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1、Digestive PropertiesDigestive AnatomyThe follow ing diagram is specific to the Kan garoo, but is comparable to that of a wallaby:消化系统属性消化系统解剖下图具体到袋鼠，但相当于一个小袋鼠的:Photo taken from the book published byStevens and Humes (1995) on Comparative Physiology of theVertebrate Digestive System (图片来自Steve ns and
2、 Humes (1995)出版的脊椎动物消化系统的比较生理学) Digestive PhysiologyThis specie has temporal, masseter and pterygoid muscles in the jaw and temple that help it chew and bite on things (Hume, 1989). Upon ope ning its mouth, the lower jaw moves forward in comparis on to the upper and the pterygoid muscle con tracti o
3、ns allow lower in cisors to rub aga inst the upper ones (Hume, 1989). This mecha nism allows for grasp ing the food and once grasped, the lips work with the ton gue to push food to the molars where it gets chewed up and passed into the stomach (Hume, 1989).消化生理这个物种在下颌和太阳穴有颞肌、咬肌和翼状肌帮助其咀嚼和咬东西。当打开它的嘴时，
4、下颌较上 颌向前移动，翼内肌的收缩使下切齿摩擦上切齿。这种机制用于抓取食物，一旦抓取，嘴唇与舌头一起工 作将食物推动到臼齿进行咀嚼，并通过此处进入胃。DLcodenum11CmcuitiTooniD(Mstal cotonRectumTubhform r fare-fromAchSCdform fore $tflmach Hnd4tomaehTubiforrift torMtcmtc100 200 mm Smatl inttrnPl&ruaPylorusTaenia0 100 2Q0rtinftL ,Sacciform T fcre-WmchPioximii ccionDigestive tr
5、act and stomach of the eastern grey kangaroo (Mucropus giganteus), a fore-gut fermenter,(东部灰袋鼠的消化道和胃，一个前肠发酵罐)50-70 kg body mass. From Hume (1982).Wallabies, alike other marsupials, are fore-gut ferme nters that have an expa nded and differe ntiated fore-stomach (Hume, 1989). Aside from being large a
6、nd complex, their stomach is sacculated and has an oesophageal groove by-pass ing the sacculated regi on (Moir et al. 1956). The sacciform regi ons (with rapid decli nes of soluble carbs) and tubiform regi ons (with uni form fibre digesti on) are resp on sible for microbial ferme ntati on in the for
7、e-stomach, whereas the hin d-stomach holds the acid-peps in-secreti ng regi on (Hume, 1989). The exter nal musculature of the fore-stomach has 3 tae nia and semi-l unar folds (Hume, 1989). Haustrati ons are formed betwee n these folds that give it a colon-like appeara nee (Hume, 1989). This colon-li
8、ke stomach reduces the digesta retention rate, which means less time is taken to break dow n the microbes of pla nt cell walls in the fore-stomach. (Hume, 1989). Whe n digesta moves through the fore-stomach, the substrate is ferme nted and based less on soluble cell contents and more on its cell-wal
9、l COn stitue nts (Hume, 1989). Due to the wallabys large sacculated stomach ankefdaekum, it is suggested pre-gastric bacteria ferme ntati on dom in ates Moir et al. 1956). This rum inan t-like digestive morphology is what allows wallabies and their kan garoo cous ins to survive on poor graz ing. (Mo
10、ir et al. 1956)像其他有袋目哺乳动物一样，小袋鼠具有一个扩大的分化了的前胃，也是前肠发酵罐。 除了是庞大而复杂的，他们的胃呈囊状，并具有一个分流囊状区域的食管沟。该囊状区域(与 用于溶性碳水化合物的快速下降)和管状区域(用于统一纤维消化)负责前胃中的微生物发 酵，反之，后胃为胃酸蛋白酶分泌区。前胃的外部肌肉组织有 3 条绦虫状和半月形皱襞。 Haustrations 是这些皱襞之间形成的，并呈结肠样外形。这个结肠样的肠袢降低了食糜滞留 率，这意味着前胃中用于分解解植物细胞壁上微生物的时间更少了。当食糜移动通过前胃时， 底物被发酵，并且更少的基于可溶性细胞内容物而是更多在其细胞壁组分。由于袋鼠的大囊 状胃和烧瓶状盲肠，决定了前胃细菌发酵占主导地位。是这种像反刍动物一般的消化道形态 让小袋鼠和他们的袋鼠兄弟们能够在贫瘠的牧场生存下来。 (莫尔等人1956年)
