Unit 1.1 Pt 1 - Biological Bases for Behavior

Evolutionary psychology

the study of behavior and the mind, using principles of natural selection

Behavior genetics

the study of how genes and the environment influence our behavior and traits

Nature vs. nurture

relative contributions of genetics vs. experience/environment on our traits/behaviors

Heredity

the genetic transfer of characteristics from parents to offspring

Ex: DNA, chromosomes, genes

Environment

any non-genetic influence

ex: what we eat, where we live, who we’re with

Genotype

exact genetic makeup

Phenotype

observable physical characteristics

Epigenetics

• Genes can be active (expressed) or inactive

• Environmental events can turn on/off genes

ex: superhero clip

Fraternal twins

develop from separate fertilized eggs

Identical twins

develop from a single fertilized egg that splits in two, creating two genetically identical organisms

• may still look/act alike

Nervous System

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

Peripheral Nervous System

sensory and motor neurons that connect the central nervous system to the rest of the body

Central Nervous System

the brain and spinal cord, responsible for processing information and coordinating actions.

Somatic

controls the body’s skeletal muscles (voluntary movements)

Autonomic

controls the glands and muscles of internal organs (involuntary, like breathing or heart beat)

Sympathetic

arouses the body, mobilizing its energy in stressful situations

Parasympathetic

calms the body down, conserves energy

Spinal cord

information highway that connects peripheral nervous system to the brain

Reflexes

simple, automatic response to a sensory stimulus

ex: blinking when dusty

Reflex arc

the pathway that a reflex takes in the body from sensation → sensory neuron → spinal cord

Neuron

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

Neurogenesis

the formation of new neurons

Sensory neurons

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

• 🤚 → 🧠

• ex: touch something hot

Motor neurons

• carry outgoing information from the brain and spinal cord to the muscles and glands

  • 🧠 → 💪

  • ex: wanting to pick up your pen

Interneurons

are within the brain and spinal cord that communication internally and intervene between the sensory inputs and motor outputs

• Couples therapy of the neurons

Glial cells

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

• band aids of the neurons

Dendrites

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

• → the radio antenna of the cell

Cell body

the cell’s life-support center

• → the “heart” of the cell

Axon

the extension of the neuron, ending in the terminal fibers 

• → the power lines of the cell

Myelin sheath

a layer of fatty tissue encasing the fibers of certain neurons; enables greater transmission speed

• → the slip n slide of the cell

Terminal branches

connect to other neuron cells

• → the airport terminal of the cell

Action potential

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

• Ions = electrically charged atoms → neuron starts very negative → -70 charge

• this means it is polarized

Resting potential

when neuron has more negative ions inside, more positive ions outside → is capable of hitting action potential, but hasn’t yet

Selectively permeable

the axon is picky about what it allowed inside its membrane → But once it does– floodgates open, letting positively charged ions in 

Threshold

level of stimulation needed to trigger an action potential → positive enough to reach -55

All-or-nothing reaction

a neuron’s reaction of either firing at full strength, or not firing at all

• like trying to flush a toilet → gotta go all the way or it won’t work!

• MUST HIT -55!!!!!

Depolarized

a temporary change in a neuron's cell membrane where the interior becomes less negative compared to the outside

Refractory period

cell rests, pumps positive sodium ions back out

• → becomes even more negative

• Cannot fire again until it rests and gets back to -70 

• → think of what happens when
  you sprint

Synapse

 the connection point between the axon tip of the sending neuron & the dendrite of the receiving neuron

Neurotransmitters

chemical messengers that cross the synaptic gap

• Released by sending neuron → travel across synapse → bind to receptor sites → influences whether or not the receiving neuron will fire

Reuptake

when the sending neuron absorbs the excess neurotransmitters

Excitatory

make an action potential more likely

ex: glutamate, acetylcholine, norepinephrine

Inhibitory

making an action potential less likely

ex: GABA

Function of Acetylcholine

Muscle action, learning, & memory

Malfunction examples of Acetylcholine

↓: Alzheimer’s disease (memory) & myasthenia gravis (muscle weakness)

Function of Norepinephrine

Alertness & arousal

Malfunction examples of Norepinephrine

↓: depressed mood

Function of GABA

Major inhibitory/calming neurotransmitter 

Malfunction examples of GABA

↓: seizures, tremors, & insomnia 

Function of Glutamate

Major excitatory neurotransmitter; also memory

Malfunction examples of Glutamate

↑: overstimulation– seizures or migraines 

Function of Substance P

Pain perception & immune responses

Malfunction examples of Substance P

↑: chronic pain

Function of Dopamine

• Movement, learning, attention, & emotion

• Reward pathways

Malfunction examples of Dopamine

• ↑: Schizophrenia

• ↓: Parkinson’s disease– tremors & decreased mobility

Function of Serotonin

• Mood, hunger, sleep, & arousal

• Stability 

Malfunction examples of Serotonin

↑: drug use can suppress natural supply

Agonists

mimic effects of natural neurotransmitter

• Ex: morphine mimics the effects of endorphins → makes that feel-good
  feeling stronger

Antagonists

• block neurotransmitter from working

  • Ex: botulin (Botox) blocks acetylcholine (paralysis)

  • Antagonists in media block the protagonist from achieving their goal → antagonist drugs block the neurotransmitter

Psychoactive drugs

• a chemical substance that alters the brain, causing changes in perceptions and mood

  • Overall effect depends on its biological effects AND the user’s expectations

Tolerance

• The result of continued consumption of a drug resulting in more consumption of a drug in order to achieve the desired effects

  • Ex: needing more and more caffeine to feel awake

Dependence

A state of physiological and psychological need to take a drug

Addiction

Compulsive drug craving and use, despite adverse consequences; biochemical changes

Psychological dependence

an obsession within the brain concerning the consumption of a drug

• Ex: craving, feelings of anxiety or depression, lack of sleep, irritability, uncertainty, romanticization, denial

Physical dependence

physiological need to take a drug → result of the body now needing the drug to function

Withdrawal symptoms

Discomfort and distress that is produced when the body does not get the required amount of a drug

Substance Use Disorder

A disorder characterized by continued substance craving and use despite significant life disruption and physical risk

Depressants

drugs that reduce neural activity, slow down bodily functions, and inhibit Central Nervous System

• Increase GABA neurotransmitters 

  • Slowed neural functioning

  • Memory disruption

  • Disinhibition

  • Reduced self-awareness and self-control

Alcohol

Doesn’t seem like a depressant on the surface

Low/high doses and long-term (Alcohol)

• Low doses: lowers inhibitions, disrupts memory & REM 

• High doses: slows sympathetic nervous system 

  • Slurred speech, reaction times, etc. 

• Long-term: brain shrinks, neurons die, prevents new neurons and synapses from forming, reduces one’s self-awareness

Expectancy effects

What you expect is more likely to happen

Barbiturates/Tranquilizers

Depressant

• Meant to induce sleep, treat anxiety and epilepsy

• Similar effects as alcohol

• Depress nervous system

Large doses and long-term (Barbiturates/Tranquilizers)

• Large doses: memory impairment 

• Long-term: Respiratory issues, lack of control

Opiates

Depressant

• opium and its derivatives: narcotics and heroin

• Purpose = lessens pain and anxiety