9— ANATOMY OF THE DOG 



produce the first sound ; this is dull and pro- 

 lonsred as heard thru the chest wall. 



The other sound is short and sharp, pro- 

 duced by the closing: of the valve between the 

 ventricle (lower part of the heart) and the 

 outgoins: artery. 



If these valves do not work properly, that 

 is, if the blood does not proceed in the right 

 direction rapidly, there is a snishingr noise or 

 murmur. 



The Poise 



The blood with its vivid red color is held 

 the sign of vigorous life. We speak of having 

 the blood of certain ancestors in our veins ; it 

 should be stated, in our arteries, for life is 

 in the arteries and death in the veins. 



There is however, no heredity, no passing on 

 of characteristics in the blood itself; that is 

 done entirely in the reproductive organs. We 

 never possess any of the actual blood of onr 

 ancestors. 



Carry Nutriment and Waste 



The two functions of the blood are first, to 

 carry the nutritive material from the diges- 

 tive system to other parts of the body ; and to 

 carry oxygen from the lungs to the building 

 tissues. Second, to carry the waste products 

 of the digestive system and other parts of the 

 body to the excretory system and to carry the 

 carbonic acid gas to the lungs from the 

 tissues. 



Thus there is constant movement, constant 

 change, constant tearing down and building 

 up by the circulatory system. 



Heart is a Muscle Pump 



The heart is, after the brain, the most vital 

 organ of the dog or of any mammal. It is 

 essentially a muscle, being hollow and in- 

 closed in a sac or membrane called peri- 

 cardium, a very tough membrane. 



The expansion and contraction of the heart 

 as a muscle, in rhythm or measured time, 

 pumps the blood thruout the body. 

 **Go-and-Retum" System 



There are really two circuits maintained at 

 the same time by the heart — the driving of 

 the blood into the arteries and capillaries at 

 each contraction, and the return of the blood 

 thru the veins into the auricles. A system of 

 valves as in any pump prevents backflow. 

 Heart a Symbol of Life and Love 



In all ages and among all peoples the heart 

 has been regarded as the very essence of life. 

 To take the heart out of a person, to get to 

 the heart of things, to say that one has lost 

 heart, that one has eaten a hearty meal, that 

 one is a hearty person, that one is of good 

 heart — all these express the age-old veneration 

 in which this organ of the body has been held. 



Life goes out with the stopping of the beat- 

 ing of the heart. As long as it beats, there 

 is no death. Day after day, month after 

 month, year after year, from the moment 

 of birth, without missing a second, whether 

 we work or play, whether we are awake or 

 sleeping, this never-ending engine keeps on 

 pumping until the very last instant: if it 



rests for Just an instant too long, life flees 

 never to come back. 



Feeling Beat of Heart 



The heart in location is the first vital or- 

 gan in the body altho the lungs encircle ic 

 It is placed in the chest and well forward 

 in the body. Its movement can be felt best 

 about at the middle of the ribs on the left 

 front side of the chest. 



The arteries are always full. Each heart 

 beat as the heart expands can be felt because 

 of the pushing of the blood into the arteries. 

 This wave constitutes the pulse. 



The veins have thin walls and do not carry 

 a pumping stream ; they have no pulse. 



The pulse varies greatly with the breed, 

 age and size of the dog ; it may range from 

 70 to 120 waves per minute. It is higher in 

 young animals, small breeds and nervous 

 sensitive breeds. A good average for the 

 adult dog of medium-sized breed and in good 

 health is a count of 90 per minute. 

 Where to Count Dog's Pnlse 



The best place to feel this wave of the fiow 

 of blood, the pulse, is to place the finger upon 

 the femoral artery, on the inside of the thigh 

 of the dog (femur bone), well up above the 

 stifle joint and almost where the thigh is on 

 a level with the belly line. 



Names of Main Arteries 



The arteries are thick tubes of elastic struc- 

 ture. When this elasticity is lost, there is 

 hardening of the arteries and high blood 

 pressure. 



The pulmonary artery from the right ven- 

 tricle supplies the lungs only. The common 

 aorta carries the supply of blood to various 

 parts of the body. The cephalic artery is 

 responsible for the supply of blood to the 

 head. 



Blood, Essential of Living Tissue 



Blood is regarded as the essential element 

 of flesh or living tissue. From the tissues it 

 is carried back thru the veins to the heart 

 to be repumped, and so on without end until 

 the end. 



Capillaries Connect Arteries, Veins 



The connection between the incoming ar- 

 tery and the outgoing vein is a system of 

 very minute vessels or tubes called capillaries, 

 a network of millions of conduits. 



Fatality in Jugular Vein 



The vein which drains the blood back from 

 the head and neck to the lungs is the jugu- 

 lar vein, corresponding to the carotid artery. 

 To sever this vein in the neck (it is near the 

 surface) brings on death instantly. 



Liver as Blood Filter 



The blood from the spleen, stomach and in- 

 testines is carried back to the heart thru one 

 large vessel called the portal vein. It first 

 leads directly to the liver ; there the blood 

 seeps into the capillaries and these unite in 

 the hepatic vein, from which the blood re- 

 turns thru the vena cava into the heart to be 

 purified and re-pumped. Thus it is evident 

 that the liver has a highly important func- 

 tion, that of straining impurities out of the 

 blood in the digestive process. 



IV. THE DIGESTIVE SYSTEM 



The digestive system is concerned with 

 taking in, preparing and disposing of food 



for the body. Chemical and mechanical changes 

 must take place before the food which is 



