AP Psychology - Unit 2: Biological Bases

Heredity

The genetic transfer of characteristics from parents to offspring.

Ex: Height and eye color

1. Dendrites

2. Nucleus

3. Cell Body (Soma)

4. Axon

5. Myelin Sheath

6. Schwann Cells

7. Nodes of Ranvier

8. Axon Terminals

Nature

The genetic and hereditary influences on an individual’s development and behavior, which are inherited from their biological parents.

Ex: Susceptibility to physical or mental conditions, temperaments, or personality traits.

Nurture

The environmental influences and experiences that shape an individual’s traits, behaviors, and development.

Ex: Culture, social interactions, and education.

Evolutionary Perspective

The idea that all human behaviors reflect the influence of physical and psychological predispositions that helped human ancestors survive and reproduce.

Natural Selection

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 onto succeeding generations.

Charles Darwin

He established principles such as natural selection and “survival of the fittest”, and he encouraged the idea of eugenics.

Eugenics

The practice of selective breeding to create ideal specimens; it’s largely considered outdated and discriminatory.

Twin Studies

Twins are observed to study the presumption that all human behaviors reflect the influence of physical and psychological predispositions that helped human ancestors survive and reproduce.

Adoption Studies

Identical twins raised in the same household aren’t always the same. Similar to how identical twins separated at birth and raised in different environments can have many similarities.

Ex: The Jim Twins

Epigenetics

The study of environmental influences on gene expression that occur without DNA change.

Ex: Although identical twins have the same DNA, their life experiences can cause their genes to be expressed differently.

Neuron

Building blocks of the nervous system; their jobs are to receive, carry, and send messages through neural impulses.

Cell Body (Soma)

The part of a neuron that contains the nucleus; the cell’s life-support center.

Axon

The segmented neuron extension that carries signals from one end to the other.

Myelin Sheath

A fatty substance encasing most neurons in the brain, which protects and insulates the axon. It speeds up the transmission of nerve impulses.

Terminal Buttons

Knobs at the end of each axon from which neurotransmitters are released into the synapse.

Synapse

The gap between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron.

• Neurotransmitters cross this gap.

Nodes of Ranvier

The spaces between Schwann cells.

Schwann Cells

Cells that produce myelin for the myelin sheath.

Dendrites

They receive signals from other neurons.

Neurotransmitters

A chemical messenger that transmits signals across a synapse from one neuron to another.

Threshold

A signal enters, and if it’s strong enough to reach the threshold, the neuron will fire.

All or None Principle

Once at the threshold, the neuron will fire, and it’ll fire with the same intensity every time.

Resting Potential

The neuron is at rest, meaning it isn’t sending a message. The interior of the neuron is slightly negative compared to the outside.

Refractory Period

A brief period where the neuron can’t fire again.

Depolarization

When the neuron fires, positive ions rush into the cell. This causes the inside of the neuron to become more positive, and creates the action potential.

Action Potential

The electrical impulse that travels down the axon.

Direction of Impulse

The one-way, specific pathway that an action potential takes along a neuron.

Multiple Sclerosis

It attacks the myelin sheaths of axon bundles in the brain, spinal cord, and optic nerves.

Ex: Selma Blair

Inhibitory

Neurotransmitters that make the next neuron less likely to fire; they slow neuro communication.

Ex: GABA

Excitatory

Neurotransmitters that make the next neuron more likely to fire.

Ex: Glutamate

Acetylcholine (ACh)

Involved in learning, voluntary muscle movement, and memory.

• Alzheimer’s disease is associated with diminished ACh functioning.

Dopamine

Linked to the anticipation of pleasurable or rewarding activities, as well as movement, attention, and learning.

• Lack of dopamine is associated with Parkinson’s disease.

• Excess dopamine is associated with schizophrenia.

Endorphins

Involved in alleviating pain.

• Those with low levels typically have chronic pain or fibromyalgia.

Serotonin

Plays a significant role in mood, appetite, and sleep.

• Low levels have been associated with depression, and may also be a factor in anxiety disorders.

Norepinephrine

Involved in arousal, alertness, and your sleep cycle.

• Low levels are associated with depression.

GABA

The primary inhibitory neurotransmitter in the brain.

• Low levels are involved in anxiety and seizure disorders.

Substance P

Involved in the transmission of pain signals.

• Undersupply linked with pain insensitivity.

• Oversupply linked to chronic pain and fibromyalgia.

Glutamate

The primary excitatory neurotransmitter in the brain.

• Oversupply can be associated with seizure disorders, and may play a role in degenerative disorders of the CNS, as well as bipolar disorder.

Antagonists

Drugs that block receptor sites.

• Curare poisoning, which paralyzes victims by blocking ACh receptors.

Agonists

Drugs that increase, or mimic, a neurotransmitter’s action.

• Morphine, which mimics endorphins by stimulating receptors involved in mood and pain sensations.

Withdrawal

The physical and psychological symptoms that occur when a person who is dependent on a substance abruptly stops or significantly reduces their intake.

• Anxiety, insomnia, depression, hallucinations, etc.

Psychoactive Drug

They stimulate, inhibit, or mimic neurotransmitter activity.

• Caffeine

Physical Dependence

A state where the body has adapted to a substance, requiring it to function normally.

• Without it, the body then begins to experience physical withdrawal symptoms.

Psychological Dependence

The emotional craving to use a substance, driven by the desire for the pleasure, escape, or mood change it provides.

• It can stem from using a substance to manage stress or emotions.

Depressants

They reduce neural activity by:

• increasing relaxation

• decreasing mood and arousal

• slowing down bodily processes

Ex: Alcohol

Stimulants

They excite neural activity by:

• increasing energy

• decreasing appetite

• creating brief feelings of euphoria

• speeding up bodily processes

Ex: caffeine, nicotine, cocaine

Hallucinogens

They distort perception by:

• causing false sensory hallucinations

• impairing memory

• causing feelings of relaxation and/or euphoria

Ex: marijuana, mushrooms, LSD

Barbiturates

Depressant drugs that slow down CNS activity by:

• reducing anxiety

• inducing sedation

• potentially causing sleep

• impairing memory and judgement

Ex: methohexital

Opiates

They decrease feelings of pain.

Ex: Heroin, morphine

Amphetamines

CNS stimulants that increase alertness, attention, and energy.

• Medically used to treat conditions like ADHD and narcolepsy.

Ecstasy

A synthetic psychoactive drug that functions both as a stimulant and a mild hallucinogen, causing:

• a short-term euphoric high

• distorted perception

It can cause long-term damage to serotonin-producing neurons.

LSD

A powerful hallucinogen that primarily affects serotonin receptors.

• It causes altered perceptions, thoughts, and emotions.

Central Nervous System (CNS)

The information highway that connects the peripheral NS to the brain.

• Made up of the brain and the spinal cord.

Peripheral Nervous System

The entire network of nerves located outside of the CNS, connecting it to the body’s limbs and organs.

• Divided into the autonomic and somatic nervous systems.

Afferent Neurons (Sensory)

Nerves that bring information TO your spinal cord or brain.

• They’re involved in your senses of vision, hearing, smell, taste, touch, pain, and temperature.

Efferent Neurons (Motor)

Nerves that receive signals FROM the brain, and carry them towards your muscles and glands so your body can take action.

• They control voluntary movements of the skeletal muscles, such as in your arms or legs.

Interneurons

Once information reaches the brain or spinal cord, they take the messages and send them elsewhere in the brain or onto efferent neurons.

Spinal Cord

The long, cylindrical bundle of nervous tissue that extends from the brainstem down the back, serving as the main communication pathway for the CNS.

• It carries both sensory and motor signals.

Somatic Nervous System

Contains the nerves you use to voluntarily activate muscles in your body.

Ex: Controlling the movement of your legs when you walk.

Autonomic Nervous System

Automatically controls gland activity and the muscles of internal organs.

Ex: Heart rate, breathing, blood pressure, and digestive processes.