Study On Structural Characteristics Of Reproductive System Of Female Adult Sepioteuthis Lessoniana

The female reproductive system of adult Sepioteuthis lessoniana was studied histologically and cytologically by means of tissue section and transmission electron microscopy.The female reproductive system includes the nidamental gland,accessory nidamental gland,oviducal glands,seminal receptacle and ovary.Detailed and accurate description of the tissue structure characteristics of each gonadal gland,analysis of the function of each gland and its role in reproductive activities.Observe the tissue section of the ovary,and divide the development period of the egg according to the characteristics of each stage of oogenesis.The following were the results of the research.1.The results showed that the surface of the nidamental gland was smooth and milky,with parallel lines on the surface.And we also observed the nidamental gland was composed of three subdivisions: glandular wall tissue,secretory lobe and connective tissue.The glandular wall tissue was composed of the outer membrane layer and the muscular layer,which was located outside of the gland.The secretory lobe was the most important structure in gland and was layered.Also connective tissue mainly existed in the junction of glandular wall tissue and secretory lobe,basement membrane of secretory lobe,and extracellular matrix between secretory cells.Further,the cell composition of the secretory lobes was dissected,which the results suggested that the secretory lobes comprises two cell types,supporting cells and secretory cells.The supporting cells were small,oval in shape,located at the base of the secretate lobe,and the number of organelles in the cells was rare.Only a few mitochondria were observed.However,the secretory cells were large and rectangular with a large number of organelles,including mitochondria,endoplasmic reticulum and golgi complex,visible in the cells.And we observed surprisingly few vesicles and protein vesicles,which were likely concentrated on the outside of the cell.Together,cilia were abundantly produced.We conclude that the nidamental gland was a typical secretory gland,primary function of the gel-forming substances was to form the third layer,which plays an essential role in protecting the fertilized egg against various environmental pollutants.2.The results showed that the accessory nidamental gland was composed of parietal glandular tissue,glandular tubules and connective tissue.Among them,the parietal glandular tissue was composed of columnar epithelial cells and muscle cells.Glandular tubules were surrounded by monolayer epithelial cells,in which there were abundant organelles including mitochondria,endoplasmic reticulum and golgi complex,etc.Glandular glands were numerous and densely packed.There was a large number of rodshaped bacteria and secreted substances in the lumen.The space between the gland tubules is filled with connective tissue,in which there were few blood vessels and muscle fibers.Accordingly,the accessory nidamental gland of S.lessoniana was a secretory gland,the secreted substances include gel-like substances that form egg sheaths and substances that provide nutrients for symbiotic bacteria.The source of symbiotic bacteria belongs to "horizontal transmission",and its secreted substances have antibacterial activity.3.The oviducal gland was surrounded by glandular wall tissue.The outer layer was composed of columnar epithelial cells,and a small amount of muscle tissue and blood vessels were distributed in the connective tissue.A small number of goblet cells were distributed in the outer layer of the glands and transparent valve,which was mainly composed of muscle tissue.Inside the gland was the secretory lobe,which showed a layered distribution and attached to the gland wall tissue.When the gland was immature,the secretory lobe exhibited a regular shape,and the gap between leaflets was large.Secretory cells comprised single columnar epithelial cells,and a small amount of mucinous gonads were generated.When the gland reached maturity,the secretory cells disappeared,the acini ruptured,and secretory material filled the gland.Under electron microscopy,the secretory cells appeared large with round or elliptic nuclei and contained a large number of organelles,such as endoplasmic reticulum,mitochondria,and golgi apparatus.In addition,numerous mucus particles were distributed inside the cells,and cilia were continuously generated externally.The clear valve was mainly composed of muscle cells with cross-cut and longitudinally cut myofilaments and abundant collagen fibers.According to the analysis,oviducal gland is an important gland in the reproductive system of female cephalopods.This gland has a secretion function,and its secreted substances form the inner layer of the egg sheath of fertilized eggs.Thus,the oviducal gland plays an important role in the incubation process of fertilized eggs.4.The seminal receptacle was composed of cyst wall tissue,central lumen and sperm storage vesicle.The number of sperm storage vesicles was large,and a few lumens were round or oval.The wall of the sperm storage vesicle cyst was composed of a single layer of epithelial cells with a large number of cilium.The vesicles were separated by connective tissue and muscle tissue.The epithelial cells of the sperm storage vesicle were closely arranged,and the nuclei were large.The cytoplasm contained a variety of organelles,including mitochondria,endoplasmic reticulum,golgi complex and vesicles.Sperms were arranged closely and orderly in the cystic lumen.The head of the sperm were oriented towards the cilium,and the flagella was located in the middle of the cystic lumen.It was concluded that the seminal receptacle of S.lessoniana could store sperm.5.The S.lessoniana oocyte individual was small and gradually increases with development and maturation;The flat follicular cells first appear and wrap the oocytes,then a layer of elliptical follicular cells was formed outside the flat follicular cells.The double-layer follicular cells gradually rolled inward into the oocyte and formed fingerlike processes.The finger-like processes gradually connected into a network and filled the whole cell.The nucleus of the oocyte was squeezed to one side.At this time,the flat follicular cells began to disintegrate,and a small amount of yolk material began to form in the process space.Finally,the follicular cells were completely disintegrated,the oocyte is filled with yolk material,and the oocyte reaches its maximum.S.lessoniana eggs occurred according to the above characteristics,be divided into the first stage(oogonia phase),the second stage(no follicular cell phase,single follicular cell phase and double follicular cell phase),the third stage(early phase of follicular cell proliferation,middle phase follicular cell proliferation and late phase of follicular cell proliferation)and the fourth stage(yolk accumulation phase,mature phase),a total of four stages of nine times.