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Kaelyn Bildsten Pat Ladue Brooke Gainer The supportive tissue of the nervous system including the network of branched cells in the central nervous system Neuroglia cells also maintain homeostasis and form myelin Neural support cell that forms the epithelial lining of the ventricle in the brain and the central canal of the spinal cord. Gives rise to the epithelial layer around the choroid plexus. Glue between neurons, providing structural and metabolic support Provides nutrients to the nervous tissue Maintains extracellular ion balance Plays a principal role in repair and scarring of the brain and spinal cord Astroclasts maintain the blood-brain barrier Regulates nutrients and dissolved gas concentrate Absorb and recycle neurotransmitters Form scar tissue after bodily injury Surround and insulate the long fibers (the axons) through which the nerves send their electrical messages. Form the insulation of the axons exclusively in the CNS Structural organization by tying clusters of neurons together Forms myelin sheath that surrounds axons structural framework Protects axons from subsequent injury: implications for deficits in multiple sclerosis Produced by Schwann cells Acts as insulation to increase the rate of transmission of signals Protects of the nerve fiber Formed of protein If an axon is severed, the myelin sheath allows the axon to grow back along the sheath, allowing the axon to return to normal Unmyelinated axons do not regenerate Part of the axon that is myelinated Internodes consist of an axon or multiple axons surrounded by a Schwann cell Located between myelinated segments Nodes exist between each Schwann cell along myelinated axons Nodes of Ranvier Regions dominated by myelinated axons Myelin has high fat content which cause it to look white Contains unmyelinated axons Makes up a major part of the brain Remove cell debris, waste, and pathogens by phagocytosis Resident macrohages of the brain and spinal column Brain and spinal column considered immune privileged organs because they are seperated by the blood-brain barrier Clustered in masses called ganglia Satellite cells surround neuron cell bodies in ganglia Schwann cells form a sheath around every peripheral axon Schwann cells also enclose segments of several unmyelinated axons Oligodendrocyte. (2010). In Encyclopædia Britannica. Retrieved February 03, 2010, from Encyclopædia Britannica Online: http://www.britannica.com/EBchecked/topic/427597/oligodendrocyte Ependymal cell. (2010). In Encyclopædia Britannica. Retrieved February 03, 2010, from Encyclopædia Britannica Online: http://www.britannica.com/EBchecked/topic/189483/ependymal-cell Astrocytes help separate man from mouse. (n.d.). Physorg. Retrieved February 3, 2010, from Physorg.com website: http://www.physorg.com/news157036357.html Baumann, N., & Pham-Dinh, D. (n.d.). Biology of Oligodendrocyte and Myelin in the Mammalian Central Nervous System . In Physiological Reviews. Retrieved February 3, 2010, from American Physiological Society website: http://physrev.physiology.org/cgi/content/full/81/2/871 Neuroglia. (n.d.). The Free Dictionary [Dictionary Entry]. Retrieved February 3, 2010, from http://medical-dictionary.thefreedictionary.com/neuroglia Neuroscience For Kids. (n.d.). Retrieved February 3, 2010, from The Society for Neuroscience website: http://faculty.washington.edu/chudler/bbb.html Ion Movement next The Transmembrane Potential 1. Passive Forces Acting across the Membrane Chemical Gradients Also known as concentration Gradients Intracellular potassium ion concentration is high which causes ions to move out of the cell Sodium ions drive ions into the cell Chemical gradients are the forces that cause the movement in and out of the cells Electrical Gradients Potassium ions go through cytoplasm faster than sodium ions do. This causes a loss in positive charge and makes for an excess in negatively charged proteins Positive and negative charges are seperated by cell membrane and stops the free movement of ions. When the positive and negative ions are seperated, potential difference arises Current A movement of charges to eliminate a potential difference. Resistance A measure of how much the membrane restricts ion movement. Electrochemical Gradient Sum of the chemical and electrical forces acting on that ion across the cell membrane. 2.Active Forces across the Membrane Passive Channels (Leak channels) Always open. Permeability changes as channel changes shape due to the response of proteins to local conditions. Ex) Sodium and Potassium leak channels during a cell’s normal resting potential. 2.Active Forces across the Membrane Active Channels (Gated Channels) Activated Open or Close in Response to Specific stimuli. Open Inactivated Closed Cannot be Opened Active Channels (Gated Channels) Chemically Regulated Channels Open or close when specific chemicals bind to receptor sites. Ex) Binding of ACh at neuromuscular Junctions Active Channels (Gated Channels) Voltage Regulated Channels Open or close in response to changes in transmembrane potential. Found in excitable membranes which can generate and conduct an action potential. Ex) Voltage regulated sodium, Potassium, and Calcium channels. Active Channels (Gated Channels) Mechanically Regulated Channels Open or close upon changes along surface of membrane. Ex) Sensory receptors that respond to physical stimuli like touch, pressure, and vibration. Graded Potentials Changes in the trans- membrane potential that cannot spread far from the area surrounding site of stimulation. A. Depolarization 1. 2. 3. 4. The trans-membrane potential is most affected at the site of stimulation and the effect decreases with distance. The effect spreads passively owing to local currents. The graded potential change may involve either depolarization or hyperpolarization. The nature of the change is determined by the properties of the membrane channels involved. The stronger the stimulus, the greater the change in the trans-membrane potential and the larger the area affected. Any shift from rest potential toward 0mV B. Repolarization Chemical stimulus is removed in normal membrane permeability is restored, transmembrane potential returns to resting Restoring normal resting potential after depolarization Combination of ion movement through membrane channels and the activity of ion pumps especially sodium and potassium pumps C. Hyperpolarization Rate of potassium outflow increases and the interior of the cell would lose positive ions. Hyper polarization in an increase in the negativity of resting potential. Action Potentials Action Potential- The electrical activity developed in a nerve cell during activity. 1. The All-or-None Principle Principle states that if a stimulus is strong enough to generate a nerve action potential, impulse is conducted along the entire neuron at maximum strength, unless conduction is altered by conditions such as toxic materials in cells or fatigue. All or None Principle Action Potentials 2.Generation of Action Potential 1. Depolarization to threshold.(-60mv) 2. Activation of sodium channels and rapid depolarization: Sodium activation gates open and membrane becomes permeable to Na⁺.(-60mv closer to positive) Action Potentials 3. Inactivation of sodium channels and activation of potassium channels: Voltage regulated channels open. At +30mv, cytosol along the interior of the membrane contains positive charges. K⁺ is moved out of the cell and the loss shifts things back to repolarization. Action Potentials 4. The voltage-regulated sodium channels return to normal and membrane is now able to generate another action potential. Voltage-regulated potassium pumps begin closing at -70mV. They do not all close at the same time causing potassium to continued to be lost and a temporary hyperpolarization occurs. All voltage-regulated channels close and membrane returns to resting state at end of refractory period. 3.Propagation of Action Potentials Continuous Propagation Basic mechanism by which an action potential is propagated along an unmyelinated axon. Saltatory Propagation The relatively rapid propagation of an action potential between successive nodes of a myelinated axon. Propagation of Action Potentials: Continuous Propagation Propagation of Action Potentials: Saltatory Propagation Propagation of Action Potentials: Saltatory Propagation References All-or-none Principle. (n.d.). Brainwave. Retrieved February 3, 2010, from Brainwave website: http://library.thinkquest.org/28457/allornone.shtml Martini, F. H. (1999). Neurophysiology. In Neural Tissue. Retrieved February 4, 2010, from Prentice Hall, Inc website: http://cwx.prenhall.com/bookbind/pubbooks/martini demo/chapter12/medialib/CH12/html/ch12_5_2.html Martini, F. H. (2006). Fundamentals of Anatomy and Physiology (L. Berriman, Ed., 7th ed.). San Francisco, CA: Pearson Education. Synapse Activity Synaptic Activity By: Josh Llaneza Mollie Worthington Logan Michel Electrical Synapses Type of synapse between 2 apposed neurons Nerve impulse is rapid Occurs by the passage of ions from one neuron to the other via the gap junction channels Can be bidirectional and unidirectional Used when fast response and coordination of timing is crucial Escape reflexes Retina of vertebrates Heart rhythm Chemical Synapses 1. 2. 3. 4. 5. 6. Type of synapse that allows a 2 neurons to communicate or a neuron to communicate with a non-neuronal cell Action Potential goes down Axon Calcium pumps open and Calcium diffuses into Axon Synaptic vesicles are forced to synaptic cleft and release Acetylcholine Acetylcholine binds with receptor sites for sodium channel Sodium is diffused into cell, making the membrane potential more positive If the potential reaches threshold level, then an action potential will be produced Cholinergic Synapses Cholinergic: Relating to nerve cells or fibers that employ acetylcholine as their neurotransmitter. Synapses: the site of functional apposition between neurons, where an impulse is transmitted from one to another, usually by a chemical neurotransmitter released by the axon terminal of the presynaptic neuron. Cholinergic Synapses: synapses with a chemical neurotransmitter that is made up of acetylcholine. Acetylcholine: plays an important role both in learning and memory and in sending messages from motor nerves to muscles, especially in the heart, bladder and stomach. Where Can a Cholinergic Synapses Found? All motor neurons activating skeletal muscle Many neurons of the autonomic nervous system especially those in the parasympathetic branch Parasympathetic: originating in the brain stem and the lower part of the spinal cord that stimulate digestive secretions, slow the heart, constrict the pupils, and dilate blood vessels. Some are found in the central nervous system as well Other Neurotransmitters Serotonin: normally involved in temperature regulation, sensory perception, mood control. Plays a major role in emotional disorders such as depression, suicide, impulsive behavior, and aggression. Norepinephrine: also called noradrenalin; doubles part-time as a hormone. Neurotransmitter = helps to regulate arousal, dreaming, and moods. Hormone = increases blood pressure, constricts blood vessels and increases heart rate - responses that occur when we feel stress. Other Neurotransmitters Cont. Glutamate and GABA (gamma-amino butyric acid): amino acids that act as neurotransmitters. The majority of synapses within the brain use glutamate or GABA. They have other functions in the body like making energy-rich molecules in cells. It is likely that they will be altered during drug addiction. This makes it difficult to treat addiction with drug therapy without causing side effects. Bibliography Cell signaling. (2007). Alzheimer society. Retrieved February 4, 2010, from Alzheimer's Association website: http://alzheimer.ca/english/ alzheimer_brain_mini_site/06.htm Chemical synapse. (2009). Absolute astronomy. Retrieved February 4, 2010, from http://www.absoluteastronomy.com/topics/Chemical_synapse Definition of acetylcholine. (n.d.). Medicine net. Retrieved February 3, 2010, from MedicineNet, Inc. website: http://www.medterms.com/script/main/ art.asp?articlekey=23278 Electrical synapse. (2009, February 24). Biology online. Retrieved February 3, 2010, from http://www.biologyonline.org/dictionary/Electrical_synapse Bibliography Cont. McKinley, & O'Loughlin. (n.d.). animation chemical synapse [Video]. Retrieved from Mcgraw hill website: http://highered.mcgrawhill.com/sites/0072495855/ student_view0/chapter14/animation__chemical_synapse__quiz_1_.html Millar, N. (2004, June 20). Synapses. In Biology mad. Retrieved February 3, 2010, from http://www.biologymad.com/master.html?http://www.biologymad.com/ NervousSystem/NervousSystem.htm Other neurotransmitters. (n.d.). Understanding addiction. Retrieved February 3, 2010, from Addiction Science Research and Education Center, College of Pharmacy, The University of Texas website: http://www.utexas.edu/research/ asrec/other_p.html Synapse. (n.d.). The free dictionary. Retrieved February 3, 2010, from Farlex, Inc. website: http://medical-dictionary.thefreedictionary.com/ cholinergic+synapse Information Processing next Information Processing by Individual Neurons Postsynaptic Potentials Mike Bell Cassie Mays Gabby Severs Postsynaptic Potentials A change in the resting potential of a postsynaptic cell following the stimulation from a presynaptic cell. (The change in a signal receiving cell such as a muscle cell after a presynaptic cell such as a motor neuron gives a neurotransmitter) Yellow- presynaptic neuron Green- postsynaptic cell Excitatory Postsynaptic potentials (EPSP) These PSPs increase the likelihood of the neural message to be turned into an action from the postsynaptic cell They make the membrane of the PS cell more positive (depolarized) and accelerates the process to get an action done Inhibitory Postsynaptic Potentials (IPSP) Opposite of EPSP An electrical charge in the membrane of a postsynaptic neuron caused by the binding of an inhibitory neurotransmitter from a presynaptic cell to a postsynaptic receptor. Makes the cell membrane of the PS cell more negative (hyperpolarized) Decreases, halts, the action’s chances of being completed •Graph Showing activity in PS cell •EPSP excites •IPSP inhibits Summation Temporal summation - transmission of an impulse by a rapid stimulation of one or more pre-synaptic neurons . Spatial summation - transmission of an impulse by simultaneous stimulation of two or more pre-synaptic neurons . The 3 distinct zones 1. Input Zone: the ligand-gated ion channels are activated by neurotransmitters, or ligands, and secreted by presynaptic terminals. This activation creates a postsynaptic potential. 2. Integrative Zone: summates the postsynaptic potentials and initiates an action potential. Action potential depends on the activation of voltage-gated ion channels. 3. Conductive Zone: then spreads along the action potential. The postsynaptic potentials require activation of ligand-gated ion channels on the postsynaptic membrane. Facilitation The amount of neurotransmitter released is not always fixed. If the first action potential caused more to be released by the second, it is called facilitation. If less is released, then its considered depression. References Burt, A. M. (n.d.). Synaptic Transmission. In Biology Reference. Retrieved February 4, 2010, from http://www.biologyreference.com/Se-T/Synaptic-Transmission.html Excitatory and Inhibitory Postsynaptic Potentials. (2001). Neuro science. Retrieved February 2, 2010, from Sinauer Associates, Inc. website: http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=neurosci&part=A477 Giuliodori, M. J., & Zuccolilli, G. (2004). Postsynaptic Potential Summation and Action Potential Initiation. In Advances in Physiology Education. Retrieved February 4, 2010, from http://advan.physiology.org/cgi/content/full/28/2/79 Postsynaptic Potential. (2008, March 11). Mondofacto [Online Medical Dictionary]. Retrieved from http://www.mondofacto.com/facts/dictionary?postsynaptic+potential Postsynaptic Potentials. (n.d.). Washington University. Retrieved February 2, 2010, from http://courses.washington.edu/conj/neuron/postsynaptic.htm Diseases The words are there. Click in the white space and they will appear. Don’t ask me why!! Has to do with the formatting. You can always go to 2nd or 3rd. What Is Parkinson's Disease? Parkinson's disease is a brain disorder that leads to several symptoms that effect the body such as; shaking, stiffness, and difficulty with walking, balance, and coordination. It affects about half a million people in the United States. The average age of onset is 60 years, and the risk of developing Parkinson's goes up with age. What Causes Parkinson's Disease? Parkinson's disease occurs when nerve cells, or neurons, in an area of the brain that controls movement die. Normally, these neurons produce an important brain chemical known as dopamine, but when the neurons are affected or die off the less dopamine is made. This shortage of dopamine causes the movement problems for the people affected by this disease. Dopamine is a chemical messenger, or neurotransmitter. Dopamine is responsible for transmitting signals for multiple spots in the brain. The connection is critical to produce smooth, movement. •Treatment and Research Although there is no cure for Parkinson's disease, medicines and surgery can often provide help with dealing with it. However, these treatments are not very effected sometimes and scientist are trying to find better ways to treat it. Recent advances in areas such as genetics, drug therapy, and brain stimulation offer hope that some day it may be possible to cure the disease, delay its onset, or prevent it altogether. •Medications “Medications for Parkinson's fall into three groups. The first group includes drugs that increase the level of dopamine in the brain. The second group affects other neurotransmitters in the body in order to ease some of the symptoms of the disease. The third group includes medications that help control non-motor symptoms (those that do not affect movement) of Parkinson's.” •“Surgical Treatments and Other Therapies Pallidotomy was once the most common surgery for Parkinson's. In this procedure, a surgeon destroys a portion of the brain called the globus pallidus. Pallidotomy can improve symptoms of tremor, rigidity, and bradykinesia, possibly by interrupting the connections between the globus pallidus and the striatum or thalamus.” http://www.buzzle.com/articles/mercury-poisoning-symptoms.html http://nihseniorhealth.gov/parkinsonsdisease/faq/faq1a.html Mercury is odorless, colorless, and tasteless. Only liquid metal at room temp. Very toxic. Used in Thermometers, Barometers, Batteries, and VaporLamps. Found as a native metal. Found within cinnabar, corderoite & livingstonite. Roughly 50% of our supply comes from Spain & Italy. Mercury breaks the barrier between blood, and the brain. Mercury binds to organelles in cells, such as mitochondria, endoplasmic reticulum, Golgi complex, nuclear envelopes and lysosomes. Although very little mercury binds to the nucleus, there is severe decrease of neuronal RNA and protein synthesis. Disrupted enzymatic systems in the glycolytic pathway in the brain. There are also irregular excitation spikes in mercuryintoxicated neurons. Sensory neurons in the spinal ganglia and granule cells in the cerebellum are the most vulnerable to mercury poisoning. Causes headaches, vertigo, tinnitus, shaking in various areas of the body. Angry fits, short term memory loss, low self esteem, inability to sleep, loss of selfcontrol, sleepiness, and difficulty learning. Mercury degenerates nerve fibers. TREATMENTS OF T.S.D ? Currently, there is no cure or effective treatment for Tay-Sachs. is a rare inherited disorder that destroys nerve cells (neurons) in the brain and spinal cord. Fatty substances called ganglioside (GM2) build up in tissues and nerve cells in the brain. This rare inherited disorder disease usually happens to babies. as nerve cells become distended with fatty material, a relentless deterioration of mental and physical abilities occurs. The child becomes blind, deaf, and unable to swallow. Muscles begin to atrophy and paralysis sets in. Other neurological symptoms include dementia, seizures, and an increased startle reflex to noise. WHAT IS MULTIPLE SCLEROSIS? Is an autoimmune disease that affects the brain and spinal cord(central nervous system), and as a result loss of certain body function and physical abilities. HOW DOES M.S AFFECT THE CENTRAL NERVOUSE SYSTEM ? It damages the myelin sheath, the material that surrounds and protects your nerve cells. M.S MAKE A PERSON HAVE: Visual disturbances Muscle weakness Trouble with coordination and balance Thinking and memory problems And since it affects your spinal cord you can be paralyzed. TREATMENTS OF M.S? At this time there is no cure for M.S. The goal is to use medication which will slow the progression of multiple sclerosis which are: (Avonex, Betaseron, or Rebif), monoclonal antibodies(Tysabri), glatiramer acetate (Copaxone), Sources (to be cited) Picture of Mercury. [Data file]. (n.d.). Retrieved from http://www.periodictable.com/Samples/080.14/ s13.JPG W, C. L. (1977). Neurotoxic effects of mercury: a review. Unpublished raw data, Univ. of Arkansas Medical School, Little Rock. Retrieved from Energy Citations Database. Facts about Mercury [Fact list]. (n.d.). Retrieved from facts-about website: http://www.facts-about.org.uk/science-element-mercury.htm Pakhare, J. (2007, May 5). Mercury Poisoning Symptoms [Facts]. Retrieved from Buzzle website: http://www.buzzle.com/articles/mercury-poisoning-symptoms.html http://nihseniorhealth.gov/parkinsonsdisease/faq/faq1a.html