Unit 1A: Biological Bases of Behavior

behavior genetics, heredity, environment, gene

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

these types of scientists study our differences and weigh the effects/interplay of … (nature – the genetic transfer of predisposed characteristics from parents to offspring that influence physical, behavioral, and mental traits/processes) and … (nurture – every non-genetic/external influence, from prenatal nutrition to the people and things around us; includes things happening to your mom while she’s carrying you — ex: alcohol)

our genetic predispositions and our surrounding environments interact – environments can trigger … activity, and genetically influenced traits can evoke responses from others

twin

behavioral genetics research on the effects of genes on individual behavior/mental processes is often conducted using …, family, and adoption studies

twin studies, heredity, 50, together, monozygotic, environments

… … are types of research using twins (purpose – to assess the relative contributions of heredity and environment to some attribute, such as intelligence)

Monozygotic (MZ) twins develop from 1 fertilized egg that has split to form 2 embryos early in development; thus, they share the same … – often referred to as identical, although they are not truly identical. Dizygotic (DZ) twins develop from 2 different fertilized eggs; thus, like other siblings, or each parent and child, they share about …% of their genes – often referred to as fraternal

These studies often compare the characteristics of identical and fraternal twins, and also twins of both types who have been raised … or apart. A particular trait is studied for appearance in sets of monozygotic and dizygotic twins; if there is more similarity in the … twins, researchers infer a genetic component for the trait

Identical twins raised together usually have more similar … than fraternal twins raised together

family studies, family

… … are types of research conducted among siblings, parents, or children to assess evidence for genetic links for characteristics or outcomes, often related to health or disease

ex: a study to assess whether individuals from the same … who share a similar genetic structure also have similar responses to a health-promotion intervention such as diet, exercise, or medication

adoption studies, biological, environment

… … are types of research that investigates the relationships among genetic and environmental factors in the development of personality, behavior, or disorder by comparing the similarities of biological parent-child pairs with those of adoptive parent-child pairs

If the children resemble their … parents, but not their adoptive families, with respect to a given trait, researchers infer a genetic component for that trait

One problem with these studies: the biological mom contributes not only her genes, but also the prenatal …; studies have found positive correlations between adopted children and their biological parents with regard to alcoholism and criminality

evolutionary psychology, natural selection, genes

… … is the study of how natural selection affects the expression of behavior and mental processes to increase survival and reproductive success

… … is the principle that inherited traits that better enable 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) – ex: individuals who exhibited behaviors conducive to survival and reproduction, such as avoiding toxic foods, were more likely to survive and pass on their …, contributing to our shared genetic heritage

eugenics, galton

Some theorists have sought to apply principles of the evolutionary perspective to humans, in discriminatory ways:

… is the pseudoscientific view that the genetic makeup of the population can be improved by selective breeding and by preventing reproduction by people with various disabilities, which the Nazis adapted to their own aims in formulating the “final solution” in WWII

brought about by francis …

nervous system, central nervous system, peripheral nervous system, nerves

the … … is the body’s speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems; it takes in information from the world and the body’s tissues, makes decisions, and sends back information and orders to the body’s tissues

the … … … consists of the brain and spinal cord; the body’s decision maker

the … … … consists of the sensory and motor neurons that connect the CNS to the rest of the body (all other nerves); carries sensory information to and motor information away from the CNS via spinal and cranial … (bundled axons that form neural cables connecting the CNS with muscles, glands, and sense organs)

somatic nervous system, autonomic nervous system

the … … … is the division of the PNS that controls the body’s skeletal muscles (also called the skeletal nervous system); it enables voluntary control of our skeletal muscles

the … … … is the division of the PNS that controls the glands and the muscles of the internal organs (such as the heart – this type of nervous system influences functions such as the heartbeat)

sympathetic nervous system, parasympathetic nervous system

the … … … is the division of the ANS that arouses the body, mobilizing its energy (ex: raises blood pressure, accelerates heartbeat, etc) – think “fight or flight”

the … … … is the division of the ANS that calms the body, conserving its energy (ex: lowers blood pressure, slows heartbeat, etc) – think “rest and digest”

these two systems are always activated, but when one is not more extreme than the other, they are balanced out

pupils, heart, glucose, saliva, decreases

the sympathetic nervous system does these things to amp you up for survival mode:

dilates …, dilates bronchi (tubes that air travels through to get to lungs), accelerates … rate and breathing, releases … from the liver, slows digestion down, releases adrenaline, slows release of tear glands, production of … is reduced, activity of intestines …, urinary output decreases (pee more)

the parasympathetic nervous system does all the opposite

neurons, dendrite, axon, terminal, synapses, neurotransmitters, myelin sheath,

… are nerve cells; they are the basic building blocks of the nervous system and they conduct electricity and “talk” to one another by sending chemical messages across a tiny gap that separates them

they consist of a cell body (or soma, the cell’s life-support center) and its branching fibers

the … fibers receive and integrate information from other cells, conducting it toward the cell body. Then, the long … fiber passes the message through its … branches to other neurons or to muscles or glands (the terminal branches of axon form junctions with other cells through … – the meeting point between neurons with small synaptic gaps – and … – chemical messengers – cross those gaps and bind to receptor sites on the receiving neuron)

axons are encased in a … …, a layer of fatty tissue that insulates them/speeds up their impulses

the nodes of Ranvier insulate axons, allowing for saltatory conduction, a faster/more efficient process of action potential propagation

Schwann cells increase the speed of nerve signal transmission by producing the myelin sheath

glial cells, schwann

… … are cells in the nervous system that support, nourish, and protect neurons, transporting their waste and providing structure, insulation, and communication; they also play a role in learning, thinking, and memory

the … cell is one of these since it produces the myelin sheath which insulates/speeds up the communication along the axon

reflex arc, sensory, interneurons, motor

In the spinal cord, the … … demonstrates how the 3 different types of neurons within the central and peripheral nervous systems work together to respond to stimuli

3 types of neurons work together in the spinal cord to create a reflex: sensory neurons, motor neurons, and interneurons

Information is brought into the spinal cord from the outside by… neurons, then the … (which are only in the spinal cord) intercept the information/send it to the brain/tell the motor neurons what to do, then the … neurons send the information back to the outside/move the muscles

neural transmission, chemical, electrical

… … is the process of sending/transmitting information through neurons – BETWEEN neurons, a … system of neurotransmitters is used to communicate, but WITHIN single neurons, … signals are used to communicate

resting potential, threshold, depolarization, action potential, refractory period, reuptake

neural transmission system in order:

… … is a neuron at rest, where the negative potassium ions are one the inside of the axon, and the positive sodium ions are on the outside of the axon, neither interacting yet

the … is the minimum intensity of the stimulus that is needed to fire a neural impulse; the excitatory neural signals (like pushing the neuron’s gas pedal) exceed the inhibitory neural signals (like pushing the neuron’s brake)

… is the movement of a cell’s membrane potential to a more positive value – positive ions are attracted into the negatively charged axon interior as the axon’s channels open (this inflow of positive ions creates an electric charge and is the action potential/the neural impulse); this only occurs at the nodes of Ranvier, and, therefore, the action potential jumps from one node to the next like a chain reaction

the … … is the neural impulse; a brief electrical charge from the mixing of the ions that travels down an axon (neurons send messages by firing impulses) – when the axon is myelinated, conduction speed is increased

the … … is the brief resting pause that occurs after a neuron has fired; subsequent action potentials cannot occur until the axon returns back to its resting potential state

… is the process by which the neurotransmitter molecules that have been released at a synapse are reabsorbed by the presynaptic (sending) neuron that released them

all-or-none

the …-…-… principle states that action potential either occurs or not — the strength of the stimulus does not affect the intensity of the action potential; all stimuli above the neuron’s threshold will trigger action potentials of identical magnitudes

multiple sclerosis, females, myasthenia gravis, progressive

disruptions to neural transmission:

… … — a disease of the CNS characterized by inflammation and multifocal scarring of the protective myelin sheath of nerves, disrupting neural transmission (first signs are blurred vision/distorted color, then later symptoms can include fatigue, weakness in the hands/feet, numbness, stiffness/muscular spasms, muscle/back pain, difficulties with coordination/balance, loss of bladder/bowel control, depression, cognitive impairments like memory or concentration issues); mostly affects … and people of ages 20-30

… … — an autoimmune disorder where the body produces antibodies against acetylcholine receptors (neurotransmitters that control muscle movement), causing faulty transmission of nerve impulses at neuromuscular junctions; affected muscles (initially those of the face and neck) are easily fatigued and may become paralyzed temporarily; it is … and eventually affects the rest of the body

excitatory, inhibitory

if the binding of a neurotransmitter to the postsynaptic (receiving) neuron site makes the neuron more likely to fire, the effect is called … (it makes the membrane become more positive) — the neurotransmitter is telling the neuron to keep sending messages

if the binding of the neurotransmitter to the postsynaptic (receiving) neuron site prevents or lessens the likelihood of the firing of the neuron, the effect is called … (it makes the membrane become more negative) – the neurotransmitter tells the neuron to stop sending messages

acetylcholine, alzheimer’s

… is an excitatory neurotransmitter involved in muscle activation, learning, and memory – causes contraction of the skeletal muscles, helps regulate heart muscles, promotes arousal in the brain, and transmits messages between the brain and spinal cord – interneuron communication (in the spinal cord)

Oversupply can cause muscle cramps, increased salivation, and muscle weakness – in severe cases, it may cause paralysis

Undersupply is linked to memory issues, learning difficulties, and may contribute to conditions like … disease and muscle weakness

norepinephrine

… is an excitatory neurotransmitter found in neurons in the ANS – governs sympathetic arousal by raising the heart rate and increasing blood pressure, giving rise to the “fight or flight” syndrome and other excitatory actions; it is also released in the brain to enhance attention, alertness, focus, and memory for emotionally charged events

Oversupply can cause anxiety, panic attacks, high blood pressure, and excessive sweating; chronic oversupply may contribute to stress disorders

Undersupply results in low energy, poor concentration, and mood disorders like depression

dopamine, schizophrenia, parkinson’s

… is an excitatory AND inhibitory neurotransmitter primarily involved in processing smooth and coordinated gross motor movements and in attention, learning, and reinforcing effects of several often-abused drugs; also involved in reward, motivation, and pleasure

Oversupply is linked to … and addictive behaviors due to overactivation of the reward system

Undersupply is associated with … disease, resulting in tremors and difficulty with movement, as well as depression and low motivation

serotonin, serotonin

… is an inhibitory neurotransmitter that regulates mood, appetite, sleep-wake cycle, dreaming, and pain, contributing to feelings of well-being and happiness; most drugs that relieve depression increase activity at serotonergic synapses

Oversupply can cause mania and … syndrome, leading to confusion, agitation, high blood pressure, and muscle rigidity

Undersupply is associated with mood disorders such as depression, anxiety, and sleep disturbances

endorphins

… are inhibitory neurotransmitters produced by the brain, acting as natural painkillers and mood enhancers, providing a sense of well-being and modulating the experience of pain or pleasure

Oversupply can suppress pain perception, leading to a lack of awareness of injury and potentially addictive behavior

Undersupply increases sensitivity to pain and may lead to feelings of sadness, depression, or difficulty managing stress, feelings of euphoria

substance p

… … is an excitatory neurotransmitter involved in transmitting pain signals to the brain, playing a role in the body’s response to pain and inflammation – causes the contraction of smooth muscle and dilation of blood vessels

Oversupply is linked to increased perception of pain and chronic pain conditions

Undersupply results in reduced pain perception, which can be dangerous if injuries go unnoticed

glutamate, alzheimer’s

… is the brain’s most abundant excitatory neurotransmitter, stimulating receptors associated with learning and memory, as well as many sensory and motor functions

Oversupply can lead to migraines and excitotoxicity, which damages nerve cells and is associated with conditions like … disease and ALS

Undersupply impairs cognitive functions like learning and memory

GABA, huntington’s

… is the main inhibitory neurotransmitter in the brain, which helps calm the nervous system and promote relaxation; regulates daily sleep-wake cycles

Oversupply can cause excessive relaxation, leading to drowsiness, impaired motor coordination, and sluggishness, can be oversupplied when we eat too much MSG (a kind of salt)

Undersupply is linked to anxiety, insomnia, restlessness, and conditions like epilepsy, tremors, and … disease due to a lack of inhibitory signals in the brain

endocrine, hormones

the … system is the body’s “slow” chemical communication system that is interconnected with the nervous system; a set of glands that secrete (produce and discharge) hormones

… are chemical messengers that are manufactured by the endocrine glands in one tissue, travel through the bloodstream, and affect other tissues including the brain

hormones, signals, hours

Endocrine system vs nervous system

endocrine gland cells secrete … directly into the bloodstream, while neurons transmit … over a neural network in general; endocrine transport may take minutes to …, while in nervous control the process may take a fraction of a second to minutes; endocrine effects are typically long-lasting, while most neural effects are short lived; many chemicals are used as both neurotransmitters and hormones, with similar effects

adrenaline

… is a hormone released by the endocrine system’s adrenal glands in response to stress or excitement, preparing the body for “fight or flight” by increasing the strength and rate of the heart beat and energy; increases blood sugar by influencing the breakdown of glycogen to glucose, dilates or constricts specific blood vessels, stimulates respiration and/or dilates respiratory passages 

Oversupply can lead to increased heart rate, high blood pressure, anxiety, difficulty sleeping, and stress-related disorders

Undersupply may result in low energy levels, poor stress response, fatigue, and weakened immune function

melatonin

… is a hormone produced by the endocrine system’s pineal gland and regulates the sleep-wake cycle by promoting sleepiness in response to darkness

Oversupply can cause excessive drowsiness, lethargy, and concentration problems; it may also disrupt the circadian rhythm (body’s 24-hour sleep-wake cycle)

Undersupply leads to insomnia and other sleep-related issues, such as difficulty falling asleep, and may impair immune function

leptin

… is a hormone produced by fat cells and regulates energy balance by signaling the brain to reduce appetite when enough fat is stored (it is at an increased level when you are full); we eat faster than this gets to our brain, making it easy to overeat

Oversupply can cause the body to develop a resistance to it, leading to overeating and potential obesity

Undersupply increases hunger and difficulty in regulating body weight, possibly leading to obesity

ghrelin

… is a hormone released primarily by the stomach and stimulates appetite, often referred to as the “hunger hormone” (it is at an increased level when you are hungry in order to communicate to your brain that you need to eat)

Oversupply leads to increased hunger, overeating, and potential weight gain

Undersupply reduces appetite, which can lead to unintended weight loss or difficulty maintaining enough energy intake

oxytocin

… is known as the “love hormone,” involved in social bonding, sexual reproduction, childbirth, and increasing feelings of trust and empathy; also stimulates uterine contractions and milk ejection

Oversupply can cause oversensitivity to social cues, anxiety, and overattachment in relationships

Undersupply is linked to difficulties in forming social bonds, lower trust, and increased feelings of loneliness or depression

psychoactive drugs, blood-brain, agonists, antagonists, reuptake inhibitors

… … are chemical substances that affect brain processes and result in altered states of consciousness, mood, and perception; these alter brain function by interacting with neurotransmitter systems

to be psychoactive, the drug must be able to enter the bloodstream and cross the …-… barrier (a feature of the blood vessels in the brain that prevent more foreign substances from entering the brain)

… are drugs that mimic or facilitate the activity of a given neurotransmitter system; enhances the effects of a neurotransmitter

… are drugs that block or impede the activity of a given neurotransmitter system; these stop the effects of a neurotransmitter either by blocking the message after it is sent, or by blocking the message from being sent entirely

… … are drugs that prevent reabsorption of neurotransmitters, increasing concentration; enhances the effects of a neurotransmitter (there are more neurotransmitters bound to the postsynaptic receptors)

tolerance, addiction, withdrawal

… is when increasingly larger doses of a drug are required to achieve the same effect (does not apply to marijuana since it stays in your system for longer, therefore actually requiring smaller doses)

… is a state of psychological and/or physical dependence on the use of drugs or other substance; this is often viewed as a disease process with strong genetic influences as the person’s brain function/structure become impaired over the course of the drug use

… refers to the symptoms associated with cessation of drug use; these symptoms are usually the opposite effects of the drug itself

stimulants, caffeine, cocaine

… are types of psychoactive drugs that increase neural activity

… is an antagonist drug that reduces drowsiness and enhances problem-solving and physical abilities, and at high doses it can result in tremors and anxiety; symptoms of withdrawal are headaches and fatigue

… is a reuptake inhibitor for dopamine (enhances effects) that causes a sense of euphoria; highly addictive, and at high doses it can cause hallucinations and delusions

depressants, alcohol, respiratory

… are types of psychoactive drugs that decrease neural activity in the CNS generally by agonizing (facilitating) GABA neurotransmission

… is an agonist for GABA that mostly disrupts memory and attention as it slows the sympathetic nervous system, and it reduces self-awareness; genetic factors play a role in its addictiveness

A blood alcohol concentration (BAC) of 0.08% causes users to experience mild excitement and declines in motor and cognitive performance, at around 0.15% people may feel nauseated, at 0.2-0.3% people may lose consciousness, and a BAC 0.4-0.5% could be fatal since the … centers of the brain become suppressed

Withdrawal can be lethal

hallucinogens, marijuana

… are drugs that significantly alter perception, thought, and mood

… is an agonist containing the psychoactive ingredient of THC and causes hallucinations, makes things more amusing, and it mildly impairs memory and distorts time perception

opioids, heroin

… are drugs that relieve pain and result in euphoria and relaxation; these interact with opioid receptors in the brain (endorphins)

… is an agonist for endorphins that relieves pain and causes a sense of euphoria; it is derived from morphine but it is more powerful, and it is very addictive