PowerPoint Presentation
The Nervous SystemLesson 5: Standard 9b. Students know how the
nervous system mediates communication between different parts of
the body and the bodys interactions with the environment. Standard
9d. Students know the functions of the nervous system and the role
of neurons in transmitting electrochemical impulses.
The Nervous SystemConsists of the brain, spinal cord, and
peripheral nervesControls and coordinates functions throughout the
body and responds to internal and external stimuliHelps maintain
homeostasis in the body through feedback loops
The Central Nervous System (CNS)Consists of the brain and spinal
cordBoth the brain and spinal cord are wrapped in a membrane called
the meningesMeningitis is caused by a bacterial infection that
causes the meninges to swell. It can be fatal. There IS a vaccine
for meningitis.Between the meninges and the CNS, there is a liquid
called cerebrospinal fluid that cushions the CNS and acts as a
shock absorber. It also allows for the exchange of nutrients and
waste between the brain and the blood.
The BrainThe place nerve impulses flow to and originate fromThe
cerebrum is the largest area of the brain and is the site of
learning, intelligence, and judgment. It is divided into two
hemispheres that are connected by a band of tissue called the
corpus callosum.The cerebellum is the second largest region of the
brain. It is responsible for coordinating and balancing the bodys
movementsThe brain stem is below the cerebellum. It connects the
brain to the spinal cord. It consists of the pons and the medulla
oblongata. It regulates the flow of information from the brain to
the rest of the body. Blood pressure, heart rate, and breathing are
controlled by the brain stem.The thalamus & hypothalamus are
found between the brain stem and the spinal cord. They receive
messages from the body and recognize hunger, thirst, anger,
fatigue, and body temperature.
The Spinal CordThe spinal cord is like a telephone wire it is
the main communication link between the brain and the body. it
transmits nerve impulses from brain to body The spinal nerves
branch out, connecting to the rest of the body. This is where the
chicken pox virus, varicella-zoster, likes to hide out and be
dormant after an infection. If you had the chicken pox as a child,
you might get shingles as an adult.some reflexes are processed in
the spinal cord
The Peripheral Nervous SystemConsists of all of the nerves that
are not part of the brain and spinal cordThe sensory division
transmits nerve impulses from sense organs to the CNSThe motor
division transmits impulses from CNS to muscles or glandsThe motor
division is further divided into the somatic and autonomic nervous
systems.The somatic nervous system regulates voluntary movementsThe
autonomic nervous system regulates involuntary movements
NeuronsNeurons are the specialized cells of the nervous
systemMost neurons have an axon, cell body, and dendritesNeurons
transmit information via electrical impulses
Neurons (continued)The cell body is the largest part of the
neuron. This is where the nucleus and most of the cytoplasm is.The
dendrites are short branches that carry impulses from the
environment or from other neurons toward the cell body The axon is
a long fiber that carries impulses away from the cell body. It is
covered in a fatty myelin sheath that insulates and protects
it.
Types of NeuronsMotor neurons carry impulses from the brain and
spinal cord to the muscles and glandsSensory neurons carry impulses
from the sense organs to the spinal cord and brainInterneurons
connect sensory and motor neurons and transmit impulses between
them.
Nerve ImpulsesDuring the video, answer the questions in your
notes.
The SynapseAt the end of a neuron, there is an axon terminal.
Usually, the neuron makes contact with another cell here. This is
where impulses are transmitted from one neuron to the next.The
synapse is the place where a neuron can transmit its impulse to
another cellThe terminals contain tiny sacs of neurotransmitters,
chemicals that are used to transmit an impulse across a synapse to
another cell