excitability
ex·cit·a·ble
E0264300 (ĭk-sī′tə-bəl)| Noun | 1. | excitability - excessive sensitivity of an organ or body part |
| 2. |  excitability - being easily excited |
| 单词 | excitability | ||||||
| 释义 | excitabilityex·cit·a·bleE0264300 (ĭk-sī′tə-bəl)
excitabilityexcite(ikˈsait) verbExcitabilityExcitability(irritability), the ability of living cells, from the simplest unicellular organisms to the nerve cells of man, to sense environmental changes and to respond to these changes (stimuli) with excitation. Excitability is linked to the existence in the cell membrane of special molecular structures possessing specific sensitivity to various stimuli, such as electric current and chemical, mechanical, and thermal agents. Since the main component of excitation in nerve and muscle cells (fibers) is action potential, the excitability of these cells is usually judged by the threshold current strength or threshold shift in potential, which is sufficient for action potential to arise. The threshold current strength is depen-dent upon the duration of the stimulus. The threshold shift in potential, however, does not change with variation in the duration of the stimulus. The generation of action potential is based on increased permeability of the cell membrane to sodium ions. Accordingly, any agent that prevents the sodium permeability of a membrane from increasing causes excitability to decrease. Local anesthetics used in medicine, such as Novocain, cocaine, and dicaine, as well as various narcotics, such as ether barbiturates, are based on this mechanism. The term “excitability” is also frequently used in medical and biological literature to characterize the state of the nerve centers in the brain and spinal cord, for example, the respiratory and vasomotor centers. In such cases excitability is judged by the lowest intensity of a stimulus that is required to elicit a reflex response. B. I. KHODOROV excitabilityirritability[ir″ĭ-tah-bil´ĭ-te]ex·cit·a·bil·i·ty(ek-sīt'ă-bil'i-tē),ex·cit·a·bil·i·ty(ek-sī'tă-bil'i-tē)excitabilityThe property of any cell or tissue capable of producing an electric signal.excitabilityany change in membrane conductance as a response to stimulation.Patient discussion about excitabilityQ. I am excited to know in what way diet helps in preventing osteoporosis? my mother is suspecting to be having osteoporosis. She regularly complains of leg pain. Upon consultation with the doctor it was found with low calcium in her blood. She was given calcium tablets and was told to increase in the diet rich in calcium. She is taking milk and yoghurt especially. She is not well yet but shows some improvement. I am excited to know in what way diet helps in preventing osteoporosis? Q. my wife is pregnant !!! i am so excited ! this is the first time out of many i hope !!! but i have concerns that i would like to share with the community here ... i am afraid of being a bad father , i am afraid i won't know how to be a father ... where do u start ... how do i support my wife after the though experince ... how do i take care of the child ... a lot of things a re running through my mind with no answer ,can any one help me to calm down ???? Q. Hello everyone !!! are you excited with the swearing of Obama To presidency??? i sure am !!! may we all get a little joy and peaceful time wit hour fresh president ... and let us all wish him a great start and a chance to change our lives ... Good Luck Mr.President Obama !!! excitability
Synonyms for excitability
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