Nervous System

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Slide 1

The Human Nervous System

Slide 2

Neuron- A Nerve Cell

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

Slide 3

Axon Structure

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

Slide 4

The Synapse

Synapse

The gap between nerve cells

Neurotransmitter

Chemicals that carry nerve signals across the synapse

Slide 5

Reflex Arc

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

Slide 6

Central Nervous System (CNS)

Brain

Spinal Cord

Slide 7

Cerebrum

Directs voluntary movement

Sensory processing

Language and communication

Learning and memory

Slide 8

Cerebellum

Regulates sense of balance

Coordinates voluntary muscle movement

Slide 9

Medulla Oblongata

Breathing

Heart rate

Blood pressure

Swallowing and digestion

Slide 10

Peripheral Nervous System (in blue)

Slide 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

Slide 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