AP Psych - Unit 2: Biological Bases of Behavior

neuron

a nerve cell; the basic building block of the nervous system

axon

the extension of a neuron that passes messages through its branches to other neurons or to muscles or glands

axon terminal

the end of a neuron where neurotransmitters are stored

cell body / soma

a neuron's cell body; it's life-support center

dendrite

the bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body

myelin sheath

a layer of fatty tissue segmentally encasing the fibers of neurons; enables faster transmission speed of neural impulses as the impulse hops from one node to the next

neurotransmitters

chemical messengers stored in the axon terminals of neurons that cross the synaptic gaps between neurons, binding with receptor sites on the receiving neuron and influencing whether that neuron will generate a neural impulse

nodes of Ranvier

gaps in the myelin sheath

nucleus

control center of a neuron

receptor sites

areas on the surface of neurons and other cells that are sensitive to specific neurotransmitters

synaptic gap

the tiny space between neurons found at the synapse

terminal branches

The branched end of the axon

vesicle

A membrane bound sac in the axon terminal of a neuron that holds neurotransmitters

action potential

a neural impulse; a brief electrical charge that travels down an axon

refractory period

a period of inactivity after a neuron has fired

threshold

the level of stimulation required to trigger a neural impulse

all-or-none response

a neuron's reaction of either firing (with a full-strength response) or not firing

depolarization

The step of action potential when sodium rushes into the cell causing the interior to lose it's negative charge

repolarization

The step of action potential when potassium rushes out the cell causing the interior to become negatively charged again

resting potential

the normal, unfired state of a neuron, when the inside of the neuron is more negatively charged than the positively-charged outside of the neuron

ions

positively or negatively charged atoms

sodium-potassium pump

a protein in the membrane of a neuron that transports sodium out of the cell and potassium into the cell to return the neuron to resting potential

synapse

the junction between the axon terminal of the sending neuron and the dendrite or cell body of the receiving neuron

reuptake

a neurotransmitter's reabsorption by the sending neuron

excitatory neurotransmitters

chemicals released from the axon terminal of a neuron that excite the next neuron into firing

inhibitory neurotransmitters

chemicals released from the axon terminal of a neuron that inhibit the next cell from firing

acetylcholine (ACh)

a neurotransmitter involved in learning, memory, and also triggers muscle contraction

dopamine

a neurotransmitter involved in movement, learning, attention, emotion, and the brain's pleasure and reward system

serotonin

a neurotransmitter involved with mood, hunger, sleep, and arousal

endorphins

a category of neurotransmitters involved in pain control and pleasure

agonist

a molecule that, by binding to a receptor site, stimulates a response

antagonist

a molecule that, by binding to a receptor site, inhibits or blocks a response

nervous system

the body's "fast" communication system, uses electrical signals and chemicals called neurotransmitters to transmit messages

central nervous system

the brain and spinal cord

peripheral nervous system

the sensory and motor neurons that connect the central nervous system to the rest of the body

somatic nervous system

the division of the peripheral nervous system that controls the body's skeletal muscles

autonomic nervous system

the part of the peripheral nervous system that controls the glands and the muscles of the internal organs

sympathetic nervous system

the division of the autonomic nervous system that arouses the body, mobilizing its energy (fight or flight)

parasympathetic nervous system

the division of the autonomic nervous system that calms the body, conserving its energy (rest and digest)

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 sensory receptors to the brain and spinal cord

motor (efferent) neurons

neurons that carry outgoing information from the brain and spinal cord to the muscles and glands

interneurons

neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs and motor outputs

reflexes

simple, automatic responses to sensory stimuli, such as the knee-jerk response

endocrine system

the body's "slow" communication system; uses chemicals called hormones to transmit messages

hormones

chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues

adrenal glands

a pair of endocrine glands that sit just above the kidneys and secrete hormones (epinephrine and norepinephrine) that help arouse the body in times of stress

epinephrine / adrenaline

chemical substance secreted by the adrenal glands when under stress, particularly responsible for immediate fight-or-flight response

norepinephrine / noradrenaline

chemical substance secreted by the adrenal glands when under stress, particularly responsible for immediate fight-or-flight response

cortisol

chemical substance secreted by the adrenal glands when under stress, particularly responsible for slower, long-term response to stress

pituitary glands

the endocrine system's "master gland" which, under the influence of the hypothalamus, regulates growth and controls other endocrine glands.

autopsy*

a dissection and examination of the brain after death

lesion

tissue destruction

electroencephalogram (EEG)

a brain scan technique that amplifies and records the electrical activity that sweeps across the brain's surface, measured by electrodes placed on the scalp; reveals brain activity

Computed Tomography (CT) Scan

a brain scan technique that uses a series of X-ray photographs taken from different angles to create a composite representation of a slice through the body; reveals structure but not function

Positron Emission Tomography (PET) Scan

a brain scan technique that detects where a radioactive form of glucose goes while the brain performs a specific task; reveals function but not structure

Magnetic Resonance Imaging (MRI)

a brain scan technique that uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of soft tissue; reveals structure but not function

functional MRI (fMRI)

a brain scan technique uses successive MRI scans to show bloodflow; reveals both structure and function

brainstem

the oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; responsible for automatic survival functions

medulla oblongata

the base of the brainstem; controls heartbeat and breathing

pons

part of the brain stem that helps coordinate movement

thalamus

the brain's sensory control center, located on top of the brainstem; directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla

reticular formation

a nerve network that travels through the brainstem and thalamus; controls arousal

cerebellum

part of the brain located to the rear of the brainstem, responsible for processing sensory input, coordinating movement and balance, and enabling nonverbal learning and memory; literally "little brain"

limbic system

neural system (including the hippocampus, amygdala, and hypothalamus) located below the cerebral hemispheres; associated with emotions and drives

amygdala

two lima bean-sized neural clusters in the limbic system; linked to emotion, particularly fear and aggression

hypothalamus

a neural structure lying below the thalamus; it directs several maintenance activities, such as eating, drinking, body temperature, and helps govern the endocrine system via the pituitary gland

hippocampus

a neural center located in the limbic system that helps process memories for long-term storage

cerebral cortex

a thin layer of interconnected neural cells covering the cerebral hemispheres; the body's ultimate control and information-processing center.

glial cells

cells in the nervous system that support, nourish, and protect neurons; may play a role in learning and thinking

frontal lobes

portion of the cerebral cortex lying behind the forehead; involved in speaking, muscle movement, making plans, and judgement

parietal lobes

portion of the cerebral cortex lying at the top of the head and toward the rear; receives sensory input for touch and is involved in mathematical and spatial reasoning

occipital lobes

portion of the cerebral cortex lying at the back of the head; receives sensory input for vision

temporal lobes

portion of the cerebral cortex lying roughly above the ears; receives sensory input for audition

motor cortex

an area at the rear of the frontal lobes that controls voluntary movements

somatosensory cortex

area at the front of the parietal lobes that registers and processes body touch

homonculus

a rendering of the human body in which each part is shown in proportion to how much of the somatosensory and motor cortexes are devoted to it

association areas

areas of the cerebral cortex that are involved in higher mental functions such as learning, remembering, thinking, and speaking rather than primary motor or sensory functions

Broca's area

brain area in the frontal lobe, usually in the left hemisphere, that controls the muscle movements involved in speech

Wernicke's area

brain area in the temporal lobe, usually in the left hemisphere, involved in language comprehension and expression

aphasia

impairment of language, usually caused by left hemisphere brain damage

plasticity

the brain's ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience

neurogenesis

the formation of new neurons

corpus callosum

large band of neural fibers connecting the two brain hemispheres and carrying messages between them

split brain

a condition resulting from surgery that isolates the brain's two hemispheres by cutting the corpus callosum that connects them

brain lateralization

specialization of function in each hemisphere of the brain

hemispheric specialization

the control of distinct neurological functions by the right and left sides of the brain

consciousness

our awareness of ourselves and our environment

cognitive neuroscience

the interdisciplinary study of the brain activity linked with cognition

dual processing

the principle that information is often simultaneously processed on separate conscious and unconscious tracks

behavior genetics

the study of the relative power and limits of genetic and environmental influences on behavior

environment

every external influence, from prenatal nutrition to the people and things around us

chromosomes

threadlike structures made of DNA molecules that contain the genes

DNA (deoxyribonucleic acid)

a complex molecule containing the genetic information that makes up the chromosomes

genes

the biochemical units of heredity that make up the chromosomes

genome

the complete instructions for making an organism, consisting of all the genetic material in that organism's chromosomes

identical (monozygotic) twins

twins who develop from a single fertilized egg that splits in two, creating two genetically identical organisms

fraternal (dizygotic) twins

twins who develop from separate fertilized eggs; genetically no closer than brothers and sisters, but they share a fetal environment

molecular genetics

the subfield of biology that studies the molecular structure and function of genes

heritability

the proportion of variation among individuals that we can attribute to genes