Microscope | Mitosis
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BIO 201 Home | Saundra Minckley
Central Nervous System
The nervous system is composed of the Central Nervous system-CNS (brain & spinal cord) and the Peripheral Nervous system-PNS (all neural tissue outside these organs). All neural tissue is made up of neurons (nerve cells). Sensory information from both the external and internal environment is transported to the CNS via afferent neurons. The CNS will integrate the information and determine what response is necessary. Motor information (responses to the various stimuli of our environments) is transported to the effector organs (muscles and/or glands) via efferent neurons. Neurons have three (3) major parts: the dendrite/s (extensions bringing information towards the cell body); the soma or cell body (integration of information and contains the nucleus) and the axon (extension taking information away from the cell body). The axon has the ability to stimulate other neurons, muscles or glands. Axons may also be myelinated. The myelin sheath acts as a form of protection and aids in speeding up the transportation of information via a process called saltation (see your textbook for definition)..
The images below are linked thumbnails. Click on
them for a larger version.
 External brain model. |
 Saggital View Brain (a) |
 Meninges |
 Sagittal View Brain (b) |
 Insula (a) |
Insula (b) |
 Spinal Cord |
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 Terminal End Bulb |
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 Cow's eye (anterior view) |
 Cow's eye (posterior view) |
 Cow's eye (anterior chamber) |
 Cow's eye (posterior chamber) |
 Human brain-1 |
 Human brain-2 |
 Human brain-3 |
 Human brain-4 |
 External eye model. |
 Eye (posterior chamber) |
 Closeup internal eye. |
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 Ear. |
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 Cochlea. |
 Tympanic membrane. |