Chap 3 & 4 (Biological Behavior, Nature vs Nurture)

What is the nervous system?

The body’s biological control center — a communication network including the brain, spinal cord, and nerves.

What happens without the nervous system?

The body becomes uncoordinated and unable to act, reason, or feel emotions.

What are neurons?

Individual nerve cells — the most important units of the nervous system.

What are the 3 main parts of a neuron?

Cell body (nucleus), dendrites (receive signals), axon (sends signals).

How many neurons are in the human nervous system?

About 100 billion.

What is a nerve?

A bundle of many long neurons.

What are the two steps of message transmission?

(1) Neural transmission within the neuron; (2) Synaptic transmission between neurons.

What is resting potential?

When a neuron is not firing; it’s polarized.

What is depolarization?

A change in charge that triggers an action potential.

What is an action potential?

An electrical impulse traveling down the axon.

What is the all-or-none principle?

Once an action potential starts, its strength always remains the same.

What is the function of the myelin sheath?

Insulates the axon and speeds message transmission.

What is a synapse?

The tiny gap between neurons where communication occurs.

What are neurotransmitters?

Chemicals that carry messages across the synaptic gap.

What are glial cells?

Helper cells that support neurons by transporting nutrients and producing myelin.

What are the main divisions of the nervous system?

Central Nervous System (CNS) and Peripheral Nervous System (PNS).

What are the parts of the CNS?

Brain and spinal cord.

What are the parts of the PNS?

Nerves connecting CNS to the rest of the body.

What are afferent neurons?

Neurons carrying sensory information to the CNS.

What are efferent neurons?

Neurons sending motor commands from the CNS to muscles/organs.

What is the autonomic nervous system?

Controls involuntary functions (heartbeat, digestion).

What does the sympathetic nervous system do?

Arousal and energy use ('fight or flight').

What does the parasympathetic nervous system do?

Rest and energy storage ('rest and digest').

What are the 3 main brain divisions?

Forebrain, Midbrain, Hindbrain.

What are the functions of the forebrain?

Thinking, emotion, memory, sensory processing.

What is the cerebrum?

The largest part of the forebrain; controls thought and voluntary movement.

What is the thalamus?

Relays sensory information to the cerebral cortex.

What is the hypothalamus?

Regulates hunger, thirst, temperature, and hormones (4 F’s: fighting, feeding, fleeing, mating).

What does the hippocampus do?

Responsible for long-term memory formation.

What does the amygdala control?

Emotions such as fear and aggression.

What is the cerebral cortex?

Outer layer of the brain; involved in consciousness and higher thinking.

What is the midbrain responsible for?

Reflexes, eye and ear movement, auditory and visual processing.

What are the functions of the hindbrain?

Controls vital processes and movement coordination.

What does the medulla control?

Breathing, heart rate, digestion, and reflexes.

What is the function of the pons?

Relays sensory info; balance and hearing.

What is the cerebellum?

Controls balance, coordination, and motor learning.

What are the 4 lobes of the brain?

Frontal, Parietal, Temporal, Occipital.

What does the frontal lobe do?

Reasoning, planning, emotions, speech (Broca’s area).

What does the parietal lobe do?

Processes touch, pain, and pressure.

What does the temporal lobe do?

Hearing, memory, and language (Wernicke’s area).

What does the occipital lobe do?

Vision and visual processing.

What is Broca’s area?

Speech production; damage causes expressive aphasia.

What is Wernicke’s area?

Understanding speech; damage causes fluent but meaningless speech.

What connects the two brain hemispheres?

Corpus callosum.

What does the left hemisphere control?

Language, logic, and analysis.

What does the right hemisphere control?

Creativity, emotion, and spatial skills.

What are split-brain patients?

People with a cut corpus callosum, limiting inter-hemisphere communication.

What does EEG measure?

Electrical activity of the brain.

What is a PET scan used for?

Showing brain activity using radioactive tracers.

What does MRI do?

Shows detailed brain structure using magnetic fields.

What does fMRI measure?

Brain activity through oxygen use (safe, no radiation).

What is brain plasticity?

The brain’s ability to reorganize and form new connections after injury.

What is neurogenesis?

Growth of new neurons in adults.

What is neural pruning?

Elimination of unused neurons for efficiency.

What is the endocrine system?

Network of glands secreting hormones that affect behavior and body function.

What is the master gland?

Pituitary gland — regulates other glands.

What hormone does the thyroid produce?

Thyroxin — controls metabolism.

What does the adrenal gland do?

Produces adrenaline, cortisol (fight/flight response).

What do the pancreas hormones regulate?

Blood sugar (insulin and glucagon).

What does melatonin from the pineal gland control?

Biological rhythms like sleep.

What does “Nature vs Nurture” study?

The influence of genetics (nature) and environment (nurture) on human behavior and diversity.

What is nature?

Genetic and biological factors affecting traits and behavior.

What is nurture?

Environmental and experiential factors like family, culture, and social context.

Who founded the study of genetics?

Gregor Mendel.

What is selective breeding?

Controlled reproduction to study heredity (e.g., in rats or plants).

What are twin studies?

Compare identical vs fraternal twins to determine genetic influence.

What are adoption studies?

Compare adopted children’s traits to biological vs adoptive parents.

What are chromosomes?

Long strands of DNA that carry genes.

What are genes?

Segments of DNA that control traits.

What are polymorphic genes?

Genes with more than one version due to mutation.

What is a dominant gene?

Expresses its trait even if only one copy is inherited.

What is a recessive gene?

Expresses only if two copies are inherited.

What are polygenic traits?

Traits controlled by multiple genes (e.g., intelligence).

What are the sex chromosomes for males and females?

Males = XY, Females = XX.

How does environment affect traits?

Genes interact with surroundings — environment can turn genes “on” or “off.”

What are examples of physical environmental influences?

Exposure to chemicals, alcohol, lead, mercury, etc.

What are examples of social influences?

Parents, peers, culture, language, beliefs, and community.

What is culture?

Shared beliefs, behaviors, and values of a group.

What is ethnicity?

People with common ancestry and cultural background.

What is ethnic identity?

A person’s sense of belonging to an ethnic group.

What’s the difference between collectivist and individualistic cultures?

Collectivist = group harmony; Individualistic = independence.

What is gene–environment correlation?

When genes and environments influence the same traits.

What is passive gene–environment correlation?

Parents provide both genes and environment (e.g., intelligent parents create stimulating homes).

What is active gene–environment correlation?

Individual seeks environments that match their traits (e.g., aggressive child → hostile setting).

What is gene–environment interaction?

Genes influence how we respond to experiences, and vice versa.

What is an example of gene–environment interaction?

Maltreated children with certain genes show higher risk for antisocial behavior.

What is gene expression?

When a gene is activated or “turned on” by certain conditions (e.g., stress).

What is sex?

Biological distinction between males and females.

What is gender?

Psychological experience of being male or female.

What is gender identity?

Internal sense of being male or female.

What is a gender role?

Cultural expectations for masculine or feminine behavior.

What is androgyny?

Having both masculine and feminine traits — flexible and adaptable.

What are the two main theories of gender differences?

Evolutionary psychology and social role theory.

What does evolutionary psychology say?

Gender traits evolved through natural selection for survival.

What does social role theory say?

Gender differences come from societal roles and expectations.