The Brain

Biological psychology- a branch of psychology concerned with the links between biology and behavior

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

Dendrite- the bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body

Axon- the extension of a neuron, ending in branching terminal fibers, through which messages pass to other neurons or to muscles or glands

Myelin sheath- a layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next

Action potential- a neural impulse; a brief electrical charge that travels down an axon. The action potential is generated by the movement of positively charged atoms in and out of the channels in the axon’s membrane

Threshold- a level of stimulation required to trigger a neural impulse

Synapse- the junction between the axon tip of the sending neuron and the dendrite and cell body of the receiving neuron. The tin gap at this junction is called the synaptic gap or cleft

Neurotransmitters- chemical messengers that traverse the synaptic gaps between neurons. When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse.

Acetylcholine (Ach) - a neurotransmitter that, among its functions, triggers muscle contraction

Endorphins- “morphine within”- natural, opiate like neurotransmitters linked to pain control and pleasure

Nervous system- the body’s speedy, electrochemical communication system, consisting of all the nerve cells of the peripheral and central nervous systems.

Central nervous system (CNS) - the brain and the spinal cord

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

Nerves- neural “cables” containing many axons. These bundled axons, which are part of the peripheral nervous system, connect the central nervous system with muscles, glands, and sense organs.

Sensory neurons- neurons that carry incoming information from the sense receptors to the central nervous system

Interneuron- central nervous system neurons that internally communicate and intervene between the sensory inputs and motor outputs

Motor neurons-