Download Nervous System (1)

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Regulation
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The coordination and control of the various life
activities within an organism.
The ability to detect changes in the environment
(stimuli) and respond to them.
Is the essential to maintain stability
(homeostasis)
Regulation can be achieved through either
Nervous control or chemical control.
Nerve Control:
•Works via the Nervous System.
•Depends on nerve cells called Neurons
•Uses electrical signals called impulses.
•Works Quickly over a Short Duration
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Chemical Control:
•Works via the Endocrine System
•Uses chemical signals called Hormones
•Works Slowly over a Long Duration
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Chemical and Nervous Control
Both Work to :
Control_____________________________
and Coordinate the body’s responses
Growth and Development
_____________________________
_____________________________
Reproduction
IMPORTANT VOCABULARY
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1. Stimulus - a change in an organism’s
internal or external environment that
initiates a response.
2. Receptors - structures specialized in
detecting stimuli
Ex. sense organs - eye, ear,
nose, tongue, skin.
3. Effectors - organs that produce responses to
stimuli
Ex. muscles or glands
IMPORTANT VOCABULARY CONTINUED
4. Response – reaction to stimuli
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5. Impulse- an electrochemical charge generated
along a neuron
6. Neuron - Cell adapted for receiving and
transmitting impulses.
THE NEURON:
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Nervous Control depends mainly on nerve cells called:
Neurons
_____________________
THE NEURON:
There are 8 essential components of a neuron.
1. Dendrites
3. Cyton
2. Nucleus
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Dendrites - fibers of the cell body which receive impulses
2.
Nucleus – organelle that houses genetic information
3.
Cyton - cell body that contains a nucleus
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THE NEURON:
There are 8 essential components of a neuron.
4. Axon
5. Myelin
4.
Axon: The fiber responsible for transmitting the impulse away from the cell
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body.
5.
Myelin – a thin layer of insulation which helps conduct the impulse faster
THE NEURON:
There are 8 essential components of a neuron.
Neurotransmitters
Synapse
Terminal
Branches
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Terminal Branch: At the end of the axon. Responsible for secreting
neurotransmitters.
7.
Synapse: junction between adjacent neurons or between neurons and effectors
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8.
Neurotransmitter: A chemical which is released into the synapse for
communication.
ex) Acetylcholine
HOW DO NEURONS TRANSMIT SIGNALS?
4. The terminal branches then TRANSMIT
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1. A stimulus is
the signal into the synapse via
SENSED by the
Dendrites.
neurotransmitters.
5. The effector then
senses the
neurotransmitter
and produces a
RESPONSE
3. The impulse is then
CONDUCTED down the
2. The Stimulus is
length of the axon to the
RECEIVED by cell body
terminal branches
via an impulse.
There are THREE types of Neurons
1. Sensory Neurons – transmits impulses from
receptors to the brain and spinal cord
a. Sense organs - are structures where
sensory neurons are concentrated
Ex. eyes, ears, nose, skin, tongue
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There are THREE types of Neurons
2. Motor neurons – transmit impulses from the
Central Nervous System (CNS) to muscles or
glands (effectors).
3. Interneurons – relay impulses between
sensory and motor neurons.
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The Nervous System is
Comprised of Two Subdivisions:
The Central Nervous System
The Peripheral Nervous System
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The Nervous System is
Comprised of Two Subdivisions:
The Central Nervous System includes the:
Brain and the Spinal Chord
CEREBRUM
CEREBELLUM
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A. Cerebrum – largest region (85% of brain)
- control of voluntary activities
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- sensory impulses are interpreted
- memory, thinking, and reasoning occur
- motor activities initiated
B. Cerebellum
- Coordinates muscle activity for smooth
muscle movements
- maintains balance, equilibrium and
posture
C. Medulla
Controls involuntary activities such as breathing,
heartbeat, blood pressure and peristalsis
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2. Spinal Cord - lies within and is protected by
the vertebrae of the spinal column.
a. Coordinates activities between the
brain and other body structures
b. It is the center for both inborn and
involuntary reflex actions
Reflex Arc - pathway in which reflexes travel
Reflex Arc - pathway in which reflexes travel
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Spinal cord
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Inter
Neuron
Sensory
Neuron
Receptor
Stimulus
Motor
Neuron
Muscle
(effector)
Reflex Arc includes (in order) :
Receptor
Sensory neuron
Interneuron in spinal cord
Motor neuron
Effector
V. Peripheral Nervous System
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Consists of all nerves
Extending throughout
the body, outside the CNS
The PNS is made up of two subdivisions
1. Somatic Nervous System - Nerves that
control voluntary muscles of the skeleton
2. Autonomic Nervous System - Nerves that
control cardiac muscle, glands, peristalsis etc.
(Considered to be an involuntary system)
Malfunctions of the Nervous System
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1. Cerebral Palsy - a group of congenital disease
characterized by a disturbance of the motor
functions
2. Meningitis - Infection of the membranes
(meninges) surrounding the brain, and or spinal
cord
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3. Stroke - caused by a cerebral hemorrhage or a
blood clot in a cerebral vessel which may result
in brain damage
4. Polio - viral disease of the CNS which may result
in paralysis, and is preventable through
immunization.
The Neuron
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CELL BODY (CYTON)
NUCLEUS
DENDRITES
AXON
NODE OF
RANVIER
TERMINAL
BRANCHES
SCHWANN CELL
NUCLEUS
MYELIN
SCHWANN CELL
TERMINAL
KNOBS