UROGENITAL SYSTEM Combination of excretory and reproductive system. Kidney is the main excretory organ of vertebrates. • Concerned with the elimination of metabolic waste products. Ovary is the female reproductive organ or gonad. Testis is the male reproductive organ. • These are concerned with the production of the reproductive cells (egg and sperm). Ducts are passageways for the excretory waste products and reproductive cells from where they are produced to the outside.
Ductsof excretory and reproductive systems are intimately associated
EXCRETORY SYSTEM Waste products of metabolism include: urea, ammonia, uric acid, creatinine, various pigments, inorganic salts, and water. These are excreted through the kidney. Nephrons are the functional units of the kidney, where the blood is filtered with these metabolic wastes. Metabolic wastes pass to the outside through ducts.
ARCHINEPHROS/HOLONEPHROS Excretory organ of primitive vertebrate ancestors. It is composed of paired archinephric ducts, located on the dorsal side of the body cavity and extending the length of the coelom. Each duct has a pair of tubules to a segment. The tubules open into a coelom through the nephrostome.
ARCHINEPHROS External glomeruli drain the coelomic fluid and are located in close proximity to the nephrostome. Larvae of hagfish and caecilians have this type of excretory organ. Tissue fluid discharge from glomerulus >coelom>nephrostomes>tubules >archinephric ducts>to the outside.
THE ANAMNIOTE KIDNEY: PRONEPHROS 1st embryonic tubules in all vertebrates called pronephric tubules because they are the 1st to develop & are anteriorly located The duct that drains the pronephros is called the pronephric duct. The pronephros is temporary & function only until glomeruli & tubules further back become functional.
THE ANAMNIOTE KIDNEY:PRONEPHROS Some have external glomerulus, while most have internal glomeruli. Internal glomeruli are small knots of arterial capillaries surrounded by the Bowman’s capsule. Renal or Malphigian corpuscle is composed of the glomerulus and the Bowman’s capsule
THE ANAMNIOTE KIDNEY:PRONEPHROS Bloodafferent arterioleglomerulus efferent arteriole postcardinal vein heart Filtrate of blood plasma- glomeruluscoelom or cavity of the Bowman’s capsuletubule pronephric ductcloaca Selective reabsorption of water and other constituents may occur as fluid passes down the tubule.
THE ANAMNIOTE KIDNEY:PRONEPHROS Pronephric tubules function only until the end of the larval stage in amphibians and equivalent stage in fishes. Glomus is the term for several united glomeruli. Pronephric chambers are larger chambers formed by expansion of the pronephric tubules.
THE ANAMNIOTE KIDNEY: OPISTHONEPHROS The kidney mass caudal to pronephric region Functional adult kidney of lampreys, most fishes and amphibians Drained by mesonephric (archinephric) duct Mesonephrossimilar to opisthonephros but mesonephros is the structure that appears during embryonic development in reptiles, birds, and mammals. When it serves as an adult kidney, it is sometimes called opisthonephros.
FATE OF NEPHROGENIC MESODERM (RED) (BOOK FIGURE15.8).
THE ANAMNIOTE KIDNEY: OPISTHONEPHROS It is different from pronephros because it lacks segmental tubules that is exhibited by the pronephros. Kidney tubules and coelom are rarely connected. Renal corpuscles with internal glomeruli are typically present.
THE ANAMNIOTE KIDNEY: OPISTHONEPHROS An opistonephric tubule has a narrow neck adjacent to the renal corpuscle. Neck is followed by the: collecting portions, which joins the archinephric duct and; secretory part, which forms the proximal and distal convoluted tubules. Urogenital organs of male salamander,
THE ANAMNIOTE KIDNEY: OPISTHONEPHROS Ureter-like duct is formed by the union of collecting ends of several collecting tubules. This may open into the archinephric duct or may connect independently with the cloaca.
THE ANAMNIOTE KIDNEY: OPISTHONEPHROSOpisthonephric kidneys of fishes Males have longer kidneys than females. Efferent ductules connect the testes with the archinephric duct. Archinephric duct becomes the ductus deferens which serve for sperm transport. Female fishes have the posterior ends of their archinephric ducts enter a common urinary sinus inside a small urinary papilla.
THE ANAMNIOTEKIDNEY:OPISTHONEPHROS Urinary papilla enters the cloaca in sharks. It opens directly to the outside in fishes without cloaca. Seminal vesicles and sperm sacs may develop for the temporary storage of spermatozoa.
THE ANAMNIOTE KIDNEY: OPISTHONEPHROSOpisthonephric kidneys of Anurans Tubules are more concentrated on the posterior end and are confined to the posterior part of the abdominal cavity. Dorsally located, retroperitoneal, and dorso- ventrally flattened Kidneys of the females have no relation to the reproductive system.
THE ANAMNIOTE KIDNEY: OPISTHONEPHROSOpisthonephric kidneys of Anurans In males, certain anterior kidney tubules became modified as efferent ductules/vasa efferentia. They connect the testis with the kidney . Archinephric duct serves to transport spermatozoa and urine. Urinary bladder is thin-walled and serve for the temporary storage of urine.
THE AMNIOTE KIDNEY Three types of kidneys that appear in succession during embryonic development of amniotes are: pronephros, mesonephros, and metanephros. The metanephros persists to become the adult kidney. Pronephros appears in the very early stages of development but soon degenerates.
THE AMNIOTE KIDNEY Mesonephros develops as the embryonic kidney in reptiles, birds, & mammals It is sometimes called the Wolffian body and the mesonephric duct is called the Wolffian duct. It functions for a short time after hatching or birth
THE AMNIOTE KIDNEY Wolffian duct serves as urinary passage but when the metanephros becomes functional, it degenerates in the female, but persists in the male. Remnants of the mesonephros are associated with the reproductive system. This include the epididymis, ductus deferens, seminal vesicle, paradidymis, and ductus aberrans in the male. In females, remnants include the epoophoron and paraoophoron in the dorsal mesentery of the ovary, and canal of Gartner in the mesentery of mammalian oviduct.
THE AMNIOTE KIDNEY: METANEPHROS Arise posterior to the mesonephros. Nephron is the functional unit. Each nephron is composed of renal corpuscles, secretory tubules, and collecting tubules. Differentiation of metanephros begins when a metanephric bud sprouts from posterior end of the mesonephric duct. Nephrogenic mesoderm surrounds the bud.
THE AMNIOTE KIDNEY: METANEPHROS Bud grows anteriorly together with the metanephric blastema, and eventually gives rise to metanephric duct or ureter, and pelvis of the kidney. Fingerlike outgrowths from the pelvis invade the kidney blastema and become collecting tubules. S-shaped tubules are organizing within the blastema. One end grows toward and encapsulates a glomerulus to form a renal corpuscle. The other end grows toward and empties into a collecting tubule.
THE AMNIOTE KIDNEY Each kidney tubule of mammals is composed of the following parts: Proximal convoluted tubule Loop of Henle with ascending and descending portions Distal convoluted tubule.
THE AMNIOTE KIDNEY Capsule is a connective tissue that surrounds the kidney. Cortex is the outer kidney substance containing renal corpuscles. Medulla is the inner substance which contains the loops of Henle and common collecting tubules Renal pyramids are the conical aggregated loops and collecting tubules. Renal papilla is a blunt tip of each renal pyramid that project into a funnel-shaped outpocketing, the calyx of the pelvis.
COMPARATIVE ANATOMY OF THEMETANEPHROSReptiles Kidneys restricted to the posterior half of the abdominal cavity and confined to the pelvic region. Generally small and compact, with lobulated surface. Urogenital system of female sphenodon
COMPARATIVE ANATOMY OF THEMETANEPHROSBirds Kidneys located in the pelvic region of the body cavity, with the posterior ends usually united. Lobed structures with short ureters which open into the cloaca. Male bird’s urogenital system
COMPARATIVE ANATOMYOF THE METANEPHROS Mammalian kidney Compact, bean- shaped organ attached to the body wall. Ureter leaves the hilum or hilus. Hilum is also the part where blood vessels and nerves enter and leave the kidney.
URINARY BLADDER Embryonic origin: ventral cloacal wall and portion of the allantois. Function: temporary storage of urine before disposal or voiding It may serve as a reservoir of water in terrestial vertebrates. Water, reabsorbed from the bladder results from the action of an andiuretic hormone. This is important to prevent dehydration. In some lower vertebrates, it may serve as recovery sites for some ions that are scarce in their niche.
URINARY BLADDER: FISHES It is an insignificant enlargement of the conjoined posterior ends of the urinary ducts. Not significant because fishes are immersed in water. Many marine fishes can extract fresh water from sea water by drinking sea water and quickly excreting the salts.
URINARY BLADDERAmphibians Large and thin walled It connects with the cloaca a short distance beyond the openings of the archinephric ducts.
URINARY BLADDER Crocodilians, snakes, Turtles some lizards, and With a pair of birds do not have urinary bladder. accessory urinary bladders which isBirds connected with the Absence in birds reduces cloaca, and functions the energy requirements as accessory organs for flight. for respiration Urinary wastes, mainly These may be filled in the form of uric acid are eliminated via the with water in females, cloaca along with the which is used to soften feces. the ground in preparing a nest.
URINARY BLADDERMammals Present in all mammals. It is muscular and connects to the outside by the urethra Lower ends of ureters opens directly into the bladder on its posterior dorsal surface.
URINARY BLADDER Much of the muscles of the bladder continues down into the urethra. In males, the urethra is longer and passes through the penis and open at the tip through the external urethral orifice or meatus. Female rats and mice have their urethra that opens independently to the outside, passing through the clitoris. In other mammals, the urethra enters a urogenital sinus or vestibule.
EFFECT OF ENVIRONMENT ON KIDNEY STRUCTURE AND FUNCTION Kidney is not only Vertebrate kidneys involved in waste have adaptations to elimination but also their environments involved in the Size of glomeruli is maintenance of water related to the amount balance in the body. of filtrate removed from the blood. Regulates the amount Larger glomeruli of water given off in indicates an increase the urine and controls of filtrate moving out the amount of salts from the blood into the kidney tubules. and other electrolytes eliminated through the urine.
EFFECT OF ENVIRONMENT ONKIDNEY STRUCTURE ANDFUNCTION Terrestial forms have reduced glomeruli. Marine teleosts do not have glomeruli in their kidneys.
EFFECT OF ENVIRONMENT ON KIDNEY STRUCTURE AND FUNCTION Kidney tubules vary The distal convoluted among vertebrates but tubule is involved in ionic all have proximal and water reabsorption. convoluted tubule Amphibians have a degree Aglomerular of selective reabsorption in kidneys of marine their distal convoluted teleosts have their tubule. proximal convoluted Reptiles, birds, and tubule as the only mammals have tubules in functional, but their their kidneys but their urine does not differ development depends on from the urine of the amount of water fishes with glomeruli. available to the animal.
EFFECT OF ENVIRONMENT ON KIDNEY STRUCTURE AND FUNCTION In desert forms, the distal convoluted tubules are very long and are capable of resorbing nearly all water, so they have a very concentrated urine. Animals which are accessible to water sources have shorter tubules and their urine is less concentrated.
EXTRARENAL SALT EXCRETION Present in vertebrates that live in salt-rich environment or that live in arid environments. Chloride-secreting glands are present on the gills of marine fishes. Rectal glands are present in elasmobranchs. Nasal or orbital glands are present in marine reptiles and birds that feed on fish from salt water. Sweat glands in mammals eliminate some salt of the body.
REPRODUCTIVE SYSTEM Vertebrates exhibit sexual reproduction. Zygote results from the union of male and female gametes. Ova and spermatozoa are produced in the gonads, the testes and ovaries respectively. Gonads are derived from the mesoderm. Deferent ducts in male, and oviducts in female transport gametes to the outside of the body.
REPRODUCTIVE SYSTEM Deferent ducts are usually the archinephric or the Wolffian ducts which also transport urine from the kidney. Wolffian ducts in amniotes persists to become the ductus deferens. Accessory sex organs bring the germ cells together. Reproductive ducts Associated glads Intromittent or copulatory organs.
OVARY Two layer of a typical ovary in mammals are: 1. cortex, outer with developing Graafian follicles. - ovum with each follicle is nourished by follicular cells. - at maturity, certain follicles push to the surface of the ovary and either rupture to liberate the ovum (ovulation), or are reabsorbed. 2. medulla, which is inner and made up of connective tissue, blood vessels, lymphatic vessels, smooth muscle, and nerve fibers.
OVARY Ovarian follicles vary in size depending upon the season when it is examined and upon the volume characteristic of each species. Larger ova in lower forms because of their yolk content. Ovary attains maximum size during the breeding season in some vertebrates
OVARY: FISHES Paired or fused. Only the right ovary fully develops and the left degenerates in some elasmobranchs. Most teleosts have saccular type ovaries which produce large number of ova during the breeding season. Ripe ova-->central ovarian cavity--->oviduct--->outside Adult teleosts lack cloaca and have separate openings from urinary and digestive systems.
OVARY: FISHES Most are oviparous while others are ovoviviparous. Some have fertilized eggs that develop while inside the ovarian follicles Others have their young that develop within the cavities of the ovaries.
OVARY: AMPHIBIAN Saccular Ova escape into the coelom through their external walls. Shape varies with the shape of the body. Fat bodies are closely associated with the ovaries.
OVARY: REPTILES Snakes and lizards’ ovaries are saccular and elongated. Turtles and crocodilians have solid ovaries. Certain ovoviviparous snakes and lizards have corpora lutea that form from ruptured follicles after ovulation.
OVARY: BIRDS Both ovaries are present in embryonic development. In most birds, the right ovary degenerates, and the left becomes the functional gonad. Stigma or cicatrix is a band located on the surface of the follicle through which mature ova escape from the ovarian follicles into the coelom.
MAMMALIAN OVARIES Located in the lumbar or pelvic region. Considered small in relation to the size of the body of mammals. Placental mammals have compact ovaries with an antrum within the graafian follicles. Covered by germinal epithelium from which oocytes arise. Some of this oocytes become mature ova during the life of the individual.
MAMMALIAN OVARIES Ovum escape the ovary when the wall of graafian follicle ruptures. Cells that remain after follicle rupture organize to form corpus luteum. Corpus luteum is one source of progesterone needed to maintain pregnancy. Before ovulation, estrogen is the predominant secretory products of the follicle cells. Atretic follicles are those that fail to rupture and degenerate.
OVIDUCTS Modifications of the Mullerian ducts, which degenerates in the males. Differentiates into regions . Posterior portion expands to become the uterus. Serves as temporary storage site for eggs or a place where the young develops.
OVIDUCTS: FISHES Some teleosts have modified abdominal pores where eggs escape from the coelom. Elasmobranchs have ostium tubae, which opens into the coelom. Narrow distensible oviduct on either side. Shell gland is an enlargement of the oviduct. Beyond the shell gland is the uterus that opens into the cloaca. Ovisac shelters and nourishes the embryo in viviparous species.
OVIDUCTS: AMPHIBIANS Paired, elongated tubes with ostia. Enlarged posteriorly to form a short uterus or uterine enlargement . Uterus opens independently into the cloaca. Uteri in most amphibians serve for temporary storage for ova. Lining of the oviducts have glands that secrete jellylike material to envelop the passing eggs. Fertilization is external Male grasp the female in amplexus.
OVIDUCTS: REPTILES Open into the coelom through slit-like ostia. Turtles and crocodilians have glands in the upper part that secrete albumen. Shell is deposited in the uterus or shell gland in snakes and lizards. Uteri enter cloaca independently. Fertilization occurs in the upper part. Some snakes and lizards are oviparous. Other reptiles are ovoviviparous.
OVIDUCTS: BIRDS Most except birds of prey have only the left oviduct that is functional. Long, coiled, and consists of several regions. Ostium is bordered by fimbriae. Albumen is secreted by the glandular portion. Isthmus is found Oviduct of a laying hen 1 Infundibulum, posterior to the glandular 2 Magnum, portion where inner and 3 Isthmus, outer shell membranes 4 Shell Gland, are deposited around the 5 Uterus with egg albumen. inside
OVIDUCTS: BIRDS Uterus or shell gland is where the hard calcareous shell of the egg is formed. Uterus opens into cloaca. Fertilization is internal and accomplished by cloacal kiss.
OVIDUCTS: MAMMALS Paired, with various degrees of fusion between the two sides. Three distinct regions in some: narrow oviduct or fallopian tube, the expanded uterus, and a terminal vagina. Cervix is the narrow lower part of the uterus which leads into the vagina. Opening of the uterus into the vagina is called os uteri
OVIDUCTS: MAMMALS Marsupialshave paired duplex uteri and paired vaginae.
OVIDUCTS: MAMMALS Other placental mammals have horns of the uterus, uterine body, and a single vagina. Uterus are classified: 1. Bipartite when there are two complete lumens within the body of the uterus. 2. Bicornuate uterus has a single lumen within the body and with two horns 3. Simplex, has no uterine horns, and the vagina opens directly into the body.
OVIDUCTS: MAMMALS Body of simplex uterus is where the fetus become implanted. Uterine wall is made up of: 1. Endometrium – uterine lining which becomes highly vascular under the stimulus of hormones. 2. Myometrium – thick muscular layer 3. Visceral peritoneum – thin outer serous membrane. - Menstruation results from degeneration or sloughing of the uterine lining followed by hemorrhage from blood vessels. - Estrogen and progesterone control these endometrial changes.
OVIDUCTS: MAMMALS Vagina is the fused terminal portion of the mullerian ducts. It opens into a urogenital sinus. Higher primates’ vagina extends almost to the exterior, opening into a shallow vestibule. Lining of vagina is cornified for reception of the penis. Marsupials have a median vagina which continue as paired lateral vaginae. Penis of male marsupials is forked at the tip.
Functions of the Scrotum male • A sac containing the reproductive testes system are: • Intrascrotal Production of sperm temperature is kept cells constant by two sets Sustaining and of muscles: transfer of the • Dartos: smooth sperm cells to the muscle that wrinkles female scrotal skin Production of male • Cremaster: bands of sex hormones skeletal muscle that elevate the testes
Testes Seminiferous tubules “sperm factories”: Produce the sperm Mature spermatozoa will move to the rete testis efferent ductules epididymis ductus deferens Also an endocrine gland as they produce testosterone
ELASMOBRANCHS’ TESTES Paired symmetrical structures Suspended by mesorchium Other fishes have elongated and lobulated testes.
AMPHIBIAN TESTES Shape corresponds to body shape Elongated in caecilians, short or irregular in urodeles Oval or rounded and more compact in anurans
REPTILES’ TESTES Oval rounded or pyriform compact structures Snakes’ and lizards testes’ have onetestes that occupies farther forward in the body cavity than the other
BIRDS’ TESTES Oval or round-shaped and changes in size depending on the period of the year.
MAMMALIAN TESTES Tunica albuginea a thin tough fibrous envelop of the testis Scrotum serves to regulate the temperature ideal for the testes to be able to produce viable sperm cells Vaginal sac is a diverticulum of the peritoneum into the scrotum Tunica vaginalis is the extension from vaginal sac . that comes in close contact with the tunica albuginea
MAMMALIAN TESTES Maybe found in the pelvic region or descend into a scrotum Some mammals’ testes descend into the scrotum only during the breeding season inguinal canal - passage between abdominal cavity & scrotum
SPERMATOZOA Vary in vertebrates and are several times smaller than the ova All possess tails for locomotion Number produced by the human male is about 4ml or 300 million per ejaculation Boar produces about ½ liter
MALE GENITAL DUCTS Some fishes (e.g., gar & sturgeon) & amphibians - mesonephric duct transmits sperm & urine Some amphibians - mesonephric duct transports only sperm; new accessory urinary duct drains the kidney
MALE GENITAL DUCTS Sharks - mesonephric duct is used primarily for sperm transport; accessory urinary duct develops Teleosts - mesonephric duct drains kidney; separate sperm duct develops Amniotes - embryonic mesonephric ducts transport sperm in adults
1.Testis / testicles (present as a pair)2. Ductus epididymidis (a pair)3.Deferent duct / Vas deferens (a pair)4. Ampulla of the deferent duct (a pair)5. Glandula vesiculosa / Seminal gland (a pair)6. Ejaculatory duct (a pair)7. Prostate (single)8. excretory duct of the prostate (several present)9. Bulbourethral gland (Cowpers glands) (a pair)10. Urethral gland (Littres gland) (several)11. Urethra (single)12. Urinary bladder(single)
COPULATORYORGANS/INTROMITTENT ORGANS Found in vertebrates that practice internal fertilization Used for introducing sperm into the female reproductive duct cartilaginous fish - appendages of pelvic fins called claspers direct sperm into female reproductive tract
COPULATORYORGANS/INTROMITTENT ORGANS snakes & lizards - have pair of HEMIPENES (pocketlike diverticula of wall of cloaca) turtles, crocodilians, a few birds, & mammals - exhibit an unpaired erectile penis
COPULATORYORGANS/INTROMITTENT ORGANS penis - usually a mammals (except thickening of floor of monotremes) - penis cloaca consisting of extends beyond body spongy erectile tissue The embryonic corpus (corpus spongiosum becomes a spongiosum) with tube with urethra grooves to direct inside & 2 additional sperm & ending in a erectile masses glans penis (sensory develop (corpus endings that reflexly cavernosa). stimulate ejaculation)
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