1. The Nervous System

2. The Nervous System has 3 Major Functions
Receives information about the other parts of the body
Interprets the information it receives
Makes the body respond to this information

3. Basic Tasks of the Nervous System
Sensory Input: Monitor both external and internal environments.
Integration: Process the information and often integrate it with stored information.
Motor output: If necessary, signal effector organs to make an appropriate response.

4. Electrical impulses are carried throughout the body by nerves.
Structure of a Neuron
The neuron is the basic unit of nervous system
Electrical impulses are carried throughout the body by nerves.
dendrites
are small extensions surrounding the cell body
which receive impulses ( mm long)
Axon
Is the longest part of the neuron which propagates the impulse
Away from the cell body (0.5mm to 1m long)

5. The neurons are the only cells that react to a
Stimulus
A stimulus is a change in the environment that results in nerve excitation.
Example: sun shining in your eyes
or hearing a sound

6. Basic Parts of Neurons
Cell body- largest part, contains nucleus and cytoplasm, directs the action of the cell
Axon- long thin fiber (can be coated with myelin) extends from cell body and carries these messages away from the cell’s body
Dendrites- network of tiny branches
When the impulses reach the end of the axon, they come to a small space called a synapse

7. NEURON STRUCTURE

8. TYPES of NEURONS
A neuron carries information from one location to another
Sensory neurons
Pick up information from the environment
Transmit impulses to the spinal cord & brain from all parts of the body
Motor neurons
Transmit impulses away from the brain and spinal cord to muscle & glandular tissue

9. Neural Impulse
Self-propagating wave of electrical disturbance that travels along the surface of a neuron’s membrane
Neurotransmitters transport messages across synapse
More detailed than needed

10. Only one direction of message for each nerve

11. Neurotransmitter released in synapse
Impulse transmitted to next neuron

12. The Central Nervous System is made of the brain and the spinal cord.

13. The BRAIN The brain controls everything in the body.
The brain is made of more than 10 billion neurons and is the biggest part of the central nervous system!

14. Parts of the BRAIN The Brain has three main parts… 1. The Cerebrum
2. The Cerebellum
3. Medulla oblongata
(The Brain Stem)

15. The Cerebrum
The Cerebrum is the largest part of the brain. The cerebrum controls your:
1. thinking.
2. memory.
3 speaking.
4. movement and identifies the information gathered by your sense organs.

17. * The cerebellum is below and to the back of the cerebrum.
The cerebellum controls your
balance and posture.

18. Medulla Oblongata (brain stem)
The Medulla (Brain Stem) connects the brain to the spinal cord.
The nerves in the brain stem control your heartbeat, breathing, and blood pressure.
Responsible for certain reflexes : coughing, swallowing, hiccups, vomiting and sneezing

19. The Spinal Cord
The spinal cord is the part of the nervous system that connects the brain to the rest of the nervous system.
The spinal cord sends messages to and from the brain.

20. The spinal cord is protected by small bones called vertebrae

21. The Peripheral nervous system
Consists of all the nerves that leave the spinal cord or brain reaching all parts of the body and vice-versa.
It has 2 types of nerves
Sensory nerves – sending info to CNS
Motor nerves – sending info to muscles
Cranial and spinal nerves

22. Nerves Contain only part of the neuron (the axon)
motor nerves contain the axons of motor neurons
Sensory nerves contain the axons of sensory neurons

23. The involuntary system (Autonomic)
The medulla oblongata controls this system. The body’s activities that you don’t think about like:
activities in your small intestine, breathing, the constriction and dilation of blood vessels
functioning of organs, liver, kidneys and glands
controls

24. The voluntary system (Somatic system)
This system controls the skeletal muscles
Responsible for the conscious control of our movement
Signals from the brain effectuate contractions of the muscles

25. Reflex
is an involuntary automatic reaction that happens without thinking about it.
A reflex happens quickly in less than a second.

27. The brain is not involved in a reflex.
Sensory Receptor
(responds to a stimulus by
producing a impulse)
Sensory Neuron
(axon conducts impulse)
Integrating Center
(Relay impulse from
sensory to motor neurons)
Motor Neuron
(axon conducts impulse
to effector)
Effector
(muscle that responds to
A motor nerve impulse)

28. Here we have a case of
“ Brainus peanutii minimalis”

30. "Funny Bone"
The “funny bone” is the only place on the arm where the nerve is not protected.
Jamming the Ulnar nerve against the bone causes pins and needles