Comparative Anatomy Urogenital System Note Set 11 Chapter 15
Urogenital System Ducts of excretory and reproductive systems are intimately associated Figure 14.1: Embryonic and evolutionary development of kidneys in vertebrates (handout).
Primitive Kidney Archinephros- primitive excretory kidney organ Holonephros Filtration system Archinephric duct- drains to cloaca or bladder Figure 14.2: Hypothetical archinephros (book figure 15.7).
Primitive Kidney (con t) Pronephros 1 st tubules to appear Anteriorly located; head kidney Involutes to form lymphoidal mass Only functions temporarily All tubules associated with pronephros Pronephric (archinephric) duct drains pronephros Figure 14.3: Pronephros region of primitive kidney.
Primitive Kidney (con t) Figure 14.4: Fate of nephrogenic mesoderm (red) (book figure 15.8). Figure 14.5: Pronephric, mesonephric, and metanephric system relationships.
Primitive Kidney (con t) Mesonephros (opisthonephros)- kidney mass caudal to pronephric region Functional adult kidney of fish and amphibians Opisthonephros in sharks Drained by mesonephric (archinephric) duct Figure 14.6: Mesonephros of Urodele (book figure 15.8) Figure 14.7: Mesonephric duct of opossum embryo (book figure 15.19).
Primitive Kidney (con t) Ductus efferens: Pronephric duct Mesonephric duct Archinephric duct Anterior portion of mesonephric tubules used in male reproductive system Figure 14.8: Urogenital system and adrenal glands of male frog.
Primitive Kidney (con t) Figure 14.9: Mesonephric kidneys with mesonephric duct (black) carrying sperm and/or urine (book figure 15.25).
Accessory urinary ducts Primitive Kidney (con t) Tubules also in reproductive sys. Path for sperm to enter mesonephric duct (sperm duct) Figure 14.10: Mesonephric kidneys with separate sperm duct (red) (book figure 15.25).
Amniote Kidney Pronephros Lost Mesonephros Mainly an embryonic kidney Involutes at birth Metanephric kidney Takes over functions of mesonephros Ureter- new duct drains met. kidney Figure 14.11: Metanephric kidney assuming superior position to remainder of urogenital system.
Amniote Kidney (con t) Mesonephric duct Sperm duct in males Ductus deferens in amphibians Vas deferens in mammals Terminate at cloaca Most amniotes Not higher vertebrates Figure 14.12: Male teleost, caudal end of urogenital system (book figure 15.18).
Embryonic Amniotes Pronephros involutes Mesonephros involutes Metanephric kidney develops Vas deferens
Urinary Bladder Most vertebrates Formation varies Fish- terminal segment of mesonephric duct Large bladders- turtles and lizards Turtles- accessory bladder
Gonads Elevated ridges medial to kidneys Gonads enlarge, suspended by mesenteries Mesorchium- males Mesovarium- females Figure 14.13: Urogenital ridge in developing embryo. Figure 14.14: Ovary of hagfish.
Gonads (con t) Bidder s organ Rudimentary ovary of toads (Bufo) If testes removed, become functional ovary Ovotestes in fish Both ovary and testis in lizards Multi-lobed testis in some species Figure 14.15: Left bidder s organ of male Bufo (book figure 15.23).
Copulatory Organs Claspers in cartilagenous fish Gonopodium in teleost Intromittent organ Hemipenes Single penis Figure 14.16: Gonopodium on male guppy.
Copulatory Organs (con t) No copulatory organs Sperm pocket- some salamanders Rudimentary copulatory organ Some amniotes (tuatara) Cloacal apposition Male and female cloacas come together Figure 14.17: Urogenital system of female sphenodon.
Muellarian ducts Copulatory Organs (con t) In males, ducts are nonfunctional In females, ducts give rise to female reproductive tract Only left reproductive tract Birds and crocodiles Raptors have vestigial right reprod. tract Figure 14.18: Mullerian ducts and gonads of male amphibians. Figure 14.19: Rudimentary oviduct of pigeon.
Copulatory Organs (con t) Duplex uterus Monotremes and marsupials Separated female reprod. tracts Bipartite uterus Rabbit Body of uterus seems unpaired yet has two lumens Bicornuate uterus Cat Two uterine horns and single lumen Abnormal human bicornuate uterus
Copulatory Organs (con t) Bicornuate uterus Cat Two uterine horns and single lumen Simplex uterus Primates Large body and horns Figure 14.21: Mammalian uteri; muellerian ducts (blackened regions) and cloaca (red) (book figure 15.47).
Cloaca Receives digestive, reproductive, and urinary products and tracts No cloaca Fish- three separate openings Mammals above monotremes Cloaca subdivisions: Coprodaeum Urodaeum Proctodaeum Figure 14.22: Cloacal cavities and urogenital structures in salamanders.
Cloaca Subdivisions Coprodeum Receives alimentary canal Simple columnar Urodeum Receives urinary and reproductive products Transitional epithelium Proctodeum Associated with excretory Stratified squamous Figure 14.23: Subdivisions of cloaca shown in bird.
Cloaca (con t) Bursa of Fabricius Lymphoid evagination off cloaca Figure 14.24: Bursa of Fabricius on young bird. Figure 14.25: Histology of Bursa of Fabricius and cloaca.
Reproduction Some vertebrates require both sexes Some verts. are asexual Reproduce parthenogenetically Some fish and lizards Embryonic humans are asexual Until differentiation of sexual structures
Differentiation of Sexual Structures Figure 14.26: Mesonephros contributions to male and female reproductive tracts.
Genital Tubercle Male- penis Differentiation of Sexual Structures (con t) Female- clitoris Genital Folds Male- penis contribution Female- labia minora Genital Swellings Male- scrotum Female- labia majora Figure 14.27: external genitalia of bisexual stage of human embryo (book figure 15.48).
Differentiation of Sexual Structures (con t) Mesonephric Duct Male- vas defferens Female- gartner s duct Muellerian Duct Male- portions are retained Female- reproductive tract Figure 14.28: Changes in female, mammalian urogenital system (book figure 15.13).
Differentiation of Sexual Structures (con t) Mesonephric Tubule Male- vasa efferentia Female- epoophoran and paraophoran Genital Ridge Male- testes Female- ovaries
Homologous Urogenital Structures Figure 14.29: Homologous urogenital structures in male and female mammals (book tbl 15.3).
Literature Cited Figure 14.1- Trauth, Stan. Handout. Figure 14.2, 14.4, 14.6, 14.7, 14.9, 14.10, 14.12, 14.15, 14.21, 14.27, 14.28, 14.29- Kent, George C. and Robert K. Carr. Comparative Anatomy of the Vertebrates. 9th ed. McGraw-Hill, 2001. Figure 14.3- http://people.eku.edu/ritchisong/342notes10.html Figure 14.5- http://connection.lww.com/products/sadler/imagebank.asp Figure 14.8- http://www2.vscc.cc.tn.us/msd/bio/1020/lab7chordateii.htm Figure 14.11- http://www.med.unc.edu/embryo_images/unit-genital/genital_htms/genital018.htm Figure 14.13, 14.14, 14.17, 14.18, 14.19- Kardong, Kenneth V. Vertebrates: Comparative Anatomy, Function, Evolution. 4 th ed. McGraw-Hill, 2006. Figure 14.16- http://www.th.physik.uni-frankfurt.de/~brandste/aqua/fauna/zucht.html Figure 14.20- http://137.222.110.150/calnet/vetrep7/page2.htm Figure 14.22- Sever, David. Reproductive Biology and Phylogeny of Urodela. Vol 1. Science Publishers, Inc, 2003. pg 334 Figure 14.23- http://member.rivernet.com.au/balehirs/bishyp6nrobirdnests.htm Figure 14.24- http://www.uic.edu/classes/dh/dh110/immunology_files/ Figure 14.25- http://www.upei.ca/histology/html/bursa_fabricus.html Figure 14.26- http://www.mun.ca/biology/desmid/brian/biol3530/db_ch12/dbngerm.html