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The Nervous System.

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Presentation on theme: "The Nervous System."— Presentation transcript:

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

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