25 Chapter 3. Key Terms
action potential
electrical signal that moves down the neuron’s axon
adrenal gland
sits atop our kidneys and secretes hormones involved in the stress response
agonist
drug that mimics or strengthens the effects of a neurotransmitter
all-or-none
phenomenon that incoming signal from another neuron is either sufficient or insufficient to reach the threshold of excitation
allele
specific version of a gene
amygdala
structure in the limbic system involved in our experience of emotion and tying emotional meaning to our memories
antagonist
drug that blocks or impedes the normal activity of a given neurotransmitter
auditory cortex
strip of cortex in the temporal lobe that is responsible for processing auditory information
autonomic nervous system
controls our internal organs and glands
axon
major extension of the soma
biological perspective
view that psychological disorders like depression and schizophrenia are associated with imbalances in one or more neurotransmitter systems
Broca’s area
region in the left hemisphere that is essential for language production
central nervous system (CNS)
brain and spinal cord
cerebellum
hindbrain structure that controls our balance, coordination, movement, and motor skills, and it is thought to be important in processing some types of memory
cerebral cortex
surface of the brain that is associated with our highest mental capabilities
chromosome
long strand of genetic information
computerized tomography (CT) scan
imaging technique in which a computer coordinates and integrates multiple x-rays of a given area
corpus callosum
thick band of neural fibers connecting the brain’s two hemispheres
dendrite
branch-like extension of the soma that receives incoming signals from other neurons
deoxyribonucleic acid (DNA)
helix-shaped molecule made of nucleotide base pairs
diabetes
disease related to insufficient insulin production
dominant allele
allele whose phenotype will be expressed in an individual that possesses that allele
electroencephalography (EEG)
recording the electrical activity of the brain via electrodes on the scalp
endocrine system
series of glands that produce chemical substances known as hormones
epigenetics
study of gene-environment interactions, such as how the same genotype leads to different phenotypes
fight or flight response
activation of the sympathetic division of the autonomic nervous system, allowing access to energy reserves and heightened sensory capacity so that we might fight off a given threat or run away to safety
forebrain
largest part of the brain, containing the cerebral cortex, the thalamus, and the limbic system, among other structures
fraternal twins
twins who develop from two different eggs fertilized by different sperm, so their genetic material varies the same as in non-twin siblings
frontal lobe
lobe involved in reasoning, motor control, emotion, and language; contains motor cortex
functional magnetic resonance imaging (fMRI)
MRI that shows changes in metabolic activity over time
gene
sequence of DNA that controls or partially controls physical characteristics
genetic environmental correlation
view of gene-environment interaction that asserts our genes affect our environment, and our environment influences the expression of our genes
genotype
genetic makeup of an individual
glial cell
nervous system cell that provides physical and metabolic support to neurons, including neuronal insulation and communication, and nutrient and waste transport
gonad
secretes sexual hormones, which are important for successful reproduction, and mediate both sexual motivation and behavior
gyrus
(plural: gyri) bump or ridge on the cerebral cortex
hemisphere
left or right half of the brain
heterozygous
consisting of two different alleles
hindbrain
division of the brain containing the medulla, pons, and cerebellum
hippocampus
structure in the temporal lobe associated with learning and memory
homeostasis
state of equilibrium—biological conditions, such as body temperature, are maintained at optimal levels
homozygous
consisting of two identical alleles
hormone
chemical messenger released by endocrine glands
hypothalamus
forebrain structure that regulates sexual motivation and behavior and a number of homeostatic processes; serves as an interface between the nervous system and the endocrine system
identical twins
twins that develop from the same sperm and egg
lateralization
concept that each hemisphere of the brain is associated with specialized functions
limbic system
collection of structures involved in processing emotion and memory
longitudinal fissure
deep groove in the brain’s cortex
magnetic resonance imaging (MRI)
magnetic fields used to produce a picture of the tissue being imaged
medulla
hindbrain structure that controls automated processes like breathing, blood pressure, and heart rate
membrane potential
difference in charge across the neuronal membrane
midbrain
division of the brain located between the forebrain and the hindbrain; contains the reticular formation
motor cortex
strip of cortex involved in planning and coordinating movement
mutation
sudden, permanent change in a gene
myelin sheath
fatty substance that insulates axons
neuron
cells in the nervous system that act as interconnected information processors, which are essential for all of the tasks of the nervous system
neuroplasticity
nervous system’s ability to change
neurotransmitter
chemical messenger of the nervous system
Nodes of Ranvier
open spaces that are found in the myelin sheath that encases the axon
occipital lobe
lobe associated with visual processing; contains the primary visual cortex
pancreas
secretes hormones that regulate blood sugar
parasympathetic nervous system
associated with routine, day-to-day operations of the body
parietal lobe
brain lobe involved in processing various sensory and perceptual information; contains the primary somatosensory cortex
peripheral nervous system (PNS)
connects the brain and spinal cord to the muscles, organs and senses in the periphery of the body
phenotype
individual’s inheritable physical characteristics
pituitary gland
secretes a number of key hormones, which regulate fluid levels in the body, and a number of messenger hormones, which direct the activity of other glands in the endocrine system
polygenic
multiple genes affecting a given trait
pons
hindbrain structure that connects the brain and spinal cord; involved in regulating brain activity during sleep
positron emission tomography (PET) scan
involves injecting individuals with a mildly radioactive substance and monitoring changes in blood flow to different regions of the brain
prefrontal cortex
area in the frontal lobe responsible for higher-level cognitive functioning
psychotropic medication
drugs that treat psychiatric symptoms by restoring neurotransmitter balance
receptor
protein on the cell surface where neurotransmitters attach
recessive allele
allele whose phenotype will be expressed only if an individual is homozygous for that allele
resting potential
the state of readiness of a neuron membrane’s potential between signals
reticular formation
midbrain structure important in regulating the sleep/wake cycle, arousal, alertness, and motor activity
reuptake
neurotransmitter is pumped back into the neuron that released it
semipermeable membrane
cell membrane that allows smaller molecules or molecules without an electrical charge to pass through it, while stopping larger or highly charged molecules
soma
cell body
somatic nervous system
relays sensory and motor information to and from the CNS
somatosensory cortex
essential for processing sensory information from across the body, such as touch, temperature, and pain
substantia nigra
midbrain structure where dopamine is produced; involved in control of movement
sulcus
(plural: sulci) depressions or grooves in the cerebral cortex
sympathetic nervous system
involved in stress-related activities and functions
synaptic cleft
small gap between two neurons where communication occurs
synaptic vesicle
storage site for neurotransmitters
temporal lobe
brain lobe associated with hearing, memory, emotion, and some aspects of language; contains primary auditory cortex
terminal button
axon terminal containing synaptic vesicles
thalamus
sensory relay for the brain
theory of evolution by natural selection
states that organisms that are better suited for their environments will survive and reproduce compared to those that are poorly suited for their environments
threshold of excitation
level of charge in the membrane that causes the neuron to become active
thyroid
secretes hormones that regulate growth, metabolism, and appetite
ventral tegmental area (VTA)
midbrain structure where dopamine is produced: associated with mood, reward, and addiction
Wernicke’s area
important for speech comprehension
