Unit 1.1Foundations of Physiological Psychology and Genetics

Physiological Psychology

Study of how biology affects behavior to examine psychological phenomena.

Traits

Distinctive characteristics determined by genetics.

Evolutionary Perspective

Applies principles like natural selection and survival of the fittest to psychology.

Eugenics

Discredited idea that some genes are superior to others.

Behavior Genetics

Studies the genetic and environmental influences on behavior and individual differences.

Heritability

The proportion of trait variance among individuals due to genetic differences.

Environmentality

The proportion of trait variation attributed to environmental factors.

Down Syndrome

Caused by an extra 21st chromosome (trisomy 21), leads to intellectual disability.

Huntington's Disease

Genetic disorder involving degeneration of the basal ganglia; symptoms include muscle impairment and appear around age 40.

Central Nervous System (CNS)

Composed of the brain and spinal cord.

Peripheral Nervous System (PNS)

All nerves outside the CNS.

Somatic Nervous System

Controls voluntary movements and sensory input/output.

Autonomic Nervous System

Regulates involuntary body functions like heartbeat and digestion.

Sympathetic Nervous System

Activates energy and arousal (e.g., fight or flight response).

Parasympathetic Nervous System

Conserves energy and calms the body (e.g., after stress, returns to homeostasis).

Neurons

Nerve cells that transmit signals through the body.

Sensory (Afferent) Neurons

Carry information to the brain.

Motor (Efferent) Neurons

Carry information from the brain to muscles.

Reflexes

Automatic responses that bypass the brain (from sensory to motor neurons).

Interneurons

Connect sensory and motor neurons; involved in learning, memory, and reflexes.

Nerves

Bundles of neurons, basic units in the nervous system.

Glial Cells

Support and protect neurons; include Schwann cells which help with neuron repair.

Resting Membrane Potential

Electrical charge inside the neuron (~ -70 mV); inside is negative compared to outside.

Polarized

Resting state: negative inside, positive outside.

Action Potential (Nerve Impulse)

Electrical signal that travels down the axon due to depolarization; leads to neurotransmitter release.

Depolarization

Inside of the neuron becomes less negative or even positive.

Repolarization

Return to resting potential after firing.

All-or-Nothing Principle

A neuron either fires completely or not at all if the threshold is reached.

Absolute Refractory Period

Neuron cannot fire again immediately after an action potential.

Relative Refractory Period

Neuron can fire again but requires a stronger stimulus.

Synapse

Gap between neurons where neurotransmitters travel.

Neurotransmitters

Chemicals that transmit signals across the synapse.

Excitatory Neurotransmitters

Increase the chance a neuron will fire.

Inhibitory Neurotransmitters

Decrease the chance a neuron will fire.

Reuptake

Process of reabsorbing excess neurotransmitters.

Enzymes

Break down leftover neurotransmitters in the synapse.

Nodes of Ranvier

Gaps in the myelin sheath that speed up signal transmission.

Myelin Sheath

Fatty covering that insulates the axon; its degradation (e.g., in multiple sclerosis) slows down signal transmission.