Biological Bases of Behavior (Final Reviewer)

Biological Bases of Behavior

explores how our thoughts, emotions, and actions are influenced by biological systems—especially the brain, nervous system, endocrine system, and genetics. It integrates psychology with biology to understand how the body and mind interact.

nature

Refers to inherited traits and genetic makeup.

nature

Example: A child inherits blue eyes from both parents.

nurture

Environmental influences that shape behavior.

nurture

Example: A child raised in a musical household may develop musical talent.

behavior genetics

Study of how genes and environment influence behavior.

behavior genetics

Example: Twin studies help determine if intelligence is more genetic or environmental.

chromosomes

Threadlike structures made of DNA that carry genes. Humans have 46 chromosomes.

chromosomes

Example: The 23rd pair determines biological sex (XX = female, XY = male).

DNA

Molecule carrying genetic instructions for development and function.

DNA

Example: ____ determines traits like height, eye color, and risk for certain diseases.

genes

Units of heredity made up of DNA.

gene

Example: A ____ for lactose tolerance allows

digestion of dairy products.

dominant trait

Trait expressed when at least one dominant allele is present.

dominant trait

Example: Brown eyes are dominant over blue eyes.

recessive trait

Trait expressed only when two recessive alleles are inherited.

recessive trait

Example: Blue eyes appear only if both parents pass on the blue eye gene.

phenotype

Observable traits of an individual.

phenotype

Example: Curly hair, dimples, or attached earlobes.

genome

Complete set of genetic material in an organism.

genome

Example: The human _____ contains about 20,000–25,000 genes.

heritability

Proportion of variation in traits due to genetics.

heritability

Example: Height has high _____, but nutrition also plays a role.

neuron

Basic unit of the nervous system that transmits information.

dendrites

Branch-like structures that receive messages from other neurons.

axon

Long fiber that carries messages away from the cell body.

myelin sheath

Fatty layer that insulates axons and speeds up signal transmission.

glial cells

Support cells that nourish and protect neurons.

resting potential

State of a neuron when it's not firing; inside is negatively charged.

depolarization

The process of making the neuron’s charge more positive

action potential

Electrical impulse that travels down the axon.

refractory period

Time after an action potential when a neuron can’t fire again.

Sensory Neurons/Afferent Neurons

Carry info from body to brain/spinal cord.

Sensory Neurons/Afferent Neurons

Example: Feeling a cold breeze on your skin.

Motor Neurons/Efferent Neurons

carry commands from brain / spinal cord to muscles

Motor Neurons / Efferent Neurons

Example: Moving your hand away from a hot stove.

interneurons

Connect neurons within the brain and spinal cord.

interneurons

Example: Processing the decision to run when you hear a loud noise.

mirror neurons

Fire when performing or observing an action.

mirror neurons

Example: Feeling pain when you see someone else get hurt.

synapse

Gap between neurons where communication occurs.

synapse

Example: Neurotransmitters cross the _____ to send signals.

neurotransmitter

Chemical messenger between neurons.

neurotransmitter

Example: Dopamine affects mood and movement.

terminal bouton

End of axon where neurotransmitters are released.

terminal bouton

Example: Releases serotonin into the synapse.

acetylcholine

Muscle movement, arousal.

acetylcholine

Example: Deficiency linked to Alzheimer’s disease.

Anandamide / 2AG

Reduce neurotransmitter release.

anandamide / 2AG

Example: Affected by THC in marijuana.

dopamine

Movement, reward, cognition.

dopamine

Example: Low levels linked to Parkinson’s; high levels to schizophrenia.

endorphins

Pain relief, pleasure.

endorphins

Example: Released during exercise ("runner’s high").

GABA

Main inhibitory neurotransmitter.

GABA

Example: Anti-anxiety meds increase _____ activity

glutamate

Main excitatory neurotransmitter; learning.

glutamate

Example: Overactivity can cause seizures.

histamine

Wakefulness, immune response.

histamine

Example: Anti____ cause drowsiness.

nitric oxide

Blood flow regulation.

nitric oxide

Example: Increases oxygen delivery to active brain areas.

norepinephrine

Alertness, memory

norepinephrine

Example: Released during stress to heighten awareness.

serotonin

Mood, appetite, sleep.

serotonin

Example: Low levels linked to depression.

stimulants

Stimulants increase activity in the central nervous system, leading to heightened alertness, energy, and mood. They often affect dopamine and norepinephrine pathways.

amphetamines

Increase dopamine release and block reuptake

amphetamines

short-term effects of _____ : euphoria, increased energy, reduced appetite

amphetamines

risks of _____ : psychosis, heart problems, insomnia, stroke

cocaine

blocks dopamine reuptake

cocaine

short-term effects of ______: intense euphoria, alertness

cocaine

risks of _____ : addiction, paranoia , heart attack

methylphenidate (ritalin)

Slows dopamine reuptake

methylphenidate (ritalin)

short-term effects of ______ : focus, alertness (used for ADHD)

methylphenidate (ritalin)

risks of ______ : elevated blood pressure, mild withdrawal

caffeine

blocks adenosine (inhibitory neurotransmitter)

caffeine

short-term effects of ______ : wakefulness, improved concentration

caffeine

risks of _____ : anxiety, insomnia, dependence

nicotine

Stimulates acetylcholine and dopamine release

nicotine

short-term effects of _______ : increased arousal, reduced stress

nicotine

risks of ______ : lung cancer, cardiovascular disease, addiction

depressants

______ slow down brain activity, often enhancing GABA (an inhibitory neurotransmitter). They are used medically for anxiety and sleep but are highly addictive.

alcohol

Enhances GABA activity

alcohol

short-term effects of ______ : relaxation, lowered inhibitions

alcohol

risks of _____ : liver damage, memory loss, accidents

benzodiazepines

boost GABA effects

benzodiazepines

short-term effects of _____ : sedation, reduced anxiety

benzodiazepines

risks of _____ : Dependence, overdose (especially with

alcohol

narcotics (opiates)

_____ bind to endorphin receptors, reducing pain and producing pleasure. They are highly addictive and dangerous in overdose.

morphine / heroin

stimulate endorphin receptors

morphine / heroin

short-term effects of _____ : pain relief, euphoria

morphine / heroin

risks of _____ : Respiratory failure, severe withdrawal, overdose

marijuana (cannabis)

______ affects cannabinoid receptors, altering perception, mood, and memory.

THC (active in marijuana)

Stimulates cannabinoid receptors

THC (active in marijuana)

short-term effects of ______ : Relaxation, altered time perception

THC (active in marijuana)

risks of ____ : Memory impairment, lung issues, reduced motivation

hallucinogens

_______ distort sensory perception and thought. They often affect serotonin pathways.

LSD

Stimulates serotonin receptors

LSD

short-term effects of _____ : Visual hallucinations, altered reality