This chapter details the principal role of the respiratory system, which is to provide an exchange of gases between the body and the environment. It outlines the functions of the respiratory system, such as its contribution to the maintenance of plasma pH and the production of sound. It also explains how the respiratory system ensures that adequate amounts of oxygen are delivered to tissues and carbon dioxide is efficiently removed when exchanging gases in a variety of environmental challenges. The chapter talks about the paired lungs that sit inside the thorax, which are formed from a series of bifurcations of a single trachea. It details how air enters the lung by a suction pump, wherein inspiration results in an increase in volume and a decrease in pressure inside the lungs.
Chapter
The respiratory system
Chapter
Water, Electrolytes, and Acid–base Balance
Lewis J. James and Gethin H. Evans
This chapter looks at water, electrolytes, and the acid–base balance. From a biological perspective, water is the most abundant compound in the human body and is the nutrient both consumed and lost in the largest amount each day. Despite its abundance in the body, water stores are regulated within a narrow physiological range, and even small deviations from normal body water stores exerts strong physiological, subjective, and behavioural responses that lead to the correction of the imbalance. The chapter then looks at the significance and functions of sodium and potassium, before discussing acid–base balance. Small changes in plasma pH, also called acid–base disturbances, can have significant consequences, as many enzymes and processes require a certain optimum pH in which they can operate.
