Download - Chapter 48 - Neurons, Synapses and Signaling
![Page 1: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/1.jpg)
Chapter 48 - Neurons, Synapses
and Signaling
By: Sam Biller + Ryan Coughlin
![Page 2: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/2.jpg)
Overview of Neurons • Neurons are nerve cells that transfer
information within the body.• The structure of Neurons allows them to
use pulses of electrical current to receive, transmit, and regulate the flow of information over long distances. • Neurons transmit sensory information,
control heart rate, coordinate hand and eye movement, record memories, generate dreams and more.
![Page 3: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/3.jpg)
![Page 4: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/4.jpg)
Neuron Organization and Structure:Cnidaria - Sea Anemone• Movements used
by a net of nerves• No Brain or
Nervous System• Cnidarians detect
and respond to stimuli from all directions. Sensing objects by touch.
![Page 5: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/5.jpg)
Neuron Organization and Structure:Annelida - Segmented Worm• No brain, have a ganglionic mass • Bundle of nerves
runningdown body• Branches into other
bundles• Sensory organs on
skin
![Page 6: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/6.jpg)
Neuron Organization and Structure:Arthropoda - Crustaceans• Very similar tothe annelidas.• Have a brain thatbraches off into nerve
bundles and cord• These each have a specific function
![Page 7: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/7.jpg)
Neuron Organization and Structure:Mammalian - Humans• Bigger more complexbrain• Nerves branched allover body• Messages travel from brain along nerves • Electric signals traveldown the neurons
![Page 8: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/8.jpg)
Action Potential
The Sodium and Potassium channels are closed.
![Page 9: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/9.jpg)
• A reduction in the magnitude of the membrane potential is called a depolarization. • Sodium Channels in a resting neuron to open, membrane's
permeability to Sodium Ions increases.
![Page 10: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/10.jpg)
• After the Membrane has been crossed the positive and negative feedback switch along the membrane because of the Sodium Ions positive charge.• Potassium Channels remain closed.
![Page 11: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/11.jpg)
• Sodium Channels become inactivated blocking the sodium ions flow.• Most Potassium Channels become open switching the positive
and negative feedback back to normal.
![Page 12: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/12.jpg)
• The Sodium Channels remain closed, but are unblocked.• Some Potassium remain open causing the membrane's
permeability to potassium ions to be higher than at rest.• As the Potassium channels begin to close and sodium
channels remain closed the membrane returns to its resting state.
![Page 13: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/13.jpg)
![Page 14: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/14.jpg)
Neurons communicate with other cells at Synapses• Action potentials are not transmitted from
neurons to other cells.
• Transmission does occur at the synapses.
• Electrical and Chemical Synapses transmit information to other cells.
![Page 15: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/15.jpg)
Electrical Synapses• Allows the electrical current to flow directly
from one neuron to the other.• Vertebrates and Invertebrates, electrical
synapses synchronize the activity of neurons for rapid behaviors. • Electrical Synapses take place in the
vertebrate brain.
![Page 16: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/16.jpg)
Electrical Synapses
![Page 17: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/17.jpg)
Chemical Synapses
![Page 18: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/18.jpg)
Chemical Synapses continued...1. The action potential arrives in the
presynaptic membrane depolarizing it.
![Page 19: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/19.jpg)
Chemical Synapses continued...2. Depolarization opens voltage-gated channels,
triggering Ca2+ in the membrane.
![Page 20: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/20.jpg)
Chemical Synapses continued...
3. Increased Ca2+ concentration causes the synaptic vesicles to fuse with the presynaptic membrane, releasing the neurotransmitters into the synaptic cleft.
![Page 21: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/21.jpg)
Chemical Synapses Continued...
4. The neurotransmitters then bind to the ligand-gated ion channels in the postsynaptic membrane which binding triggers opening, allowing Sodium and Potassium to diffuse through.
![Page 22: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/22.jpg)
Chemical Synapses Continued...• Neurotransmitter is not part of the ion
channel• Neurotransmitter binds to metabotropic
receptor• Activates a signal transduction pathway in
the postsynaptic membrane involving a second messenger
![Page 23: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/23.jpg)
Neurotransmitters 100 different types Acetylcholine – Amino Acids Biogenic Amines Neuropeptides Gases
![Page 24: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/24.jpg)
DiseasesMotor Neuron Diseases (MND) - destroy neuron cells which are important in health and everyday life and functioning.MND controls: voluntary muscle actions, such as swallowing, breathing, speaking, talking, hand gestures, and walking.Examples of Diseases:
Amyotrophic lateral sclerosis (ALS or Lou Gehrig’s Disease)
Progressive Muscular Atrophy - Causes Weaknesses in the hands and the lower body.
![Page 25: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/25.jpg)
Diseases Epilepsy – a brain disorder in which a bunch
of nerve cells start to signal abnormally When the signals happen so fast,
sometimes as quick as 500 times per second, a person has a seizure.
![Page 26: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/26.jpg)
![Page 27: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/27.jpg)
Diseases Continued...
There is no cure for Neuron related diseases.
There is no cause for Neuron related diseases, but some are inherited.
![Page 28: Chapter 48 - Neurons, Synapses and Signaling](https://reader036.vdocuments.net/reader036/viewer/2022081507/56816616550346895dd962e1/html5/thumbnails/28.jpg)
Work Cited• "Motor Neuron Diseases." - Symptoms, Causes, Treatments.
Web. 25 Mar. 2012. <http://www.localhealth.com/article/motor-neuron-diseases>.
• Reece, Jane B., and Neil A. Campbell. Biology. Boston, MA: Cummings, 2011. Print.
• "Google Images." Google Images. Web. 25 Mar. 2012. <http://images.google.com/>.
“MedicineNet.com.”MedicineNet. Web. 25 Mar.2012.<http://www.medicinenet.com/sizure/article.htm.