Urogenital organs of the frog - Visual Dictionary
The excretory and reproductive systems are closely senshido.info share certain common passages such as in males where urinary tract. The excretory system of a frog consists of a kidney pair, a pair of ureters, a urinary or the genitourinary system because often the reproductive and urinary system The phylogenetic tree shows the relationship and evolution of animals. A frog's excretory system is made up of the kidneys, bladder, ureters, and the cloaca. The kidneys are in charge of filtering blood and removing the urea and.
Blood comes to glomeruli from afferent arterioles which have a wider lumen then the capillaries so that the blood in glomeruli is under high pressure which causes filtration of blood. The glomerular filtrate does not contain corpuscles nor plasma proteins, it has plasma, wastes and crystalloids consisting of urea, inorganic salts, glucose and large quantities of water.
In the convoluted tubules selective reabsorbtion of useful substances takes place. The substances that are useful, such as glucose, amino acids, inorganic chlorides and some water are reabsorbed from the filtrate and put back into the blood of the capillaries of renal veins, while harmful substances such as urea and other salts along with water form urine which passes through the collecting tubes into ureters and goes to the cloaca.
It is stored in the urinary bladder for a time. When bladder is full, its involuntary muscles contract, the urine is forced into the cloaca which is voided at intervals through the cloacal aperture. Male reproductive system Fig. Copulatory organs are absent. The testis are rounded or ovoid, light yellow bodies attached to the antero-ventral surfaces of the kidneys by a double fold of peritoneum, the mesorchium.
Actually each testis is surrounded by peritoneum, which is extended dorsally as a double membrane, the mesorchium, to the dorsal side of the body cavity, where its becomes continuous with the general coelomic lining.
Just in front of each testis are found attached yellowish finger-like processes. They serve as a sort of storehouse of nutrients which are provided to the developing spermatozoa and during hibernation. The vasa efferentia consist of a variable number of slender tubes arising from the inner margin of testis and extend within the mesorchium and then enter the inner margin of the kidney to open into the Bidders, canal.
In this way sperms enter the ureter of kidney through vasa efferentia. Bidders canal and collecting tubules. The vasa efferentia are originally outgrowths of the walls of the Malpighian corpuscles which become connected with the testis. Ureter in male frog is a urinary duct as well as a vas deferens to convey the urine and spermetozoa. Hence, it is called a urinogenital duct.
Both the ureters open into the dorsal wall of cloaca separately on urinogenital papillae. Histological, each testis Fig.
In the connective tissue are found blood capillaries and lymph vessels, nerves, muscle fibres and groups of interstitial cells in between the lubules. These cells secrete a hormone testosterone which brings the secondary sexual characters of the individual.
The wall of tubule is lined by germinal cells which produce sperms by spermatogenesis. The mature sperms are found in bundles in the lumen of tubules floating in the spermatic fluid. From the ureter they pass into the vesicula seminalis where they are stored. The excretory organs are the same in female frog as found in male frog, but they do not have any connection with the reproductive organs.
The ureter does not dilate as vesicula seminalis and no ducts from ovaries open into the kidneys. Some platyhelminthes self fertilize. Other animals switch between being male and female, a condition called sequential hermaphroditism. In addition to sexual reproduction, the fusion of the egg and sperm, some animals can reproduce asexually.
In asexual reproductiongenetic material is not combined. Therefore, it produces an offspring that is genetically identical to the parent. Types of asexual reproduction include budding, fission, and parthenogenesis.
Parthenogenesis occurs in rotifers, some bees, wasps, ants, and several species of fish, lizards, and amphibians.
Some animals switch between sexual and asexual reproduction, and some reproduce only asexually. Fertilization can happen internally or externally. External fertilization occurs in most sea-living creatures as well as freshwater fish and amphibians. In external fertilization both eggs and sperm are shed into water and fertilization, development, and growth of the zygote all take place outside the body.
Internal fertilization occurs when egg and sperm are joined inside of the body. The zygote can develop inside of the reproductive tract, as in mammals. Birds and reptiles have internal fertilization but lay eggs. The zygote develops inside the egg but outside of the body.
Excretory and Reproductive Systems
Invertebrates that have internal fertilization also lay eggs. The Excretory System Vertebrates have a closed circulatory systemwhich means that they have arteries and veins that transport blood. Cellular metabolism produces waste and uses nutrients and water. The circulatory system carries water and nutrients to cells and carries waste products away from cells.
Water and nutrients come from ingestion and digestion. Waste removal is critical to maintaining internal homeostasis. Nitrogen is the most toxic byproduct of cellular metabolism. The body must excrete nitrogen.
Nitrogen is commonly produced as ammonia from cells. Many animals will convert ammonia, which is extremely toxic, into a less toxic form of nitrogenous waste. By the time they arrive the gonad has prepared itself by becoming male or female.
In the male changes are under the influence of the Y chromosome we know this because of the few unfortunates who don't have oneor who have an unusual number of X chromosomes. Part of the male development is the formation of interstitial cells, the hormone producing testosterone cells of the testis.
The testosterone influences duct development. With testosterone the mesonephric duct develops to become the vas deferens and associated structures; without it the mesonephric duct atrophies and the paramesonephric duct becomes the oviduct and most of the uterus.
In some individuals the tissues are unable to respond to testosterone. Lets look at the developing male and female reproductive systems. In the male the indifferent gonad responds to the effects of the Y chromosome to develop testis cords which become horseshoe shaped and enclosed within the thickened tunica albugina of the gonad. The free ends of the horseshoes are in contact with the redundant mesonephric duct. The paramesonephric duct develops in response to placental and maternal hormones, but is unused and later regresses.
A little later we find that the mesonephric duct has continued to develop and forms the epididymis, the ductus vas deferens and the seminal vesicles. The paramesonephric duct has regressed, to be represented only by the appendix testis proximally and the utriculus prostaticus, a small diverticulum in the prostate gland distally. You will also note that the right hand side of the slide shows a different relationship between parts, because it covers the period of the descent of the testes.
These were originally situated on the posterolateral abdominal wall but, as they develop migrate by differential growth to lie behind an outpushing of the anterior abdominal wall, the vaginal process vagina here as elsewhere means scabbard.
Frog and Human by Ana Saladar on Prezi
This is assisted by the gubernaculum the governor a band of contractile connective tissue. The testes ultimately lie in the scrotum, and the duct system is rearranged to pass from the scrotum back into the abdominal wall, in the inguinal canal, before it unites with the terminal duct of the excretory system, the urethra to enter the penis.
In the female things take a slightly different course. The medullary cords the testicular cords of the male degenerate because there is no Y chromosome. They are replaced by epithelial inpushings of the covering of the developing ovary, which break up to form follicles.
This is where the white mouse comes in. This is a black-eyed white mouse, not the normal albino which has pink eyes. It is white, anaemic and sterile because it carries a mutation in a gene which governs the ability of migrating cells to navigate.
One of these great navigations is that of pigment cells into the coat, the other is germ cells to the ovary and testis.