Nervous
System
Delanie Cyr
Jacob Butcher
Jacklyn Jaronik
Claudia Bishop
Nervous system: Central and
Peripheral
The Nervous system is stream lined to send rapid signals
from cell to cell to maintain homeostasis and
coordinate body organs and functions.
Central and Peripheral
Systems
There
are two basic types of nervous
systems:
CNS
(Central Nervous System)
PNS
(Peripheral Nervous System)
Central Nervous System
Consists
It
of the brain and spinal cord
coordinates information received from
sensory receptors and initiates responses
Peripheral Nervous System
Contains
a afferent division composed of
sensory receptors and sensory neurons,
and an efferent division composed of
motor neurons.
Sensory Receptors and Motor
Nerves
Sensory
receptors detect changes in the
environment and transmits this information
along sensory or afferent nerves to the
CNS
Motor
nerves transmits impulses from the
CNS to the PNS
Structure of Nervous Tissue
Located in the brain, spinal cord, ganglia, and nerves.
It is composed of two types of cells, Neurons and
Neuroglia
Neurons conduct action potentials and are the
structural and functional units of nervous tissue
Neuroglia are cells that support, protect, and furnish
nutrients to neurons, and augment the speed of neuron
transmission
Structure of a Neuron
Can be over 3 feet long (longest nerve in your body)
Three basic parts to a neuron:
Dendrites- receive information from receptors or other
neurons and send it back out to the cell body
Cell Body-usually has a triangular or cone shaped area
called the axon hillock
Axon- extends from the axon hillock, is the elongated
fiber that extends from the cell body to the terminal
endings and transmits the neural signal.
Structure of a Neuroglia Cell
Generally smaller and more abundant the neurons.
Six types of neuroglia cells, four located in the CNS, and
two located in the PNS.
CNS:
Astrocytes
Oligodendrocytes
Microglia
Ependymal Cells
PNS:
Schwann Cells
Satellite Cells
Classification of a Neuron
Three
classifications of a neuron based on
their function:
Sensory(afferent)- changes the stimulation into an
action potential or nervous impulse that travels along
the axon to a spinal cord.
Interneuron- structurally a multipolar neuron and
comprises about 90% of the neurons in the CNS.
Motor neuron (efferent)- takes the impulse out of the
spinal cord via a spinal nerve to an effector.
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