5. Shunts are inserted to drain excess fluid into a vein in the neck


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D. Multiple Sclerosis 1. Myelin sheath around neurons is destroyed 2. Cells become inflexible 3. Electrical impulses short circuited 4. Loss of muscle control


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E. Concussion 1. Mild hit to the head 2. Causes dizzinessF. Contusion 1. Major tissue damage 2. Loss of motor activities 3. Brain stem contusion causes coma for days or a lifetime


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G. Cerebral Edema 1. Bleeding in the brain 2. Accidents 3. Sports 4. Brain swells causing damge


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H. Cerebrovascular Accident 1. Stroke 2. Blood doesn’t reach the brain 3. Can be mild or severe depending

on where the blockage occurred and how long


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I. Alzheimers 1. Degeneration of brain function 2. Effect memory and mood 3. Cause unknown 4. Little treatment


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J. Parkinson’s Disease 1. Degeneration of dopamine releasing neurons 2. Lack of dopamine cause an over reaction of basal nuclei 3. Muscle tremors, head rolling


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K. Huntington’s Disease 1. Degeneration of neurons 2. Inhibition of basal nuclei 3. Jerky, flapping motions, mental deterioration 4. No cure


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A. Olfactory I –Sense of SmellB. Optic II – Sense of sightC. Oculomotor III – Fibers that move the

muscles of the eyeballs except oblique and lateral rectus

D. Trochlear IV – Supplies motor impulses for one eye muscle the oblique


PVIII. Cranial Nerves

E. Trigeminal V – Facial skin, nose and mouth sensory cells. Motor nerves for chewing.

F. Abducens VI – Motor neurons to the lateral rectus muscle that rolls the eye


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G. Facial VII –Taste anterior buds, motor neurons for facial expression, tears

H. Vestibulocochlear (Auditory) VIII- Sense of hearing, sense of balanceI. Glossopharyngeal IX – Motor nuerons

for swallowing, sensory neurons for posterior taste buds


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J. Hypoglossal XII – Senses from the tongue and motor neurons for tongue movement.


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Nervous System Galena Park High School A&P Instructor: Terry E. Jones