1. Functions of the Nervous System
A network of _______ of nerve cells linked together in a highly organized fashion to form the rapid ______ center of the body.
Functions include:
Integrating center for __________, movement, and almost all other body ___________.
The mysterious source of those traits that we think of as setting humans apart from animals

2. Basic Functions of the Nervous System
Sensation
Monitors changes/events occurring in and outside the body. Such changes are known as _________and the cells that monitor them are ___________.
________________
The parallel processing and interpretation of sensory information to determine the appropriate response
Reaction
Motor output.
The activation of muscles or glands (typically via the release of _______________________ (NTs))

3. Nervous Tissue Highly Cellular Two types: ____________
Functional, signal conducting cells
Supporting cells

4. Neurons The functional and structural unit of the ____________ system
Specialized to ___________ information from one part of the body to another
Most contain the following:
Cell body (__________)
One or more specialized, slender processes (_______________)
An input region (______________)
A conducting component (________)
A secretory (output) region (________ __________)

5. Neurons ___________ _______________
Contains __________ plus most normal organelles
Responsible for producing _________ and secreations needed for communication
_______________
Thin, branched processes whose main function is to receive incoming _______.
increase the surface area of a neuron to increase its ability to communicate with other neurons

6. Neurons ___________ Most neurons have a _______ axon
a long (up to 1m) process designed to convey info away from the cell body
Originates from a special region of the cell body called the ______ ________
Transmit signals from the soma toward the end of the axon where they cause neurotransmitter release
Often branch sparsely, forming ________________.
Each collateral ends in a ________ ________, which contains _______ _____________ – membranous bags of neurotransmitters.

7. Axons
Surrounded by a ____________ _____________, a wrapping of lipid which:
Protects the axon and electrically isolates it
________________ the rate of signal transmission
The myelin sheath is made by ________________ for nerves found in the brain and spinal cord and by ___________ ________ for nerves found outside brain and spinal cord
This wrapping is never complete. Interspersed along the axon are gaps where there is no myelin – these are ________ ___ __________.

8. Neuroglia Outnumber neurons by about ________ to 1
6 types of supporting cells
1. ________________
Star-shaped, abundant, and versatile
Maintain the chemical _____________ of neurons (i.e. K+)
Involved in the formation of the blood brain barrier
Control the types of materials that pass from blood to neurons

9. Neuroglia _____________ ___________________ Specialized immune cells
Carries out ________________
Repairs nerve cell damage
Basis of many nervous system disorders
___________________
Line the cavities of the brain and spinal cord
Produces _______________ fluid (bathes, nourishes and protects)
Have cilia to help circulate cerebrospinal fluid

10. Neuroglia 4. _____________________ 5. _________________
4. _____________________
Form an insulating cover called the _________ _________ for neurons found in the brain and spinal cord
Helps the transmission of stimuli along the axon
5. _________________
Found in the ______________ nervous system
Provides a framework for neurons to create connections

11. Neuroglia 6. __________________ 7. _________________
Small cells that cover the surface of neurons of the brain and spinal cord
Maintain _________ environment and assist in nerve cell repair
7. _________________
Form __________ _________ around nerves located outside of the brain and spinal cord
Gaps between Schwann cells are called _______ ___ _________

12. Communication Begins with the _____________ of a neuron.
One neuron may be stimulated by another, by a __________ cell, or even by some physical event such as pressure.
Different types neurons include:
Sensory neurons (________)- provide info about internal and external environment
Association neurons (_________)- integrate information and send commands
Motor neurons (____________)- synapse with muscles or glands

13. Communication
Thus, neurons need to be able to conduct information in 2 ways:
From one end of a neuron to the other end.
- Accomplished with __________ using action potentials
Across the minute space (_________) separating one neuron from another.
- Accomplished using chemicals via ____________________

14. Resting Potential
Chemically unstable condition in which the neuron is highly polarized (charge inside the cell is __________ millivolts)
This is due to the Na+/K- pump which keeps a higher concentration of sodium ions __________ of the cell than on the __________ of the cell
Changes in mV allow for the generation of ________ potentials and thus informative intercellular communication

15. Action Potential
Is a chain reaction that causes the neuron to lose its ___________ potential
It is the _____________ signal that rapidly travels the along the axon
Its started by an influx of ________ ions into the neuron
The action potential takes place as follows:

16. Action Potential
__________ receive stimulus causing the sodium channels to open and allowing Na+ to rapidly enter cell.
If enough channels open the cytoplasm's charge will reach __________ mV
The cell now reaches its _____________
A threshold must be obtained for the action potential to travel (___________) across the cell membrane

17. Action Potential
2. At threshold, many more Na+ channels open causing the charge of the cytoplasm to ______ mV.
The cell is now in ___________ (has lost its resting potential -70mV)
3. Depolarization continues down length of axon producing AP propagation down the axon to the ____________

18. Action Potential
4. Sodium channels close/___________ channels to leave the cell open causing positive charges
Loss of positive charges inside causes cell to become more negatively charged which is called ____________
5. ______________________ is the event where repolarization goes beyond the resting potential to a charge of ________mV and has 2 purposes:
1. __________ ______________- prevents the neuron from receiving another stimulus during repolariazation
2. Prevents AP from traveling in the opposite direction

19. Action Potential
6. ___________ phase- Na+/K- pumps work to return cell to _________ potential by pumping out Na+ and in K-
7. The cell will remain in the refractory period and cannot ____________ with another cell until recovery phase is complete

20. Action Potential Conduction
The manner and speed in which it travels depends on whether the neuron is ____________ or __________.
Unmylinated axons
Slow (5 to _______ m/sec)
The wave of de- and repolarization simply travels from one patch of membrane to the next adjacent patch. (like falling ___________)
Mylinated axons
Fast (10 to _______ m/sec)
Depolarization occurs only in the _________ (nodes of Ranvier) which decreases the total area of membrane that depolarized
AP __________ from node to node

21. Chemical Signals
One neuron will transmit info to another neuron or to a -_________ or gland cell by releasing chemicals called ________________.
The site of this chemical interplay is known as the ______________.
An axon terminal (_________ _________) will abut another cell, a neuron, muscle fiber, or gland cell.
This is the site of _______________ – the conversion of an electrical signal into a chemical signal.

22. Synaptic Transmission
An AP reaches the axon terminal of the ____________ cell and causes Voltage-gated _______ channels to open.
Ca2+ rushes in, binds to regulatory proteins & initiates NT ____________.
NTs diffuse across the synaptic cleft and then bind to receptors on the ______________ membrane and initiate some sort of response on the postsynaptic cell.

23. Effects of Neurotransmitters
Different neurons can contain different ________________
Different postsynaptic cells may contain different _______________
There are two types of neurotransmitters:
___________- helps the post-synaptic cell reach threshold, making it more likely to produce an AP (i.e. catecholamines, acetylcholine)
_____________- make it more difficult for a neuron to produce an action potential (i.e. serotonin)

24. Reflexes
A ________ is a rapid, predictable motor response to a stimulus. Unlearned and _____________.
Reflexes involving skeletal muscles and somatic motor neurons are _________. (i.e. knee-jerk, balance, ducking)
Reflexes controlled by autonomic neurons are ____________. (i.e. urinating, vomiting, sneezing, breathing)
Spinal reflexes are integrated within the spinal cord while cranial reflexes are integrated in the brain.
Reflexes may be inborn or learned.