1. The Nervous System

2. The Nervous System Gathers information both externally and internally
Transmits this information for processing
Processes the information to determine the best response
Sends information to the muscles, glands and organs so they can respond appropriately

3. The Nervous System Central Nervous System (CNS)
Brain and Spinal Cord
Main Control Center
Processes information
Sends instructions to other parts of the body
Peripheral Nervous System (PNS)
Nerves that extend throughout the body
Gathers and delivers information
Works with the Central Nervous System

4. The Nervous System Structure of the Neuron Cell body
Dendrites receive and carry information toward the cell body
Axon carries nerve impulses away from the cell body
Glial cells protect, support and assist neurons
In the PNS, the glial cells are Schwann cells
Schwann cells are wrapped by a myelin sheath

5. Neuron

7. The Central Nervous System
Brain
Brain Stem: Joins brain to spinal cord
Cerebellum: Center of coordination
Cerebrum: Largest part of brain, conscious thought
Cerebral Cortex: Sensory, motor and association areas
Spinal Cord
Relays nerve impulses to and from the brain
Controls spinal reflexes

8. Parts of the Brain 2 cerebral hemispheres Further divided into lobes
Parietal Lobe – somatic sensory area, impulses traveling from the body’s sensory receptors are localized & interpreted here
Ex. pain, cold, touch
Occipital Lobe – visual area
Temporal Lobe – auditory area and olfactory area
Frontal Lobe – primary motor area – skeletal muscles, also specialized area for fine motor control such as speech

10. Cerebral Cortex – sensory and motor areas

11. Cerebellum 2 hemispheres Balance
Under occipital lobe of cerebrum
Balance
Coordinates body movements (makes movements smooth)

12. Cerebellum (colored purple)

13. Brain Stem 3 inches long, diameter of thumb, base of brain 3 parts:
Midbrain – reflex centers for hearing and vision
Pons – (means bridge), center for breathing
Medulla oblongata – merges into spinal cord
Automatic, homeostatic functions
Such as: heart rate, blood pressure, breathing, swallowing, vomiting and digestion

15. Spinal Cord Continuation of brain stem
2-way conduction pathway to and from the brain and a major reflex center
Cushioned and protected by meninges
Meninges = connective tissue membranes
31 pairs of spinal nerves arise from the spinal cord

16. The Peripheral Nervous System
Somatic Nervous System
Controls voluntary responses of skeletal muscles
May involve some reflex reactions
Autonomic Nervous System
Controls the activities of smooth muscles, organs, and glands
Divided into:
Sympathetic Nervous System which controls the response of the body to stress
Parasympathetic Nervous System which controls the functions of the body related to rest and digestion

17. The Nervous System Senses and Sensory Receptors Sight Hearing Balance
Taste
Smell
Touch
Temperature
Pain

18. The Nervous System Problems
Regeneration doesn’t occur with nerves that begin in the brain or spinal cord
Peripheral nerves may regenerate if they are partially cut or crushed
Spinal cord injuries
Stroke
Multiple Sclerosis (MS): Body’s own immune system attacks myelin sheath of nerve fibers
Amyotrophic Lateral Sclerosis (ALS) or Lou Gehrig’s Disease: Destroys motor neurons in spinal cord and brain
Alzheimer’s Disease: Degeneration of the brain’s cortex