1. Ashfah, Journey, Mohammed, Javon, Daniel, Ian- 740
The Nervous System
Ashfah, Journey, Mohammed, Javon, Daniel, Ian- 740

2. Definition
The nervous system is a complex system of nerves and cells which send signals to and from the brain and spinal cord, to the rest of the body.

3. Major Structures Functions
Brain
Spinal Cord
Nerves
Sense Organs
Maintain homeostasis
Regulate all other organ systems
Control senses and movement
Maintains involuntary responses to stimuli in living organisms
Sense Organs = Eyes, Nose, Ears, Mouth, Skin…
Stimuli: Something that can elicit or evoke a physiological response in a cell, a tissue, or an organism.

4. Neurons One of the most important parts of the brain and body.
Send and receive electro-chemical signals to and from the brain and nervous system.
They are the basic parts of the nervous system.
Each neuron is made of cells called dendrites and an axon.
Axon = long extension of the cell that transmits information from the cell to the brain
Dendrites transmit information to the neuron from the rest of the body

5. The Structure of a Neuron
Dendrites receive information in the form of nerve impulses from other neurons, and transmits that to the soma (cell body). If the electrical impulse toward the soma is powerful enough, it will generate an action potential.
The soma is where the nerve impulses (signals) are joined and passed on.
Then, the axon transmits the signal. They transmit information away from the cell body.
Terminal buttons located at the end of the neuron send the signal onto other neurons. At the end of the terminal button is a gap known as a synapse. Neurotransmitters are used to carry the signal across the synapse to other neurons.
Neurotransmitters: (as defined by psychology.about.com) “A chemical messenger that carries, boosts, and modulates signals between neurons and other cells in the body.”
Synapse: A small gap at the end of a neuron that allows a signal to pass from one neuron to the next.

7. When a neuron isn’t sending a signal, it is called “Resting Potential”
Action Potential
The part of the process that occurs during the firing of a neuron: Part of the neural membrane opens to let positively charged ions in and negatively charged ions out = Electrical nerve impulse is carried down the nerve through a series of action potentials. bb

8. Central Nervous System + Peripheral Nervous System
Nervous System = 2 Parts
Central Nervous System + Peripheral Nervous System

9. The Central Nervous System (CNS)
Brain:
The major control network for the body's functions and abilities
Enables conscious communication with our body and automatic operation of vital organs
Spinal Cord:
The spinal cord carries out two main functions:
It connects a large part of the peripheral nervous system to the brain.
Information (nerve impulses) reaching the spinal cord through sensory neurons are transmitted up into the brain.

10. The Peripheral Nervous System (PNS)
Sensory Nervous System -
Mainly controls conscious actions and sends signals to control touch the brain. It also controls skeletal muscle and external sensory organs (like skin).
Somatic Nervous System (division) -
Controls the sense of touch
Autonomic Nervous System -
Mainly controls involuntary muscles and actions
Sympathetic Nervous System (division) -
Controls activities that increase energy expenditures.
Parasympathetic Nervous System (division) -
Controls activities that conserve energy expenditures.

11. 2 Types of Cells (PNS): Carrying Info to CNS - Sensory Nervous Cells
Carrying Info from CNS - Motor Nervous Cells

12. Layout of autonomic nervous system

13. Reflex Arc
A nerve pathway in the body that connects certain muscle groups with others, without involving the brain. The relfex arc’s primary purpose is to control involuntary movement in reaction to some sort of stimuli. (ex.blushing, coughing,shivering,sneezing,etc.) bb

14. Diagram of the Reflex Arc
The reflex arc connects a sensory nerve and a motor nerve with only passing through a relay neuron(Interneuron) in between
An example of a knee reacting to the stimuli of being hit with a tendon hammer in the patellar tendon

15. More Vocabulary!!! Acetylcholine: The most common neurotransmitter
Cerebellum: The part of the brain involved with voluntary movement (highly important for doing day-to- day tasks)
Cerebrum: The largest part of the brain
Ganglia: A mass of nerve tissue outside the CNS
Medulla Oblongata: The part of the brain controlling involuntary actions
Mixed Nerve: A nerve containing both sensory and motor fibers
Energy expenditure: The amount of energy/calories a person needs to carry out a physical action/function