Lecture 1 Flashcards
What two systems are the nervous system made up of?
Central Nervous System and Peripheral Nervous System
What makes up the CNS?
Brain and spinal cord
What makes up the PNS?
Cranial nerves and spinal nerves
What system can regenerate axons?
Peripheral Nervous System
What cells make up the nervous system?
Neurons and glial cells
What is the role of glial cells?
To support neurons, there are 50-100 glial cells per neuron
Approximately how many neurons are in the human brain?
10^12
What are the three types of neurons?
- Multipolar
- Pseudo-unipolar
- Bipolar
Which neurons are typically multipolar?
Motor neurons
Which neurons are typically pseudo-unipolar?
Sensory neurons
Which neurons are typically bipolar?
Eye and nose
What are the 4 parts of the neuron?
Dendrites, body/soma, axons, axon terminals
What makes up the neuron cell membrane?
Phospholipid bilayer (separates inside cell from outside cell)
What requires no energy to pass through the phospholipid bilayer?
O2 and CO2
How do O2 and CO2 move in and out of the cell?
Move down the concentration gradient
How many Na+ and K+ ions are pumped in and out of the cell?
3 Na+ ions pumped OUT
2 K+ ions pumped IN
T/F pumps are never turned off
True, if a pump is off the person is dead
What do “leak” ion channels allow?
Allow lots of K+ to exit the cell
Allow little Na+ to enter the cell
T/F “leak” ion channels are always open
True
What are the 3 types of gated Na+ ion channels?
- Modality/Pressure gated
- Transmitter/Ligand gated
- Voltage gated
Which gated ion channel responds to a physical stimulus?
Modality/Pressure gated
Which gated ion channel responds to chemical binding?
Transmitter/ligand gated
Which gated ion channel responds to changes in electrical potential?
Voltage gated
Which channel is fast opening?
Voltage gated Na+ channel
Which channel is slow opening?
Voltage gated K+ channel
What are the charges on the inside and outside of the cell?
Inside the cell is negatively charged
Outside the cell is positively charged
What causes Na+ to flow into the cell?
A stimulus
What is resting membrane potential?
-70 mV
Between what voltage does a local/graded potential occur at?
-70 to -55 mV
No action potential is generated
What voltage must be reached to get to the threshold to generate an action potential?
-55 mV
What flows into the cell when fast opening channels are opened? What is this called?
Influx of Na+
Depolarization
What generates the action potential?
The influx of Na+ and reaching the threshold
What flows out of the cell when slow opening channels are opened? What is this called?
K+
Repolarization
T/F action potentials are all or nothing
True (action potential = nerve impluse)
