AP Psych Unit 1: Hormones and Neurons

Central Nervous System (CNS)

The brain and spinal cord; responsible for processing information and coordinating responses.

Peripheral Nervous System (PNS)

All nerves outside the brain and spinal cord; connects the CNS to the rest of the body.

Somatic Nervous System

The division of the PNS that controls voluntary movements of skeletal muscles and carries sensory information to the CNS.

Autonomic Nervous System

The division of the PNS that regulates involuntary functions such as heart rate, digestion, and breathing.

Sympathetic Nervous System

The division of the autonomic nervous system that arouses the body and prepares it for action, especially during stress.

Parasympathetic Nervous System

The division of the autonomic nervous system that calms the body and restores it to a resting state.

Dendrites

Branching extensions of a neuron that receive signals from other neurons or sensory receptors.

Soma (Cell Body)

The main part of a neuron that contains the nucleus and maintains the cell.

Axon

The neuron extension that carries neural impulses away from the cell body toward other cells.

Myelin Sheath

A fatty layer surrounding some axons that insulates them and speeds up neural impulses.

Axon Terminals / Synaptic Knobs

Small branches at the end of an axon that release neurotransmitters into the synapse.

Resting Potential

The neuron's stable, negatively charged state when it is not firing; about -70 mV.

Action Potential

A brief electrical impulse that travels down a neuron's axon when the neuron fires.

Threshold

The minimum level of stimulation needed to trigger an action potential.

All-or-None Response

The principle that a neuron either fires completely or does not fire at all; stronger stimuli do not produce a stronger action potential.

Refractory Period

A brief period after an action potential when a neuron cannot fire again or requires stronger stimulation to fire.

Acetylcholine (ACh)

A neurotransmitter involved in muscle movement, learning, memory, and attention.

Dopamine

A neurotransmitter involved in movement, motivation, reward, attention, and learning.

Serotonin

A neurotransmitter involved in mood, sleep, appetite, and other functions.

Norepinephrine

A neurotransmitter and hormone involved in alertness, arousal, attention, and the stress response.

GABA (gamma-aminobutyric acid)

The brain's major inhibitory neurotransmitter; it reduces neural activity.

Glutamate

The brain's major excitatory neurotransmitter; important for learning, memory, and neural communication.

Endorphins

Neurotransmitters that reduce pain and can produce feelings of pleasure or well-being.

Reuptake

The process by which a sending neuron reabsorbs neurotransmitters from the synapse.

Agonist

A chemical that increases or mimics a neurotransmitter's effects.

Antagonist

A chemical that blocks or reduces a neurotransmitter's effects.

Endocrine System

The body's system of glands that releases hormones into the bloodstream.

Hormones

Chemical messengers released by endocrine glands that travel through the bloodstream and affect target cells.

Pituitary Gland

A small endocrine gland at the base of the brain that regulates many other endocrine glands and body processes.

Adrenal Glands

Glands located above the kidneys that release hormones involved in stress, arousal, and metabolism.

Cortisol

A hormone released during stress that helps increase available energy and regulate the body's stress response.

Oxytocin

A hormone involved in social bonding, trust, childbirth, and breastfeeding.

Melatonin

A hormone that helps regulate the sleep-wake cycle and is released more in darkness.

Ghrelin

A hormone that increases hunger and signals the brain that the body needs food.

Leptin

A hormone released by fat cells that helps signal fullness and regulate long-term energy balance.