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The tunica albuginea is composed of short connective tissue fibers. It is located immediately inside the surface epithelium (previously known as germinal epithelium) which is continuous with the peritoneum. It is non-vascularised. [1] It is thinner than the tunica albuginea of the testis, and its thickness varies across the ovary. [1]
The primitive jawless fish have only a single testis, located in the midline of the body, although even this forms from the fusion of paired structures in the embryo. [2] Under a tough membranous shell, the tunica albuginea, the testis of some teleost fish, contains very fine coiled tubes called seminiferous tubules.
The ovary changes structure and function beginning at puberty. [2] Since the ovaries are able to regulate hormones, they also play an important role in pregnancy and fertility. When egg cells (oocytes) are released from the fallopian tube, a variety of feedback mechanisms stimulate the endocrine system, which cause hormone levels to change. [10]
Many of the features found in ovaries are common to all vertebrates, including the presence of follicular cells and tunica albuginea There may be hundreds or even millions of fertile eggs present in the ovary of a fish at any given time. Fresh eggs may be developing from the germinal epithelium throughout life.
Stromal cells associated with maturing follicles may acquire endocrine function and secrete estrogens. The entire ovarian stroma is highly vascular. [1] On the surface of the organ this tissue is much condensed, and forms a layer (tunica albuginea) composed of short connective-tissue fibers, with fusiform cells between them.
The outer layer of cells of an apical meristem. This is known as the tunica. In biology, a tunica (/ ˈ t (j) uː n ɪ k ə /, [1] UK: / ˈ tʃ uː n ɪ k ə /; pl.: tunicae) is a layer, coat, sheath, or similar covering. The word came to English from the Neo-Latin of science and medicine.
Tunica albuginea may refer to: Tunica albuginae (clitoris), the fibrous-elastic sheath of connective tissue that surrounds the shaft and glans of the clitoris; Tunica albuginea oculi, the tough fibrous layer that covers most of the eyeball; Tunica albuginea (ovaries), the connective tissue covering of the ovaries
The embryological origin of granulosa cells remains controversial. In the 1970s, evidence emerged that the first cells to make contact with the oogonia were of mesonephric origin. It was suggested that mesonephric cells already closely associated with the oogonia proliferated throughout development to form the granulosa cell layer. [2] [3] [4]