URINOGENITAL SYSTEM

comparative anatomy

1. URINOGENITAL SYSTEM PRESENTED BY:FATIMA KHARBE

2. URINOGENITAL SYSTEM URINARY SYSTEM OF VERTEBRATES INCLUDE KIDNEYS AND THEIR DUCTS. REPRODUCTIVE SYSTEM INCLUDES MALE AND FEMALE GONADS AND THEIR DUCTS. THE 2 SYSTEMS ARE INTIMATELY RELATED MORPHOLOGICALLY IN VERTEBRATES HENCE THE TWO SYSTEM ARE AS DESCRIBED AS UROGENITAL OR URINOGENITAL SYSTEM

3. BASIC STRUCTURE OF EMBRYONIC KIDNEY Pair of compact organs lying on either side of dorsal aorta. Each kidney is composed of large no of units called as URINIFEROUS TUBULES OR NEPHRONS. Kidney tubules arise in the embryo in a linear series from mesoderm. Each uriniferous tubule is differentiated into 3 parts. 1.PERITONEAL FUNNEL 2.MALPIGHIAN BODY 3.TUBULE

4. Urinary System - Kidneys Kidneys are pair of compact organs lying on either Side of dorsal aorta. Evolution of kidney takes place as: ARCHINEPHROS PRONEPHROS MESONEPHROS METANEPHROS

5. ARCHINEPHROS Excretory organ of ancestral vertebrates. Also called as HOLONEPHROS 0r complete kidney as it runs throughout the entire length of coelom . Composed of pair of archinephric ducts. Each duct has a pair of tubules to a segment. Each tubule is opened by a nephrostome in coelom . Near each nephrostome there is an external glomerulus . All tubules are drained into duct Which opens in cloaca .

6. Archinephros Larvae of caecilians and Hagfish have this type of excretory system. Tissue fluid discharge from glomerulus << coelom << Nephrostome <<tubules<< Archinepric ducts<< cloaca .

7. PRONEPHROS 1 Embryonic tubule to appear hence called as pronephros . Also called as head kidney. Composed of pronephric ducts. Consist of 3 to 15 tubules segmentally arranged, Each tubules open into coelom by nephrostome . Also projecting into coelom there is an external glomerulus . In some cases glomeruli unite to form glomus .

8. PRONEPHROS All tubules of pronephros open into the pronephric duct. Which opens into cloaca .. Pronephros is functional only in embryonic or larval stage,and it is soon replaced by mesonephros . Pronephros is retained throughout life in adult cyclostomes and teleost fishes. Filtrate of blood through glomerulus << coelom << nephrostome << Tubule<< pronephric duct<< cloaca .

9. MESONEPHROS Develops from middle part of intermediate mesoderm. Form soon after degradation of pronephros . Mesonephros is functionally better than pronephros bcoz mesonephric tubules are numerous in number. They develop internal glomeruli .

10. MESONEPHROS They are also termed as wolffian body. Mesonephros is functional only in embryos in amniotes. In sharks n caecilians tubules extend posteriorly Throughout coelom such kidney is called as OPISTHONEPHROS.

11. Mesonephros Soon with the degradation of pronephros the pronephric duct forms the wolfian or mesonephric duct. In amniotes mesonephros is functional only in the embryos and replaced by metanephros in adults Nephrpstomes are generally lacking in embryonic amniotes.

12. METANEPHROS Arise posterior to the mesonephros . It’s the functional kidney of higher vertebrates or amniotes. it is formed from the posterior end of the nephrogenic mesoderm. When all metanephric tubules develop all mesonephric ducts disappear except those Associated with testis in male forming vasa efferentia . It shows greater multiplication and concentration of nephrons . It s functional unit is nephron .

13. METANEPHROS Renal Cortex: Renal corpuscle Convoluted tubules Renal Medulla: Collecting ducts Loop of Henle Each Minor calyx drains a tree of collecting ducts within a renal pyramid Pyramids are separated by columns of cortical tissues called renal columns The Renal pyramids

14. Nephron The tubules differentiates into the 1) Bowman’s capsule 2) Proximal convoluted tubule 3) Loop of Henle 4) Distal convoluted tubule The distal convuluted tubule fuses with the collecting duct Renal corpuscle = Bowman’s capsule/ glomerulus . The nephron is the metanephric excretory unit. The origin of the Renal corpuscle and tubules is distinct from the collecting duct ( Metanephric duct) Duct systems merge Renal duct – sequence of differentiation renal corpuscle 􀃆 proximal tubule 􀃆 distal tubule Loop of Henle elongates into the medulla

15. URINARY BLADDER

16. Urinary bladder Most vertebrates have urinary bladder to store urine before it is discharged. FISHES: enlargement of mesonephric ducts called TUBAL BLADDER . AMPHIBIANS: termed as CLOACAL BLADDER. AMNIOTES : ATLONTOC BLADDER Mammals lack cloaca hence the kidney ducts or ureter lead directly into the urinary bladder which opens into URETHRA

17. GENITAL SYSTEM Vertebrates exhibit sexual reproduction. Sexes are separate with exception of few hagfishes and few bony fishes. Male gonads…..Testes ….. produces sperms Female gonads …..Ovaries ….produces ova Gonads originate as a pair of genital ridges. Generally 1 pair of gonad are present but some vertebrates have single gonad.

18. TESTES AND MALE GENITAL DUCTS . TESTES: Seminiferous tubules: sperm factory Produces sperm Mature spermatozoa will move to rete testis Then to efferent dutules << epididymis <<vas deferens<<urethra. Testes also act as an endocrine gland produces teststerone .

19. OVARIES Ovaries are found in pairs except in some cyclostomes and teleosts . Ovary shows layer of germinal epithelium showing ova in various stages of development. Mature eggs are releasesd in the oviduct . This process is termed as OVULATION.

20. In the absence of testosterone: The mesonephric duct degenerates The Mullerian duct develops uninhibited Mullerian duct - cranial funnel-shaped opening to the coelom forms the fimbriare of the infundibulum The cranial Mullerian duct forms the uterine tubes The caudal end of the Mullerian ducts fuse to form the uterovaginal canal that later forms the uterus and the superior vagina

21. Intromittant organs: useful when fertilization is internal; introduce sperm into female reproductive tract found in some fish, some birds, reptiles, & mammals cartilaginous fish - appendages of pelvic fins called claspers direct sperm into female reproductive tract snakes & lizards - have pair of HEMIPENES turtles, crocodilians, a few birds, & mammals - exhibit an unpaired erectile penis penis - usually a thickening of floor of cloaca consisting of spongy erectile tissue (corpus spongiosum ) with grooves to direct sperm & ending in a glans penis (sensory endings that reflexly stimulate ejaculation)

22. GOT BORE??