Introduction to Biological Psychology and Action Potentials

Vocabulary flashcards covering biological psychology concepts, neuron anatomy, action potential mechanics, and experimental principles from the lecture.

Experimenter effect

A phenomenon in research where the outcome of an experiment is influenced by or depends on the experimenter.

Neuron

A single nerve cell specialized in transmitting, processing, and moving information from one point to another.

Nerve

A bundle composed of individual neurons.

Sensory neuron

A type of neuron connected to sense organs that collects information from outside the body and carries it inside.

Motor neuron

A type of neuron that connects to muscles and transmits signals to stimulate muscle movement.

Interneuron

A neuron located between sensory and motor neurons that connects the two systems.

Cell body

The central part of a neuron containing the nucleus that carries out housekeeping functions, including bringing in nutrients and eliminating waste.

Dendrites

Root-like extensions of a neuron designed to receive information from outside the neuron and bring it into the cell body.

Axon

A long, cord-like structure of a neuron that transmits electrical signals away from the cell body toward other cells.

Axon terminals

Structures located at the end of an axon that receive outgoing signals from inside the neuron and pass them out to adjacent cells.

Myelin sheath

Fatty tissue surrounding certain axons that protects them and speeds up signal transmission by $100\text{ times}$.

Multiple sclerosis

A disease characterized by the breakdown and destruction of myelin sheaths surrounding axons.

Action potential

A brief, sudden reversal of electrical polarity across a neuron's cell membrane that propagates along the axon.

Resting membrane potential

The electrical voltage difference across a neuron's membrane when at rest, typically measured at approximately $-70\text{ mV}$.

Depolarization

The phase of an action potential in which sodium ions rush into the cell, shifting the internal membrane charge from negative to positive (up to approximately $+30\text{ mV}$).

Repolarization

The phase of an action potential where sodium channels close and potassium ions rush out of the cell, returning the internal voltage back to its original negative charge.

Hyperpolarization

A temporary negative overshoot following repolarization where the internal membrane potential briefly becomes more negative than the resting potential.

Sodium-potassium pump

A active membrane transport mechanism that maintains concentration gradients by continually pumping sodium out of the cell and potassium into the cell.

Axon hillock

The trigger zone located at the junction between the soma and the axon where voltage-gated ion channels are highly concentrated and action potentials originate.

Threshold

The critical membrane voltage value (typically about $-55\text{ mV}$) required to open voltage-gated ion channels and initiate an action potential.

Refractory period

The period during and immediately after an action potential during which the cell membrane is recharging and cannot easily generate another action potential.

All-or-none principle

The rule stating that a neuron generates either a complete action potential or no action potential at all, meaning all action potentials are uniform in strength.

Neural thresholds

The varying sensitivity levels assigned to different neurons that enable the sensory system to distinguish between light and strong stimuli.

Helmholtz

The researcher who conducted an experiment in $1850$ to measure the speed of nerve impulse conduction in humans.