Download The Nervous System

The Nervous System
The Nervous System
Neurons (Nerve Cells)
Fundamental cellular units
of the central and the
peripheral nervous system
Receive, process and
transmit information/
chemical and electrical
signals
Dendrite
Receives information from other
neurons or the external environment
Cell body (soma)
Has typical cell components used for
cell maintenance
Axon
Transfers information to other
neurons
Axon terminal is where the synapse is located/ structure that
passes an electrical or chemical signal to another neuron
Sensory neurons (afferent) send impulses to the brain and
spinal cord
Motor neurons (efferent) send impulses from the brain
and spinal cord to the glands and muscles throughout the
body
Neuroglia/ Glial Cells / Glia
Ø  Nerve glue
Ø  Do not transfer any information
Ø  Provide metabolic support and protection for neurons
in the central and peripheral nervous systems
Ø  More numerous than neurons?
The Nervous System
Central nervous system
(CNS)/ Brain and spinal cord
Peripheral nervous system
(PNS)
Ø Bundles of nerve fibers or
axons that conduct information
to and from the central nervous
system
Ø Includes sensory neurons and
motor neurons
Central Nervous System (CNS)
Coordinates the actions of the voluntary muscles and the
conscious thought processes
The Brain
The Developing Brain
Ø By the age of six, 95% of the brain is formed
Ø A growth spurt in adolescence occurs in the frontal
cortex, where the “executive functions” of planning,
organization, and rational thinking are controlled
Ø By the early to mid 20s, a more mature adult brain
results
The Teenage Brain
Spinal Cord
The cylindrical bundle of
nerve fibers and associated
tissue that is enclosed in the
spine and connects nearly all
parts of the body to the brain
Meninges
Membrane covering the brain and the spinal cord
Peripheral Nervous System (PNS)
The peripheral
nervous system
consists of the nerves
that branch out from
the brain and spinal
cord
These nerves form
the communication
network between the
CNS and the body
parts
Peripheral Nervous System is divided into:
The somatic nervous system (SNS)/ voluntary activities
The autonomic (ANS) nervous system/ involuntary
activities
Sympathetic nerves prepare the body for stress
and action in times of emergency/ slowing
digestion, increasing heart rate, respiration and
blood pressure
Parasympathetic nerves restore the body’s
systems to normal once the emergency is over