Q1: |
what is the function of the cerebrum |
A. N HUMBLE |
9/2/2009 |
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Q2: |
why SQUIDS are sensitive to measure small magnetic fields and How? |
rizwana |
9/2/2009 |
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Q3: |
is it can be download free |
vineeta |
10/10/2008 |
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No it cannot be downloaded for free , you will either have to subscribe or download by paying for the animation |
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Q4: |
how acation potential occur please explain |
bhupesh |
10/7/2008 |
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Q5: |
What is the gap between two neurons where chemicals are released during an impulse traveling from one neuron to another? |
Nishat |
1/5/2008 |
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Q6: |
What is the role of myelin's sheath in transmission of signals? |
anmol |
5/2/2008 |
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Myelin is composed of about 80% lipid fats and 20% proteins that act as a dielectric. It sheaths the axons. Myelin sheath allows rapid and efficient transmission of impulses along the nerve cells from 5 to 30 m/s whereas an unmyelinated one transmits them at 0.5 to 2 m/s. It does this both by insulating and containing the nerves. A nerve impulse is a wave of depolarising current (action potential) that travels along the entire neuron by allowing charged ions of Na and K to flood through channels in the semi-permeable membrane around the nerve cell. At rest (resting potential), the neuron and the surrounding space act as a "capacitor" storing current that is released during the action potential. Since fat inhibits the propagation of electricity, the signals jump from one gap to the next. |
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Q7: |
Why do bruises hurt more in cold weather? |
nishi |
5/2/2008 |
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Bruise happens when a part of the body is struck and the muscle fibers and connective tissue underneath are crushed but the skin doesn't break. When this occurs, blood from the ruptured capillaries (small blood vessels) near the skin's surface escapes by leaking out to tissues under the skin. With no place to go, the blood gets trapped, forming a red or purplish mark that's tender when you touch it. Now since the skin is cold the warm blood leakage may cause pain. However note that the nerve cells that transmit impulses work more slowly as do the muscles controlling your fingers, low temperatures also reduce the efficiency of pain receptors, so putting an ice pack on a bruise helps to reduce swelling and damage, but also helps with the pain. |
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Q8: |
Why is there a difference in how food tastes if the nose is blocked? |
nishi |
5/2/2008 |
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Flavor is determined by the aroma (smell), taste (sweet, sour, salty or bitter quality), texture, temperature and spiciness (or irritation) of food and beverages. All of these sensory experiences together form "flavor". 75% of what we perceive as taste actually comes from our sense of smell. The average human recognizes around 10,000 different odors. Taste is to a great extent determined by smell so a loss of smell often leads to a loss of taste. When you chew your food, odors go to the back of the mouth where the olfactory system translates them into flavor. Many flavors are recognized through the sense of smell like the flavor of coffee. Taste buds allow us to perceive only bitter, salty, sweet, and sour flavors. It's the odor molecules that give us most of our taste sensation. |
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Q9: |
can i get free anmiation on nervous system |
shailesh |
11/9/2007 |
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Almost free, Rs. 82 for viewing it online |
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Q10: |
What is the therapeutic role of neuronal stem cells? |
Muneeb Ahmad Faiq |
18/4/2007 |
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Neural stem cells are able to produce new neurones in adults, their present and future application area are treatment of degenerative brain diseases such as Parkinson and Alzheimer, metabolic disorders, muscular dystrophies, spinal cord repair and brain tumors. They have been found to take on some of the characteristics of retinal cells and extended into the optic nerve, to build neural pathways. |
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Q11: |
what is the mechanism by which Dengue virus causes thrombocytopenia |
Muneeb Ahmad Faiq |
21/3/2007 |
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It is under research, In case of DHF platelet destruction happens - 1) Complement activation-virus antigens bind to human platelets in the presence of virus-specific antibody and the immune-mediated clearance of platelets was involved in thrombocytopenia 2) Virus induced suppression of bone marrow synthesis of platelet 3) In humans, virus takes control of macrophages that engulfs it and uses it for replication and transport thus causes direct destructive action of bone marrow precursor cells. |
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Q12: |
i want animation for physiology topics, please let me know how to get them |
samuel christopher.s |
3/3/2007 |
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For viewing full version animation, either a subscription or purchase of the animation is required. You can purchase the animation by putting it in your shopping cart (click on add to cart tab), buy and download it or simply subscribe by purchasing hours and view the animation online. Please use either shopping cart or subscription links for purchasing product or subscription; we accept credit cards, demand draft, PayPal and many other modes of payment. Refer payment FAQ for details. |
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Q13: |
how animation can be started |
ahmad khalaf |
14/12/2006 |
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For viewing full version either buy and download the animation or subscribe and view the animation online. Please use either shopping cart or subscription links for purchasing product or subscription; we accept credit cards, demand draft and many other modes of payment. |
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Q14: |
when we concentrate our eyes on a edge of a coloured (eg. red) column in a white or yellw background for a moment then we can see a light green or light blue small column along the edge. how can we explain it physically? |
manjula |
3/8/2006 |
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The chromatic aberration of the eye brings about those fringes that you see are due to refraction by our lens of light of different wavelengths and due to color opponent cells in the visual neurons. In them one part of the receptive field (e.g., the center) is sensitive to light in one part of the visible spectrum (e.g., red light), while another part of the field (e.g., the surround) is sensitive to another part of the spectrum (e.g., green light). Refer "opponent-color theory" for more info. |
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Q15: |
Is those synaptic vesicles naturally occur in presynaptic cells? how are they formed actually? |
angela |
18/7/2006 |
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New vesicles are re-formed from invagination from the plasma membrane and transported to the nerve terminal then filled with transmitter molecules. Syndapin I /amphiphysin /Endophilin I proteins bind to dynamin, a protein, they induce negative membrane curvature. Vesicles are attached to the membrane from which they are made by a 'neck'. Dynamin forms a helix around the neck of nascent vesicles. Its extension causes the vesicle to break away from the membrane and transported to terminal. |
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Q16: |
what is a graded potential? |
mwatipasha |
27/6/2006 |
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These are short lived, small (<10mV ) and short distance signals, they weaken with distance from source while action potential travel long distance and retain the same strength throughout. Local changes in membrane potential by a stimulus or chemical messenger – receptor interaction cause them. This causes a flow of Na+ into the cell, this imbalance spreads electric potential changes along cell membranes. Are used by dendrites (for example retinal ) for returning signals from sense organs. |
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Q17: |
can you outline the sequence of events involved in neuronal transmission and how can a biochemical imbalance occur |
Elisa |
8/3/2006 |
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Genetics (extra chromosome in down’s syndrome), drug use ( alcohol) , nutritional environment (Serotonin and catecholamines are readily affected by diet), the aging process (lowering of dopamine in Parkinson’s disease) are generally the cause for chemical imbalance. The sequence is synthesis-storage-release-recognition and inactivation of neurotransmitters. It is not possible to detail it here. This article on our site may help http://www.goalfinder.com/articles.asp#5 |
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Q18: |
What are the other words for neurotransmitter? |
hussein |
20/2/2006 |
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small-molecule transmitters, neuro active peptides, chemical messengers others that are closely related but not meaning the same are synaptic messengers and cannabinoid receptors. |
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