Biological Bases of Behavior 2

Soma

Nucleated cell body.

Nerves

Bundles of neurons.

Neurons

The basic unit of the nervous system.

Dendrites

Look like branches of a tree and receive input from other neurons through receptors on their surface.

Axon

Long, tubelike structure that responds to input from the dendrites and soma.

Myelin Sheath

Fatty coating that works as an insulator for the axon.

Nodes of Ranvier

Small gaps between myelin that look like beads on a string.

Terminal Buttons

Knobs on the branched end of the axon.

Synapse

Gap between the terminal buttons.

Neurotransmitters

Chemical messengers.

Resting Membrane Potential

An electrical potential across the plasma membrane of approximately -70 millivolts (mV)

Leak Channels

Channels that are open all the time and that simply allow ions to "leak" across the membrane according to their gradient.

Action Potential

Also referred to as a nerve impulse. Is also a disturbance in the membrane potential.

Excitatory

type of neurotransmitters that serve to excite the cell or cause the neuron to fire.

Inhibatory

type of neurotransmitter that serves to inhibit (or stop) cell firing.

Enzymes

After a neurotransmitter is released and has conducted the impulse to the next cell or cells, it is broken down by ___________________.

Reuptake

Process of absorbing neurotransmitters back into the cell that released it.

Acetylcholine

A key neurotransmitter that affects memory function, as well as muscle contraction, particularly in the heart.

Serotonin

A key neurotransmitter that is related to arousal, sleep, pain sensitivity, and mood and hunger regulation.

Dopamine

A key neurotransmitter that is associated with movement, attention, and reward; dopamine imbalances may play a role in Parkinson's disease and in schizophrenia.

GABA or gamma-Aminobutryic acid

An inhibitory neurotransmitter.

Glutamate

An excitatory neurotransmitter and the all-purpose counterpart to GABA.

Norepinephrine

A key neurotransmitter which affects levels of alertness; a lack of this neurotransmitter is implicated in depression.

Endorphins

A key neurotransmitter that is the body's natural painkiller.

Endocrine System

Provides another way by which various parts of our bodies relay information to one another. This system works through groups of cells known as glands, which release substances called hormones.

Pituitary Gland

Also known as the master gland that releases hormones.

Hormones

Are different from neurotransmitters in that they coordinate a wide range of responses, are present in the bloodstream, and affect the body for long periods of time compares with neurotransmitters.

Adrenocorticotropic Hormone (ACTH)

Stressful situations cause the pituitary to release __________.

Adrenal Glands

Release a hormone that results in fight-or-flight reactions.

Epinephrine

Adrenaline

Thyroid Gland

Located at the front of the neck and produces thyroxine.

Thyroxine

Is important for regulating cellular metabolism.

Trait

Distinctive characteristics or behavior patterns that are determined by genetics.

Dominant Trait

More likely to be expressed in offspring than is a recessive trait.

Genotype

Comprises all of the possible combinations of genes.

Phenotype

Observable result.

Down Syndrome

Occurs when there are three copies of the twenty-first chromosome, which generally causes some degree of intellectual disability.

Heritability

Used to discuss the degree of variance among individuals that can be attributed to genetic variations.

Environmentality

The degree to which a trait's expression is caused b the environment in which an organism lives.

Nature vs. Nurture Debate

Is concerned with the relative influences of genetics and environment. The debate is no longer this, but rather, how the two forces interact with one another.

Michael Gazzaniga

split-brain research; understanding of functional lateralization in the brain; published works in cognitive neuroscience

Huntington's chorea

A rare genetic disease in which the central nervous system degenerates and the individual loses control over voluntary movements, with the symptoms often appearing after age 40.

Corpus Callosum

A thick band of nerve fibers that connects the left and right hemispheres of the brain, allowing them to communicate.

Broca’s Area

A region in the frontal lobe responsible for speech production and language processing.

Confidentiality

The ethical principle of keeping participants’ personal information private and secure in research.

Consent

The process of obtaining permission from participants after fully explaining a study’s purpose, risks, and procedures.

Deception

Intentionally misleading participants about aspects of a study, only if necessary and followed by a debriefing.

Sampling Bias

An error that occurs when a sample does not accurately represent the population being studied.

Ethical vs Unethical in Experiments

Ethical experiments follow guidelines protecting participants’ rights and welfare, while unethical ones violate these protections.

Protection from Harm

Ensuring participants are not physically or psychologically injured during or after a study.

Institutional Review Board (IRB)

A committee that reviews research proposals to ensure they meet ethical standards for human subjects.

Reticular Activating System

A network of neurons in the brainstem that regulates wakefulness, attention, and arousal.