UNIT 1: BIOLOGICAL BASIS OF BEHAVIOR

Nature (Heredity)

Our genetic makeup and DNA passed down from our parents.

Nurture (Environment)

Everything from family and friends to culture and experiences.

Twin studies

Comparing identical and fraternal twins to see how much behavior is genetic vs. environmental.

Adoption studies

Examining if adopted children are more like their biological or adoptive parents.

Family studies

Analyzing shared traits among relatives.

Evolutionary perspective

The idea that behaviors evolved because they helped ancestors survive and reproduce.

Natural selection

The process where traits that enhance survival get passed on.

Mutations

Random changes in DNA that can lead to new traits.

Behavior genetics

The study of how much genes and environment affect our behavior.

Genes

The basic unit of heredity.

Genome

The complete set of genetic instructions for an organism.

Epigenetics

How environment can influence gene expression without changing the DNA itself.

Central Nervous System (CNS)

The brain and spinal cord

acts as the command center processing information and sending instructions.

The central nervous system

Reflexes

Automatic responses to stimuli that skip the brain for speed.

Reflex arc

Neural pathway of a reflex where signals travel only to the spinal cord and back.

Peripheral Nervous System (PNS)

All nerves outside the brain and spinal cord

Somatic Nervous System

Controls voluntary movements of skeletal muscles.

Autonomic Nervous System

Controls involuntary actions like heartbeat

Sympathetic nervous system

Prepares the body for action in stressful situations (fight or flight).

Parasympathetic nervous system

Calms the body down after a stressful event (rest and digest).

Neurons

Specialized cells that transmit electrical signals and carry out brain communication.

Sensory neurons (afferent)

Carry traffic from sense organs toward the brain.

Motor neurons (efferent)

Carry information away from the brain and spinal cord to muscles and glands.

Interneurons

Relay messages from sensory neurons to other interneurons or motor neurons.

Glial cells

The brain's support staff that protects

Cell body (Soma)

The neuron's control center housing the nucleus and producing energy.

Dendrites

The listeners of the neuron that receive incoming signals from other neurons.

Axon

The talker of the neuron that sends signals to other neurons or muscles.

Myelin sheath

A fatty layer around the axon that speeds up electrical signal transmission.

Node of Ranvier

Un-insulated gaps formed between myelin sheaths capable of electrical activity.

Axon terminal buttons

Branches at the end of an axon containing neurotransmitters and performing reuptake.

Synapse

The small gaps between neurons where communication occurs.

Action potential

A brief electrical charge that travels down the axon.

All-or-nothing principle

A neuron either fires completely or it doesn't fire at all.

Depolarization

When a neuron's charge becomes less negative

Refractory period

The time a neuron needs to reset after firing before firing again.

Resting potential

The state of a neuron when it is ready to fire but hasn't yet.

Na+ (Sodium)

Positive ion involved in action potential depolarization.

K+ (Potassium)

Ion involved in the electrochemical balance of neural firing.

Neurotransmitters

Chemical messengers that transmit signals across the synapse.

Excitatory neurotransmitters

Chemical messengers that encourage neurons to fire.

Inhibitory neurotransmitters

Chemical messengers that prevent neurons from firing.

Dopamine

Neurotransmitter involved in reward and motivation.

Norepinephrine

Neurotransmitter that arouses alertness and energy.

Glutamate

The most common excitatory neurotransmitter

Substance P

Neurotransmitter involved in transmitting pain signals to the brain.

Acetylcholine

Transmits messages from motor neurons to voluntary skeletal muscles.

GABA

Inhibitory neurotransmitter that calms the nervous system.

Serotonin

Inhibitory neurotransmitter that regulates mood and sleep.

Endorphins

Natural pain killers produced by the nervous system.

Multiple Sclerosis (MS)

Disorder where the myelin sheath is damaged

Myasthenia Gravis

Autoimmune disorder attacking acetylcholine receptors

Endocrine system

A slower communication system that uses hormones instead of neurotransmitters.

Hormones

Chemical messengers traveling through the bloodstream affecting behavior and mood.

Adrenaline

Hormone that increases heart rate and energy.

Oxytocin

Hormone influencing bonding and social behaviors.

Leptin

Hormone that regulates hunger and fat storage.

Ghrelin

Hormone that stimulates hunger.

Melatonin

Hormone that regulates sleep-wake cycles.

Psychoactive drugs

Substances affecting brain activity and leading to changes in perception

Agonists

Drugs that mimic neurotransmitters or enhance their actions.

Antagonists

Drugs that block neurotransmitter activity.

Reuptake inhibitors

Drugs that prevent reabsorption of neurotransmitters

Stimulants

Drugs that speed up body functions and enhance energy.

Depressants

Drugs that slow down body functions and neural activity.

Hallucinogens

Drugs that alter perception and can cause hallucinations.

Tolerance

The need to take more of a drug to achieve the same effect.

Addiction

A compulsive craving for a substance despite harmful consequences.

Withdrawal

Negative physical and psychological symptoms when stopping a drug.

Substance use disorder

When drug use becomes uncontrollable and interferes with daily life.

Hindbrain

Old brain structures shared with less sophisticated life forms.

Cerebellum

Helps coordinate voluntary movements

Brainstem

Lower part of the brain connecting to the spinal cord (medulla

Medulla oblongata

Controls life-supporting functions like heartbeat

Pons

Bridge between lower and upper brain

Reticular formation

Nerve network in the brainstem playing an important role in wakefulness and arousal.

Midbrain

Located near the center of the brain

involved in processing visual and auditory information.

Midbrain

Forebrain

The largest part of the brain containing higher-level processing structures.

Thalamus

The brain's switchboard processing and sending sensory information (except smell).

Limbic System

Helps regulate memory

Hypothalamus

Controls sexual behavior

Amygdala

Almond-shaped cluster in the limbic system controlling basic emotions like fear and anger.

Hippocampus

Structure in the limbic system that helps process new memories for permanent storage.

Contralateral control

Principle where the right brain hemisphere controls the left side of the body and vice versa.

Cerebral Dominance

Tendency of each brain hemisphere to exert control over different functions.

Left hemisphere

Brain hemisphere associated with logic

Right hemisphere

Brain hemisphere associated with artistic

Corpus Callosum

Large band of neural fibers connecting the two brain hemispheres.

Split-brain

Condition in which a patient has separate consciousness in each hemisphere due to corpus callosum severance.

Frontal lobe

Controls judgment

Broca's area

Region in the frontal lobe directing muscle movements involved in speech.

Motor cortex

plans, controls, and executes voluntary muscle movements throughout the body

Parietal lobe

Controls information processing

Sensory cortex

Receives incoming touch sensations from the rest of the body.

Temporal lobe

Processes sound

Wernicke's area

Region in the temporal lobe that understands and processes spoken and written language.

Occipital lobe

Contains the primary visual cortex helping interpret information from the eyes.

Binocular cues

Depth cues that depend on two eyes.