A collection of neurons and supportive tissue running from the base of the brain down the center of the back, protected by a column of bones.
Somatic Nervous System
The subdivision of the peripheral nervous system that connects to sensory receptors and to skeletal muscles; sometimes called the skeletal nervous system.
Autonomic Nervous System
The subdivision of the peripheral nervous system that regulates the internal organs and glands.
Sympathetic Nervous System
The subdivision of the autonomic nervous system that mobilizes bodily resources and increases the output of energy during emotions and stress.
Parasympathetic Nervous System
The subdivision of the autonomic nervous system that operates during relaxed states and that conserves energy.
A cell that conducts electrochemical signals; the basic unit of the nervous system; also called a nerve cell.
Cells that support, nurture, and insulate neurons, remove debris when neurons die, enhance the formation and maintenance of neural connections, and modify neural functioning.
A neuron's branches that receive information from other neurons and transmit it toward the cell body.
A neuron's extending fiber that conducts impulses away from the cell body and transmits them to other neurons.
Immature cells that renew themselves and have the potential to envelop into mature cells; given encouraging environments, stem cells from early embryos can develop into any cell type.
The site where transmission of a nerve impulse from one nerve cell to another occurs; it includes the axon terminals, the synaptic cleft, and receptor sites in the membrane of the receiving cell.
The brain's ability to change and adapt in response to experience - for example, by reorganizing or growing new neural connections.
A brief change in electrical voltage that occurs, between the inside and the outside of an axon when a neuron is stimulated; it serves to produce an electrical impulse.
A chemical substance that is released by a transmitting neuron at the synapse and that alters the activity of a receiving neuron.
Chemical substance it he nervous system that are similar in structure to opiates; involved in pain reduction, pleasure, and memory and known technically as endogenous opioid peptides.
Chemical substances, secreted by organs called glands, that affect the functioning of other organs.
A hormone, secreted by the pineal gland, that is involved in the regulation of daily biological rhythms.
A hormone, secreted by the pituitary gland, that stimulates uterine contractions during childbirth, facilitates the section of milk during nursing and seems to promote, in both sexes, attachment and trust in relationships.
Hormones that are produced by the adrenal glands and that are involved in emotion and stress.
Hormones that regulate the development and functioning of reproductive organdies and that stimulate the development of male and female sexual characteristics; they include androgens, estrogens, and progesterone.
The part of the brain at the top of the spinal cord, consisting of the medulla and the pons.
A structure in the brain stem responsible for certain automatic functions, such as breathing and heart rate.
Reticular Activating System
A dense network of neurons found in the core of the brain stem; it arouses the cortex and screens incoming information.
A brain structure that regulates movement and balance and is involved in the learning of certain kinds of simple responses.
A brain structure involved in emotions and drives vital to survival, such as fear, hunger, thirst, and reproduction; it regulates the autonomic nervous system.
A small endocrine gland at the base of the brain, which releases many hormones and regulates other endocrine glands.
A brain structure involved in the arousal and regulation of emotion and the initial emotional response to sensory information.
The largest brain structure, consisting of the upper part of the brain; divided into two hemispheres, it is in charge of most sensory, motor, and cognitive processes. From the Latin for "brain".
A collection of several tin layers of cells covering the cerebrum; it is largely responsible for higher mental functions.
Lobes at the lower back part of the brain's cerebral cortex; they contain areas that receive visual information.
Lobes at the top of the brain's cerebral cortex; they contain areas that receive information on pressure, pain, touch, and temperature.
Lobes at the sides of the brain's cerebral cortex; they contain areas involved in hearing, memory, perception, emotion, and language comprehension.
Lobes at the front of the brain's cerebral cortex; they contain areas involved in short-term memory, higher-order thinking, initiative, social judgement, and speech production.
A long-lasting increase in the strength of synaptic responsiveness, thought to be a biological mechanism of long-term memory.