APP: Unit 1A - Biology & Sleep

nature-nurture issue

the longstanding controversy over the relative contributions of our heredity and our environment to the development of psychological traits and behaviors

natural selection

the principle that, among the range of inherited trait variations, those contributing to reproduction and survival will most likely be passed on to succeeding generations

evolutionary psychology

the study of behavior and mental processes using the principles of natural selection

behavior genetics

the study of the relative power and limits of hereditary and environmental influences on behavior and mental processes

mutation

a random error in gene replication that leads to a change

environment

every external influence, from prenatal nutrition to our experiences with 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

identical twins

monozygotic twins; twins who develop from a single fertilized egg that splits in two and are therefore genetically identical

monozygotic twins

identical twins; twins who develop from a single fertilized egg that splits in two and are therefore genetically identical

fraternal twins

dizygotic twins; twins who develop from separate fertilized eggs and are therefore genetically no closer than other siblings

dizygotic twins

fraternal twins; twins who develop from separate fertilized eggs and are therefore genetically no closer than other siblings

interaction

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

epigenetics

the study of the molecular mechanisms by which environments can influence genetic expression without actually changing DNA

heritability

the proportion of variation among individuals that we can attribute to genes

genetic predisposition

an inherited tendency or susceptibility toward a particular condition or behavior

nervous system

the body's "fast" communication system, uses electrical signals and chemicals called neurotransmitters to transmit messages

central nervous system

the brain and spinal cord

brain

the mass of nerve tissue that is the main control center of the nervous system

spinal cord

a major part of the central nervous system which conducts sensory and motor nerve impulses to and from the brain

peripheral nervous system

the sensory and motor neurons that connect the central nervous system 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; sometimes called afferent neurons

motor neurons

efferent neurons; neurons that carry outgoing information from the brain and spinal cord to the muscles and glands; sometimes called efferent neurons

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

autonomic nervous system

the part of the peripheral nervous system that controls the glands and the muscles of the internal organs

sympathetic nervous system

the division of the autonomic nervous system that arouses the body, mobilizing its energy (fight or flight)

parasympathetic nervous system

the division of the autonomic nervous system that calms the body, conserving its energy (rest and digest)

reflex

a simple, automatic response to a sensory stimulus, such as the knee-jerk response

reflex arc

a simple nerve pathway that includes a sensory neuron detecting a stimulus, an interneuron in the spinal cord, and the motor neuron that produces an automatic response

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

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

axon

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

axon terminal

the end of a neuron where neurotransmitters are stored

myelin sheath

a layer of fatty tissue segmentally encasing the fibers of neurons; enables faster transmission speed of neural impulses as the impulse hops from one node to the next

multiple sclerosis

an autoimmune disease marked by tremors, weakness, loss of coordination, paresthesia, and more; caused by deterioration of the myelin sheath

glial cells

cells in the nervous system that support, nourish, and protect neurons; may play a role in learning, thinking, and memory

action potential

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

resting potential

the normal, unfired state of a neuron, when the inside of the neuron is more negatively charged than the positively-charged outside of the neuron

depolarization

the first step of action potential when sodium ions rush into the cell causing the interior to lose it's negative charge

repolarization

the second step of action potential when potassium ions rush out the cell causing the interior to become negatively charged again

refractory period

the period after an action potential when a neuron cannot fire again

threshold

the level of stimulation required to trigger a neural impulse

all-or-none response

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

synapse

the junction between the axon terminal of the sending neuron and the dendrite or cell body of the receiving neuron

neurotransmitters

chemical messengers stored in the axon terminals of neurons that cross the synaptic gaps between neurons, binding with receptor sites on the receiving neuron and influencing whether that neuron will generate a neural impulse

reuptake

the process in which a neurotransmitter is reabsorbed into the sending neuron

excitatory neurotransmitters

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

inhibitory neurotransmitters

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

acetylcholine (ACh)

a neurotransmitter that enables muscle action, learning, and memory; undersupply linked to Alzheimer's disease

dopamine

a neurotransmitter that influences movement, learning, attention, and emotion; oversupply linked to schizophrenia, undersupply linked to Parkinson's disease

serotonin

a neurotransmitter that affects mood, hunger, sleep, and arousal; undersupply linked to depression

norepinephrine

a neurotransmitter that helps control alert and arousal; undersupply linked to depression

GABA

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

glutamate

an excitatory neurotransmitter involved in memory; oversupply linked to migraines or seizures

endorphins

a category of neurotransmitters involved in pain control and pleasure; overuse of opioids might suppress the body's natural supply

substance P

a neurotransmitter involved in pain perception and immune response; oversupply linked to chronic pain

myasthenia gravis

an autoimmune disease marked by severe weakness, loss of muscle control, and paralysis; caused by the blocking of ACh transmission

agonist

a molecule that, by binding to a receptor site, stimulates a response

antagonist

a molecule that, by binding to a receptor site, inhibits or blocks a response

reuptake inhibitor

a substance that slows or blocks the reabsorption of a neurotransmitter into the sending neurons, keeping it in the synaptic gap

endocrine system

the body's "slow" communication system; uses chemicals called hormones to transmit messages

hormones

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

adrenaline

hormone secreted by the adrenal glands when under stress, particularly responsible for immediate fight-or-flight response

leptin

a hormone produced by the body's fat cells that suppresses hunger and increases metabolism

ghrelin

a hormone produced by the stomach that stimulates hunger

melatonin

a hormone produced by the pineal gland that induces sleep

oxytocin

a hormone released by the pituitary gland that is enables important functions such as orgasm during sex, labor contractions during childbirth, and milk flow while nursing; seems to promote social bonding

pituitary gland

the endocrine system's "master gland" which, under the influence of the hypothalamus, regulates growth and controls other endocrine glands.

psychoactive drug

a chemical substance that alters perceptions and moods

substance use disorder

continued substance craving and use despite significant life disruption and/or physical risk

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 craving of drugs or certain behaviors despite known adverse consequences

withdrawal

the discomfort and distress that follow discontinuing the use of an addictive drug

depressants

drugs - such as alcohol - that reduce neural activity and slow body functions

opioids

drugs - such as heroin - that typically act as pain relievers

stimulants

drugs - such as caffeine, nicotine, and cocaine - that excite neural activity and speed up body functions

hallucinogens

drugs - such as marijuana - that distort perceptions and evoke sensory images in the absence of sensory input

near-death experience

an altered state of consciousness reported after a close brush with death, often similar to drug-induced hallucinations

lesioning

when studying the brain, the destruction of neural tissue, either naturally or experimentally, which enables observation of its effects on behavior

stimulation

when studying the brain, the electrical or chemical activation of neural tissue, which enables observation of its effects on behavior

EEG

a brain scan technique that amplifies and records the electrical activity that sweeps across the brain's surface, measured by electrodes placed on the scalp; reveals brain activity

MEG

a brain imaging technique that measures magnetic fields from the brain's natural electrical activity; reveals brain activity

CT scan

a brain scan technique that uses a series of X-ray photographs taken from different angles to create a composite representation of a slice through the body; reveals structure but not function

PET Scan

a brain scan technique that detects where a radioactive form of glucose goes while the brain performs a given task; reveals function but not structure

MRI

a brain scan technique that uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of soft tissue; reveals structure but not function

fMRI

a brain scan technique uses successive magnetic resonance imaging scans to reveal changes in bloodflow; reveals both structure and function

hindbrain

includes the medulla, pons, and cerebellum; directs essential survival functions such as breathing, sleeping, wakefulness, coordination, and balance

midbrain

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

brainstem

the oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; responsible for automatic survival functions

medulla

the base of the brainstem; controls heartbeat and breathing

pons

part of the brain stem that helps coordinate movement and controls sleep

thalamus

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

reticular formation

a nerve network that travels through the brainstem and thalamus; filters information and controls arousal; aka the reticular activating system

reticular activating system

a nerve network that travels through the brainstem and thalamus; filters information and controls arousal; aka the reticular formation

cerebellum

part of the brain located to the rear of the brainstem, responsible for processing sensory input, coordinating movement and balance, and enabling nonverbal learning and memory; literally "little brain"