AP Psych Unit 1A: Heredity, Neurons, Drugs, Brain

nature-nurture issue

the longstanding controversy over the relative contributions that genes and experience make to the development of psychological traits and behaviors. Today's science views traits and behaviors as arising from the interaction of nature and nurture

natural selection

the principle that the inherited traits enabling an organism to survive and reproduce in a particular environment will (in competition with other trait variations) most likely be passed on to

succeeding generations

behavior genetics

the study of the relative power and limits of genetic and environmental influences on behavior

mutation

a random error in gene replication that leads to a change

environment

every nongenetic influence, from prenatal nutrition to the people and things around us

heredity

the genetic transfer of characteristics from parents to offspring

genes

the biochemical units of heredity

genome

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

twin studies

A research design in which hereditary influence is assessed by comparing the resemblance of identical twins and fraternal twins with respect to a trait

adoption studies

assess hereditary influence by examining the resemblance between adopted children and both their biological and their adoptive parents

identical (monozygotic) twins

individuals who developed from a single fertilized egg that split in two, creating two genetically identical organisms

fraternal (dizygotic) twins

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

eugenics

selectively breeding humans to promote certain characteristics

family studies

researchers assess hereditary influence by examining blood relatives to see how much they resemble one another on a specific trait

interaction

the interplay that occurs when the effect of one factor (such as environment) depends on another factor (such as heredity)

epigenetics

"above" or "in addition to" (epi) genetics the study of the molecular mechanisms by which environments can influence genetic expression (without a DNA change)

kinship studies

studies comparing the characteristics of family members to determine the importance of heredity in complex human characteristics (includes twin, adoption, and family studies)

nervous system

the body's speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems

central nervous system (CNS)

brain and spinal cord

peripheral nervous system (PNS)

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

nerves

bundled axons that form neural "cables" connecting the central nervous system with muscles, glands, and sense organs

sensory neurons

neurons that carry incoming information from the sensory receptors to the brain and spinal cord

motor neurons

neurons that carry outgoing information from the brain and spinal cord 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

somatic nervous system

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

autonomic nervous system

the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms (involuntary)

sympathetic nervous system

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

parasympathetic nervous system

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

reflexes

simple, automatic responses to sensory stimuli, such as the knee-jerk response

reflex arc

neural pathway that controls an involuntary, automatic response to a stimulus, known as a reflex; composed of a single sensory neuron and a single motor neuron (can do it with just parasympathetic NS and spinal cord, no brain needed!)

neuron

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

cell body

the part of a neuron that contains the nucleus the cell's life-support center

dendrites

a neuron's bushy, branching extensions that receive messages and conduct impulses toward the cell body

axon

the segmented neuron extension that passes messages through its branches to other neurons or to muscles or glands

neural transmission

electrochemical communication within and between neurons and the final destination

myelin sheath

covers the axon of some neurons and helps speed neural impulses

axon terminal (part of terminal branches)

the endpoint of a neuron where neurotransmitters are stored

neural impulse

action potential, electrical signal traveling down the axon

multiple sclerosis

a chronic disease of the central nervous system marked by damage to the myelin sheath; disrupts neural transmission

myasthenia gravis

a chronic autoimmune disease that affects the neuromuscular junction and produces serious weakness of voluntary muscles; associated with disruption of neural transmission

excitatory neurotransmitters

chemicals released from the terminal buttons of a neuron that excite the next neuron into firing

inhibitory neurotransmitters

chemicals released from the terminal buttons of a neuron that inhibit the next neuron from firing

glial cells

cells in the nervous system that support, nourish, and protect neurons

action potential

a neural impulse; a brief electrical charge that travels down an axon

resting potential

the state of the neuron when not firing a neural impulse

synapse

the gap between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron

depolarization

the process during the action potential when positive ions rush into the cell causing the interior to become more positive

polarization

state in which positive ions are outside the axon, while negative ions are inside the axon

threshold

the level of stimulation required to trigger a neural impulse

all-or-none response (all-or-nothing principle)

a neuron's reaction of either firing or not firing

refractory period

a period of inactivity after a neuron has fired

neurotransmitters

chemical messengers that cross the synaptic gaps between neurons

reuptake

a neurotransmitter's reabsorption by the sending neuron

dopamine

a neurotransmitter associated with movement, attention and learning and the brain's pleasure and reward system; schizophrenia (too much), Parkinson's disease (too little); addiction

acetylcholine

enables muscle action, learning, and memory; Alzheimer's disease (too little)

serotonin

A neurotransmitter that affects hunger, sleep, arousal, and mood; depression

norephinephrine

helps control alertness and arousal; depression (too little)

glutamate

major excitatory neurotransmitter involved in memory; migraines or

seizures

endorphins

neurotransmitters that influence the perception of pain or pleasure

substance P

involved in pain perception and immune response

GABA (gamma-aminobutyric

acid)

major inhibitory neurotransmitter; undersupply linked to seizures, tremors, and insomnia

agonist

a molecule that increases a neurotransmitter's action

antagonist

a molecule that inhibits or blocks a neurotransmitter's action

endocrine system

the body's "slow" chemical communication system a set of glands and fat tissue that secrete hormones into the bloodstream

hormones

chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues

adrenaline

a hormone released into the bloodstream in response to physical or mental stress or emergency (fight-or-flight)

fight or flight response

an emotional and physiological reaction to an emergency that increases readiness for action

leptin

a hormone produced by adipose (fat) cells that regulates appetite by sending signals of fullness to the brain

ghrelin

hormone secreted by stomach; sends hunger signals to the brain

melatonin

a hormone released by the pineal gland that produces sleepiness

oxytocin

a hormone released by the pituitary gland that causes contractions in childbirth, stimulates of milk production in breastfeeding, and influences social bonds

psychoactive drug

a chemical substance that alters perceptions and moods

substance use disorder

a disorder characterized by continued substance use despite resulting life disruption

reuptake inhibitor

chemical that binds to axon terminals prevents reuptake/reabsorption, which can cause an increase of that NT

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

withdrawal

the discomfort and distress that follow discontinuing an addictive drug or behavior

addiction

an everyday term for compulsive substance use (and sometimes for dysfunctional behavior

patterns, such as out-of-control gambling) that continue despite harmful consequences

depressants

drugs that reduce neural activity and slow body functions, e.g., alcohol, opioids

stimulants

drugs that excite neural activity and speed up body functions; e.g., nicotine, caffeine, cocaine, ecstasy (also a hallucinogen)

opioids

opium and its derivatives; they depress neural activity, temporarily lessening pain and anxiety, e.g., heroin, oxycontin

hallucinogens

psychedelic ("mind-manifesting") drugs that distort perceptions and evoke sensory images in the absence of sensory input, e.g., LSD, marijuana/cannabis, ecstasy (also a stimulant)

neuroplasticity

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

lesioning

tissue destruction. Brain lesions may occur naturally (from disease or trauma), during surgery, or experimentally (using electrodes to destroy brain cells)

EEG (electroencephalogram)

an amplified recording of the waves of electrical activity sweeping across the brain's surface. These waves are measured by electrodes placed on the scalp

fMRI (functional MRI)

a technique for revealing blood flow and, therefore, brain activity by comparing successive MRI scans. fMRI scans show brain function as well as structure

CT scan

CT (computed tomography) scan

a series of X-ray photographs taken from different angles and combined by computer into a composite representation of a slice of the brain's structure

PET (positron emission tomography)

a technique for detecting brain activity that displays where a radioactive form of glucose goes while the brain performs a given task

MRI (magnetic resonance imaging)

a technique that uses magnetic fields and radio waves to produce computer-generated images of soft tissue. MRI scans show brain anatomy

brain stem

part of the hindbrain; includes the midbrain, pons, medulla (oblongata)

medulla

the base of the brainstem; controls heartbeat and breathing

reticular formation

a nerve network that travels through the brainstem into the thalamus it filters information and plays an important role in controlling arousal; controlled by reticular activating system

hindbrain

consists of the medulla, pons, and cerebellum directs essential survival functions, such as breathing, sleeping, and wakefulness, as well as coordination and balance

midbrain

found atop the brainstem connects the hindbrain with the forebrain, controls some motor movement, and transmits auditory and visual information

forebrain

consists of the cerebral cortex, thalamus, and hypothalamus manages complex cognitive activities, sensory and associative functions, and voluntary motor activities

cerebellum

the hindbrain's "little brain" at the rear of the brainstem its functions include processing sensory input, coordinating movement output and balance, and enabling nonverbal learning and memory

reward system

structures in the brain activated during pleasurable activities; includes hypothalamus and nucleus accumbens

cerebral cortex

the intricate fabric of interconnected neural cells covering the forebrain's cerebral hemispheres

the body's ultimate control and information-processing center

limbic system

neural system located mostly in the forebrain — below the cerebral hemispheres — that includes

the amygdala, hypothalamus, hippocampus, thalamus, and pituitary gland; associated with

emotions and drives

thalamus

the forebrain's sensory control center, located on top of the brainstem it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla

hypothalamus

a limbic system neural structure lying below (hypo) the thalamus it directs several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system, and is linked to emotion and reward