neurons and the brain
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 cell body
Axon: the extension of a neuron, ending in branching
terminal fibers. Used to pass messages to other neurons or
muscles and glands
Myelin Sheath: A layer of fatty tissue surrounding the axon
of many neurons. Speeds up message transmission
• Neural connections are VERY small. It’s hard to see, even
with a microscope
• Terminal branches of one neuron connect to the soma or
dendrite of another neuron creating a synapse
Synapse: the connection point of one neuron to another
Neurotransmitters: chemical messages that are sent across
synapses to start an impulse (message)
1. Message formed and sent from the soma. Don’t forget
that messages are simply neurotransmitters (chemicals)
2. Message travels down the axon
3. Message is sped up by the Myelin Sheath
4. Message reaches terminal branch and prepares to jump
5. Message jumps synapse
6. Message is received by the next neuron
Nervous System: the body’s speedy, electrochemical
communication system
Central Nervous System (CNS): The brain and spinal chord
Peripheral Nervous System (PNS): the sensory and motor
neurons that connect the central nervous system to the rest of
the body. Two parts:
1. Autonomatic (ANS): controls the glands and muscles of
the internal organs. AUTOMATIC
2. Somatic (SNS): controls the body skeletal muscles
SKELETAL
Mirror Neurons Video (TED Talks)
Endocrine System: the body’s slow chemical communication
system that uses hormones and the blood stream
Hormones: chemical messengers, made by endocrine glands
Pituitary Gland: regulates growth and controls other
endocrine glands. Located under the Hypothalamus
Adrenal Glands: a pair of endocrine glands just above the
kidneys that produce adrenaline and noradrenaline which
arouse the body in times of stress
• The Nervous System is FAST and is ELECTROCHEMICAL
• The Endocrine System is SLOW and uses HORMONES