Download Nerve Tissue Notes

WARM UP
“The secret of action is to begin.”
1. What does this mean to you?
2. How can you apply this to
Biology II?
Nerve Tissue
Levels of Organization
• Organism
–Organ System
»Organ
• Tissue
• Cell
• Organelle
• Molecule
– Atom…
• Each level depends on many cooperating structures at
the levels below
Nervous System
• Quick control over all body functions
– Electrochemical signals
Nervous Organs
• Brain
– 100 billion neurons forming connections
Nervous Organs
• Spinal cord
– Bundled neuron
pathway
– Protected by meninges
and vertebrae
Nervous Organs
• Spinal cord con’t….
– Structure
• White matter: axons w/ sheath
• Gray matter: dendrites, cell bodies, neuroglials
• Central canal
Nerve Tissue
• Made of connected
neurons and neuroglial
cells
– Control over responses
– Transmit electrical and
chemical signals
Nerve Cell – The Neuron
• Dendrites receive info
• Cell body, with trigger zone at end
• Axon sends impulses
Nerve Cell – The Neuron
• Axon sends impulses
– Myelin sheath, made of Schwann cells, wraps
around axons and speeds up signals
Electrochemical Nerve Signal
• Reversal of
charge
– (– to + to –)
• Travels down
axon
Electrochemical Nerve Signal
• Controlled by ion flow
– Sodium+ pumped in
– Potassium+ pumped
out
Electrochemical Nerve Signal
• Neurotransmitters
cross synapse
– Acetylcholine
– Serotonin
– Norepinephrine
– Dopamine
– GABA
• Received by receptors
WRAP UP
• Which part of a neuron is most
important, and why?
WARM UP
• Explain why nerve signals are
described as “electrochemical.”
WRAP UP
• List the 3 parts of a neuron and
describe the function of each.