Zoey RentzComparative AnatomySkeletal SystemThe skeletal structure of the frog leg has similarities to the human leg. The frog leg, as shown below, has three parts. The femur, the largest bone in the leg, and is hollow. It provides support and connects the pelvis to the lower leg. It is also called the thighbone. The head of the femur connects to the acetabulum, in the pelvis, and creates a ball and socket joint. The other end of the femur connects with the tibiofibula forming a hinge joint. The tibiofibula is the bone of the lower leg. There is a long groove along the length of the bone, indicating that the tibiofibula is formedby the fusion of the two bones, the tibia and the fibula. There are four anklebones, also called the tarsals. The astragalus and calcaneum form a joint with the tibio fibula. They are much longer than the other two tarsals. The next rows of tarsals are much smaller, and are round in shape. Next the metatarsals form the foot; there are five metatarsal bones, which are long and slender. The toes, called phalanges, are attached to the metatarsals. The number of phalanges attached to the metatarsals is 2, 2, 3, 4, and 3. The toes are long and narrow. The human leg is also has a femur, which is the largest bone in the leg. It is the thighbone and connects with the acetabulum in the pelvis forming a ball and socket joint. The other end of the femur forms two hinge joints one with the tibia and one with the fibula. This joint is called the knee. A bone present in humans that is absent in frogs is the patella. The patella is commonly known as the kneecap. It protects the knee joint. In the frog the tibia and fibula are fused, forming the tibiofibula. Inhumans these bones remain separate. The tibia is the shinbone and is the larger of the two bones in the leg. It connects the knee to the ankle. The smaller of the two bones in the leg is called the fibula. It connects the knee to the lateral ankle. The anklebone is called theZoey Rentztalus and is connected with the heel bone. The heel bone is called the calcaneus, which is present in frogs, is also present in humans. In humans the calcaneus is the largest bone in the foot. There are five metatarsals in the foot, which connect the tarsals to the toes. The toes in humans are also called phalanges, as they were in the frog. The difference is the number of phalanges attached; in humans the pattern is 2, 3, 3, 3, 3.Humans who are bipedal and walk upright, which may account for the skeletal differences between frogs and humans. Especially in the lower leg, and foot you can see the major differences between the human and the frog skeleton. The calcaneus bone in a frog is longer; a frog leaps forward and needs these angles in its legs. Humans have the same bone with the difference being that humans walk upright. Overtime, possibly due to gravity this bone has evolved and become a broader, rounder bone in the foot. The other difference being the toes, the phalangeal patternis different between frogs and humans. The frog has a different amount of phalangesin its toes because of its need to leap. The frog pelvic girdle is made upthe ilium bones, the ischium, and the pubis. The socket formed by the pelvic girdle is called the acetabulum, which articulates with the femur bone of the leg. The ilium bones are long and attached to the sacrum.There are some slight differences in the anatomy of the pelvis between frog species. The differences are based on how the frog primarily moves. In the picture to the left, the long bone, which runs in between the ilium, is called the urostyle. It is the fused vertebrae at the base of the spine. The frog also doesn’t have any ribs. The extensions off the vertebrae are part of the spine. In humans many of the same bones are shared between the two species. The major difference being the orientation of the bones, since humans walk upright. Humans also have fused vertebrae at the base of the spine, called the coccyx. It is much shorter than the urostyle in frogs, but it does make up the back of the pelvis. Itis beginning to look as if gravity plays a role in the size and shapes of the bones. Humans walk upright and as a result gravity has made these bones shorter and take on slightly different functions. Humans unlike frogs have 24 ribs. There are twelve ribs on each side of the thoracic cavity. They attach to the thoracic vertebrae and protect the organs in the chest.Zoey RentzThe bones of the arm are similar to those of the legs. In frogs and humans the arm bone is called the humerus. The forearm bones are fused together in a frog and are called the radioulna. In humans these bones are separate, being called the radius and the ulna. Frogs have 4 fingers, while humans have five. A frog’s skull is divided into two parts, the part, which houses the brain, and the part, which forms the jaw. A human skull is similar in that the upper part of the skull contains many bones that are connected by sutures, while the mandible is connected to the skull by a joint. The skull is attached to the spine at the atlas, as it is in humans. As opposed to frog who have very limited motion of their head, humans have a wide range of movementdue to the axis bone that allows the head to move in all directions.Muscular SystemLooking at the way humans and frogs move can show some difference in muscle structure. Humans walk upright, while frogs walk on all fours. Humans have developed strong muscles in the legs, which allow us to walk upright with out falling over. Frogs have delevopled muscles, which assist it in jumping and leaping. In humans there are many muscles associated with breathing. The diaphragm in humans rasises and lowers with each breath, and is absent in frogs. The muscles of the chest, which expand the chest during breathing are, also absent in frogs. Circulatory SystemBoth frogs and humans have a heart, but there are drastic differences between the two. Frogs have only one ventricle, while humans have two. Frogs have a chamber before their right atrium called the sinus venosus, which is the frog’s pacemaker. In humans the pacemaker of the heart is called the SA node, as a fetus humans have a sinus venosus, which during development evolves into the SA node. Both humans and frogs have 2 atria. In frogs veins bring blood to the left and right atria, which arethen pumped into the single ventricle. Since there is only one
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