What is it and how does it work???. The nervous system consists of the brain, spinal cord, sensory...
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What is it and how does it work???. The nervous system consists of the brain, spinal cord, sensory organs, and all of the nerves that connect these organs
The nervous system consists of the brain, spinal cord, sensory
organs, and all of the nerves that connect these organs with the
rest of the body. Together, these organs are responsible for the
control of the body and communication among its parts.
Slide 3
The nervous system is divided into the CNS and the PNS. 1. CNS
(Central Nervous System) which is the brain and spinal cord 2. PNS
(Peripheral Nervous System) which consists of all of the nerves
that lie outside of the CNS
Slide 4
Central Nervous System The brain and spinal cord form the
control center known as the central nervous system (CNS), where
information is evaluated and decisions made.
Slide 5
Peripheral Nervous System (PNS) The sensory nerves (neurons)
and sense organs of the peripheral nervous system (PNS) monitor
conditions inside and outside of the body and send this information
to the CNS. Motor neurons in the PNS carry signals from the control
center to the muscles, glands, and organs to regulate their
functions.
Slide 6
Center of the nervous system Coordinates all of the bodys
activities Most complex organ in the human body Made of
approximately 100 billion nerve cells (neurons) Three major parts
are the cerebrum, cerebellum, and brain stem Cerebrum: higher brain
functions, interpreting sensory impulses, and initiating muscle
movements; stores information Cerebellum: helps to control motor
functions such as balance, posture, and coordination of complex
muscle activities Medulla: processes involuntary body functions
related to homeostasis; monitors blood pressure and oxygen levels
and regulates heart rate, controls the rate of breathing, vomiting,
sneezing, coughing, and swallowing reflexes BRAIN
Slide 7
Slide 8
*How do messages from the brain reach all parts of the body?
*How do messages from all parts of the body reach the brain? NERVE
CELLS ARE CALLED NEURONS!!!
Slide 9
The messages are carried through electrical and chemical
signals. The messages can travel at slightly different rates but
some have been recorded to travel up to 250 mph (366.7 feet per
second)!!! (Messages to muscles for coordination are some of the
fastest while those for pain are some of the slowest) How a Neuron
Fires (video) http://www.youtube.com/watch?v=C4Gt322-XxI
Slide 10
How does your body/brain know what to react to in order to
maintain homeostasis? The nervous system maintains homeostasis by
controlling and regulating the other parts of the body. A deviation
from a normal set point acts as a stimulus to a receptor, which
sends nerve impulses to a regulating center in the brain. The brain
sends information to act in such a way that a response to the
stimulus occurs. (Hmmmrespond to stimuli, adapt to changes, we have
heard this beforethink, characteristics of living things) Example:
receptors throughout the body are constantly sensing temperature,
if the temperature deviates away from the average 98.6 F, neurons
take the information to the hypothalamus in the brain and the
information is interpreted, then a response in sent to parts of the
body to react in a specific way was a lowering of body temperature,
the effector acts to increase body temperature.
Slide 11
What helps the brain receive information from outside the body?
The sensory organs (the five senses). SightHearingTouch Taste
Smell
Slide 12
Reflex vs. Reaction Reaction is voluntary while reflex is
involuntary Reaction takes place through sensory nerves that bring
back messages from the brain to the motor nerve. In a reflex
reaction, sensory nerves bypass the brain and go up to the spinal
cord. This is why a reflex is faster than a reaction. Reflex
Examples
Slide 13
NERVOUS SYSTEM FUN FACTS - There are more nerve cells in the
human brain than there are stars in the Milky Way. - If we lined up
all the neurons in our body it would be around 600 miles long. - A
newborn baby's brain grows almost 3 times during the course of its
first year. - The left side of human brain controls the right side
of the body and the right side of the brain controls the left side
of the body. - A new born baby loses about half of their nerve
cells before they are born. - As we get older, the brain loses
almost one gram per year. - There are about 13, 500,00 neurons in
the human spinal cord.