The excitability of different tissues varies widely. Some tissues are highly excitable whereas others are dull. While considering the excitability of a tissue two factors are to be considered: (a) The strength of the current used, and (b) The duration of the current flowing through the tissue. These two factors bear an inverse relation. The stronger the current the lesser [...]
The following factors affect excitability and contractility and therefore alter in various ways, the nature of the simple muscle curve: Factor # 1. Strength and Duration of Stimuli: For stimulation to occur, two factors are necessary—a minimum strength and an adequate duration of the stimulus. Chronaxie, which includes both these factors is the measure of excitability of a tissue. Factor [...]
In this article we will discuss about the structure of respiratory tract of humans with the help of suitable diagram. Also learn about its functions. i. Upper respiratory tract extends from the upper nares to the vocal cord. (Fig. 8.1) ii. Lower respiratory tract extends from the vocal cord to the alveoli. Trachea: The trachea (windpipe) is a cartilaginous and [...]