Chapter 2 Flashcards
what is the NERVOUS SYSTEM?
a network of billions of cells within the brain and the body, that are responsible for all aspects of what you think, feel, and do
what are the THREE BASIC FUNCTIONS of the nervous system?
- (1) receiving SENSORY INPUT from the world through basic senses
- (2) processing information through attention, perception, and memory
- (3) response to information through action
what are the TWO DIVISIONS of NERVOUS SYSTEM?
- CENTRAL NERVOUS SYSTEM (CNS):
- the part of the nervous system that consists of the nerve cells in the brain and the spinal cord
- PERIPHERAL NERVOUS SYSTEM (PNS):
- the part of the nervous system that consists of all the nerve cells throughout the body except those in the brain and spinal cord
both divisions constantly are in contact with one another
what are NEURONS?
- the nerve cells that are the basic units of the nervous system
- help receive, integrate, and transmit info in the nervous system
- operate through electrical impulses, and communicate through chemical signals
what are the specific parts of a NEURON (5)?
- dendrites
- axons
- terminal buttons
- synapse
- neurotransmitters
dendrites
branchlike extensions of the neuron’s cell body with receptors that receive information from other neurons
axons
- a long, narrow outgrowth of a neuron’s cell body that lets the neuron transmit information to other neurons
- can be very long in length
- **nerve is really a bundle of axons
terminal buttons
parts of the neuron at the end of axons that release chemical signals from the neuron into the synapse
synapse
the gap between the terminal buttons of a sending neuron and the dendrites of a receiving neuron
neurotransmitters
chemicals that carry signals from one neuron to another
what are the THREE PHASES OF NEURAL COMMUNICATION?
- PHASE ONE - TRANSMISSION PHASE
- electrical signals created in the cell body travel along axon and release of neurotransmitters in terminal buttons
- PHASE TWO - RECEPTION PHASE
- dendrites of other neurons receive signals from sending neurons
- PHASE THREE - INTEGRATION PHASE
- neurons begin to assess and integrate incoming signals
- all three phases continue to repeat and transmit specific signals
- similar to reposting an instagram post for example
neuron membrane
- barrier that separates the inside of the neuron from the outside environment
- helps regulate neuron’s electrical activity
- semipermeable - ions are able to pass through
ions
- electrically charged chemicals
- ex. sodium and potassium ions
- help neurons communicate
neuron resting state
- the electrical charge INSIDE the neuron is more NEGATIVE than the electrical charge OUTSIDE
- overall difference in charges = creates a BALANCE between the various ions
incoming stimulation
- causes positively charged sodium ions to move INSIDE the MEMBRANE
(more positive on the INSIDE)
- with enough stimulation = creation of an action potential
action potential
neural impulse that travels along the axon and then causes the release of neurotransmitters into the synapse
refractory period
- neuron returns to resting state
- the neuron is LESS RESPONSIVE to incoming stimulation and less likely to fire an action potential
- ex. social battery is dead after a night out, less likely to go out another time
myelin sheath + relation to MS disorder
a fatty material that covers and insulates some axons to allow for faster movement of electrical impulses along the axon
presynaptic neuron
the neuron that sends the signal
postsynaptic neuron
the neuron that receives the signal
receptors
- specialized structures that respond to certain types of neurotransmitters
- ex. lock and key example
- once binded with specific receptors, neurotransmitters are released back into synapse
how to avoid constant stimulation of these neurotransmitters?
- REUPTAKE:
- neurotransmitters are reabsorbed by the presynaptic neuron
- ENZYME DEGRADATION:
- enzymes destroy neurotransmitters within synapse
what signals does the POSTSYNAPTIC NEURON PROCESS?
- EXCITATORY
- signal that excites the neuron — increasing the likelihood of an action potential
- INHIBITORY
- signal that inhibits the neuron — decreasing the likelihood of an action potential
- signals are received in bunches of thousands
- if enough to reach certain threshold — postsynaptic neuron will fire its own action potential
agonist
- drugs that enhance the actions of neurotransmitters
- ex. nicotine (agonist) acts similar to acetylcholine
- binds to acetylcholine receptors
- enhancing motor coord. + attention
antagonists
- drugs that inhibit the actions of neurotransmitters
- ex. drug naloxone (antagonist)
- binds with endorphin receptors—blocks any opioids from binding
acetylcholine
- responsible for MOTOR CONTROL - MUSCLES
- binds with receptors on muscle cells - muscle contraction
- helps attention, memory, learning, and sleeping
norepinephrine
- a neurotransmitter involved in AROUSAL/ALERTNESS/ADERNALINE
- in our bodies; epinephrine (adrenaline)
serotonin
- neurotransmitter involved in wide range of PSYCHOLOGICAL ACTIVITES
- emotional states, impulse control, and dreaming