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The Human Nervous System

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

1 The Human Nervous System

2 Neuron- A Nerve Cell Contains the nucleus and other organelles
Cell body Contains the nucleus and other organelles Dendrites Receive stimuli Conduct impulses toward the cell body Axon Carries impulses away from the cell body

3 Axon Structure Insulating coat of plasma membranes
Myelin sheath Insulating coat of plasma membranes Sections of sheath are called “Schwann Cells” Unmyelinated axons carry impulses much slower than myelinated axons Nodes of Ranvier Bare axonal membrane between Schwann cells

4 The Synapse Synapse The gap between nerve cells Neurotransmitter
Chemicals that carry nerve signals across the synapse

5 Reflex Arc The reflex arc responds to a stimulus without the immediate involvement of the brain

6 Central Nervous System (CNS)
Brain Spinal Cord

7 Cerebrum Directs voluntary movement Sensory processing
Language and communication Learning and memory

8 Cerebellum Regulates sense of balance
Coordinates voluntary muscle movement

9 Medulla Oblongata Breathing Heart rate Blood pressure
Swallowing and digestion

10 Peripheral Nervous System (in blue)

11 Peripheral Nervous System
Sensory Division Bring information to the CNS Motor Division Carries signals away from the CNS Somatic (voluntary) nervous system controls skeletal muscle action Autonomic nervous system (involuntary) controls organ systems and smooth muscle

12 Divisions of the Autonomic Nervous System
Sympathetic Stress responses (Fight or Flight) Pupils dilate Mouth dries up (saliva decreases) Heart rate increases Blood flow to skeletal muscle increases Parasympathetic Relaxation response Heart rate slows Pupils constrict Stimulates salivation Digestive processes stimulated

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