AL AZHAR University Faculty of Medicine Past Paper (2024/2025) - Kidney Development PDF

# AL AZHAR UNIVERSITY ## Faculty of Medicine for Girls ### Year 2-Semester 3 #### Academic year: 2024/2025 #### Module Name: Renal module. #### Code: IPM-07-20318. #### Credit hours: 5 ## Anatomy & Embryology department ### Development of the kidney #### Dr. Amina Mohamed Tolba # Intended learning...

# AL AZHAR UNIVERSITY ## Faculty of Medicine for Girls ### Year 2-Semester 3 #### Academic year: 2024/2025 #### Module Name: Renal module. #### Code: IPM-07-20318. #### Credit hours: 5 ## Anatomy & Embryology department ### Development of the kidney #### Dr. Amina Mohamed Tolba # Intended learning out comes (ILOs): By the end of this lecture, we will be able to: 1. Identify the Embryological origin of urinary and genital systems. 2. Describe the stages of development of the kidney. 3. Memorize the congenital anomalies of the kidney. # Pregnant woman in her 10th week of gestation during routine examination the doctor noticed that polyhydramnios which was most probably due to an organ absence. ## How can you diagnose this case? # Development of the urinary and genital systems - The urogenital system develops from the intraembryonic mesoderm. - Intermediate mesenchyme (mesoderm) - Paraxial mesoderm - Neural groove - Embryonic ectoderm - Lateral mesoderm - Notochord - Amnion - Coelomic spaces - After folding of the embryo, the intermediate mesoderm is carried ventrally, and the urogenital ridge is formed on each side of the dorsal aorta. - Neural tube - Neural crest - Somite - Urogenital ridge - Dorsal aorta - Intraembryonic coelom - Somatopleure - Notochord - Umbilical vesicle - Intraembryonic coelom - Extraembryonic coelom - Developing spinal ganglion - Notochord - Nephrogenic cord - Midgut - Lateral fold - Umbilical vesicle - The part of the urogenital ridge that gives rise to the urinary system is called nephrogenic cord. # I. Development of the Kidneys Development of the kidneys passes through 3 stages: ## 1. The pronephroi: - These transitory, nonfunctional structures appear in the 4th week. - They are represented as a few cell clusters and tubular structures in the neck region opposite to the 7th to the 14th somites. - The pronephric ducts run caudally and open into the cloaca. - The rudimentary pronephroi are degenerate. - Most of the pronephric ducts persist and are utilized by the next set of the kidneys and its name is changed and called mesonephric ducts. ## 2. The mesonephroi: - These large; elongated; excretory organs appear late in the 4th week caudal to the rudimentary pronephroi. - It appears at a lower-level opposite to 14th to 28th somites in the thoracic and upper lumbar region of the embryo. - They are well developed and function as transient kidneys for about 4 weeks. - It consists of glomeruli and mesonephric tubules. These tubules open into the mesonephric ducts which open into the cloaca. - The mesonephroi degenerate toward the end of the 1st trimester. - In male, the mesonephric tubules become the efferent ductules of the testes. The mesonephric duct gives rise to paradidymis; appendix of epididymis; duct of epididymis; ductus deferens; ureter; pelvis; calices; collecting tubules; ejaculatory duct and seminal gland. - Mesonephric (wolffian) duct - Paramesonephric (müllerian) duct - Testis - Ovary - Ductus deferens - Prostatic utricle - Müllerian tubercle - Epididymal duct - Urogenital sinus - Uterus - Testis - Efferent ductules - Male - In female, the mesonephric tubules become the Epoophoron and Paroophoron. The mesonephric duct gives rise to appendix vesiculosa; duct of epoophron; duct of Gartner; ureter; pelvis; calices and collecting tubules. - Fimbriated end of uterine tube - Epoophoron - Uterus - Uterine tube - Ovary - Paroophoron - Gartner's duct - Ovary - Urethra - Cervix - Gartner's duct - Female - Vagina - Cervix ## 3. The metanephroi: - It is the primordia of permanent kidneys which begin to develop early in the 5th week and start to function about 4 weeks later. - The permanent kidneys develop from 2 sources: - The ureteric bud - The metanephric mass Both primordia of the metanephros are of mesodermal origin. # Metanephric diverticulum development - It is an outgrowth from the mesonephric duct near its entrance into the cloaca. - It is the primordium of the ureter; renal pelvis; calices and collecting tubules. - As it elongates, it penetrates the metanephric mass of the intermediate mesoderm. - The stalk of it becomes the ureter and its expanded cranial end forms the renal pelvis. - Allantois - Cloaca - A - Gut - Mesonephric duct - B - Bladder - Metanephric diverticulum - Cloaca - Urachus - Mesonephric duct - C - Renal pelvis - D - Cephalic major calyx - Renal pelvis - E - Buds of arched collecting tubules - Caudal major calyx - Ureter - Primary straight collecting tubules - Metanephrogenic tissue - Developing minor calyces - The straight collecting tubules undergo repeated branching, forming generations of tubules, major calices, minor calices and collecting tubules. # Metanephric tubules (primordia of nephron) development - It is a mass of the intermediate mesoderm derived from the caudal part of the nephrogenic cord. - The end of each arched collecting tubule form metanephric vesicles. - The metanephric vesicles elongate and become metanephric tubules. - The proximal ends of these tubules are invaginated by glomeruli. - Collecting ducts - Distal convoluted tubule - Collecting tubule - A - Metanephric blastemal cap - Nephric vesicle - Glomerulus - Ampulla - B - C - D - E - F - The glomerular filtration begins around the 9th fetal week. Their number increases until the 32 week with increase in the rate of filtration after birth. - The renal corpuscle and its proximal convoluted tubules; loop of Henle and distal convoluted tubule constitute a nephron. - The nephrons become continuous with the collecting tubules to form the tubules. - Bowman's capsule - Collecting duct - Proximal convoluted tubule - Loop of Henle ## Fetal kidneys - They are divided into lobes. - This lobulation diminishes toward the end of fetal period, but the lobes are still inducated in the kidneys of a newborn infant. - These lobulation disappears by the end of the first postnatal year during infancy as the nephrons increase and grow. - At term, each kidney contains 800,000 to 1000,000 nephrons. - The increase in kidney size after birth results mainly from the elongation of the proximal convoluted tubules as well as an increase of interstitial tissue. - Functional maturation of the kidneys occurs after birth. ## Positional Changes of Kidneys - Initially the metanephric kidneys lie close to each other in the pelvis ventral to the sacrum. - As the abdomen and pelvis grow, the kidneys gradually come to lie in the abdomen and move farther apart and attain their adult position by 9th week. - Initially the hilum faces ventrally however as the kidney ascends it rotates medially 90 degrees. - By the 9th week the hilum is directed anteromedially. - Kidneys Change Position during weeks 6-9 of development - ASCENT = due to growth of caudal embryo - ROTATION = 90 degrees medially ## Changes in Blood Supply of kidneys - Initially, the renal arteries are branches of the common iliac and median sacral arteries. - As the kidneys ascend, they receive their blood supply from the distal end of the aorta. - Then, they receive new branches from the aorta. The most cranial arterial branches from the abdominal aorta become the permanent renal arteries. - When the kidneys become in contact with the suprarenal glands in the 9th week their ascend stops. - Suprarenal gland - Mesonephros - Suprarenal artery - Aorta - Suprarenal gland - Gonad - Renal artery - Kidney - Sites of former renal arteries - Common iliac artery - Renal artery - Kidney - Mesonephric duct - A - Left kidney - B - C - D - Ureter - Ureter - Gonad - Bladder - Normally, the caudal branches undergo involution and disappear. # Congenital Anomalies of the kidney ## 1. Cystic kidney Disease: ### A. Polycystic kidney: - It is an autosomal disorder. - It is diagnosed at birth by ultrasonography. - Both kidneys contain many hundred small cysts which results in renal insufficiency. - Death of the infant usually occurs shortly after birth. ### B. Multi-cystic dysplastic kidney disease (MDK): - It results from dysmorphology during development of the renal system. - Their outcome is generally good. - NORMAL KIDNEY - MULTICYSTIC KIDNEY - Ureter connects normal kidney to bladder - Bladder - Unformed ureter - Normal kidney - Polycystic kidney. ## 2. Horseshoe kidney: - It results from fusion of caudal ends of both kidneys. - The interconnecting bridge becomes trapped behind the inferior mesenteric artery so that the kidneys come to rest in low lumbar region. ## 3. Ectopic pelvic kidney - The kidney is arrested in some part of its normal ascent. - It usually is found at the pelvic brim. ## 4. Renal agenesis: - Unilateral renal agenesis results due to absence of formation of one ureteric bud. - It often causes no symptoms. - Bilateral renal agenesis is associate with oligohydramnios. # References: - Drake, R. A. Wayne Vogl, W. and Mitchell, A. (2017): Gray's Anatomy for Students. Elsevier. - Kadasne, D.K. (2011): “Kadasne's Textbook of Embryology". 1st ed. Jaypee Brothers Medical Publishers. - Moore, K. L.; Persaud, T.V.N.; Torchia, M. G. (2013): “The Developing Human". Clinically Oriented Embryology. 8th ed. Saunders Elsevier. Philadelphia. - Moore, K. L.; Dalley, A. F. and Agur, A. M. R. (2010): Clinically Oriented Anatomy.6th Edition, Lippincott Williams & Wilkins, Philadelphia. - Romanes, G. J.: Cunning hams Manual of Practical Anatomy.13th ed. London, Oxford University Press. New York, Bombay. - Ronald W. Dudek, R. W. (2014): “BRS Embryology". 6th ed. Lippincott Williams & Wilkins. - Sadler, T. W. (2019): “Langman's Medical Embryology".9th ed. Lippincott Williams& Wilkins. Philadelphia, New York, London, Hong Kong, Sydney, Tokyo. pp. 298-301. - Singh, V. (2017): “Textbook of Clinical Embryology".2nd ed. Elsevier, Relx India Pvt. Ltd. - Snell, R.S. (2008): “Clinical Anatomy by Regions". 8th ed. Lippincott Williams& Wilkins. Philadelphia, New York, London, Hong Kong, Sydney, Tokyo. P. 253. # Thank You - An image containing Arabic calligraphy with the words "والع " and "ما ترجوه " and "سوف يكون ". The words in the image are in yellow with a black background. There are also some small yellow flowers on the left side of the Thank you. The word thank you is in a pink color.