松江鲈鱼皮肤的显微和亚显微结构观察

采用光学显微镜、扫描电镜和透射电镜,对松江鲈鱼（Trachidermus fasciatus）成体皮肤的显微结构和亚显微结构进行了观察。结果表明,松江鲈鱼体表不同部位皮肤的厚薄不一,但基本结构相似。皮肤由表皮和真皮层构成。松江鲈鱼的皮肤裸露无鳞,表皮层较薄,由约4～8层细胞构成,主要由复层上皮细胞和黏液细胞及基底细胞组成。表层细胞呈扁平、多边形, 细胞之间主要靠桥粒紧密连接,连接处形成增厚的边缘嵴状突起。表皮细胞游离面向内凹陷,表面形成指纹状微嵴。黏液细胞呈圆形或卵圆形,散布在上皮细胞之间。黏液细胞内的黏原颗粒具有椭圆颗粒状、均匀致密的块状和疏松丝状3种不同形态。真皮通过基膜与表皮相连,由稀疏层和致密层构成。真皮结缔组织在腹部较厚而在其他部位较薄。表皮与真皮连接处有色素层,头部、背部、尾柄和体侧皮肤色素细胞分布多,色素层明显,而腹部和颏部皮肤缺少色素。松江鲈鱼黄河群体真皮层中有角质棘状突起,而滦河群体则无。头部、体侧和尾柄处皮肤上还分布有侧线孔和表面神经丘等感觉器官。     

金佛拟小鲵幼体皮肤的显微结构观察

采用光镜和扫描电镜对金佛拟小鲵(Pseudohynobius jinfo)幼体皮肤进行组织学和形态学观察。金佛拟小鲵幼体皮肤由表皮和真皮构成。不同部位皮肤厚度不同,头部背侧皮肤最薄,其厚度为(45.99±12.77)μm,尾部腹侧的皮肤最厚,其厚度为(95.21±42.72)μm。表皮角质层仅躯干背部和尾部明显,由仍具有一定生理活性的复层扁平上皮细胞构成。皮肤腺体包括黏液腺和颗粒腺。黏液腺广泛分布于身体各个部位的皮肤,颗粒腺呈区域性分布,仅见躯干部和尾部皮肤,其体积大于黏液腺。毛细血管多分布于真皮疏松层腺体周围,与表皮层紧密接触并凸向表皮。色素细胞主要分布于表皮和疏松层的交界处,呈多细胞聚集的状态,形成厚度不一的色素层。     

雄性峨眉髭蟾“胡子”的组织结构特征

采用石蜡切片与苏木精-伊红染色及扫描电镜,对雄性峨眉髭蟾Leptobrachium boringii的角质刺及其周边皮肤进行了显微结构和亚显微结构的观察。显微结构观察发现,峨眉髭蟾的角质刺属于皮肤衍生物,突起呈倒"V"形。角质刺由表皮和真皮构成,表皮为复层扁平上皮,可分成4层;最外层细胞角质化,细胞轮廓不清,被染成深红色。真皮由疏松结缔组织构成,分辨不出致密层与疏松层,其内未见皮肤腺,但有少量色素细胞与毛细血管分布。表皮嵴伸入到真皮层,在以往的无尾两栖类研究中未见报道。角质刺基部可见皮肤褶翻起将其包裹在内,皮肤褶向上延伸形成角质刺。扫描电镜观察表明,角质刺顶端呈锥形的"小山丘"状,表面可分辨出表皮细胞轮廓,细胞为呈覆瓦状排列的角质化细胞。角质刺与皮肤交界处为多边形的角质化细胞。角质化上皮细胞的上表面与下表面均具有凹凸不平的花纹结构,细胞之间以镶嵌的方式连接。     

爪鲵皮肤的显微结构和呼吸作用(图版Ⅵ)

本文报道了爪鲵皮肤和腺体的显微结构特点及腺体和毛细血管的分布特点。其表皮较薄,由2～7层细胞构成,真皮厚度与腺体大小有关,致密层在腹部较厚而在其他部位稀少。爪鲵皮肤不仅具有粘液腺和颗粒腺,而且还出现了一种特殊的类似脂肪细胞构成的腺体,该腺体只分布于体背部与体腹部的交界处。颗粒腺集中在躯体和尾的背部,粘液腺主要集中分布于腹部。毛细血管在皮肤中极其丰富,背部分布密度明显大于腹部。毛细血管分布于表皮下,并常向表皮突起,突起处表皮细胞层数减少,形成皮肤的血气呼吸屏障,以保证皮肤有效的呼吸作用的完成。     

爪鲵皮肤的显微结构和呼吸作用

本文报道了爪鲵皮肤和腺体的显微结构特点及腺体和毛细血管的分布特点。其表皮较薄 ,由 2～ 7层细胞构成 ,真皮厚度与腺体大小有关 ,致密层在腹部较厚而在其他部位稀少。爪鲵皮肤不仅具有粘液腺和颗粒腺 ,而且还出现了一种特殊的类似脂肪细胞构成的腺体 ,该腺体只分布于体背部与体腹部的交界处。颗粒腺集中在躯体和尾的背部 ,粘液腺主要集中分布于腹部。毛细血管在皮肤中极其丰富 ,背部分布密度明显大于腹部。毛细血管分布于表皮下 ,并常向表皮突起 ,突起处表皮细胞层数减少 ,形成皮肤的血气呼吸屏障 ,以保证皮肤有效的呼吸作用的完成。     

西藏蟾蜍皮肤的组织学观察

为了解西藏蟾蜍Bufo tibetanus与其高海拔生活环境的适应性,采用常规石蜡切片和苏木精-伊红染色方法,对西藏蟾蜍雌雄性头部、躯干和四肢的背、腹侧皮肤显微结构进行了观察、测量和比较。结果显示皮肤的基本结构与已报道的无尾两栖类相似,由表皮和真皮组成。表皮较薄,由5~8层细胞构成,由外到内分为角质层、中间层和基底层。真皮较厚,分为疏松层和致密层。各部位大多表现为背侧皮肤厚度大于腹侧,相应部位大多为雌性大于雄性。皮肤厚度的变化在一定程度上与西藏蟾蜍运动方式和繁殖期间抱对行为相适应。皮肤腺体分粘液腺和颗粒腺2种。色素细胞主要分布在疏松层近表皮处,但在表皮和腺体周围也可见色素细胞的不连续分布。皮肤中毛细血管极其丰富,不仅在表皮下几乎成连续分布,而且在腺体周围也有密集分布。西藏蟾蜍皮肤结构明显表现出与生活环境中强紫外辐射和缺氧环境相适应的特点。     

似鲇高原鳅皮肤与鳍的组织学观察

采用石蜡切片技术及H.E和AB-PAS染色方法,对似鲇高原鳅(Triplophysa siluroides)头部、腹部、背部、侧线部和尾部皮肤结构及胸鳍、腹鳍、背鳍、臀鳍和尾鳍的组织结构进行观察。各部位皮肤均由表皮和真皮构成,真皮包括疏松层和致密层,不同部位皮肤厚度不同。表皮层腹部最厚,为(84.62±10.82)μm,侧线部最薄,为(14.97±3.95)μm,各部位表皮厚度差异显著。表皮层分布着黏液细胞、棒状细胞及味蕾。疏松层头部最厚,为(282.71±70.56)μm,尾部最薄,为(29.07±4.88)μm,该层分布有黑色素细胞、空泡状细胞和颗粒腺,而黏液腺分布于致密层。各部位的鳍均由表皮层、胶原纤维层、胶原下层及鳍条构成,表皮层与皮肤表皮层组成相似,鳍条是矿化的结缔组织。     

石磺科3种贝类皮肤显微结构比较

应用石蜡切片和H.E染色技术,对石磺科(Onchidiidae)3个属的代表物种:瘤背石磺(Onchidium struma)、平疣桑椹石磺(Platevindex mortoni)和里氏拟石磺(Paraoncidium reevesii)的皮肤进行了组织学观察及参数测量比较。结果表明,3种石磺的皮肤虽然厚度不一,但基本结构相似,均由角质膜、表皮和真皮构成。角质膜是一层覆盖于表皮角质层上的蛋白质薄膜;表皮由多层上皮细胞构成,包括角质层、颗粒层和生发层;真皮包括疏松层和致密层,疏松层中嵌有颗粒腺和黏液腺两种腺体。3种石磺的皮肤厚度、各组织相对厚度及腺体数量等均存在差异。将结构差异与石磺的栖息环境进行比较分析后得到:陆栖为主的瘤背石磺皮肤表皮角质化程度高,颗粒腺发达;以水栖为主的里氏拟石磺表皮角质化程度相对低,黏液腺发达;而水陆两栖的平疣桑椹石磺,皮肤角质化程度介于前述二者之间,颗粒腺与黏液腺均不发达。研究结果体现了三者不同的生态适应特征,也为深入探讨海洋无脊椎动物从海洋向陆地进化的研究提供形态学依据。     

十一种无尾两栖类物种皮肤和肺显微结构

无尾两栖类动物的呼吸方式为肺呼吸和皮肤辅助呼吸,为探究两种呼吸器官的显微结构,本文采用解剖学和组织学的方法,对大蹼铃蟾(Bombina maxima)、腺角蟾(Megophrys glandulosa)、中华蟾蜍(Bufo gargarizans)、华西雨蛙(Hyla gongshanensis)、昭觉林蛙(Rana chaochiaoensis)、滇蛙(Dianrana pleuraden)、双团棘胸蛙(Gynandropaa yunnanensis)、贡山树蛙(Rhacophorus gongshanensis)、斑腿泛树蛙(Polypedates megacephalus)、饰纹姬蛙(Microhyla fissipes)、多疣狭口蛙(Kaloula verrucosa)的皮肤和肺的形态及显微结构进行观察。结果显示,背部和腹部皮下可见血管交错成网状,皮肤由表皮层和真皮层构成。除华西雨蛙外,其余10种均有分布于真皮疏松层与致密层间的钙化层;色素细胞位于疏松层上层,体背色素层较发达。肺囊状,中空密布血管,分为大小相当的左右肺叶,两肺叶相通并与心粘连,无气管和支气管。肺由肺囊壁、隔膜、毛细血管、肺泡细胞等结构组成。肺囊壁分为胸膜层、中间层和内层:胸膜层由扁平细胞构成,中间层由结缔组织构成,内层由肺细胞和毛细血管组成,隔膜由毛细血管和结缔组织构成,游离隔膜向中部靠拢可形成半封闭腔室,结合隔膜与肺囊壁形成封闭小腔室。在这11个物种中,肺较发达的个体,其皮肤结构中黏液腺的数量就会相对较少,组织形态学特征表现出与环境适应性关系较大,而受到系统发育关系影响较小。     

红瘰疣螈皮肤的显微结构观察

对我国Ⅱ级重点保护野生动物红瘰疣螈(Tylototriton shanjing)成体的皮肤结构进行了显微观察。观察结果表明,其皮肤厚薄、微血管、色素分布,以及腺体的分布和大小等方面在身体的不同部位存在差异:头和背部的皮肤厚于腹部;黑色素细胞多分布于真皮浅层,以腹部及背侧无瘰粒处多见;真皮层富含黏液腺和颗粒腺,但分布不均匀;头嵴棱部及背部瘰粒下方颗粒腺的数量多、体积大,并充满分泌物;表皮下腺体外突,其表皮细胞层数减少,形成分泌物有效通道。同时,将红瘰疣螈皮肤与其他两栖类相比可知,其以上皮肤结构特征均体现了红瘰疣螈对山区阴湿环境中陆栖生活的重要适应。     

Structure of the skin of an air-breathing mudskipper, Periophthalmus magnuspinnatus

The epidermis of the mudskipper Periophthalmus magnuspinnatus consisted of three layers: the outermost layer, middle layer and stratum germinativum. Extensive vascular capillary networks were present near the superficial layer of epidermis and outermost layer. The diffusion distance between the vascular capillaries and the surface of epidermis was c . 1.5 ± 0.9μm. The middle layer consisted of small or voluminous cells swollen by epidermal cells. Due to the swollen cells, the thickness of the epidermis increased and the epidermis appeared web-like. The swollen cells contained tonofilaments, lucent contents and desmosomes. Fine blood capillaries were also discernible in this layer. Well-developed lymphatic spaces containing lymphocytes existed in the stratum germinativum. Numerous blood capillaries were present under the basement membrane. The dermis consisted of a stratum laxum and stratum compactum, and there was a definite area with acid mucopolysaccharides and a small scale in the stratum laxum. The skin had an epidermal pigment cell, dendritic melanophores (-cytes) containing melanin granules within their cytoplasm, and two kinds of dermal pigment cells, melanophores and colourless pigments containing reflecting platelets.     

Local cutaneous water barrier in cold- and heat-acclimated pigeons (Columba livia) in relation to cutaneous water evaporation

The thermoregulatory function of the skin differs in adult cold-acclimated and heat-acclimated rock pigeons (Columba livia). In general, the cutaneous evaporative cooling mechanism is not activated by appropriate stimuli in cold-acclimated pigeons in contrast to heat-acclimated pigeons. We studied with electron microscopy whether the differences in the function of the skin are reflected in the structure of the epidermal water barrier of these two extreme acclimation states. The epidermis of cold-acclimated pigeons is attenuated, and the underlying dermis lacks any intimate vascularization. Both the extracellular and the intracellular domains in the stratum corneum contain organized lamellar lipids. At the stratum transitivum-stratum corneum interface, multigranular body secretion is indicated by the highly convoluted cell membranes and membraneous sacculae enclosing the multigranular bodies. Alternatively, multigranular bodies retain in the corneocytes, and the lipoid material originated from them is reprocessed to broad lamellae. The keratohyalin (KH) granules are spotlike and oriented as cortical bands beneath the plasma membrane. In heat-acclimated pigeons, the epidermis displays modified patches side by side with basic structural type of epidermis. The modified areas are characterized by hypertrophy and abundance of dermal capillaries adjacent to the hypertrophied patch. No lamellar lipids are discerned in the dilated extracellular space. The structure of multigranular bodies is abnormal, and the numbers of lipid droplets in the outer viable epidermis and stratum corneum are decreased. The transitional cells contain stellate KH granules, which form a network throughout the cell. It is concluded that cold-acclimated pigeons have a lamellar, extracellular water barrier, the cutaneous water evaporation is minimized, and heat is stored in the body core. Acclimation to heat leads to formation of structurally heterogeneous skin. The structurally modified skin patches show disruption of the barrier-forming machinery in the multigranular bodies and marked reorganization of fibrillar proteins and electron-dense KH masses in the transitional layer. Thus water barrier adjustments in cold- and heat-acclimated pigeons manifest the dynamic function of avian skin as a thermoregulatory organ.     

Ultrastructural features of skin pigmentation in the lizard Heloderma suspectum with emphasis on xanto‐melanophores

The morphological origin of the dark and pink‐orange areas in the skin of the venomous lizard Heloderma suspectum is not known. Histology and electron microscopy show that dark‐grey areas of the skin derived from dermal chromatophores localized in specific areas present underneath the epidermis. A dynamic chromatophoric unit in the dermis is absent. In the darkest areas of the skin, the accumulation of melanosomes in cells of the beta‐layer contributes to increase the black intensity. In the orange‐pink areas, the superficial dermis contains xantophores storing numerous carotenoid vesicles, rare or absent lamellated pterinosomes and a variable number of melanosomes. These xanto‐melanophores predominate over the remaining chromatophores and form a continuous stratum underneath the epidermis. Beneath this lipoid‐rich stratum, iridophores are infrequent and do not form a continuous layer in the dermis. In the paler areas of the skin, melanophores are sparse in both superficial and deeper part of the dermis where irregularly oriented bundles of collagen fibrils are present. The prevalent xanto‐melanophores localized in the pink‐orange areas of the skin contribute to an effective sunlight protection in desert conditions in addition to the darker regions occupied by melanophores.     

Localization of prolactin receptor in the dorsal and ventral skin of the frog (Rana ridibunda)

The dorsal and ventral skin in amphibians plays an important role in osmoregulation. Prolactin hormone is involved in regulation of amphibian skin functions, such as water and electrolyte balance. Therefore, amphibians may be useful as a model for determining the sites of the prolactin receptor. In this study, prolactin receptor was detected in frog dorsal and ventral skin using immunohistochemical staining method. Prolactin receptor immunoreactivity was localized in all epidermal layers except stratum corneum of dorsal skin epidermis, stratum germinativum layer of ventral skin epidermis, myoepithelial cells, secretory epithelium and secretory channel cells of granular glands in both skin regions. The mucous glands and secretory granules of granular glands did not show immunoreactivity for the prolactin receptor. According to our immunohistochemical results, the more widespread detection of prolactin receptor in dorsal skin epidermis indicates that prolactin is more effective in dorsal skin. Presence of prolactin receptors in epidermis points out its possible osmoregulatory effect. Moreover, detection of receptor immunoreactivity in various elements of poison glands in the dermis of both dorsal and ventral skin regions suggests that prolactin has a regulatory effect in gland functions.     

The ultrastructure of the integument of the American eel,Anguilla rostrata

Summary The morphology and ultrastructure of the lateral body integument of the leptocephalus, glass eel, pigmented elver, and adult stages of the American eel, Anguilla rostrata, were examined with light and electron microscopy. The integument consists of an epidermis separated by a basal lamina from the underlying dermis. Three cell types are present in the epidermis in all stages. Filament-containing cells, which are the principal structural cell type, are increasingly numerous at each stage. Mucous cells, which secrete the mucous that compose the mucous surface coat, are also more numerous in each subsequent stage and are more numerous in the anterior lateral body epidermis than in the posterior lateral body epidermis of the adult. Club cells, whose function is unknown, are most numerous in the glass eel and pigmented elver. Chloride cells are common in the leptocephalus which is marine and infrequent in the glass eel. They are not present in the pigmented elver and adult which inhabit estuaries and fresh-water. Lymphocytes and melanocytes are also present in some stages. The dermis comprises two layers: a layer of collagenous lamellae, the stratum compactum, and an underlying layer of loose connective tissue, the stratum spongiosum.There is a progressive increase in epidermal thickness at each stage which is paralleled by an increase in the thickness of the stratum compactum. Rudimentary scales are present in the dermis of the adult. The increase in the number of epidermal filament-containing cells, epidermal thickness and stratum compactum thickness is correlated with an increased need for protection from abrasion and mechanical damage as the eel moves from a pelagic, oceanic habitat to a benthic, freshwater habitat. The increase in mucous cell numbers is likewise correlated with an increased need for the protective and anti-bacterial action of the mucous surface coat in the freshwater environment.This investigation was supported by NIH research grant NS-11276 from National Institute of Neurological Diseases and Stroke to Dr. J.D. McCleave and by N.S.F. Grant GD 38933 to the Bermuda Biological Station, St. Georges West, Bermuda. Bermuda Biological Station Contribution No. 668     

On the vascularization and structure of the skin of a Korean bullhead Pseudobagrus brevicorpus (Bagridae, Teleostei) based on its entire body and appendages

To investigate the vascularization and structure of the skin and its relationship to cutaneous respiration in Pseudobagrus brevicorpus , a histological study by light microscopy was carried out on 15 regions of the skin, including eight body regions, six fins and the barbel. The skin consisted of the epidermis, dermis and subcutis in all regions, except for the barbel that had a relatively thin dermis and subcutis. The epidermis was composed of the outermost layer, the middle layer and the stratum germinativum. There were two kinds of gland cells: the unicellular mucus cells and large club cells. The middle layer had a small number of fine blood capillaries accompanied by dermal collagen in all regions; the mean number of blood capillaries ranged from 0.9 to 5.9. The mean diffusion distance between the capillary endothelial cells and the surface of the epidermis ranged from 50.6 to 126.8 μm. Based on these intra-epithelial blood capillaries, the relative surface area of the respiratory epithelium ranged from 0.1 to a maximum value of 1.2%. The dermis lacking scales had collagen bundles arranged parallel to each other, but vertical fiber bundles around the dorso-lateral regions were seen at intervals. Sensory organs such as taste buds, pit organs and lateral canals were found whereby the taste buds in particular were more abundant in the epidermis of the barbel. The vascularization of the skin may be closely related to an additional respiratory system used to deal with an extreme hypoxic condition during dry seasons.     

Induction of epidermal mucous metaplasia by culture of recombinants of undifferentiated epidermis and retinol-treated dermis in a chemically defined medium

Epidermal mucous metaplasia of cultured skin is known to be induced by excess retinol. Studies were made on whether retinol affects primarily the epidermis or the dermis during retinol-induced epidermal mucous metaplasia of 13-day-old chick embryonic skin in culture. When recombinants of 13-day-old normal epidermis and retinol-treated dermis were cultured for 7 days in chemically defined medium in the absence of retinol, hormones, and serum, they showed altered epidermal differentiation toward secretory epithelium (mucous metaplasia). Thus retinol acted primarily on dermal cells.     

A comparative study on vascularization and the structure of the epidermis of an amphibious mudskipper fish,Scartelaos gigas (Gobiidae,Teleostei), on different parts of the body and the appendages

Epidermal structure of the amphibious mudskipper, Scartelaos gigas (Gobiidae), was investigated in relation to their terrestrial adaptation whereby a histological study on the epidermis of 15 regions including nine body regions, five fins and the sucking disc was carried out. The structure of the epidermis consists of three layers: an outermost layer with polygonal cells or rather flattened cells, small cells and mucous cells; a thick middle layer with voluminous cells swollen by epidermal cells; and the stratum germinativum. A dermal bulge was located at each apical area of the epidermis of almost all body regions, but was not existent in the operculum and the appendages, including none of the fins or the sucking disc. In the epidermis of the body regions, the dermal bulges had numerous dermal capillaries just beneath the stratum germinativum. By contrast, the appendages never had dermal capillaries due to the absence of the dermal bulge. Based on these results, the cutaneous air uptake in S. gigas would seem to be more effective in the upper body regions that are most often exposed to air than in the lower body regions, however, cutaneous air uptake is not likely to occur in the appendages.