Chapter Two Flashcards
biological psychology
the scientific study of the links between biological (genetic, neural, hormonal) and psychological processes. Some biological psychologists call themselves behavioral neuroscientists, neuropsychologists, behavior geneticists, physiological psychologists, or biopsychologists.
What do phrenology and biological psychology have in common?
They share a focus on the links between the brain and behavior. Phrenology faded because it had no scientific basis—skull bumps don’t reveal mental traits and abilities.
plasticity
the brain’s ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience.
neuron
a nerve cell; the basic building block of the nervous system.
cell body
the part of a neuron that contains the nucleus; the cell’s life-support center.
dendrites
a neuron’s often bushy, branching extensions that receive and integrate messages, conducting impulses toward the cell body.
axon
the neuron extension that passes messages through its branches to other neurons or to muscles or glands.
myelin [MY-uh-lin] sheath
a fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop from one node to the next.
glial cells (glia)
cells in the nervous system that support, nourish, and protect neurons; they also play a role in learning, thinking, and memory.
action potential
a neural impulse; a brief electrical charge that travels down an axon.
threshold
the level of stimulation required to trigger a neural impulse.
refractory period
in neural processing, a brief resting pause that occurs after a neuron has fired; subsequent action potentials cannot occur until the axon returns to its resting state.
all-or-none response
a neuron’s reaction of either firing (with a full-strength response) or not firing.
When a neuron fires an action potential, the information travels through the axon, the dendrites, and the cell body, but not in that order. Place these three structures in the correct order.
dendrites, cell body, axon.
How does our nervous system allow us to experience the difference between a slap and a tap on the back?
Stronger stimuli (the slap) cause more neurons to fire and to fire more frequently than happens with weaker stimuli (the tap).
synapse [SIN-aps]
the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. The tiny gap at this junction is called the synaptic gap or synaptic cleft.
neurotransmitters
chemical messengers that cross the synaptic gaps between neurons. When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse.
reuptake
a neurotransmitter’s reabsorption by the sending neuron.
What happens in the synaptic gap?
Neurons send neurotransmitters (chemical messengers) across this tiny space between one neuron’s terminal branch and the next neuron’s dendrite or cell body.
What is reuptake? What two other things can happen to excess neurotransmitters after a neuron reacts?
Reuptake occurs when excess neurotransmitters are reabsorbed by the sending neuron. Neurotransmitters can also drift away or be broken down by enzymes.
endorphins [en-DOR-fins]
“morphine within”—natural, opiate-like neurotransmitters linked to pain control and to pleasure.
Serotonin, dopamine, and endorphins are all chemical messengers called ______________.
neurotransmitters
agonist
a molecule that increases a neurotransmitter’s action.
antagonist
a molecule that inhibits or blocks a neurotransmitter’s action.
Curare poisoning paralyzes its victims by blocking ACh receptors involved in muscle movements. Morphine mimics endorphin actions. Which is an agonist, and which is an antagonist?
Morphine is an agonist; curare is an antagonist.
nervous system
the body’s speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems.
central nervous system (CNS)
the brain and spinal cord.
peripheral nervous system (PNS)
the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body.
nerves
bundled axons that form neural cables connecting the central nervous system with muscles, glands, and sense organs.
sensory (afferent) neurons
neurons that carry incoming information from the body’s tissues and sensory receptors to the brain and spinal cord.