Download sensory neurons

Neuron (Nerve Cell)
• Cell Body
– Cytoplasm
– Nucleus
• Axon
– Carry messages away
from the cell body to
other neurons
• Dendrites
– Carry messages to the
cell body
Types of Neurons
Receptor Cells
Receives information from a stimulus
•
•
Sensory Neurons
–
Carry the impulse to the spinal cord
•
•
Travels the length of the arm to the
spinal cord
Interneurons
–
Impulse is transmitted to the brain and
the motor neurons via synapses
•
•
For example - your finger gets hit by a
hammer
Travels to the brain to register pain and
out to the finger
Motor neurons
–
Sends the processed information back
to finger
•
Carries impulse to the effector cells in
the fingers, hand and arm
Nerve Impulses
• 120 meters per second =
speed at which impulses
travel in the body.
• Synapse – gap between
two neurons (axon and
dendrite)
– Impulse travels from one
neuron to the next by
sending chemicals across
a gap to activate the next
neuron.
Reflex Arc
1. Hand touches open
flame or hot burner
2. Impulse travels to
spinal cord
3. Impulse sent to brain
and back to hand.
4. Hand pulls back
before pain is
registered by brain
3.
2.
1.
4.
Nervous System
•
Two major divisions
1. Central Nervous
System (CNS)
•
brain and spinal cord
2. Peripheral Nervous
System
•
motor and sensory
neurons
Central Nervous System
Development of the brain
Conception - newborn
Sagittal Section of Brain
cerebrum
Corpus callosum
cerebellum
pons
Medulla
oblongata
Inferior view of Brain
Olfactory
Lobes
Frontal lobe
of the
cerebrum
Medulla
oblongata
cerebellum
Regions of the Brain
• Cerebrum - thought and reasoning
–
–
–
–
•
•
•
•
Frontal - thinking, talking, remembering, moving
Parietal - touching
Occipital - seeing
Temporal – tasting, smelling, hearing
Cerebellum – coordination of muscular movements
Medulla Oblongata – involuntary responses
Pons – band of nerves linking the medulla and the cerebellum
Olfactory – sense of smell
Spinal Cord
Peripheral Nervous System
• Consist of the
neurons (receptor and
motor) which lead to
and from the central
nervous system
• Two divisions
– Sensory Somatic
– Autonomic