Biopsychology Study Guide Questions

define “nervous system”

a network of cells that carries information through the body

what are the parts of a neuron?

dendrites, soma, axon, axon terminals

what is a dendrite?

a long, branch-like structure that receives messages from other neurons

what is the soma?

the cell body of the neuron responsible for maintaining life

what is an axon?

long, tubelike structure that sends messages to other cells

what are axon terminals?

rounded areas at the end of axon branches responsible for communicating with other neurons

what is the function of the myelin sheath?

to insulate; prevent the electrical charge from escaping; increases speed at which the signal travels

what are the gaps in the myelin sheath called, and why are they important?

the nodes of ranvier; voltage gated ion channels open at the nodes to allow sodium ions to flow into the axon

which two ions play an important role in maintaining and changing the membrane potential of a neuron?

sodium and potassium

what are ligand-gated ion channels?

channel proteins that require a ligand molecule to allow molecule to pass through them into the membrane

what are voltage-gated ion channels?

channel proteins that open in response to a change in electric potential

where are sodium ions concentrated at resting potential?

outside the cell

where are potassium ions concentrated at resting potential

within the cytoplasm or intracellular fluid

what other factors contribute to a positive charge outside of the cell and a negative charge within the cell?

chloride ions outside the cell and negatively charged proteins within the cell

what is excitatory postsynaptic potential?

depolarization; the membrane potential becomes less negative, readying the neuron to fire

what is inhibitory postsynaptic potential?

hyper polarization; the membrane potential becomes more negative, making the neuron less likely to fire

first step of the action potential

cell is at resting potential (-70 mV)

second step of the action potential

threshold of excitation is reached (-55 mV)

third step of the action potential

depolarization (~ -30 mV)

fourth step of the action potential

peak action potential is reached (+30 mV)

fifth step of the action potential

re-polarization occurs (~10 mV)

sixth step of the action potential

hyper-polarization (~ -80 mV)

seventh step of the action potential

cell returns to resting potential

what triggers an action potential?

when neuron receives a signal at the dendrites, (due to a neurotransmitter binding to its receptors) small gates open on the membrane, allowing Na ions to move into the cell

what is depolarization?

the membrane potential becomes less negative (Na ions move into cell)

what is repolarization? 

cell begins to return to its resting potential by closing Na gates and opening K gates

what is hyperpolarization?

the cell briefly becomes more negative than resting potential after repolarization

what happens when an action potential reaches the axon terminal of a neuron?

it arrives at the terminal button, causing the synaptic vesicles to release neurotransmitters into the synaptic cleft

what is a synapse?

the synapse is the site where neurons release and receive neurotransmitters

what are the parts of a synapse?

1. presynaptic membrane

2. postsynaptic membrane

3. space between neurons

why do neurons use chemicals to communicate with each other across the synapse?

neurotransmitters and receptors have a lock-and-key relationship (?)

what is reuptake? what is its function?

reuptake is the return of excess neurotransmitters to the neuron that released them to clear the synapse

what is enzymatic degredation?

the breaking down of excess neurotransmitter by enzymes

what are neurotransmitters?

the chemical messengers of the nervous system

function of acetylcholine

excitatory or inhibitory, involved in arousal, attention, memory; controls muscle contractions

function of GABA

major inhibitory neurotransmitter; involved in sleep, inhibits movement

function of glutamate?

major excitatory neurotransmitter; involved in learning, memory formation, nervous system development, and synaptic plasticity

function of norepinepherine?

mainly excitatory, involved in arousal and mood

function of dopamine?

excitatory or inhibitory; involved in control of movement and sensations of pleasure

function of serotonin

excitatory or inhibitory; involved in sleep, anxiety, mood, and appetite 

what are the subdivisions of the nervous system?

central and peripheral

describe the central nervous system and all its components

composed of the brain and spinal cord (responsible for transmitting messages between the brain and the rest of the body)

describe the peripheral nervous system and all its components

made up of neurons with long axons and dendrites, branches out from spinal cord and brain to reach the body’s extremities; divided into somatic and autonomic divisions

what is the somatic nervous system responsible for?

voluntary movement

what is the autonomic nervous system responsible for?

controls smooth muscle, cardiac muscle, and glands, involuntary movement

what is the sympathetic branch of the autonomic nervous system responsible for?

fight, flight, freeze response; prepares an organism for stressful situations, engages all the organism’s resources

what is the parasympathetic nervous system responsible for?

maintaining normal functions, acts to calm the body after an emergency or stressful situation has ended

describe the medulla oblongata and its function

regulates vital functions; breathing, circulation, and swallowing

describe the pons and its function

involved in sleep and arousal

describe the reticular formation and its function

group of fibers that carry stimulation related to sleep and arousal through the brain stem

describe the cerebellum and its function

coordinates fine muscle movement, balance

describe the thalamus and its function

relay center for incoming sensory information

describe the hypothalamus and its function

regulates basic biological needs: hunger, thirst, temperature control

describe the cerebrum (cerebral cortex) and its function

involved in sensing, thinking, learning, emotion, consciousness, and voluntary movement

what is the corpus callosum and its function?

a large bundle of axons that connects the two hemispheres of the brain

what are the four lobes of the cerebral cortex?

1. frontal

2. parietal

3. temporal

4. occipital

what is the function of the frontal lobe?

responsible for cognition, recent memory, planning of movement, some aspects of emotion

function of the parietal lobe?

body sensation

function of the temporal lobe?

hearing, advanced visual processing

function of the occipital lobe?

vision

what is the homunculus?

visual representation of how much of our motor cortex is dedicated to certain areas of our bodies