Comparative Vertebrate Anatomy - Essay Example

[Insert s s Insert Identification information here] [Insert here] [Insert here] Comparative Vertebrate Anatomy Question number 1: Seals which belong to this taxonomic order: Kingdom Animalia, Phylum Chordata, Subphylum Vertebrata, Class Mammalia, Order Carnivora, Suborder Pinnipedia, Family Phocidae, Subfamily Phocinae, Genus Phoca, Species Phoca vitulina have a counter-current system in their flippers to maintain the body temperature even though blood circulates to these flippers and back to the core of the body(Norwalk, 2005). The body temperature of seals is protected by their thick layer of subcutaneous blubber against their living environment's (cold sea water) temperature which is ranging from 0 to 15C. Their flippers though can not be covered with subcutaneous blubber because it will interfere with its function as paddles and fins. The seal's flippers are composed of living cells that needs constant blood oxygen supply. The dilemma is that the circulation of blood to the flippers will bring back ice-cold venous blood to the interior of the seals body. This dilemma is solved with the counter-current exchange system that is existent in these animals' flippers. Venae comitantes are veins that surround the limb arteries of the seals to prevent the return of cold venous blood to the body of the seal(Koeslag, 1995). Before the oxygenated blood enters the arteries of the flippers, the heat which is present that blood releases its heat through the venae comitantes to the cold venous blood. The oxygenated blood that enters the flipper arteries is cold as it circulates the flippers but when in enters the veins through the venae comitantes it is warmed near the body temperature (35C) utilizing the heat that it released before its entry in the flipper artery. Thus, the counter-current exchange mechanism of the seals' flippers prevent the alteration of the normal internal body temp of the animal which is 37C even though blood is continuously circulating to the flippers(Koeslag, 1995). Human beings also have a counter-current mechanism that is similar to that of the seals. Homo sapiens or humans belong to this taxonomic order: Kingdom- Animalia, Phylum Chordata, Subphylum Vertebrata, Class Mammalia, Subclass Eutheria, Order Primata, Suborder Arthropoidea, Family Hominidae, Genus Homo, and Species Sapiens(Goodman, 1999). The limbs of human beings are equipped with a counter-current system that maintains the normal temperature of the blood flows from the limbs during cold weather(Koeslag, 1995). Closely at the deep center of the limbs, the arteries of humans are strategically located. These arteries are also surrounded by venae comitantes or deep veins which receives the blood that circulated the limb arteries for transportation to the center of the cardiovascular system. The normal temperature of human blood is 37C so the oxygenated blood before entering the limb arteries transfers the heat to the venae comitantes making the oxygenated blood cold to about 20C. Then before entering the veins of the limbs the deoxygenate blood is warm to 37C in the venae comitantes. The temperature of the blood that is returned to the heart therefore remained unaltered that is still 37C. The process of blood circulation in the limbs in cold weather is slow to facilitate the function of the counter-current system(Koeslag, 1995). During warm weather that counter-current system of the human limbs is switched off because the circulation of blood to the limbs is increased compromising this system. The venae comitantes is not utilized instead the blood from the limb arteries return to through the subcutaneous veins. The blood circulating during hot weather is cooled with the facilitative dilation of the superficial veins and constriction of the venae comitantes(Koeslag, 1995). Question number 2: Camel or Camelus spp. are dessert animals that posses this taxonomic characteristic: Kindon Animalia, Phylum Chordata, Subphylum Vertebrata, Class Mammalia, Order Artiodactyla, Family Camilidae(Myers, 2000). The ability of the camel to survive in the dessert environment wherein there is a limited water supply and high temperature is rooted to the physiological systems of camels that adapted to this type of environment. Salamanders on the other hand are amphibians similar to the frogs that are in need of water in order to be able to reproduce. The physical appearance of the salamanders is likened to that of the reptiles thus sometimes they are mistaken to be reptiles. Unlike the reptiles the salamanders have no ears, scales, and claws; and they have moist skin. There two types of salamanders: aquatic and terrestrial. The aquatic salamanders like the aquatic cave-dwelling salamander -Texas Blind Salamander (Typhlomolge rathbuni) have tails that are compressed to facilitate swimming whereas the terrestrial ones have more rounded tails. The majority of the larval salamanders have gills because their first stages of life are in the water like the frog tadpoles. Majority though of these gills are metamorphosing in adults except for the mudpuppies and the waterdogs that retain the gills all their life(Bishop, 2003). The adaptation of the camels to the intense heat and lack of water in the dessert is facilitated by their osmoregulatory system. During the absence of water the osmoregulatory system of the camel elevates its body temperature to prevent the loss of water in from its body through persperation or evaporation. The body temperature of camels during nightime is at 35C and then rises to 41C to compensate for the lack of water and the intense heat during this period. This physiologic capacity of the camel enables them to survive the intense heat and scarcity of water in the dessert lands. Osmoregulation in salamanders is not associated with intensive heat that occurs in the dessert camels but due to the difference in the osmolarity of the salamander's body and that of the water. The water in the cave environment is fresh water and with lesser amounts of mineral salt thus the fluids in the body of the salamander must be of relative amounts of salt to that of the water so that diffusion of water from the salamander's body can be prevented. The integumentary system of the camels is also well adapted for the intensive heat in the dessert environment. The camel's thick and felted hair helps in stopping perpiration so as to prevent further loss of water during times that there is a scarcity of water like in the dessert environment. Aside from the association of the integumentary system in the osmoregulation to prevent the evaporation of water from the camel's skin through perpiration, the integumentary system of the camels is equipped with thick fur. This thick fur serves as heat insulating system of camels and also protects them from cold climatic conditions. Salamanders have moist skin like the other amphibian species. This is incontrast to the dry skin that is an adaptation of the camels to the dry and hot environment. If the skins of the camels are moist the water will evaporate continously leading to the decreased amounts of water in the camel's body. This can cause problems because the dessert environment has a scarcity of water so the dessert camel needs to conserve the water that is in its body in order to survive. The dry skin thus is well suited for camels so that they can adapt to their environment. Question number 3: The heart of the amphibians is three chambered wherein it is composed of one ventricle and two atria (right and left). The impure blood from the body is which contains little amounts of oxygen is received by the right atrium while the left atrium collects lung purified oxygenated blood. These two different types of blood pass through a single ventricle wherein they are partially mixed. Blood from the single ventricle then flows into the truncus arteriosus (a large artery after the ventricle). Mixing of some blood in the ventricle is not prevented because the ventricle is not divided into two parts. The unpurified and purified blood though is not totally mixed due to the timing of the contractions of the two atria. The blood that has been mixed is transported to the skin to undergo oxygenation. The pericardium of an amphibian's heart protects this organ inside the coelom. The amphibian and reptile heart due to the lesser numbers of chambers is not as efficient to that of the crocodiles and humans. The decreased efficiency of the reptilian and amphibian hearts are best for their body functions because they are cold blooded animals that have lesser tasks when compared to the complicated functions of the mammalian hearts. Reptiles also have three-chambered hearts with an exemption of the crocodile wherein their hearts have four chambers like the mammals. The double-circuit pump of the crocodile heart is with separate pulmonary and systemic trunks. The heart of the crocodile is unique among the reptilians to facilitate their cruising in the murk for several hours without surfacing to breath-air. A crocodile's heart is equipped with a unique type of valve that actively regulates blood flow between its body parts and its lungs. Compared to other vertebrates the valve of the crocodile's heart is distinctive because it has cog teeth that are composed of nodules of connective tissue instead of passive flap-like valves. Blood is diverted away from the lungs to the body of the crocodile by the mesh of cog teeth. These cog teeth are located in the right ventricle of the crocodile heart and functions as blood pumping tissue for the pulmonary artery that supplies the lungs and aorta that in turn supplies blood to the body. This mechanism facilitates the crocodile to move under the water for several hours without surfacing for air. The mammalian heart has similar number of chambers to that of the crocodilian heart which is four: left and right ventricle; and, left and right atrium. The skeletal and smooth muscles of the heart are special kind of muscle tissue that adapts to the muscular contraction rate facilitating the regular pumping rhythm. The chambers, electrical nodes, and the valves are the primary parts of the heart. The pumping of the blood out of the heart is a function of the ventricles while the two atria serve as collecting vessels of blood from various body parts. The presence of valves in the mammalian heart serves as preventive structure for blood backflow. The sequence of the passage of blood from the various organs of the body is as follows: entry of deoxygenated blood is in the superior and inferior vena cava, and then the blood pass to the right atrium before flowing to the right ventricle, then it passes to the pulmonary arteries for and gas exchange occurs in the lungs, after that the oxygenated blood from the lungs enters the heart again through the pulmonary vein and pass through the left atrium, and then it flows into the left ventricle wherein it is pumped out of the organ through the aorta. The mammalian heart as well as the avian heart is the most efficient system due to the presence of valves that prevents backflow and intermixing of the oxygenated and deoxygenated blood. The mammalian heart is appropriate as four chambers to make certain that all the body tissues are supplied with oxygenated blood in order to facilitate the functions of all the organs of the body. The maintenance of temperature in these warm blooded animals is allowed by the higher oxygen supply due to increased activity of the heart. The capacity of the mammalian heart to pump more oxygenated blood compared to the non-mammalian species is apt because of: the larger mammalian size thus increased number of tissues that needs to be supplied with oxygenated blood; and the much complicated life style of mammals. Works Cited Read More