Psychology 2e - Chapter 3

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

A chemical that mimics the action 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

A limbic system structure involved in memory and emotion, particularly fear and aggression.

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

The part of the PNS that controls the glands and the muscles of the internal organs.

axon

A threadlike extension of a neuron that carries nerve impulses away from the cell body.

biological perspective

the psychological perspective that emphasizes the influence of biology on behavior

(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

the intricate fabric of interconnected neural cells that covers the cerebral hemispheres; the body's ultimate control and information-processing center

chromosome

a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.

computerized tomography (CT) scan

imaging technique in which a computer coordinates and integrates multiple x-rays of a given area

corpus callosum

A thick band of axons that connects the two cerebral hemispheres and acts as a communication link between them.

dendrite

Branchlike parts of a neuron that are specialized to receive information.

deoxyribonucleic acid (DNA)

A double-stranded, helical nucleic acid molecule capable of replicating and determining the inherited structure of a cell's proteins.

diabetes

A condition in which the body is unable to produce enough insulin, the hormone required for the metabolism of sugar

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

The largest and most complicated region of the brain, including the thalamus, hypothalamus, limbic system, and cerebrum.

fraternal twins

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

frontal lobe

The lobe at the front of the brain associated with movement, speech, and impulsive behavior.

functional magnetic resonance imaging (fMRI)

MRI that shows changes in metabolic activity over time

gene

sequence of DNA that codes for a protein and thus determines a trait

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 organism

glial cell

nervous system cell that provides physical and metabolic support to neurons, including neuronal insulation and communication, and nutrient and waste transport

gonad

female or male reproductive organ that produces sex cells and hormones; ovary or testis

gyrus

(plural: gyri) bump or ridge on the cerebral cortex

hemisphere

left or right half of the brain

heterozygous

having two different alleles for a trait

hindbrain

division of the brain containing the medulla, pons, and cerebellum

hippocampus

a neural center located in the limbic system; helps process explicit memories for storage

homeostasis

A tendency to maintain a balanced or constant internal state; the regulation of any aspect of body chemistry, such as blood glucose, around a particular level

homozygous

having two identical alleles for a trait

hormone

Chemical messengers, mostly those manufactured by the endocrine glands, that are produced in one tissue and affect another

hypothalamus

A neural structure lying below the thalamus; it directs several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion and reward.

identical twins

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

lateralization

specialization of the two cerebral hemispheres for particular operations

limbic system

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

longitudinal fissure

separates cerebral hemispheres

magnetic resonance imaging (MRI)

technique that uses magnetic fields to indirectly visualize brain structure

medulla

an extension of the spinal cord into the skull that coordinates heart rate, circulation, and respiration

membrane potential

the voltage difference across a membrane

midbrain

Region between the hindbrain and the forebrain; it is important for hearing and sight.

motor cortex

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

mutation

change in a DNA sequence that affects genetic information

myelin sheath

A layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next.

neuron

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

neuroplasticity

the ability within the brain to constantly change both the structure and function of many cells in response to experience or trauma

neurotransmitter

chemical messengers that cross the synaptic gaps between neurons

Nodes of Ranvier

Gaps in the myelin sheath to which voltage-gated sodium channels are confined.

occipital lobe

A region of the cerebral cortex that processes visual information

pancreas

Regulates the level of sugar in the blood

parasympathetic nervous system

the division of the autonomic nervous system that calms the body, conserving its energy

parietal lobe

A region of the cerebral cortex whose functions include processing information about touch.

peripheral nervous system (PNS)

the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body.

phenotype

An organism's physical appearance, or visible traits.

pituitary gland

The endocrine system's most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands.

polygenic

multiple genes affecting a given trait

pons

A brain structure that relays information from the cerebellum to the rest of the brain (sleep and arousal)

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

part of frontal lobe responsible for thinking, planning, and language

psychotropic medication

drugs that treat psychiatric symptoms by restoring neurotransmitter balance

range of reaction

asserts our genes set the boundaries within which we can operate, and our environment interacts with the genes to determine where in that range we will fall

receptor

protein that detects a signal molecule and performs an action in response

recessive allele

An allele whose phenotypic effect is not observed in a heterozygote.

resting potential

the state of the neuron when not firing a neural impulse

reticular formation

a nerve network that travels through the brainstem into the thalamus and plays an important role in controlling arousal (Sleep/wake cycle, alertness, and motor activity

reuptake

process by which neurotransmitters are taken back into the synaptic vesicles

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

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

somatosensory cortex

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

ex// touch, temperature, pain

substantia nigra

midbrain structure where dopamine is produced; involved in control of movement

sulcus

depressions or grooves in the cerebral cortex

sympathetic nervous system

the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations

synaptic cleft

a gap into which neurotransmitters are released from the axon terminal

synaptic vesicle

storage site for neurotransmitters

temporal lobe

An area on each hemisphere of the cerebral cortex near the temples that is the primary receiving area for auditory information

terminal button

axon terminal containing synaptic vesicles

thalamus

relays messages between lower brain centers and cerebral cortex

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