AP PSYCHOLOGY UNIT 4: Biological Bases of Behavior Set I

Neuron

a nerve cell; the basic building block of the nervous system

Dendrites

a neuron’s bushy, branching extensions that receive messages and conduct impulses towards the cell body

Axon

the neuron extension that passes messages through its branches to other neurons, or to muscles or glands

Myelin Sheath

a fatty tissue layer, segmentally encasing the axons of some neurons; enables vastly greater transmission speed is neural impulses hop from one node to the next

Action Potential

a neural impulse; a brief electrical charge that travels down an axon

Refractory Period

a period of inactivity after a neuron has fired

Threshold

the level of stimulation required to trigger a neural impulse

All-Or-None Response

a neuron’s reaction of either firing with a full strength response or not firing

Synapse

the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron

Neurotransmitters

chemical messengers that cross the synaptic gap between neurons. when released by the sending neuron, they travel across the synapse and bind to receptors sites on the receiving neuron thereby influencing whether that neuron will generate a neural impulse

Reuptake

a neurotransmitter’s reabsorption by the sending neuron

Endorphins

“morphine within” -natural opiate-like neurotransmitters link to pain control and to pleasure

Agonist

a molecule that, by binding to a receptor site, stimulates a response

Antagonist

a molecule that by, binding to receptor site, inhibits or blocks a response

Nervous System

the body’s speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems

CNS

the brain and the spinal cord

PNS

the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body

Nerves

bundled axons that form neural “cables” connecting the central nervous system with muscles glands, and sense organs

Sensory Neurons

neurons that carry incoming information from the sensory receptors to the brain and spinal cord

Motor Neurons

neurons that carry outgoing information from the brain and spinal cord to the muscles and glands

Interneurons

neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs and motor outputs

Somatic Nervous System

the division of the peripheral nervous system that controls the body’s skeletal muscles

ANS

the part of the peripheral nervous system that controls the glands and the muscles of the internal organs

Sympathetic Nervous System

the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations

Parasympathetic Nervous System

the division of the autonomic nervous system that calms the body, conserving its energy

Endocrine System

the body’s “slow” chemical communication system; a set of glands that secrete hormones into the bloodstream

Hormones

chemical messengers that are manufactured by the endocrine glands travel through the bloodstream and affect other tissues

Adrenal Glands

a pair of endocrine glands that sit just above the kidneys and secrete hormones that help arouse the body in times of stress

Pituitary Glands

the endocrine system’s most influential gland. under the influence of the hypothalamus, it regulates growth and controls other endocrine glands