Comparative Anatomy Urogenital System

1
Comparative AnatomyUrogenital System

• Note Set 11
• Chapter 15

2
Urogenital System

• Ducts of excretory and reproductive systems are
  intimately associated

Figure 14.1 Embryonic and evolutionary
development of kidneys in vertebrates (handout).
3
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).
4
Primitive Kidney (cont)

• Pronephros
• 1st 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.
5
Primitive Kidney (cont)
Figure 14.4 Fate of nephrogenic mesoderm (red)
(book figure 15.8).
Figure 14.5 Pronephric, mesonephric, and
metanephric system relationships.
6
Primitive Kidney (cont)

• 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).
7
Primitive Kidney (cont)

• 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.
8
Primitive Kidney (cont)
Figure 14.9 Mesonephric kidneys with mesonephric
duct (black) carrying sperm and/or urine (book
figure 15.25).
9
Primitive Kidney (cont)

• Accessory urinary ducts
• 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).
10
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.
11
Amniote Kidney (cont)

• 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).
12
Embryonic Amniotes

• Pronephros involutes
• Mesonephros involutes
• Metanephric kidney develops
• Vas deferens

13
Urinary Bladder

• Most vertebrates
• Formation varies
• Fish- terminal segment of mesonephric duct
• Large bladders- turtles and lizards
• Turtles- accessory bladder

14
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.
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Gonads (cont)

• Bidders 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 bidders organ of male Bufo
(book figure 15.23).
16
Copulatory Organs

• Claspers in cartilagenous fish
• Gonopodium in teleost
• Intromittent organ
• Hemipenes
• Single penis

Figure 14.16 Gonopodium on male guppy.
17
Copulatory Organs (cont)

• 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.
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Copulatory Organs (cont)

• Muellarian ducts
• 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.
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Copulatory Organs (cont)

• 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
20
Copulatory Organs (cont)

• 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).
21
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.
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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.
23
Cloaca (cont)

• 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.
24
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

25
Differentiation of Sexual Structures
Figure 14.26 Mesonephros contributions to male
and female reproductive tracts.
26
Differentiation of Sexual Structures
(cont)

• Genital Tubercle
• Male- penis
• 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).
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Differentiation of Sexual Structures
(cont)

• Mesonephric Duct
• Male- vas defferens
• Female- gartners duct
• Muellerian Duct
• Male- portions are retained
• Female- reproductive tract

Figure 14.28 Changes in female, mammalian
urogenital system (book figure 15.13).
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Differentiation of Sexual Structures
(cont)

• Mesonephric Tubule
• Male- vasa efferentia
• Female- epoophoran and paraophoran
• Genital Ridge
• Male- testes
• Female- ovaries

29
Homologous Urogenital Structures
Figure 14.29 Homologous urogenital structures in
male and female mammals (book tbl 15.3).
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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/342n
  otes10.html
• Figure 14.5- http//connection.lww.com/Products/sa
  dler/imagebank.asp
• Figure 14.8- http//www2.vscc.cc.tn.us/MSD/BIO/102
  0/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. 4th ed.
  McGraw-Hill, 2006.
• Figure 14.16- http//www.th.physik.uni-frankfurt.d
  e/brandste/aqua/fauna/zucht.html
• Figure 14.20- http//137.222.110.150/calnet/vetrep
  7/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/balehi
  rs/Bishyp6nroBirdNests.htm
• Figure 14.24- http//www.uic.edu/classes/dh/dh110/
  Immunology_files/
• Figure 14.25- http//www.upei.ca/histology/html/bu
  rsa_fabricus.html
• Figure 14.26- http//www.mun.ca/biology/desmid/bri
  an/BIOL3530/DB_Ch12/DBNGerm.html