Urogenital System The Urinary System Components: Kidneys and Associated Tubules Function: Waste elimination Feces deals with Digestive system Kidney main organ for excretion/waste excretion Mammalian Kidney (picture) Not all kidneys like these, more primitive kidneys Outermost layer is the renal capsule – protects the kidney Cortex Medulla – inside, composed of renal pyramids microscoping components Minor Calyx Major Calyx Out through the Ureter as urine for mammals

Structure of the Kidney Uriniferous tubule one of the most basic units of the kidney Starts off as a blood vessel supplied by renal artery Blood vessel ends in Glomerulus – for filtration Renal capsule - receive the filtered material into Nephron – Proximal, Intermediate, Distal Collecting Tubule to Calyx

Path of blood (Outside) Renal artery – into branchings of blood vessels and enters glomerulus (for filtration) – forced into renal capsule – proximal, intermediate, distal tubules (reabsorption of salt and water) – collecting tubules – out – to the ureter and out of the body Embryonic Origins of the Kidney

Origin: Expansion of intermediate mesoderm develops from Nephric ridge After Nephric ridge develops, Nephrotome like myotomes (mostly stem cellular in origin) will develop Within Medial end of Nephrotome, develop into glomerulus found in both sides paired Distal end develop common nephric duct serve as pathway for urine or excretory material

Plan: Coelom and Nephric duct both sides will develop uriniferous tubule Development of kidney is Tripartite (three parts in higher vertebrates)

In other there will only be one or two parts Pronephros – develop first, usually found in fish Mesonephros – middle, middle cartilagenous fish, amphibians Metanephros – usually kidney found in mammals Develop sequentially pronephros developing first Pronephros anterior, tubules, pronephric duct Glomeruli extends from roof of coelom and filters into them Usually transient found in fish Glomerulus extend towards coelom and filter whatever substances there , after secretion waste products outward through ducts Usually found in fishes, pronephros can still develop in other parts of the kidney or fused with other components Mesonephros middle, Taps into pronephric tubules In a way branching out of pronephros Embryonically functional, in lower vertebrates or middle vertebrates they can persist into adulthood Opisthonephros – sometimes if they have posterior tubules developing into pronephros, adult form of kidney in sharks Have pronephric orgins Metanephros posterior, arises from mesonephros Adult kidney we have Grows into posterior region of the nephric ridge

Phylogeny of the Kidney

More primitive vertebrates have pronephros (agnathans, some fish) Pronephric duct – connected to the pronephros drain out the primitive kidney they have Glomus – cluster of glomeruli for filtration, after filtration pronephric duct and out of the body Mesonephros – pronephros will degenerate, sharks teleosts and amphibians, develop into further tubules, branches out, from inside the body, filtration out through mesonephric duct, earlier called pronephric duct since branchings of pronephros that develop into mesonephros more appropriately named mesonephric duct Kidney Phylogeny: Tetrapods Metanephros – mesonephros degenerate and development of new tubules Connected tubules connected to adult kidneys connected to Cloaca and out of the body Cloaca not present in all organisms A lot have misconception that higher vertebrates such as mammals will not have pronephros or mesonephros they will have embryonically but degenerate and branch out to metanephros Function: Excretion

Removal of byproducts of metabolism Carbon dioxide, water Nitrogenous waste (ammonia) Three main types of excretory materials in vertebrates classified as: Ammonotelism – organisms that secrete ammonia, ammonia diffuses out through epithelium (gills) and usually washed away from water Ammonia highly toxic, excreted by fish Ammonia comes from nitrogen metabolism Body have to excrete toxic products so as not to interfere with normal metabolic functions Uricotelism – secrete uric acid, usually found in birds and reptiles How is it significant in terms of habitat? sludgelike – mostly solid, organisms are usually terrestrial, Not much water Significant in terms of water conservation Sludge is filtered in kidney, goes into cloaca with other elements and compounds Ureotelism – different compound is secreted. Urea is secreted Uric acid and urea are not toxic forms Ammonia is converted to Urea and Uric acid Organisms don’t live in water so have to convert it to non toxic form for metabolic functions not to suffer Urea excreted in the form of urine with a lot of other compounds Excreted in the form of urine Function: Osmoregulation Regulation of body salt and water levels, problematic for animals that live in the water Kidney (absorption of salt and water) Cloaca seen in birds (Ureotelic organisms) Large intestine (reabsorption of water so as not to allow organisms to dessicate)

Urinary bladder (water absorption) Osmoregulation: Elimination and conservation Filtration kidneys: usually found in invertebrates, secretion kidneys, dependent on body secretions, glomerular filtrate, secretions along tubules, reabsorption of substances by the tubules Depending on habitat and need for osmoregulation they will have diff. features Glomerulus size, presence of glomerulus Tubule length - how much salts or water reabsorbed Loop of Henle – found in mammals, loop within tubules of intermediate Vasa recta – assoc. to loop of henle for more reabsorption of water Osmoregulation: Elimination and conservation Elimination Freshwater fish – large glomeruli for filtering solutes in its blood to keep salt level homeostatic to keep it roughly equal, long distal tubule for more salt reabsorption, filter a lot of salt whatever filtrate left, salts will be reabsorbed Water moves in too much water it will bloat and eventually burst Has to have salts for high metabolic function Conservation Marine fish – no glomerulus, no distal tubules for extra salt reabsorption,secretion-dependent, tissues will have lower concentration of salt, in order for fish to not lose solute it will have no glomerulus, no distal tubules Terrestrial – loop of henle modification, mostly in dessicating and drying environments,extra effort in reabsorption of water in loop of henle

Reproductive System Contain Gonads, secretions, hormones, gametes and associated ducts

For Females (image) Tunica albuginea - outermost Cortex Medulla – innermost, like in kidneys Ova – primary oocytes, secondary oocytes Follicle Cells – in between them

Eggs are stored in the ovaries Eggs go to the fallopian tube then uterus When the egg is fertilized, it is in uterus it will stay there When not fertilized, flushed by blood by menstruation For males semen is usually formed in the testes Seminiferous tubules move to rete testis then stored in the epididymis Mature sperm cells outside or progenitor cells, earlier stages of development when get to lumen stored in the middle Lumen Epithelial layers

Embryonic Origin Forms in the genital ridge Undifferentiated gonads – there is no distinction bet. males and females Extraembryonic: germ cells come from this In Females: migrate into cortex In Males: migrate into medulla Organs: salvaging from urinary tract in order to form their own tubules

Embryonic Origin: Gonads Wolfian duct develop into several ducts Mullerian duct regenerate These ducts connected to the testes sometimes can be the ureter If no male hormoness mulfian

Duct Fates Pronephric duct initially connected to 1. Kidney (E) – eventually connected to 2. Adult Testes (Vas deferens) Wolfian duct initially be the 1. Mesonephros (E) – eventually be the 2. Adult Kidney (Ureter) Mullerian duct – Parallel; Wolffian – Female Reproductive System Oogenesis Start of with primary oocyte undergoes Meiosis 4 products 1st product is the Mature Ovum which can be fertilized and polar bodies that can regenerate – for nutrition, contribute cytoplasmic material to ovum, nutrients organelles for future organisms or babies

Cross section of cat ovary Tunica Cortex and medulla As eggs mature they migrate inwards Spermatogenesis for males (image up) There will be no polar bodies One parent cell give rise to Spermatids – adult sperm cell In many organisms there will be two ovaries (paired) In other vertebrates only one ovary will be functional Specifically in lamphreys one gonad will fail to develop Sometimes it degenerates sometimes it fuses Essentially it will produce just one

Comparative Urogenital Anatomy – Females

Agnathans (lamphreys) Ovary will not be connected to any duct

Eggs directly deposited to the coelom Eggs can exit through pores of the body Ophisthonephros – derivative of the mesonephros with addition of posterior tubules Will still have posterior tubules leading to the mesonephric duct Osteichthyes Ovary separate outpocketings leading out of the body, for excretion Sharks Smaller ophistonephros Tetrapods Metanephros In Amphibians Kidneys – connected to pronephric duct, Ovary lead to ovisac and lead to cloacal opening, cloaca for wastes, secretions and other reproductive functions Comparative Urogenital Anatomy – Males

Area for ejaculation and waste excretion the same Agnathans Testis separate Opisthonephros for excretion of waste Gar Sturgeon Share the same, opisthonephros Sharks Testis found anteriorly, opisthonephros posterior,share the tubules Amphibians separate, will still share same cloacal opening for removal wastes Amniotes have the testis leading out to wolfian duct then metanephros then lead out to ureter Copulatory Organs Ussually found in males Intromittent organs for delivering sperm

Chondricthyes – claspers, one clasper to cloaca and other ridges for delivering sperm into the cloacal opening of another organism Teleosts – pelvic and anal fins modified Gonopodium modification for direct delivery of sperm Anurans – amplexus, mating ritual males have larger, stimulate them to release their sex cells, male frog will be on top of the female frog Urodeles – spermatophore packets of sperm and spermatecha found in females for storing of sperm Male release spermatophore like a capsule and female bites of the cap bag of sperm Apodans – cloacal eversion, amphibians, caecilians limbless salamanders look like snakes, when they mate they will have cloaca diversion, where sperm will be deposited Caudata and urodela, Salamanders Anura and caecillians Squamates snakes and lizards, hemipenis – retract in side body Crocodylians, rhynchocephalians, Testudines, some birds and mammals – true penis, big mass of areas where blood can be deposited Some birds – rub cloacas for cloacal transfer