Mods 9-11 review

Acetylcholine (ach)

A neurotransmitter that enables learning and memory and also triggers muscle contraction.

Action potential

A neural impulse: a brief electrical charge that travels down an axon, The action potential is generated by the movement of positively changed atoms in and out of channels in the axon's membrane.

Adrenal glands

A pair of endocrine glands just above the kidneys. The adrenals secrete the hormones epinephrine (adrenaline) and norepinephrine (noradrenaline), which help to arouse the body in times of stress.

Agonist

Excite neurons by mimicking natural neurotransmitters or blocking their reuptake to keep more of them in your system. (pretends to be something else)

Amygdala

Two lima bean-sized neural clusters that are components of the limbic system and are linked to fear and aggression.

Antagonist

Inhibit neural impulses by blocking receptor sites or diminishing their release.

Autonomic nervous system

The part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division arouses: its parasympathetic division calms.

Axon

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

Brainstem

The oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull: the brain-stem is responsible for automatic survival functions.

Central nervous system (CNS)

The brain and spinal cord.

Cerebellum

The "little brain" attached to the rear of the brain-stem; its functions include processing sensory input and coordinating movement output and balance.

Dendrites

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

Electroencephalogram (EEG)

An amplified recording of the waves of electrical activity that sweep across the brain's surface. These waves are measured by electrodes placed on the scalp.

Endocrine system

The body's 'slow" chemical communication system:set of glands that secrete hormones into the bloodstream.

Endorphins

"Morphine within"-natural, opiatelike neurotransmitters linked to plain control and to pleasure.

Hormones

Chemical messengers, mostly those manufactured by the endocrine glands, that are produced in one tissue and effect another.

Hypothalamus

A neural structure lying below (hypo) the thalamus: is directs several maintenance activities (eating,drinking,body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion.

Limbic system

A doughnut-shaped system of neuronal structures at the border of the brain-stem and cerebral hemispheres: associated with emotions such as fear and aggression and dives such as those for food and sex. Includes the hippocampus, amygdala, and hypothalamus.

(MRI) Magnetic resonance imaging

A technique that uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of soft tissues: allows us to see structures within the brain.

Medulla

The base of the brain-stem: controls heartbeat and breathing.

fMRI-Functional MRI

A technique for revealing blood flow and, therefore, brain actity by comparing successive MRI scans. MRI scans show brain anatomy: FMRI scans show brain function.

Myelin sheath

A layer of fatty tissue segmentally encasing the fibers pf many neurons: enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next.

Neuron

A nerve cell: the basic building block of the nervous system

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 weather that neuron will generate a neural impulse.

Parasympathetic nervous system

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

Peripheral nervous system (PNS)

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

Pituitary gland

The endocrine system's most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands. Master gland

(PET) Positron emission tomography

A visual display of the brain activity that detects where a radioactive form of glucose goes while the brain performs a given task.

Resting potential

Neuron is in its normal, resting state. Ions within the cell give the axon a small negative charge, fluid outside is positive charged.

Somatic nervous system

The division of the peripheral nervous system that controls the body's skeletal muscles. Also called the skeletal nervous system.

Sympathetic nervous system

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

Synapse

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

Thalamus

The brains sensory switchboard, located on the top of the brain-stem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla.

Motor Neurons

Efferent Neurons; a nerve cell forming part of a pathway along which impulses pass from the brain or spinal cord to a muscle or gland.

absolute refractory period

the period immediately following the firing of a nerve fiber when it cannot be stimulated no matter how great a stimulus is applied

all or none principle

states that the strength of a response of a neuron or muscle fiber is not dependent upon the strength of the stimulus. If a stimulus is above a certain threshold, a neuron or muscle fiber will fire.