Brain & Biological Sciences HW 1 Review

neuron

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

interneurons

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

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

nervous system

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

central nervous system

brain and spinal cord

peripheral nervous system

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

Nerves

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

somatic nervous system

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

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).

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

reflex

a simple, automatic response to a sensory stimulus, such as the knee-jerk response

cell body

Largest part of a typical neuron; contains the nucleus

dendrites

a neuron's bushy, branching extensions 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.

glial cells

cells in the nervous system that support, nourish, and protect neurons

action potential

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

threshold

the level of stimulation required to trigger a neural impulse

refractory period

a period of inactivity after a neuron has fired

all or nothing 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

neurotransmitter

chemical messengers that cross the synaptic gaps between neurons

endorphins

"morphine within"--natural, opiatelike neurotransmitters linked to pain control and to pleasure.

dopamine

A neurotransmitter associated with movement, attention and learning and the brain's pleasure and reward system.

serotonin

A neurotransmitter that affects hunger,sleep, arousal, and mood.

Acetylcholine (ACh)

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

GABA

a major inhibitory neurotransmitter

Glutamate

A major excitatory neurotransmitter; involved in memory

Norepinephrine

A neurotransmitter involved in arousal, as well as in learning and mood regulation

agonist

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

antagonist

a molecule that inhibits or blocks a neurotransmitter's action

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