AP Bio Systems-Chapter Part 4 Flashcards
Describe nervous system
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What’s the most specialized cell in animals
The neuron
What are parts of the neuron
Cell boys Axon Axon tips Dendrites Axon hillock Myelin sheath
How do impulses go through neurons
One direction. Enter dendrites, leave axon tips
Dendrites
Incoming signals enter here
Each dendrite is connected to another neuron at the synapse
Axon hillock
The start of the axon, where an action potential begins between axon and cell body
Myelin sheath
Layers of myelin insulate neurons
Speeds transmission of APs
Made up of Schwann cells
Axon terminal
Where 2 neurons come together at the synapse
What are the 3 types of neurons
Sensory neuron
Interneuron
Motor neuron
Where do these cells “live”
In a sea of charged ions (anions=negative, K+, charged amino acids (aa-) )
more concentrated in the extracellular fluid (cations = positive) NA+ Cl-
Membrane is __________
What does this mean
Polarized Negative inside, positive outside Allows for membrane potential Allows for charged gradient Stores energy like a battery
What’s prevalent in membrane
Lots of pump proteins and Jon channels
Main concentration of ions
What resets following a nerve signal
Concentrations
What controls openings to channels
Different types of gates
What are these types of gates
Mechanical
Voltage
Ligand
Mechanical gates
Opened by force
Voltage gates
Opened by voltage
Ligand gates
Opened by ligand binding
Action potential
Which neuron actually happens
What are the 2 types of nerve signals
Electrical - ion exchange
Binary - all r nothing
How is action potential generated
Wave = nerve impulse –> brain –> fingertips in millseconds
Threshold
In Amount of stimuli needed for. A stimulus to fire off (action potential)
Either ______ or _______
Fire
Don’t
There is an amount of time where
A neuron can’t refire
In an all or nothing signal, neural membrane polarity is
Constantly fluctuating around the resting potential
For an action potential to be generated, the membrane must be depolarized to
A threshold potential
Nerve terminals
Impulse has to jump the synapse
Junction between neurons had to move quickly form one cell to the next
