November 3, 2015

Objectives:
◦ 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 memory
 Short-term memory
 Thinking and decision
making
 Interactions 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 changes

Peripheral Nervous System (PNS)
◦ Made up of all the nerves in the body
◦ Connects the CNS to the rest of the body
Motor System
Part of the peripheral nervous system
 Carries out the orders from the brain and
spinal cord
 Made 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 Tissue

Made 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 debris
 Ependymal cells: cover the lining of
cavities
 Oligodendrocytes: make a lipid insulation
called myelin

Glial Cell Types in PNS:
Schwann cells: make myelin for the PNS
 Satellite cells: support cells

Neuron Parts
Neuron body: functions in cell metabolism
Dendrites: receive signals from the environment and other
cells
 Axon: generates and sends signals to other cells
 Axon terminal: connects to a receiving cell
 Synapse: space between the axon terminal and the receiving
cell


◦ Called a neuromuscular junction if the receiving cell is a skeletal
muscle cell


Myelin sheath: lipid insulation that covers parts of the axon
Nodes of Ranvier: bare spots between the myelin
Neuron Classification

Neurons can be classified by either
structure or function
Neuron Structural Classification
Bipolar: one dendrite and one axon
 Multipolar: many dendrites and one axon
 Unipolar: has two projections extending from
the same end of the neuron body

Neuron Function Classification
Sensory neurons: input neurons
 Motor neurons: output neurons
 Interneurons: carry information between
neurons
