1. Nervous System

2. What is the Function of the Nervous System?
Controls all body functions through:
Controlling muscles
Coordinating activity of the organs
Enables senses to work properly
The Nervous System can be divided into 2 parts:
Central Nervous System (CNS)
Peripheral Nervous System (PNS)

3. Central Nervous System (CNS)
Made up of the brain and spinal cord
Brain = receive nerve impluses from spinal cord
Spinal cord = contains nerves that carry messages from the brain to the body.

4. Peripheral Nervous System (PNS)
Contains only nerves
These nerves connect the body to the spinal cord
There are two major subdivisions of the PNS:
Somatic Nervous System
Autonomic Nervous System

5. Somatic Nervous System
Controls voluntary body movements – or conscious movement
For example:
Action of skeletal muscle
Receiving external stimuli, which helps with sight, hearing, smell, etc.

6. Autonomic Nervous System
Controls involuntary body movements – or unconscious movement (body functions that you don’t have to think about)
Regulates functions such as:
Stomach, intestines, bladder
Heart rate
Breathing
Blood vessels
Muscles in the eyes

7. Autonomic Nervous System continued….
Can be divided into 2 systems:
Sympathetic Nervous System - involved in the fight or flight response; causes an “adrenaline rush”
Parasympathetic Nervous System - involved in relaxation. It is responsible for “rest and digest”.
Each of these subsystems operates in the opposite of the other (see picture on next slide)

9. That was a lot of information. Let’s review:
The nervous system can be divided into 2 systems. What are the names of these systems?
The ____________ is the brain and the spinal cord.
The ___________ is the other nerves.
The PNS can be further broken down into:
Which of these systems controls voluntary movement? And involuntary movement?
The autonomic nervous system can be divided into which 2 parts? What is the key function of each of these parts?

10. Organizational Chart of the Nervous System
Central Nervous System (CNS)
Autonomic Nervous System
Peripheral Nervous System (PNS)
Somatic Nervous System
Parasympathetic Nervous System
Sympathetic Nervous System

11. Structure of the Nervous System
The neuron is the functional unit of the nervous system.
Humans have about 100 billion neurons in their brain alone!
All neurons have three parts: the dendrite, cell body, and the axon.

12. The Structure of the Neuron
Dendrites - receive information from another cell and transmit the message to the cell body.
Cell body - contains the nucleus, mitochondria and other organelles typical of eukaryotic cells.
Axon - conducts messages away from the cell body.

13. 3 Types of Neurons
1. Sensory neurons - carry messages from sensory receptors to the central nervous system.
2. Motor neurons - transmit messages from the central nervous system to the muscles (or to glands).
3. Interneurons - are found only in the central nervous system where they connect neuron to neuron.
See picture on next slide

15. How do Neurons work?
Synapse - the junction between a nerve cell and another cell
Messages travel within the neuron as an electrical impulse.
Neurotransmitters are exchanged between neurons and the receiving cells
Neurotransmitters carry the “message” to the other cell.

17. A final review:
What type of neuron connects neuron to neuron and is only found in the CNS?
Interneuron
Neurotransmitter
Motor neuron
Sensory Neuron
What is the junction between a nerve cell and another cell called?
Synapse
Hormone
Dendrite

18. Review continued… What are the 3 parts of a neuron?
What is the function of each part?
What substance is responsible for carrying the message from the neuron to the receiving cell?
Synapse
Neurotransmitter
Neuron
Mitochondria