Download THE CONTROL SYSTEMS

THE CONTROL SYSTEMS
•NERVOUS
AND
ENDOCRINE
Introduction to nervous system
There are 3 main parts
to your Nervous System
1. Your Nerves
2. Your Brain
3. Your Spinal Cord
Your Nerves
Your nerves are made of
nerve cells called
neurons that transmit
messages.
They carry messages from
all parts of your body to
your spinal cord and
brain.
They carry messages
away from your spinal
cord and brain to all
parts of your body.
• Those nerve cells are called neurons.
• Size-wise, these cells are among the smallest cells in
your body, but can be the longest cells as well.
How can this be?
• Cell bodies are small, but axons can be really long.
neuron
Cell Body
Dendrites
Synapse
Axon
Class Activity- Neuron Model
Here's the most simple model of a neuron I can think of...and
you don't need any supplies.
It's your hand! Hold out your arm and spread your fingers.
Your hand represents the "cell body" your fingers
represent "dendrites" bringing information to the cell
body; your arm represents the "axon" taking information
away from the cell body.
• The message that is transmitted
through neurons is called an impulse.
• It enters the neuron through the
dendrite and is carried away from
the cell body through the axon.
• Why are there so many dendrites
entering a neuron?
• To receive messages from all
sides/other neurons
• Neurons don’t actually touch each other to transmit an impulse. The
impulse must move across a small space called a synapse in order to
move from one neuron to another.
• A chemical must be present in this space in order for the signal to be
transmitted
• The signal will always move in the same direction: from the axon of
one neuron to the dendrite of the next.
There are 3 types of neurons:
Type of Neuron
Location
Receives
from:
Sends
To:
Sensory
Neuron
Sense
organs
Stimuli
from
environme
nt/
Body
Brain or
spinal cord
(it’s a
receiver)
Interneuron
Spinal
cord
Sensory
neuron
Motor
neuron
(relays)
Motor neuron
Muscle or
gland
interneurons
Muscle or gland
(makes
something
happen)
• An automatic response to a stimulus is known as a reflex.
• Most reflexes cannot be controlled consciously
• Why is this a good thing?
• So that you don’t have to take time to think about it!
The path of an impulse when an object
moves toward your face and you blink in
response to the stimulus—Let’s say
someone throws a ball at you and it’s
coming toward your face:
The stimulus is the moving object, which
triggers a sensory neuron in the eye to
send a signal to the interneuron in the
spinal cord which then sends the impulse
to the motor neuron which is attached to a
muscle that makes the eye blink.
The Reflex:
interneuron
Sensory neuron
Motor neuron
Muscle
contracts
Spinal cord
• Central Nervous System: made up of
the brain and spinal cord
• Peripheral Nervous System: made up
of all nerves, including cranial and
spinal nerves
The Brain by Brainpop
Brain Clip
CEREBRUM
CEREBELLUM
BRAIN STEM
YOUR BRAIN HAS THREE PARTS:
Part
CEREBRUM
Function
•Divided into 2 hemispheres
•Interprets impulses from
senses
•Stores memories
•Controls voluntary muscles
The Brain & memory
YOUR BRAIN HAS THREE PARTS:
Part
Function
CEREBELLUM
•Coordinates voluntary muscle
movements.
•Maintains balance and muscle
tone
YOUR BRAIN HAS THREE PARTS:
Part
Function
•Connects brain to spinal cord
BRAIN STEM
•Controls heartbeat,
breathing, blood pressure,
coordinates muscle
movements.
Nerves by Brainpop
SPINAL CORD
• There are 31 pairs of spinal nerves—
• Some are called somatic and control skeletal
muscles
• Some are called autonomic and control
heartbeat, breathing, digestion, salivary
glands.
Spinal Cord by Brainpop
SPINAL CORD
• Is an extension of brain stem and is
considered part of the central nervous
system.
• Is made up of bundles of neurons.
• Is about as big around as an adult thumb.
• Is approximately 43 cm in length.
• Contains cerebrospinal fluid. Why?
• To cushion neurons in the spinal cord
The Endocrine System
•Glands of the endocrine system receive electrical
messages from the brain and release hormones
into the blood stream.
• Hormones carry a chemical signal to target
tissues.
• These chemical signals may be released slowly
over long periods of time or may affect a tissue
immediately and then slowly dissipate.
The Endocrine System
•
•
•
•
•
•
•
•
Regulates activities using chemical signals.
Hormones the chemical signals that affect
mood
growth
blood sugar regulation
metabolism
digestion
fight or flight response.