Leukodystrophies. These are disorders that cause abnormalities and the destruction of myelin‚ the “white matter” that protects nerve fibers in the brain. Myelin is essentially made up of water proteins and mostly lipids‚ it covers the axons of all neurons in the form of a myelin sheath as it helps insulate the nerve fibers and promotes rapid transmission of nerve impulses. Myelin is produced by two different types of Glial cells‚ Oligodendrocytes produce myelin in the central nervous system (Brain
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five stages: 1. The vagus nerve stimulate the sinoatrial node or SAN‚ which is the pacemaker of the heart. Is a small area in the upper wall of the Right atrium‚ close to the vena cava; the fibers of the of the SAN contract 70 times each minutes‚ and after that the impulse is disperse across the atrial cardiac muscle. 2. Simultaneous contraction occurs in both‚ the right and the left; that is mean between tricuspid and bicuspid valves. 3. The atria contraction sends impulses
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exposure to loud sounds can cause additional cochlear damage. The only way to prevent noise induced hearing loss is to limit exposure to loud sounds and wear ear protection. What happens when cochlear damage occurs? Thousands and thousands of tiny nerves called ‘hair cells’ line the inside of the snail-shaped structure‚ the cochlea. Each hair cell is responsible for picking up a different sound‚ sort of like keys on a piano‚ but on a much more detailed scale. All of the hair cells work in concert
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What Is Neurotransmitter? Neurotransmitter is a chemical that is released from a nerve cell which thereby transmits an impulse from a nerve cell to another nerve‚ muscle‚ organ or other tissue. (Webster new world medicine dictionary. http://www.medterms.com/script/main/art.asp?articlekey=9973) What are Hormones? Hormones are chemicals that carry messages from organs of your body to your cells. The glands that secrete hormones are part of the endocrine system (pituitary‚ thyroid‚ adrenals
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was functioning properly and was able to maintain her own rhythm the majority of the time. The problem was occasionally the nerve impulses from her brain to her heart were not able to connect. This miscommunication‚ so to speak‚ was causing her heart rate to drop and at times‚ stop. She was diagnosed with SSS or “Sick Sinus
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To Treat Anxiety Disorders?”‚ Dr. Brian Brennan tells us that benzodiazepines “work by binding to a receptor which is located on neurons in the brain called the (GABA) receptor (see Figure 3).” The GABA receptor‚ as explained before‚ stops certain impulses in the brain that can lead to anxiety attacks. Benzodiazepines help the GABA receptor to work properly and prevent symptoms of anxiety disorders by allowing even more chloride ions into the neuron‚ which makes it even more resistant to
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are not possible in the cardiac muscle tissue. a. Cardiac cells have long action potentials and long twitches‚ therefore do not show temporal summation. Act 2 1. Explain the effect that extreme vagus nerve stimulation had on the heart. a. The vagus nerve stimulation caused the heart to flat line restart and react normally. The response after the stimulation that resumed the heart is called the vagal escape. 2. The SA node of the heart is located in the right
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in electrical potential associated with the passage of an impulse along the membrane of a muscle cell or nerve cell. An action potential occurs when a neuron sends information down an axon‚ away from the cell body. A threshold is the minimum amount of stimulation needed to start a neural impulse (you know‚ the electrical impulses that travel throughout your body carrying important information). Action potentials generated by neural impulses are "all or nothing‚" meaning the signal reaches the
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|Bipolar neurons |Unipolar neurons |Multipolar neurons | |transmit impulses generated by olfactory‚ visual‚ |Convey impulses from variety of specialized and |Transmit both sensory and motor nerve impulses | |vestibular‚ and auditory receptor endings ( sensory in|nonspecialized receptors | |
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The first is a story of Mary‚ a brilliant scientist that has been forced to investigate the world from a black and white room. Mary specializes in the neurophysiology of vision and acquires all physical information about sight and colour by examining wavelength combinations and how they react with the retina and central nervous system. Then‚ Jackson supposes that Mary is released from her black and white room
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