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Showing posts with the label Autotomy

Struktur Ekor Kadal

Cauda Lacertilia tertutup oleh integumen yang bersisik terdiri dari bahan tanduk. Di bagian sebelah dalam integumen berturut-turut terdapat otot tersusun segmental, jaringan lemak perivertebral mengelilingi vertebra caudales dan medulla spinalis yang terletak dalam canalis vertebralis. Serabut-serabut syaraf perifer terletak pada lapisan lemak dan otot serta pembuluh darah terletak di ventral vertebrae (Soesilo, 1982). Secara umum, integumen pada Reptilia terdiri atas 2 lapisan yaitu lapisan luar (epidermis) dan lapisan dalam (dermis) yang dipisahkan oleh membrana basalis yang tipis. Epidermis tersusun atas beberapa lapisan dari luar ke dalam yaitu stratum corneum, stratum granulosum, stratum spinosum dan stratum germinativum. Lapisan sel-sel yang paling dalam (stratum germinativum) aktif membelah secara terus menerus untuk menggantikan lapisan sel terluar epidermis yang terlepas. Pada individu dewasa, lapisan sel terluar ini tersusun atas sel mati yang memipih dan mengalami penandukan...

Gekko gecko

Gekko gecko (Tokay Gecko), locally known to Indonesians as Tokek, is a member of Suborder Lacertilia which can be found from northeast India to southern China and throughout Southeast Asia. There are two identified subspecies of Tokek, those are G. g. gecko (Linnaeus, 1758) and G. g. azhari (Mertens, 1955), the latter is endemic to Bangladesh. This arboreal lizard naturally lives in tropical rain forest but some of them have entered human habitation (Kongbuntad et al., 2016). The taxonomical classification of G. gecko displayed on Integrated Taxonomic Information System (ITIS) is as followed:  Kingdom       : Animalia  Phylum            : Chordata  Subphylum    : Vertebrata  Class              : Reptilia  Order             : Squamata  Suborder        : Gekkota  Family   ...

Axial Skeletal Formation in Regenerating Lizard Tail

Lizard tail regeneration, particularly the cartilage regeneration, is a compelling phenomenon to be studied as it has been widely known that the regenerative capacity of cartilage after injury/trauma is very limited (Tuan et al., 2013). Urodeles are capable to regenerate tissues similar to the originals (Lozito & Tuan, 2015) while the regenerated tail of lizard is considered as an imperfect replica due to the several anatomical differences (Fisher et al., 2012). One stand out structure of those imperfections is that the axial skeleton of regenerated tail is lack of bony structures, but instead, it is composed of cartilage (Alibardi & Meyer-Rochow, 1989). The caudal vertebrae of the original tail will be replaced by a continuous, unsegmented cartilage tube surrounding the growing ependymal canal. This cartilage tube only exists in the regenerated tail of lizard and is maintained throughout the life of the organism. An experiment conducted by Lozito & Tuan (2015) showed that ...

Lizard Tail Regeneration

Lizard ability to regrow its tail following tail amputation is known as regeneration (Hutchins et al., 2016). Regeneration process is initiated by the formation of blastema from the dedifferentiated cells (Daniels et al., 2003; Alibardi & Lovicu, 2010). Later on, Alibardi (2015) stated that progenitor cells also play an important role in this process. These blastemal cells will proliferate and then differentiate to form new tissues to replace the lost/damaged tissue (Carlson, 2007; Narayanan, 2015). Regeneration process is divided into four stages: (1) wound healing stage, lasting up to 10 days post-autotomy (dpa); (2) blastema formation ranging from 10-15 dpa; (3) tail growth and differentiation ranging from 15-25 dpa; and (4) tail maturation when the tail becomes fully scaled (Alibardi, 2009) which is usually studied from 25-60 dpa (Fisher et al., 2012) with no currently known endpoint. Ependymal cells lining the central canal of the original spinal cord appear to be crucial for ...

Lizard Tail Autotomy

Tail autotomy is a common defense mechanism found in lizards (Bely & Nyberg, 2010; Hill et al., 2012; Russell et al., 2015). The autotomized tail will continue to twitch for up to 30 minutes due to the event of anaerobic metabolism (Dial & Fitzpatrick, 1983; Higham & Russell, 2010). This event will divert the attention of predator, giving a chance for the lizard to escape (Daniels, 1983). Even though autotomy may save their lives, lizards performing autotomy have to deal with the loss of tail vital functions in movement (Bateman & Fleming, 2009), establishing social status (Fox & McCoy, 2000; Meyer et al., 2002), and as fat-storage organ (Clark, 1971). Lizards which are using their tail to store fat most likely return to the site where they lost their tail and eat the autotomized tail to make up for the loss of the major fat reserve which comprises half or more total body fat (Congdon et al., 1974; Lin et al., 2006; Naya et al., 2007; Sanggaard et al., 2012). Moreov...

Lizard Tail Structures

McLean and Vickaryous (2011) studied epimorphic regeneration in Eublepharis macularius (Leopard Gecko) and the results showed that the transverse section of the tail is circular to ovoid and the skeletal system is located in the center. The histological observation also showed that the tail is separated into quadrants by the presence of connective tissue known as septa emerging from (1) the neural spine in the dorsal region, (2) chevron bone in the ventral region, and (3) transverse processes on both lateral sides. Both dorsal (epaxial) and ventral (hypaxial) quadrants consist of perivertebral adipose tissue, connective tissue and musculature. The outer part of the tail is well-protected by integument system modified into scales. Various tissues lie under the skin, from the outside in: segmented musculature, perivertebral adipose tissue surrounding the caudal vertebrae and the spinal cord located inside the vertebral canal. Peripheral nerve fibers can be found in the adipose and muscle...