白枕鹤的呼吸系统及其生态适应

THE RESPIRATORY SYSTEM OF WHITE-NAPED CRANE AND ITS ECOLOGICAL ADAPTATION

白枕鹤的呼吸系统由喉头、气管、鸣管、肺及气囊组成。喉头有淋巴小结分布。气管在龙骨突起内盘旋,并随年龄而增长,软骨环逐渐骨化。鸣管由左右两个支气管特化而成,呈膜状扁管入肺。肺的长度约占躯干的1/2。气囊几遍布全身,高度发达。整个呼吸系统的结构,与其高空飞翔生活相适应。

5 dead Whitt-naped Cranes were collected from Anhui Province during winter. 4 of them were anatomized to observe the macro and micro structures, another one was made into a casting mould specimen for the observation of the form and distribution of air sacs. Throat Contains stratified pavement epithelium, dense connective tissue, striated muscle and cartilage. The cartilage is ossified and with large cavities. There are Lymph nodules within the connective tissue. Trachea Winds within keel and lengthens with the bird growth (Fig. 1). It is composed of mucous membrane, fibracartilage membrane and membrana externa. The cartilage rings ossify gradually, the vacuities within it enlarge and fuse to form the marrow cavities. Syrinx Comes from a pair of specialized bronchi. Its internal lcteral wall is Tympanic membrane, mainly contains fibrous connective tissue, the middle part of cartilage of external lateral wall is ossified and with marrow cavities. Lungs It is as half long as the body length. Air sacs There are one pair of neck air sacs, one interclavicular air sac, one pair of prothoracic air sacs, one pair of metathoracic air sacs, one pair of proabdominal air sacs and one pair of postabdominal air sacs. Except for a small part in the abdomen (81mm X 40mm), air sacs distribute all over the body and enclose throat and abdomen. The branches of interclavicular air sac stretch into the osseous lacuna of keel and form keel air sac. These are all different from those of chicken and doves.