ch 12 nervous system pt 2 Flashcards
Regeneration is possible if:
Neuron cell body is intact and enough neurilemma remains
After a traumatic injury pns axons can…
Regenerate
CNS axon regeneration is
extremely limited
What are pumps?
Active transport, needs energy, sodium-potassium pumps
What are channels?
More proteins
What are leak channels?
Always open
What are chemically gated channels?
Closed unless when neurotransmitters bind
What are voltage gated channels
Closed unless membrane charge changes (neg charge)
Three states of voltage gated Na+ channels
resting, activation, inactivation state
What is resting state gates?
Activation gate closed, inactivation gate open
What is the Na+ movement in resting state?
Can’t go through
What is activation state gates
Activation and inactivation gates open
What is the Na+ movement in activation state?
Can move through channel
What is inactivation state gates
Activation gate closed, inactivation gate open
What is the Na+ movement in activation state?
Can’t go through
What are mechanically gated channels?
Closed unless open in response to a stimulus
What is in an entire plasma membrane of a neuron?
Leak channels, Na+ and K+ pumps, resting potential
What is in the receptive segment?
Dendrites and cell body
What gate is in the receptive segment?
Chemically gated channels Cl-
What gate is in the initial segment?
voltage-gated Na+ and K+ channels
What is in the initial segment?
Axon hillock
What is in the conductive segment?
Axon and its branches
What is gate is in the conductive segment?
Voltage-gated Na+ and K+ channels
What is in the transmissive segment?
Synaptic knobs
What gate is in the transmissive segment?
Voltage-gated Ca2+ channels and pumps
What is voltage energy (potential energy)
Inside and outside cell; concertation gradient
What is electrical energy?
Movement of ions
What is resistance energy?
Opposition to movement of ions such as membrane
What is current energy?
When channels open
What is Ohms law?
current = voltage/resistance
How is voltage energy exist?
Exists across the membrane due to unequal distribution of ions
How is current energy generated?
Generated when ions diffuse through channels