1. Health Occupations
Nervous System

2. Nervous System Complex & highly organized
Coordinates all of the many activities of the body
Allows body to respond and adapt to changes that occur both inside and outside of the body

3. Neuron Also called nerve cell Basic structural unit of nervous system
Parts of neuron
Cell body
Nucleus inside cell body
Nerve fibers
Dendrites – carry impulses to cell body
Axon – carry impulses away from cell body
Many covered with myelin sheath (fat covering)
Increases rate of transmission of impulses
Insulates & maintains the axon

4. Neuron Axon lies close to dendrites of many other neurons
Synapse – space between neurons
Impulses coming from an axon jump synapse to get to the dendrite of a neuron that will carry the impulses in the right direction
Neurotransmitters – special chemicals located at end of axon to allow impulses to pass from neuron to another
Impulses may follow many different routes

5. 1. Dendrites
3. Nucleus
4. Axon
6. Terminal
branches
5. Myelin Sheath
2. Cell body

6. Nerves Combination of many nerve fibers
Located outside brain & spinal cord
Afferent – sensory
Messages to brain & spinal cord
Efferent – motor
Messages from brain & spinal cord
Associative – both sensory & motor

7. Divisions of nervous system
Central nervous system
Brain
Spinal cord
Peripheral nervous system
Nerves
Autonomic nervous system
Separate division of peripheral nervous system
Controls involuntary body functions

8. Central nervous system
Brain
Mass of nerve tissues
Protected by membranes & cranium
Cerebrum
Largest & highest section of brain
Convolutions – folds found on outer part
Lobes
Frontal, parietal, temporal, occipital
Named after bones that surround them
Responsible for reasoning, thought, memory, speech, sensation, sight, smell,hearing, & voluntary body movement

9. Brain Cerebellum Diencephalon Below back of cerebrum
Responsible for coordination of muscles, balance, posture, muscle tone
Diencephalon
Between cerebrum & midbrain
Thalamus
Relay center to direct sensory impulses to cerebrum
Hypothalamus
Regulates & controls ANS, temperature, appetite, water balance, sleep, constriction & dilation of blood vessels, anger, fear, pleasure, pain, affection

10. Brain Midbrain Pons Below cerebrum at top of brain stem
Responsible for conducting impulses between brain parts & eye reflexes
Pons
Below midbrain in brain stem
Responsible for conducting messages to other parts of brain & reflexes like chewing, tasting, production of saliva, respiration

11. Brain Medulla oblongata Lowest part of brain stem
Connects with the spinal cord
Responsible for regulating heartbeat, respiration, swallowing, coughing, & blood pressure

12. Ventricles
Convolutions
Cerebrum
Cerebellum
Midbrain
Pons
Medulla oblongata
Spinal cord

13. Spinal cord Continues down from the medulla oblongata Ends at L1 or L2
Surrounded & protected by vertebrae
Responsible for many reflexes
Carries sensory messages to brain (afferent)
Carries motor messages away from brain (efferent)

14. Meninges 3 membranes Cover & protect brain & spinal cord
Dura mater – thick, tough outer layer
Arachnoid membrane – middle layer, delicate & weblike
Pia mater – innermost layer
Closely attached to brain & spinal cord
Contains blood vessels that nourish nerve tissue

15. Ventricles 4 hollow spaces located in brain
Connect with each other & with subarachnoid space
Filled with CSF
Fluid circulates continually between ventricles & through subarachnoid space
Serves as shock absorber
Carries nutrients to brain & spinal cord
Helps remove metabolic products & wastes
Produced by choroid plexuses in ventricles
After circulating, absorbed into blood vessels of the dura mater & returned to bloodstream through arachnoid villi

16. Peripheral Nervous System
Made up of all the nerves
Consists of cranial nerves & spinal nerves
Cranial nerves
12 pairs & branches
Responsible for special senses like sight, hearing, taste, smell
Receive general sensations like touch, pressure, pain, temperature
Send out impulses for voluntary & involuntary muscle control

17. Peripheral Nervous System
Spinal nerves
31 pairs & branches
Carry messages to & from spinal cord
Sensory & motor
8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 pair of coccygeal spinal nerves
Each nerve goes directly to a particular part of the body or networks with other spinal nerves to form a plexus, supplying sensation to a larger segment of the body

18. Autonomic Nervous System
Part of PNS
Helps maintain a balance in the involuntary functions of body, but allows body to react in emergency
2 divisions – sympathetic & parasympathetic
Usually 2 systems work together
Maintain homeostasis
Controls involuntary body functions at proper rates

19. Autonomic Nervous System
Sympathetic
Acts in time of emergency – fight/flight
Prepares body to act
Increases heart rate, respirations, BP
Slows activity in digestive tract
Parasympathetic
Counteracts actions of sympathetic after emergency is over
Slows heart rate, respirations
Lowers BP
Increases digestive activity

20. Diseases & Abnormal Conditions
Cerebral Palsy
Disturbance in voluntary muscle action
Caused by brain damage
Lack of oxygen to brain &/or birth injury
Prenatal rubella (German measles) & infections
Spastic, athetoid, & atactic (most common)
Symptoms
Exaggerated reflexes & seizures
Tense muscles & contractures
Speech impairment
Muscle spasms & tremors
Mental retardation in some cases

21. Cerebral palsy Treatment but no cure PT, OT, & speech tx
Muscle relaxants & anticonvulsive druges
Casts & braces
Orthopedic surgery for severe contractures

22. Cerebrovascular Accident (CVA)
Stroke, apoplexy
Blood flow to brain is impaired resulting in lack of oxygen & destruction of brain tissue
Causes
Cerebral hemorrhage
HTN
Aneurysm
Weak blood vessel
Occlusion or blockage
Atherosclerosis
Thrombosis (blood clot)

23. CVA Symptoms – vary depending on area & amount of brain tissue damaged
Loss of consciousness
Weakness & vertigo
Hemiplegia (paralysis on 1 side)
Dysphagia (difficulty swallowing)
Visual disturbances & difficulty swallowing
Aphasia (speech impairment)
Incontinence

24. CVA Immediate treatment 1st THREE hours
Thrombolytic (clot busting) drugs
Angioplasty of cerebral arteries
CT scans needed to determine cause
Neuroprotective agents can be used to prevent permanent brain damage to neurons

25. CVA Treatment Depends on symptoms present
Directed toward helping person recover from OR adapt to symptoms present
PT, OT, speech therapy ESSENTIAL

26. Encephalitis
Inflammation of brain caused by virus, bacteria, or chemical agent
Mosquitoes are common vector
Symptoms vary – fever, extreme weakness, lethargy, visual changes, HA, N & V, stiff neck & back, seizures, coma
Treatment – supportive
Antiviral & antiseizure meds
Maintenance of fluids & electrolytes
Monitoring of respiratory & kidney function

27. Epilepsy
Brain disorder associated with abnormal electrical impulses in neurons of brain
Causes – brain injury, birth trauma, tumors, toxins (lead & carbon monoxide)
Many cases are idiopathic
Absence (Petit mal) seizures
Milder, characterized by loss of consciousness lasting several seconds
Common in children
Usually disappears by late adolesence

28. Epilepsy Tonic-clonic (grand mal) seizures
Most severe
Loss of consciousness lasting at least several minutes
Convulsions with violent thrashing movements & shaking
Hypersalivation, foaming at mouth
Loss of body functions
Treatment – antiseizure medications

29. Hydrocephalus
Excessive accumulation of CSF in ventricles & subarachnoid space
Usually caused by congenital defect, infection, or tumor that obstructs the flow of CSF
Symptoms –
Abnormally large head & prominent forehead with bulging eyes
Irritability
Distended scalp veins
Retardation when pressure prevents proper development of brain

30. Hydrocephalus
Treatment – surgical implantation of a shunt between ventricles & veins, heart, or abdominal peritoneal cavity to drain excess CSF

31. Meningitis
Inflammation of meninges of brain &/or spinal cord caused by bacteria, fungus, virus, or toxins (lead, arsenic)
Symptoms
High fever
HA, back & neck pain, stiffness
N & V
Delirium & confusion
Coma & death if untreated
Treatment – antibiotics, anticonvulsants, meds for pain & cerebral edema

32. Multiple Sclerosis
Chronic, progressive, disabling condition resulting from degeneration of the myelin sheath in the CNS
Usually occurs between 20 – 40
Unknown cause
Progresses at different rates
Early symptoms
Visual disturbances
Weakness, fatigue
Poor coordination
Tingling & numbness

33. Multiple sclerosis Later symptoms
Tremor, spasticity of muscles
Paralysis
Speech impairment
Emotional swings
incontinence
Treatment – PT, muscle relaxants, steroids, psychological counseling
Goal is to maintain functional ability

34. Neuralgia
Nerve pain
Caused by inflammation, pressure, toxins, & other diseases
Treatment directed towards eliminating cause

35. Paralysis
Brain or spinal cord injury destroys neurons & results in loss of function & sensation below level of injury
Hemiplegia – paralysis on 1 side of body
Paraplegia – paralysis in lower extremities
Quadriplegia – paralysis of arms, legs, & body
No cure, research being done towards repair
Treatment – supportive, PT, OT

36. Parkinson’s Disease
Chronic progressive condition involving degeneration of brain cells
Usually occurs in people over 50
Symptoms
Tremors, stiffness, muscle rigidity
Forward leaning position & shuffling gait
Difficulty stopping when walking
Loss of facial expression & drooling
Mood swings with frequent depression
Behavior changes

37. Parkinson’s Disease Treatment but no cure
Levodopa used to relieve symptoms
In selected cases, surgery to selectively destroy a small area of brain to control involuntary movements or implant a device
PT to treat rigidity

38. Shingles or herpes zoster
Acute inflammation of nerve cells
Caused by herpes virus, similar to chicken pox
Characteristically, occurs in thoracic area on 1 side of body & follows path of the affected nerves
Symptoms – fluid filled vesicles, severe pain, redness, itching, fever, abnormal skin sensations
Treatment – relief of pain & itching until inflammation subsides, usually 1-4 weeks