Question

2.1 would you expect the cecum to be relatively large or small in herbivorous turtles? 3.2 how many chambers does a turtles heart have? 3.3 how many aortae do turtles have? 3.4 how many functional lungs do turtles possess? 3.5 how are turtles able to stay submerged beneath water for such long periods of time? 3.6 explain blood shunting and the advantage to a three - chambered heart for aquatic turtles. urogenital system reptiles have a metanephric kidney that is more efficient than fish and amphibian kidneys and is more adept at conserving water. the paired kidneys typically are offset in the turtle, with the right kidney in front of the left (fig. 21.10). urine from the ureters (of the colon) from the ureters and then flows backward into the bladder for storage. turtles have large urinary bladders and accessory bladders, and can recirculate urine through their bodies to reuse the water in it. the location of gonads varies slightly in males and females. in females, the ovaries are attached to the posterior of the lungs near the rear of the shell (fig. 21.11a). as eggs mature in the ovaries, they pass into the oviducts, where the eggs are fertilized and subsequently encased in their protective, leathery shells by shell glands. in males, the testes are attached to the kidneys (fig. 21.11b). male turtles and tortoises possess a single copulatory organ, the penis, which is housed in the front portion of the cloaca within the base of the tail and everts into the proctodeum during copulation. during copulation, the male mounts the females shell from behind and locks his hind legs underneath her shell. to achieve intromission, the male often stands on his hind legs while balancing his plastron against the females carapace. in many species, such as eastern box turtles, the males plastron has a concave portion that fits against the convex curvature of the females carapace, making this balancing act somewhat less awkward.

Explanation:

3.1 Herbivorous turtles need to digest plant - based material which is harder to break down. A relatively large cecum can harbor more symbiotic bacteria that aid in the fermentation and digestion of plant matter.
3.2 Turtles have a three - chambered heart (two atria and one ventricle).
3.3 Turtles have two aortae. One aorta carries oxygenated blood from the left side of the ventricle and the other aorta can carry a mix of oxygenated and deoxygenated blood from the right side of the ventricle.
3.4 Turtles have two functional lungs which they use for gas exchange when out of water.
3.5 Turtles can stay submerged for long periods due to several factors. They have a slow metabolic rate which reduces oxygen demand. They can also perform cloacal respiration (gas exchange through the cloaca) in some species, taking up oxygen from water.
3.6 Blood shunting in turtles with a three - chambered heart allows for redirection of blood flow. In aquatic turtles, this can be advantageous as it allows them to bypass the lungs when submerged (since gas exchange is not occurring in the lungs then), conserving energy and oxygen. For example, during diving, deoxygenated blood can be directed more towards the body tissues instead of being pumped to the non - functioning lungs.

Answer:

3.1 The cecum is relatively large in herbivorous turtles.
3.2 A turtle's heart has three chambers.
3.3 Turtles have two aortae.
3.4 Turtles possess two functional lungs.
3.5 Turtles can stay submerged due to a slow metabolic rate and in some species, cloacal respiration.
3.6 Blood shunting in aquatic turtles with a three - chambered heart allows redirection of blood flow to bypass the lungs during submersion, conserving energy and oxygen.