Chapter 3 Flashcards
What are neurons?
building blocks of the nervous system
nerve cells specialized for communication
100 billion at birth
make connections with other neurons
What are glial cells?
supporting neurons (keeping them in place)
manufacture or transport nutrients
form the myelin sheath
absorb toxins and waste materials
protects the brain from toxins via blood-barrier
during development, glial cells guide neurons to their proper place in the brain
modulating communication between neurons
What is the resting neuron?
neurons communicate through changes in charge between the interior and exterior of the axon
membrane potential difference when resting is -70 mV
membrane is semi-permeable
What happens when a neuron is “in action”?
action potential: a sudden reversal in the neuron’s membrane voltage, the shift from an negative interior to a positive interior is depolarization
all-or-none, always the same strength, uniform
originates near cell body, moves along axon to terminal
What happens after the action potential in a neuron?
absolute refractory period: brief interval when a neuron cannot fire another AP
occurs after each AP
the neuron needs to reset
What are the steps of an action potential?
- Resting
- Sodium channels open and sodium rushes in
- Sodium channels snap shut and potassium channels open to let potassium out
- Sodium-potassium pump return everything back to normal (3 Na+ for 2 K+)
What are graded potentials?
caused by excitatory/inhibitory postsynaptic potentials (EPSP/IPSP)
sum u to cause an action potential or not
depends on the charge entering the cell
can bring the cell closer (EPSP) or further (IPSP) from the threshold to fire an action potential
What is myelin?
glial cells insulate axons to increase the speed of signal transmission, along with efficiency
insulates axons in CNS
nodes of ranvier allow AP to jump which increases speed
What are neurotransmitters?
chemicals that carry messages across the synapse
What are the steps that neurotransmitters go through in the synapse?
- NT are synthesized
- NT are stored into vesicles
- NT released into the synapse
- NT bind to receptor sites on dendrite of post synaptic cell, location that uniquely recognizes the NT
- Removal of NT from the synapse
What is the function of the neurotransmitter glutamate?
excitatory
many functions including learning/memory
What is the function of the neurotransmitter GABA?
inhibitory
many functions including anxiety/motor control
What is the function of the neurotransmitter acetylcholine?
excitatory
muscular movement and memory
What is the function of the neurotransmitter norepinephrine?
both excitatory and inhibitory
learning, memory, wakefulness, eating
What is the function of the neurotransmitter serotonin?
inhibitory
mood, sleep, eating/arousal
What is the function of the neurotransmitter dopamine?
both excitatory and inhibitory
voluntary movement, emotional arousal, learning, motivation, pleasure
What is the function of the neurotransmitter endorphin?
inhibitory
numbs pain
What are agonists?
enhance neuron’s ability to synthesize, store, or release NT
mimic the action of a NT (bind to receptor site)
inhibits reuptake
What are antagonists?
reduce neuron’ ability to synthesize, store or release NT
prevent NT from binding to receptor site by blocking it
What are sensory neurons?
carry messages from sense to spinal cord and brain
What are motor neurons?
transmits output impulses from the brain and spinal cord to muscles/organs
What are interneurons?
link the input and output functions
What is the peripheral nervous system?
nerves that extend outside the central nervous system
contains the somatic nervous system