Hereditary, Nervous System, and Hormonal Influences in Psychology

Heredity

The transmission of characteristics and traits from parents to offspring via genetic information.

Genetics

The scientific study of heredity and the variation of inherited characteristics.

"Nature"

The influence of inherited biological and genetic factors on development.

Environment

The external conditions and influences that affect the development and behavior of an organism.

"Nurture"

The influence of environmental factors, such as experience and learning, on development.

Evolutionary Perspective

A psychological approach that analyzes human thought and behavior by considering how natural selection has shaped them over time.

Natural Selection

The process by which organisms better adapted to their environment tend to survive and produce more offspring.

Eugenics

A set of beliefs and practices aimed at improving the genetic quality of a human population, historically through methods like selective breeding and sterilization.

Twin Studies

Research used to estimate the heritability of traits by comparing identical and fraternal twins.

Adoption Studies

Research that compares traits of adopted children with those of their biological and adoptive parents to assess the relative influence of genes and environment.

Family Studies

Research that examines the extent to which a disorder or trait is shared among family members.

Central Nervous System (CNS)

The system composed of the brain and the spinal cord.

Peripheral Nervous System (PNS)

The system consisting of the nerves connecting the CNS to the rest of the body.

Autonomic Nervous System

The part of the PNS that controls internal organs and glands, regulating involuntary functions (e.g., heart rate, digestion).

Somatic Nervous System

The part of the PNS that controls the body's skeletal muscles, enabling voluntary movement.

Sympathetic Nervous System

The branch of the autonomic nervous system that mobilizes the body's resources for "fight or flight" responses.

Parasympathetic Nervous System

The branch of the autonomic nervous system that calms the body, conserving energy ("rest and digest").

Neurons

Specialized cells that transmit chemical and electrical signals in the nervous system (the basic building block of the nervous system).

Glial Cells

Cells in the nervous system that support, nourish, and protect neurons.

Reflex Arc

A neural pathway that controls a reflex action, bypassing the brain for a faster response.

Spinal Cord

A long bundle of nerve tissue that extends from the lower part of the brain to the lower back; the main pathway for information connecting the brain and body.

Sensory Neurons (Afferent)

Neurons that carry incoming information from the sensory receptors to the central nervous system.

Motor Neurons (Efferent)

Neurons that carry outgoing information from the central nervous system to the muscles and glands.

Interneurons

Neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs and motor outputs.

Neural Transmission

The process of communication between neurons, involving electrical signals within the neuron and chemical signals across the synapse.

All-or-Nothing Principle

A neuron's reaction of either firing (with a full-strength response) or not firing at all.

Depolarization

The process during the action potential when positive ions rush into the neuron, making the inside less negative and promoting the electrical impulse.

Refractory Period

A period of inactivity after a neuron has fired, during which it cannot generate another action potential.

Resting Potential

The state of a neuron when it is not firing, with a net negative charge inside relative to the outside.

Reuptake

The reabsorption of a neurotransmitter by the sending neuron after it has been released into the synapse.

Threshold

The level of stimulation required to trigger a neural impulse (action potential).

Multiple Sclerosis

A disease involving damage to the myelin sheath, leading to impaired communication between the brain and the body.

Myasthenia Gravis

A chronic autoimmune neuromuscular disease characterized by varying degrees of weakness of the skeletal (voluntary) muscles.

Neurotransmitters

Chemical messengers that cross the synaptic gaps between neurons.

Excitatory Neurotransmitter

A chemical that makes the receiving neuron more likely to fire an action potential.

Inhibitory Neurotransmitter

A chemical that makes the receiving neuron less likely to fire an action potential.

Dopamine

A neurotransmitter associated with movement, attention, learning, and the brain's pleasure and reward system.

Serotonin

A neurotransmitter that affects mood, hunger, sleep, and arousal.

Norepinephrine

A neurotransmitter involved in alertness and arousal, and a hormone that helps control stress and mood.

Glutamate

A major excitatory neurotransmitter involved in memory and learning.

GABA (Gamma-Aminobutyric Acid)

A major inhibitory neurotransmitter in the central nervous system.

Endorphins

Natural, opiate-like neurotransmitters linked to pain control and pleasure.

Substance P

A neurotransmitter and neuromodulator that functions as a pain signal.

Acetylcholine (ACh)

A neurotransmitter that enables muscle action, learning, and memory.

Hormones

Chemical messengers manufactured by the endocrine glands that travel through the bloodstream.

Adrenaline (Epinephrine)

A hormone secreted by the adrenal glands, especially in conditions of stress, increasing heart rate, muscle strength, blood pressure, and sugar metabolism.

Leptin

A hormone produced by fat cells that regulates appetite and energy balance.

Ghrelin

A hormone produced in the stomach that stimulates appetite (the "hunger hormone").

Melatonin

A hormone that regulates the sleep-wake cycle.

Oxytocin

A hormone that acts as a neurotransmitter, involved in social bonding and trust (the "love hormone").

Psychoactive Drugs

Chemical substances that alter perceptions and moods.

Agonists

Drugs that mimic or increase the effects of a neurotransmitter.

Antagonists

Drugs that block or decrease the effects of a neurotransmitter.

Reuptake Inhibitors

Drugs that prevent neurotransmitters from being reabsorbed by the presynaptic neuron, thus increasing their concentration in the synaptic cleft.

Stimulants

Drugs that excite neural activity and speed up body functions (e.g., caffeine, cocaine).

Depressants

Drugs that reduce neural activity and slow down body functions (e.g., alcohol, barbiturates).

Hallucinogens

Psychedelic drugs that distort perceptions and evoke sensory images in the absence of sensory input (e.g., LSD, marijuana).

Opioids

Drugs used to relieve pain, often derived from opium (e.g., morphine, heroin).

Tolerance

The diminishing effect with regular use of the same dose of a drug, requiring the user to take larger and larger doses before experiencing the drug's effect.

Addiction

Compulsive drug craving and use, despite adverse consequences.

Withdrawal

The discomfort and distress that follow discontinuing an addictive drug or behavior.

Brainstem

The oldest part and central core of the brain, responsible for automatic survival functions.

Medulla

The base of the brainstem that controls heartbeat and breathing.

Reticular Activating System (RAS)

A nerve network in the brainstem that plays an important role in controlling arousal and sleep/wake transitions.

Cerebellum

The "little brain" at the rear of the brainstem; functions include processing sensory input and coordinating movement and balance.

Limbic System

Neural system (including the hippocampus, amygdala, and hypothalamus) associated with emotions and drives.

Thalamus

The brain's sensory control center; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla.

Hypothalamus

A neural structure lying below (hypo) the thalamus; directs several maintenance activities (e.g., eating, drinking, body temperature).

Pituitary Gland

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

Hippocampus

A neural center located in the limbic system that helps process explicit memories for storage.

Amygdala

Two lima-bean-sized neural clusters in the limbic system linked to emotion, particularly fear and aggression.

Cerebral Cortex

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

Hemispheres (Cerebral)

The two halves of the brain, the left and the right, which differ in some functions.

Corpus Callosum

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

4 Lobes

The four major divisions of the cerebral cortex: frontal, parietal, occipital, and temporal.

Motor Cortex

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

Sensory Cortex

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

Prefrontal Cortex

The frontmost part of the frontal lobe, involved in judgment, planning, and processing new memories.

Split Brain Research

Studies on patients whose corpus callosum has been cut, showing the specialized functions of the left and right hemispheres.

Broca's Area

A region of the frontal lobe involved in speech production and articulation.

Wernicke's Area

A region of the temporal lobe involved in language comprehension and expression.

Aphasia

Impairment of language, usually caused by damage to Broca's area (speaking impairment) or Wernicke's area (understanding impairment).

Cortex Specialization

The concept that different areas of the cerebral cortex perform different functions (also known as localization of function).

Contralateral Hemispheric Organization

The principle that the brain is cross-wired, meaning each hemisphere controls the opposite side of the body.

Brain Plasticity

The brain's ability to change, especially during childhood, by reorganizing after damage or building new pathways based on experience.

Scans (EEG, fMRI)

Techniques used to study the structure and function of the brain.

EEG (Electroencephalogram)

A recording of the waves of electrical activity sweeping across the brain's surface.

fMRI (Functional Magnetic Resonance Imaging)

A technique for revealing blood flow and, therefore, brain activity by comparing successive MRI scans.

Lesioning

The experimental destruction of brain tissue to study the effects on behavior or function.

Consciousness

Our awareness of ourselves and our environment.

Circadian Rhythm

The biological clock; regular bodily rhythms (e.g., temperature and wakefulness) that occur on a 24-hour cycle.

Jet Lag

A temporary disruption of the body's circadian rhythms caused by rapid travel across time zones.

NREM Sleep Stages

The non-rapid eye movement stages of sleep (NREM-1, NREM-2, NREM-3/4).

Hypnogogic Sensations

Feelings of falling or floating, often experienced during the brief NREM-1 stage of sleep.

REM Sleep (Rapid Eye Movement)

A recurring sleep stage during which vivid dreams commonly occur; also known as paradoxical sleep.

Paradoxical Sleep

Another name for REM sleep, due to the combination of high brain activity (like being awake) and muscle paralysis.

Dreaming

A sequence of images, emotions, and thoughts passing through a sleeping person's mind.

REM Rebound

The tendency for REM sleep to increase following REM sleep deprivation.

Activation-Synthesis Theory

The theory that dreams are the brain's attempt to make sense of random neural activity (activation) that occurs during REM sleep (synthesis).

Consolidation Theory

The idea that dreams help to file away and solidify memories and experiences from the day.