Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Conduction in Myelinated Axons
The myelin sheath provides insulation for the axon preventing movements of Na+ and K+ through the membrane. Therefore, if this myelin sheath was continuous no action potential would be generated. Fortunately, gaps or nodes of Ranvier occur in the myelin. Since the cable properties of axon can conduct depolarisations over very short distance (1-2 mm), the nodes of Ranvier must be close together (actually they are 1 mm apart). Studies have shown that the Na+ channels are concentrated at the nodes and absent from the regions between two nodes. Action potential therefore occurs only at the nodes of Ranvier and seems to leap from node to node. This is called saltatory conduction. The spread of depolarisation between the nodes is very fast and fewer action potentials are needed. Therefore, the rate of conduction is much faster than in unmyelinated fibres.
This peculiar structure and mode of conduction in myelinated fibres is responsible for the fast conduction of impulses in motor nerves of vertebrates even though the nerves are very thin. The greatest advantage of myelinated fibres comes from their smaller size and so a highly complex nervous system with high conduction velocities can occur without occupying too much of space.
In which of the following functional groups ionization is stabilized by resonance? Select one: a. Carboxyl b. Hydroxyl c. Amine d. Aldehyde e. All of the above
Define the Prevention of diseases - Function of Vitamin E? Because of its anti-oxidant function and its role in inhibiting cell proliferation of smooth muscles, vitamin E can b
Temperature - Aquatic Habitats The water temperature changes less rapidly than the temperature of air because water has a considerably higher specific heat than air, that is l
What are the Sources of Vitamin K? As mentioned above, in plants, the only important molecular 'form of vitamin K is phylloquinone. Phylloquinone is distributed ubiquitously th
Timing and number of doses It has been common practice to give antibiotics at the time of anesthesia induction, which results in adequate serum and tissue levels of the drugs;
Explain Cis-trans isomers Atoms or groups are called cis or trans to one another when they project respectively on the same or on opposite sides of a reference plane identi
Q What are halophile, methanogen archaebacteria and thermoacidophile? There are three peculiar types of archaebacteria the halophile archaebacteria only survive in salt-rich en
Etiology -Although this approach less desirable, it is useful, short-term option if the etiology of the condition remains unknown. - The patient must inform about what will
Question 1 How would you perform ABO blood grouping? Add a note on advantages and disadvantages of each method. Also discuss the precautions you may take to avoid errors in variou
Explain the Dark Adaptation of Vitamin A? In the early stages of VAD, the individual cannot see objects in dim light. This' phenomenon is used as a criterion for assessment in
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd