What part of the digestive system would you see in a cross-section anterior to the gizzard? What structure in the earthworm has a similar function as the human heart? Explain your answer. What do two earthworms exchange during mating? Explain your answer. Describe the difference between a closed and an open circulatory system. Do earthworms have a front and a back end? Explain your answer. What characteristics distinguish an annelid from other worms?
Preview: ... the digestive system would you see in a cross-section anterior to the gizzard? A. The ORAL CAVITY: Mouth, Tongue, Pharynx Q. What structure in the earthworm has a similar function as the human heart? Explain your answer A. The lateral heart is the blood pumping org ...
The full tutorial is about 199 words long .
Earthworm. This time you will give me "A"
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- Posted on May. 31, 2011 at 04:14:42AM
Preview: ... heart and blood vessels. Contractions keep blood circulating in one direction. Smaller blood vessels supply the gut, nerve cord, and the body wall. Blood glands are present on the 4th, 5th and 6th segments. They produce blood cells and haemoglobin which is dissolved in blood plasma. Â The largest blood vessel is the longitudinal Dorsal Vessel which has muscular walls. It is situated above the alimentary canal. Peristaltic contraction occur at the rear end of the vessel and drive blood forward towards the anterior end of the animal, backflow being prevented by a series of valves.Â The dorsal vessel connects with the smaller, more contractile, ventral vessel via 5 pairs of contractile â€˜pseudo heartsâ€™ located in segments 7-11. Each â€˜pseudo heartâ€™ possesses 4 valves which permit the blood to flow only towards the ventral vessel. These structures in the earthworm have a similar function as the human heart. Â 3. What do two earthworms exchange during mating? Â Earthworm is hermaphrodite (bisexual), i.e., testes and ovaries are present in the same individual (Figure 7.13). There are two pairs of testes present in the 10th and 11th segments. Their vasa deferentia run up to the 18th segment where they join the prostatic duct. Two pairs of accessory glands are present one pair each in the 17th and 19th segments. The common prostrate and spermatic duct (vary differential) opens to the exterior by a pair of male genital pores on the ventro-lateral side of the 18 th segment. Four pairs of spermathecae are located in 6th-9th segments (one pair in each segment). They receive and store spermatozoa during copulation. One pair of ovaries is attached at the inter-segmental septum of the 12th and 13 th segments. Ovarian funnels are present beneath the ovaries which continue into oviduct, join together and open on the ventral side as a single median female genital pore on the 14th s ...
Earthworm.doc (44K) (Preview)
The full tutorial is about 1399 words long plus attachments.
Earthworm.doc (44K) (Preview)