What are gonads in fish?
What are gonads in fish?
Male fishes usually have paired testes that produce sperm. Females usually have paired ovaries that produce eggs. The two long pale organs are the testes, the male gonads. The deep red strips of tissue either side of the backbone are the kidneys.
What do gonads develop into?
The development of the gonads is part of the prenatal development of the reproductive system and ultimately forms the testes in males and the ovaries in females. The gonads initially develop from the mesothelial layer of the peritoneum.
What advantage does gonads provide to the species survival?
In higher animals, the gonad functions in creating gametes and producing hormones necessary for the functioning of complex life.
How do fish relate to gonadal and reproductive development?
The gonadal development is cyclical and seasonal in most fish species. Germ cell renewal, differentiation, development, and the release of sperm/oocytes throughout each reproductive cycle result in gonadal alterations that characterize different reproductive phases.
What are the gonads in the male reproductive system?
Both men and women have gonads. In males, they are the testes, or testicles, the male sex glands that are part of the male reproductive system. The female gonads, the ovaries, are a pair of reproductive glands.
In which stage the development of gonads are completed?
By the eighth week of gestation, Leydig cells of the testes begin to produce testosterone and the testes can influence sexual differentiation of the genital ducts and external genitalia. Formation of the external genitalia is completed by the 12th week.
Which three basic structures are necessary for development of the gonad?
The gonads develop from three sources: the mesothelium (coelomic epithelium) lining the posterior abdominal wall, the underlying mesenchyme (intermediate mesoderm), and the primordial germ cells.
What is the main function of the gonads?
The gonads, the primary reproductive organs, are the testes in the male and the ovaries in the female. These organs are responsible for producing the sperm and ova, but they also secrete hormones and are considered to be endocrine glands.
What is the location and function of the gonads?
The female gonads, the ovaries, are a pair of reproductive glands. They are located in the pelvis, one on each side of the uterus, and they have two functions: They produce eggs and female hormones.
What does gonadal mean?
(gō′năd′) An organ in animals that produces gametes, especially a testis or ovary. [New Latin gonas, gonad-, from Greek gonos, procreation, genitals; see genə- in Indo-European roots.]
What are the male and female hormones produced in the gonads and their functions?
Endocrine system: gonads and their hormones: The gonads are the sex organs. Male testes produce androgens, while female ovaries produce estrogen and progesterone. The ovaries produce hormones, such as estrogen and progesterone, which cause secondary sex characteristics and prepare the body for childbirth.
Are gonads presumptive testes in zebrafish?
In several 7 week‐old zebrafish with altered gonadal morphology, enhanced numbers of gonial cells arranged in cyst‐like groups appeared. These gonads were interpreted as presumptive testes. In one fish out of 32 individuals examined, spermatocytes were detected, in addition to the gonial cells.
Is zebrafish an intersex hermaphrodite?
The developmental pattern described identifies zebrafish to be a juvenile hermaphrodite. The results of this study are of relevance for the use of gonadal histopathology as endpoint in endocrine disruption testing, particularly in order to avoid false diagnoses of ‘intersex gonads’ in zebrafish.
What are the changes in gonad morphology during gonostomy in fish?
Starting with week 5, some fish showed alterations of gonad morphology, including a decrease in the number and size of the oocytes, an enhanced basophilia and irregular shape of the oocytes, and finally their degeneration into residual bodies.
