Transcript NERVOUS SYSTEM II

NERVOUS SYSTEM II
PP 1016-1024
NEURONS
1. Axons: extension of cell body
2. Axon terminal: end of the axon
3. Dendrites: receive action potentials (electrical
impulse/message) from other neurons
4. Synapse: gap between neurons
5. Myelin sheath: lipid layer around axon
(insulator)
6. Schwann cells: produce myelin sheath
SENSORY NEURONS
Taste and Smell
• Chemoreceptors
• Scent and taste are just chemicals
Vision
• Photoreceptors
• 2 types: cones
(bright light) and
rods (dim light)
Hearing and balance
• Mechanoreceptors
• the neurons look like
hair and move to the
vibration of air (hearing)
or movement of fluid
(balance)
Pressure and Temperature
• Mechanoreceptors and thermoreceptors
Tissue damage
• Pain receptors
NERVE IMPULSES
• Think of the impulse as electrical and negative
• Resting potential: inactive due to “negatively”
charged inside as compared to impulse
• Action potential: helps the transmission of an
electrical impulse by making inside more “positive”
• When the impulse reaches the end (axon
terminal) neurotransmitters are released
from the neuron, into the synapse, to
receptors in the next cell (dendrite)