The Nervous and Endocrine Systemsneurons and the brain

NeuronsNeuron: a nerve cell. The basic building block of the nervous systemDendrite: The bushy, branching extensions of a neuron that receive messages and conduct impulses toward cell bodyAxon: the extension of a neuron, ending in branching terminal fibers. Used to pass messages to other neurons or muscles and glandsMyelin Sheath: A layer of fatty tissue surrounding the axon of many neurons. Speeds up message transmission

The Neuron

How Neurons Communicate• 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 anotherNeurotransmitters: chemical messages that are sent across synapses to start an impulse (message)

Neural Network

Synapse

Step-by-Step1. 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 Sheath4. Message reaches terminal branch and

prepares to jump5. Message jumps synapse6. Message is received by the next neuron

Nervous SystemNervous System: the body’s speedy, electrochemical communication systemCentral Nervous System (CNS): The brain and spinal chordPeripheral 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. AUTOMATIC2. Somatic (SNS): controls the body skeletal

muscles SKELETAL

Nervous System (copy the chart into notes)

Mirror NeuronsMirror Neurons Video (TED Talks)

The Endocrine SystemEndocrine System: the body’s slow chemical communication system that uses hormones and the blood streamHormones: chemical messengers, made by endocrine glands

A Few Endocrine GlandsPituitary Gland: regulates growth and controls other endocrine glands. Located under the HypothalamusAdrenal 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 and Endocrine Systems• The Nervous System is FAST and is

ELECTROCHEMICAL• The Endocrine System is SLOW and uses

HORMONES