1. Lecture 6 The evolution and development of the kidney Because … 1)Many of the most common diseases of the kidney and lower urinary tract and developmental in origin, so you need to understand development 2)Human urinary tract development seems an impossible-to-remember mess unless you understand how it evolved. Both images: wikipedia commons

2. Vertebrate evolution agnatha ichthyes amphibiareptiliamammalia aves Chordata (invertebrata) Everything down this way has a very different excretory system (similar genes & proteins but v different anatomy)

3. Lamprey embryo: Note no true glomerulus, no LoH Image source: Life of Vertebrates (Young)

4. Adult: mesonephros pronephros Image source: Life of Vertebrates (Young)

6. Reproductive system

7. Vertebrate evolution agnatha ichthyes amphibiareptiliamammalia aves Chordata (invertebrata) Everything down this way has a very different excretory system (similar genes & proteins but v different anatomy)

8. Image source: Life of Vertebrates (Young)

9. Vertebrate evolution agnatha ichthyes amphibiareptiliamammalia aves Chordata (invertebrata) Everything down this way has a very different excretory system (similar genes & proteins but v different anatomy)

11. Mouse: image by kind permission of Kirsi Sainio

14. Branching of the ureteric bud

15. The excretory nephrons have a separate origin from the ureteric bud;

16. From "The Kidney" (Vize, Bard, Woolf, Academic Press)

18. Summary of events in metanephros development 1) Metanephric mesenchyme attracts ureteric bud. 2) Ureteric bud invades mesenchyme and starts to branch into a tree 3) Clumps of mesenchyme cells differentiate into nephrons. 4) As all this goes on, the kidneys 'ascend' into the lumbar region (really, the rest of the body grows past them).

19. Development of the bladder

21. Formation of the Trigone;

23. Sex-specific development of nephric and Mullerian ducts. MALE Indifferent gonad develops testis cords Testis cords connect to some mesonephric tubules (- >epidydymis) Mullerian duct regresses Distal neprhic duct sprouts seminal vesicles – the part of the nephric duct distal to this is the ejaculatory duct Urethra sprouts prostate and bulbourethral glands. FEMALE Indifferent gonad develops into an ovary Upper Mullerian ducts become fallopian tubes Mullerian ducts converge & fuse to become the uterovaginal canal Neprhic ducts and mesoneprhos degenerates Uterovaginal canal forms uterus and upper part of vagina. (Lower part from urogenital sinus)

24. Components of semen Testis – sperm Prostate – citric acid, enzymes, acidic proteins Sem. Ves. – fructose, basic proteins

25. Timing of release Prostate Epididymis Sem. Ves

27. Derivatives of the cloacal region – his & hers Genital tubercle – Glans and shaft of penis (male) (Phallus) Glans and shaft of clitoris (female) Urogenital Sinus – Penile urethra (male) Lower vagina (vestibule) (female) Urethral fold - Surrounds urethra of penis (male) Labia minora (female) Labioscrotal fold- Scrotum (male) Labia Majora (female)

28. Congenital Abnormalities We’ll consider the kidney first, then the bladder, then the external genitalia

29. Renal Agenesis Bilateral – No kidneys form. Rare; fatal after birth. Lack of amniotic fluid causes Potter’s Facies. Unilateral – One kidney missing. Common (1/500). Often no clinical implications unless some bright surgeon removes the working one (yes, it has happened!).

30. Flat nose Flat chin Ears against head

31. Congenital Cystic Disease

32. Wilms Tumour

33. Other abnormalities Supernumerary ureters (cause trouble when one opens somewhere other than the trigone of the bladder – eg the vagina). Pelvic kidneys )kidney fail to ascend, perhaps because they are caught in the aortic bifurcation Horseshoe kidneys – the kidneys fuse (pelic kidneys particularly prone to this).

34. Congenital Abnormalities of Cloacal Development Failure of correct positioning of Rathke and Tourneaux folds results in; Rectovaginal fistula Rectoprostatic fistula Rectoclocal canal (rectum, vagina and urethra unite inside body). In males, incomplete migration of the urethral groove from the base of the penis to its tip results in hypospadias.