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For instance, in birds, male and female somatic cells may exhibit intrinsic differences due to CASI, but the extent to which these differences manifest in tissues can be influenced by circulating hormones such as estrogen and testosterone. Hormones act as amplifiers, enhancing or suppressing sex-specific characteristics that are intrinsically ...
Most male fish have two testes of similar size. In the case of sharks, the testes on the right side is usually larger [citation needed].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.
A gonad, sex gland, or reproductive gland [1] is a mixed gland and sex organ that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. [2] The male gonad, the testicle, produces sperm in the form of spermatozoa. The female gonad, the ovary, produces egg cells
Most normal female fish have two ovaries. In some elasmobranchs, only the right ovary develops fully. In the primitive jawless fish and some teleosts, there is only one ovary, formed by the fusion of the paired organs in the embryo. [57] Fish ovaries may be of three types: gymnovarian, secondary gymnovarian or cystovarian.
In these cases, a small number of female gonads were observed within male individuals, typically ranging from 2 to 5 gonads out of a total of 45–50. An extraordinary occurrence of complete sex reversal was documented in B. belcheri, where a female amphioxus raised in laboratory conditions underwent a transformation into a male (Zhang et al ...
Sea urchins are dioecious, having separate male and female sexes, although no distinguishing features are visible externally. In addition to their role in reproduction, the gonads are also nutrient storing organs, and are made up of two main type of cells: germ cells, and somatic cells called nutritive phagocytes. [20]
In embryology, the genital ridge (genital fold or gonadal ridge) is the developmental precursor to the gonads. The genital ridge initially consists mainly of mesenchyme and cells of underlying mesonephric origin. Once oogonia [clarification needed] enter this area they attempt to associate
The prostate is found in the mantle tubule and penis are both connected to the gonoduct; which are connected to the testis (produce sperm). During sex, the sperm travels along the mantle tube in which seminal fluid fills the mantle tube and exits the body via the penis and enters the female's gonopore. [16] Additional reproductive structures ...