Comprehensive Guide to Biological Psychology and Consciousness

Chromosomes

Threadlike structures made of DNA molecules that contain genes; humans have 46 chromosomes.

DNA

A complex molecule containing the genetic information that makes up the chromosomes.

Gene

The biochemical units of heredity that segments of DNA capable of synthesizing proteins.

Genome

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

Genotype

The specific genetic makeup of an individual; the 'blueprint'.

Phenotype

The observable physical and behavioral characteristics of an individual, resulting from the interaction of the genotype with the environment.

Dominant Gene

The member of a gene pair that controls the appearance of a certain trait.

Recessive Gene

A gene that is expressed only when it is matched with a similar gene from the other parent.

Monozygotic Twins

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

Dizygotic Twins

Fraternal twins that develop from separate fertilized eggs; genetically no closer than ordinary brothers and sisters.

Heritability

A statistical estimate of the proportion of variation among individuals in a group that can be attributed to genes.

Down Syndrome

A genetic condition caused by an extra copy of chromosome 21 (Trisomy 21).

Turner Syndrome

A condition in females where there is only one X chromosome (XO), causing physical shortness and infertility.

Klinefelter’s Syndrome

A condition in males with an extra X chromosome (XXY), leading to minimal sexual development.

Phenylketonuria (PKU)

A rare genetic condition where the body cannot break down the amino acid phenylalanine.

Neuron

The fundamental unit of the nervous system, responsible for receiving, processing, and transmitting electrochemical information.

Dendrites

Branching extensions of a neuron that receive messages and conduct impulses toward the cell body.

Soma (Cell Body)

The part of a neuron that contains the nucleus and maintains the life of the cell.

Axon

The extension of a neuron through which messages pass to other neurons or to muscles/glands.

Myelin Sheath

A layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed.

Terminal Buttons

Small knobs at the end of an axon that release neurotransmitters.

Action Potential

A brief electrical charge that travels down an axon, occurring when a neuron is stimulated to its threshold.

Resting Potential

The polarized state of a neuron when the inside is negatively charged relative to the outside.

Neurotransmitters

Chemical messengers that cross the synaptic gaps between neurons.

Reuptake

The process by which the sending neuron reabsorbs the excess neurotransmitters from the synapse.

Acetylcholine (ACh)

A neurotransmitter involved in muscle action, learning, and memory; deterioration marks Alzheimer’s disease.

Dopamine

A neurotransmitter associated with movement, learning, attention, and emotion; excess linked to schizophrenia.

Serotonin

A neurotransmitter that affects mood, hunger, sleep, and arousal; undersupply is linked to depression.

Norepinephrine

A neurotransmitter involved in alertness and arousal; undersupply can depress mood.

GABA

A major inhibitory neurotransmitter; undersupply is linked to seizures and insomnia.

Glutamate

The major excitatory neurotransmitter; oversupply can produce migraines or seizures.

Corpus Callosum

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

Hemispheres

The two halves of the brain, each responsible for different functions; generally, the left is analytical and the right is creative.

Pituitary Gland

The 'Master Gland' that regulates growth and controls other endocrine glands.

Circadian Rhythm

The biological clock regulating regular bodily rhythms that occur on a 24-hour cycle.

NREM-1

The initial stage of sleep characterized by light sleep and hallucinations.

REM Sleep

A distinct stage of sleep where dreams occur and muscles are relaxed.

Insomnia

Recurring problems in falling or staying asleep.

Narcolepsy

A condition characterized by uncontrollable sleep attacks, often directly into REM sleep.

Sleep Apnea

A sleep disorder causing temporary cessations of breathing and repeated awakenings.

Night Terrors

High arousal and appearance of terror; occur during NREM-3 and are seldom remembered.