QUESTIONS AND ANSWERS 103 



Lungs: Eliminate carbon dioxide and water. 



Faeces consist of the undigested portion of the food which is indi- 

 gestible, together with that which though digestible has escaped 

 absorption ; mixed with these are water, coloring substances, mucin, 

 organic matters, inorganic salts, bile pigment, volatile fatty acids, 

 remains of digestive fluids, microorganisms, etc. 



Define excretion. Mention four ways in which waste matter of the 

 body is eliminated. 

 Excretion refers to the throwing off or ejection of waste matter, 

 formed in the body, which is not intended to be retained in the 

 body and if retained would be harmful. 



"Waste matter is eliminated by the urine, faeces, skin and expired 

 air. 



Explain the meaning of four of the following : chordae tendinae, haema- 

 tin, GoU's column, bile salts, accommodation. 



Chordae tendiuEe are the small tendinous cords, attached to the 

 free border of the heart valves, which unite the latter to the walls. 



Haematin is the iron-containing substance of the haemoglobin. 



GoU's column is the superior median tract or column of the 

 spinal cord. 



Bile salts, two in number, glycoeholate and taiu-ocholate, are 

 formed in the liver by the union of cholalie acid with glycin and 

 taurin. 



Accommodation refers to the power which the eye possesses of 

 focusing itself for near and distant objects. 



Define and illustrate five of the following terms: absorption, chyle, 

 excretion, ferment, tidal air, phagocytosis, alimentation. 



Absorption is the process of taking up fluids or other sub- 

 stances by the skin, mucous surfaces or absorbent vessels, e.g., 

 absorption of chyle by the lacteals. 



Chyle is the milky fluid taken up by the lacteals from the digested 

 food in th6 intestines. 



Excretion is the act or process of eliminating waste matter from 

 the body, e.g., urea is excreted by the kidneys. 



Ferment is a substance which decomposes or causes fermentation 

 in other substances with which it comes in contact, e.g., pepsin 

 changes proteids into peptones. 



Tidal air is the quantity of air taken in and expelled by an 

 ordinary respiration. In the horse it amounts to about 250 cubic 

 inches. 



