U.1 – Biological bases of behaviour

Genetic predisposition

The increased chance of developing a specific trait or condition due to one’s genetic code.

Chromosomes

46 chromosomes in 23 pairs, containing DNA.

DNA

Deoxyribonucleic acid, the carrier of genetic information.

Genes

Discrete segments of DNA that control specific protein production for human traits.

Identical twins

Also known as monozygous twins; they originate from one fertilized egg and share the same genetic makeup.

Turner’s syndrome

A chromosomal condition where an individual is born with only a single X chromosome in the 23rd pair, leading to physical abnormalities.

Klinefelter’s syndrome

A condition where males have an extra X chromosome (XXY), resulting in minimal sexual development and extreme personality traits.

Down syndrome

A genetic disorder caused by an extra chromosome on the 21st pair, characterized by physical and intellectual disabilities.

Neurons

Individual nerve cells that compose the entire nervous system.

Dendrites

Rootlike parts of neurons that receive signals from other neurons.

Myelin sheath

A fatty covering around the axon of some neurons that speeds up neural impulses.

Neurotransmitters

Chemicals that enable neurons to communicate with each other.

Synapse

The space between the terminal buttons of one neuron and the dendrites of another.

Action potential

The electric message firing of a neuron, which occurs when the cell reaches a threshold.

All or none principle

The principle that a neuron either fires completely or does not fire at all.

Frontal lobe

The largest area of the cerebral cortex, responsible for higher functions such as thinking and reasoning.

Broca’s area

A region in the frontal lobe responsible for controlling the muscles involved in speech production.

Wernicke’s area

Located in the temporal lobe, it is involved in language comprehension.

Circadian rhythm

The metabolic and thought process pattern that regulates sleep and wakefulness.

REM sleep

Rapid Eye Movement sleep, characterized by intense brain activity and vivid dreams.

Insomnia

The most common sleep disorder, characterized by difficulty falling or staying asleep.

Narcolepsy

A rare sleep disorder characterized by periods of intense sleepiness and sudden sleep attacks.

Sleep apnea

A disorder where an individual stops breathing for short periods during the night, causing brief awakenings.

Dreams

Psychological experiences that occur during sleep, often analyzed for their content and meaning.

Transduction

The process of transforming physical stimuli into neural impulses.

Sensory adaptation

The decreasing responsiveness to stimuli due to constant exposure.

Psychoactive drugs

Chemicals that induce alterations in perception and consciousness.

Stimulants

A category of drugs that increase alertness and arouse the autonomic nervous system.

Depressants

Drugs that slow down the functioning of the nervous system.

Hallucinogens

A class of drugs that alter perception and produce sensory hallucinations.

Taste buds

Taste receptors located on papillae, responsible for the perception of taste.

Olfaction

The sense of smell, where chemicals in the air activate receptors in the nose.

Kinesthetic sense

Feedback from receptors in muscles and joints about the position and orientation of body parts.

Vestibular sense

The sense that helps us understand our body's orientation in space.

Genetic predisposition

The increased chance of developing a specific trait or condition due to one’s genetic code.

DNA

Deoxyribonucleic acid, the molecule that carries genetic information.

Genes

Discrete segments that control specific protein production for human traits.

Dominant

A genetic trait that is expressed over a recessive trait.

Recessive

A genetic trait that is not expressed when a dominant trait is present.

Identical twins

Twins that develop from one fertilized egg and share the same genetic makeup.

Chromosomal abnormalities

Conditions that arise from incorrect chromosome formations or combinations.

Klinefelter’s syndrome

A chromosomal condition affecting males, characterized by an extra X chromosome (XXY).

Down syndrome

A genetic disorder caused by an extra chromosome on the 21st pair, resulting in physical and intellectual disabilities.

Neuroanatomy

The study of the structure and function of the nervous system.

Neurons

Individual nerve cells that make up the entire nervous system.

Dendrites

Rootlike parts of the neuron that receive signals from other neurons.

Axon

A wirelike structure that transmits signals away from the cell body.

Myelin sheath

A fatty covering around the axon that speeds up neural impulses.

Neurotransmitters

Chemicals that enable neuron communication by binding to receptor sites.

Synapse

The space between the terminal buttons of one neuron and the dendrites of the next.

Resting potential

The slightly negative charge of a neuron at rest.

Action potential

The electric message firing of a neuron that occurs when the threshold is reached.

All or none principle

The principle stating that a neuron either fires completely or not at all.

Excitatory neurotransmitters

Chemicals that promote the firing of the next cell.

Inhibitory neurotransmitters

Chemicals that prevent the firing of the next cell.

CNS (Central Nervous System)

Consists of the brain and spinal cord.

PNS (Peripheral Nervous System)

All the nerves in the body that are not part of the CNS.

Somatic nervous system

Controls voluntary muscle movements.

Autonomic nervous system

Controls involuntary body functions.

Sympathetic nervous system

Part of the autonomic nervous system that responds to stress (fight or flight).

Parasympathetic nervous system

Part of the autonomic nervous system that conserves energy and helps the body return to homeostasis.

Hormones

Chemicals released into the bloodstream that affect various bodily functions.

Adrenaline

A hormone activated during 'fight or flight' situations that speeds up bodily processes.

Insomnia

A common sleep disorder characterized by difficulty falling or staying asleep.

Narcolepsy

A sleep disorder causing periods of intense sleepiness and sudden sleep attacks.

Sleep apnea

A sleep disorder where breathing repeatedly stops and starts during sleep.

Dreams

Thoughts, images, or emotions that occur during sleep, particularly during REM.

Circadian rhythm

The body's internal clock that regulates sleep-wake cycles.

Transduction

The conversion of signals from the environment into neural impulses.

Sensory adaptation

The decreased sensitivity to a constant stimulus over time.

Cocktail party effect

The ability to focus one's auditory attention on a particular stimulus while filtering out others.

Synesthesia

A condition where stimulation of one sense leads to automatic experiences in another sense.

Prosopagnosia

The inability to recognize faces.

Trichromatic theory

The theory that three types of cones detect three primary colors.

Opponent process theory

The theory that color perception is controlled by the activity of opposing colors.

Place theory

The theory that the pitch we hear is related to the specific place on the cochlea that is stimulated.

Frequency theory

The theory that the pitch we hear is based on the rate at which the auditory nerve fires.

Conduction deafness

Hearing loss caused by problems with the ear's mechanical system.

Nerve deafness

Hearing loss caused by damage to the hair cells in the cochlea.

Gate control theory

The theory that the perception of pain is controlled by a 'gate' that opens and closes to sensory signals.

Taste receptors

Sensory cells that detect taste, located on the papillae of the tongue.

Olfactory bulb

The part of the brain that processes smell information.

Vestibular sense

Sense that helps with balance and spatial orientation.

Kinesthetic sense

Sense that provides feedback on the position and movement of body parts.