Nervous System
• Nervous System
– Brain
– Spinal cord
– Nerves
• Functions of nervous system
– Regulates and coordinates all body activities
– Center of all mental activity, including thought,
learning, and memory
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Nervous System Divisions
• Central Nervous System (CNS)
– Brain
– Spinal Cord
• Processes and stores sensory and motor
information
• Controls consciousness
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Nervous System Divisions
• Peripheral Nervous System (PNS)
– 12 Pairs of Cranial Nerves
– 31 Pairs of Spinal Nerves
• Transmits sensory and motor impulses back and
forth between CNS and rest of body
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Nervous System Divisions
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Peripheral Nervous System
• Somatic Nervous System (SNS)
– Provides voluntary control over skeletal
muscle contractions
• Autonomic Nervous System (ANS)
– Provides involuntary control over smooth
muscle, cardiac muscle, and glandular
activity and secretions in response to the
commands of the central nervous system
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Cells of the Nervous System
• Neuron
– Cell body
• Contains the nucleus and cytoplasm
– Axon
• Conducts impulses away from the cell body
• Some axons are covered with a myelin sheath
– Dendrite
• Conducts impulses toward the cell body
– Synapse
• Space between two nerves which the impulse
must cross
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Cells of the Nervous System
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Central Nervous System
• Brain
– Surrounded by bone for
protection
– Enclosed in cranium
• Spinal cord
– Surrounded by vertebrae for
protection
– Surrounded by meninges and
cerebrospinal fluid
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Layers of protection
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Meninges-Membranes
• Dura mater
– Outermost layer of meninges
– Tough, white connective tissue
• Arachnoid membrane
– Middle layer of the meninges
– Resembles a spider web
• Pia mater
– Innermost layer of the meninges
– Tightly bound to the surface of the brain and
spinal cord
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Structures of the Brain
• Cerebrum
– Largest and uppermost portion of the brain
– Controls consciousness, memory,
sensations, emotions, voluntary movements
• Cerebellum
– Attached to the brain stem
– Maintains muscle tone
– Coordinates normal movement and balance
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Structures of the Brain
• Brain Stem
– Region between brain and spinal cord
– Consists of midbrain, pons, and medulla
oblongata
– Serves as pathway for impulses between brain
and spinal cord
– Controls respiration, blood pressure, and heart
rate
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Spinal Cord
• Pathway for impulses traveling to and from
brain
• Carries 31 pairs of spinal nerves
– Affects limbs and lower part of body
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Homework
• Find and print out a diagram of a human
brain.
• It should include each main part and what
that part controls.
• Tape this diagram in your notebook.
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It should like something like this:
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