November 3, 2015Objectives:

◦Label the structure of a neuron◦Explain how the nervous system is broken up into parts

◦Differentiate between neurons and glial cells

Journal:◦What makes up the nervous system?

Nervous System

Functions of the Nervous System:Long-term memoryShort-term memoryThinking and

decision makingInteractions with

the world

Parts of the Nervous System

Central Nervous System (CNS)◦Made up of the brain and spinal cord◦Controls all basic bodily functions and

responds to external changesPeripheral Nervous System (PNS)

◦Made up of all the nerves in the body◦Connects the CNS to the rest of the

body

Motor SystemPart of the peripheral nervous systemCarries out the orders from the brain

and spinal cordMade up of two branches:

◦Somatic Nervous System Controls skeletal muscle Under conscious control

◦Autonomic Nervous System Controls smooth muscle, cardiac muscle, and

glands Not under conscious control

Parts of the Autonomic Nervous System

Parasympathetic◦Resting and

digesting branch ◦Deal with normal

body functions Sympathetic

◦Body’s alert system that kicks in when you are in danger

◦Fight or flight response

Nervous TissueMade up of:

◦Neurons: carry out control functions, amitotic

◦Neuroglia also known as Glial Cells: support cells for the nervous tissue, able to divide

Glial Cell Types in CNS:Astrocytes: metabolic and

structural support cells for the nervous tissue

Microglia: remove debrisEpendymal cells: cover the lining

of cavitiesOligodendrocytes: make a lipid

insulation called myelin

Glial Cell Types in PNS:Schwann cells: make myelin for

the PNSSatellite cells: support cells

Neuron Parts

Neuron body: functions in cell metabolismDendrites: receive signals from the environment and other

cellsAxon: generates and sends signals to other cellsAxon terminal: connects to a receiving cellSynapse: space between the axon terminal and the

receiving cell◦ Called a neuromuscular junction if the receiving cell is a skeletal

muscle cellMyelin sheath: lipid insulation that covers parts of the axonNodes of Ranvier: bare spots between the myelin

Neuron ClassificationNeurons can be classified by

either structure or function

Neuron Structural ClassificationBipolar: one dendrite and one axonMultipolar: many dendrites and one

axonUnipolar: has two projections

extending from the same end of the neuron body

Neuron Function ClassificationSensory neurons: input neuronsMotor neurons: output neuronsInterneurons: carry information

between neurons