1. Nervous System

2. The Neuron Also called the nerve cell
It is the basic structural unit of the nervous system

3. The Neuron Part of the Neuron Cell Body Nucleus (inside the cell body)
Nerve Fibers

4. Nerve Fibers Dendrites Axon Carries impulses TOWARD the cell body
Single nerve fiber that carries impulses AWAY from the cell body

5. Nerve Fibers Myelin Sheath Lipid (fat) cover over the axon
Increases the rate of transmission of an impulse
Insulates and protects the axon

6. Nerve Impulses
Axon of a neuron lies close to the dendrites of many other neurons
Synapse
Space between dendrites of one neuron and axon of another neuron
Impulses “jump” the synapse

7. Nerve Impulses Neurotransmitters
Special chemicals located at the end of each axon
Allows the nerve impulse to pass from one neuron to another via the synapse or synaptic cleft
Synapse is the space between the axon of one neuron and the dendrites of the next

8. Nerves
Bundle of nerve fibers (neuron, dendrites, axons, etc) enclosed by connective tissue
Nerve impulses travel to and from the brain at the rate of 170 mph

9. Types of Nerves AFFERENT/Sensory EFFERENT/Motor
Carries messages from all parts of the body (sensory organs) to the brain and spinal cord
EFFERENT/Motor
Carries messages from the brain and spinal cord to muscles and glands

10. Division of the Nervous System
Two main divisions
Central Nervous System
Brain and Spinal Cord
Peripheral Nervous System
Made up of the nerves in the body
Broken down into Autonomic and Somatic divisions

11. Central Nervous System
Brain
Mass of nerve tissue
Protected by membranes and the cranium (skull)

12. Central Nervous System
CEREBRUM
Largest and highest section of the brain
Has convolutions (folds)
Separated into lobes which are named from the skull bones that surround them
Frontal (1 lobe)
Parietal (2 lobes)
Temporal (2 lobes)
Occipital (2 lobes)

13. Central Nervous System
Cerebellum
Diencephalon
Section below the cerebrum
Responsible for coordination of muscles, balance and posture, and muscle tone
Located between the cerebrum and midbrain
Contains two structures
Thalamus – acts as relay center
Hypothalamus – regulates Autonomic Nervous System

14. Central Nervous System
Midbrain
Located below the cerebrum at the top of the brain stem
Responsible for conducting impulses between brain parts
Responsible for certain eye reflexes

15. Central Nervous System
Pons
Located below the midbrain in the brain stem
Responsible for conducting messages to other parts of the brain
Responsible for certain reflex actions including chewing, tasting, production of saliva
Assists with respirations

16. Central Nervous System
Medulla Oblongata
Lowest part of the brain stem
Connects with the spinal cord
Responsible for regulating the heart beat, respirations, swallowing, coughing, and blood pressure

17. Central Nervous System
Spinal Cord
Continues down from the medulla oblongata
Ends at the 1st or 2nd lumbar vertebra
Surrounded and protected by the vertebrae
Carries AFFERENT (sensory) messages to the brain
Carries EFFERENT (motor) messages from the brain to the nerves that go to muscles and glands

18. Central Nervous System
Meninges
Three membranes that cover and protect the brain and spinal cord
Dura mater
Thick, tough outer layer
Arachnoid
Middle, delicate web like layer
Pia mater
Innermost layer
Closely attached to the brain and spinal cord
Contains blood vessels that nourish the nerve tissues

19. Central Nervous System

20. Peripheral Nervous System
Consists of cranial nerves and spinal nerves
12 Cranial Nerves
On Old Olympus Towering Tops A Finn Versus German Viewed All Hops
See worksheet
Spinal nerves
31 pairs and their branches
Carries messages to and from the spinal cord

21. Peripheral Nervous System
Spinal nerves
31 pairs and their branches
Carries messages to and from the spinal cord
Plexus
Each nerve goes directly to a particular part of the body or network with other spinal nerves
Supplies sensation to large segments (Dermatomes) of the body

22. Plexus
Cervical
Brachial
Lumbar
Sacral

23. Dermatomes

24. Autonomic Nervous System
Important part of the Peripheral Nervous System
Helps maintain a balance in the involuntary functions
Heart rate, respirations, temperature, digestion, etc.
Allows the body to react in times of emergency

25. Autonomic Nervous System
Two divisions
Sympathetic Nervous System
Parasympathetic Nervous System
Two systems work together to
Maintain HOMEOSTASIS (balanced state)
Control involuntary body functions at proper rates

26. Autonomic Nervous System
Sympathetic Nervous System
“Fight or Flight”
Acts in times of emergencies
Prepares the body to act
Increases heart rate, respirations, and blood pressure
Slows down the digestive tract

27. Autonomic Nervous System
Parasympathetic Nervous System
Counteracts the actions of the Sympathetic system after an emergency
Lowers heart rate, respirations, and blood pressure
Increases activity of the digestive tract

28. Graphic Organizer
CNS and PNS

30. Pathophysiology - CVA Cerebrovascular Accident (CVA)
Also called Stroke
Blood flow to the brain has been interrupted resulting in lack of oxygen to the brain and therefore destruction of brain tissue
Causes
Cerebral hemorrhage from hypertension, aneurysm (weak blood vessel), trauma
Occlusion (blockage) caused by atherosclerosis (fat build up) or thrombus (blood clot)

31. Pathophysiology - CVA Symptoms
Varies depending on the area of the brain affected and the amount of brain tissue damaged
Loss of consciousness
Dizziness
Weakness
Paralysis on one side of the body (hemiplegia)
Mental confusion
Visual disturbances
Aphasia (speech and language impairment)
Incontinence

32. Treatment - CVA
Like a heart attack, the quicker treatment is administered the less the damage occurs
Within first three hours give thrombolytic (clot bursting) drugs such as TPA
CT scan done first because if caused by hemorrhage cannot give thrombolytic
Angioplasty – opens cerebral artery, dissolves clot and restores blood flow

33. Treatment - CVA
Long term treatment depends on the damage that has occurred
Often need therapies such as physical, occupational, and speech therapies
May need assistive devices such as canes, walkers, and braces
Prevention of blood clots – thin blood
Take ASA, Coumadin, etc for the rest of your life
Treat underlying conditions such as high blood pressure, atherosclerosis, diabetes, etc

34. Pathophysiology – Parkinson’s Disease
Chronic, progressive condition involving degeneration of brain cells
Usually occurs in persons over 50 years of age but not always
Caused by lack of or imbalance of a neurotransmitter, dopamine, in the brain
Cells that produce dopamine stop producing and die
When dopamine levels drop neurons start firing abnormally causing the classic tremors

35. Pathophysiology – Parkinson’s Disease
Symptoms
Tremors, stiffness, and muscular rigidity
Cog Wheeling
Pill rolling
Forward leaning position and a shuffling gait
Difficulty in stopping while walking
Loss of facial expression and drooling
Parkinson’s Mask
Mood swings, behavioral changes, and frequent depression

36. Treatment – Parkinson’s Disease
No known cure
Medication to lessen symptoms and possibly slow progression
Levodopa – synthetic dopamine
Physical therapy and assistive devices to limit the muscular rigidity

37. Other Diseases of the Nervous System
Paraplegia = paralysis of the lower extremities
Encephalitis = inflammation of the brain caused by virus, bacteria, or chemical agent
Hydrocephalus = excessive accumulation of cerebrospinal fluid in the ventricles

38. Other Diseases of the Nervous System
Neuralgia = nerve pain
Epilepsy = condition involving abnormal electrical impulses in the brain resulting in convulsions or seizure
Cerebral palsy = disturbance in voluntary muscle action caused by brain damage
Multiple sclerosis = A chronic, progressive, disabling condition resulting from a degeneration of the myelin sheath