1. Nervous System
The Neuron is the basic unit of the nervous system. Commonly referred to as a “nerve.”
**Nucleus
**Cell body
**Schwann cells
**Nodes of Ranvier
**Dendrites
Bonus: label all parts with asterisk
**axon
**Axon terminals

2. The neurons connect the brain to the entire body and its parts
The neurons connect the brain to the entire body and its parts. But the neurons do not touch each other!
**Synaptic cleft or gap is the gap between neurons

3. Messages are sent from one neuron to the next via chemicals called Neurotransmitters. In this case, the message of pain is being transmitted by a neurotransmitter called “Substance P” **A Neurotransmitter is a chemical released by 1 neuron that has an effect on another neuron
Substance P
Pain
Receptor

4. Each Neuron has specific receptors for each neurotransmitter, which then relay the message through the axon of the neuron toward the axon terminal.

5. *During a nerve impulse, there is a reversal of polarity in the axon

6. Hmwk: p 1009 #1, 4

7. The Dendrites are the receiving end of the neuron and the axon terminal is the sending end
Receives information, carries to cell body
Cell body contains nucleus
***Axon is cell extension
(conducts action potential)
Transmits information away from cell body to the axon terminal
Cell has only 1 axon

8. If the message is being sent to a muscle to contract, the last axon terminal will end at a motor end plate of the target muscle/muscles. That message will stimulate the muscle to contract… This happens in a millisecond. That’s fast!

9. *Axons are covered with a lipid layer called the myelin sheath
***Myelin sheath increases the speed of nerve impulses or action potential

10. **Resting Potential
Resting cell membrane is more permeable to potassium ions than sodium ions
More positive charges leave the cell than enter it
***Sodium ions are more concentrated outside the cell
*Potassium ions are more concentrated inside the cell
*The inside of the cell is negatively charged
The outside of the cell is positively charged

11. ***Brain
*Visual information is processed by the occipital lobe in the brain
**Cerebral cortex is the outer layer of the cerebrum
*Cerebellum smoothes and coordinates movements like walking and running
*The brain stem connects the cerebral hemisphere with the cerebellum

12. **Diencephalon
*Contain important relay centers
Made up of the thalamus and hypothalamus

13. **Spinal Cord
Like an interstate, it carries information back and forth
The outer
Composed of a white matter (insulates)
The inner
Composed of **gray matter made up of
Dendrites, axons, cell bodies but **does not include motor neurons

14. There are three parts to the nervous system:
1. The Central Nervous System (CNS)
a) Brain
(includes cranial neurons-so that lobes of the brain can talk to each other)
b) Spinal Cord
(includes spinal neurons, which relay messages from the body’s extremities and internal organs to the spinal cord)

15. There are three parts to the nervous system
*The Central Nervous System (CNS)
*Is made up of the Brain and the spinal cord

16. 2. ***The Peripheral Nervous System (PNS)
*This connects the brain and spinal cord to the rest of the body
**Sensory receptor is a neuron that detects stimuli
* Two principal components of the peripheral nervous system are :
*Sensory
*Motor
**Includes Spinal Nerves (spinal cord = CNS)

17. *Somatic Nervous system part of the PNS
*Contains neurons that control skeletal muscle
**Afferent Neurons
Collect information from the body and transmit it toward the CNS
Includes neurons in the ear, **eyes (optic nerve)
Efferent Neurons
Transmit information away from the CNS.
**Included in the PNS:
Somatic system
Autonomic system
Sensory system

18. 3. **Autonomic Nervous System
Involuntary muscle contractions in digestive and cardiovascular systems.
This happens ”automatically!”
You do not have to think about it.
**A spinal reflex is an example of an involuntary movement

19. Autonomic nervous system has two parts:
*Sympathetic division
*In times of stress it is the sympathetic nervous system is activated
Parasympathetic division

20. Hmwk Pg 1015 #1,3, 4, 5

21. Sensory system
Sense organs
Eyes, ears, nose, mouth, and skin

22. **Hearing and Balance Auditory canal
Connect to external ear with tympanic membrane (eardrum)
**Tympanic membrane
**Vibrates in response to sound waves
Eustachian tube
Opening to throat
Equalizes pressure on both sides of the tympanic membrane

23. *Cochlea
Inner ear
*Coiled tube essential to hearing
**Contain hair cells are important for hearing and balance
*Semicircular canals
*Essential for balance

24. **Auditory information
**Travels to the brain stem  thalamus  cerebral cortex

25. Vision Retina Pupil Iris Lens Rods Cones
Light sensitive inner layer of eye
Receives image formed by lens
Transmits them through optic nerve to the brain
Pupil
Opening at center of iris
Controls amount of light that enters the eye
Iris
Colored circular part of eye
Lens
Convex transparent structure in the eye that focuses light on retina
Rods
Detects dim light
Plays major role in non-color and night vision
Cones
Distinguishes color
Sensitive to bright light
Bonus: Rods detect dim light. Impt for night vision
Cones distinguishes color, sensitive to bright light

26. *Photoreceptors in the retina convert light energy to electrical signals

27. Taste and Smell
Pressure and Temperature