- •Preface and Acknowledgments
- •Contents
- •Contributors
- •1: Embryology for Urologists
- •Introduction
- •Renal Development
- •Pronephros
- •Mesonephros
- •Metanephros
- •Development of the Collecting System
- •Critical Steps in Further Development
- •Anomalies of the Kidney
- •Renal Agenesis
- •Renal Aplasia
- •Renal Hypoplasia
- •Renal Ectopia
- •Renal Fusion
- •Ureteral Development
- •Anomalies of Origin
- •Anomalies of Number
- •Incomplete Ureteral Duplication
- •Complete Ureteral Duplication
- •Ureteral Ectopia
- •Embryology of Ectopia
- •Clinical Correlation
- •Location of Ectopic Ureteral Orifices – Male (in Descending Order According to Incidence)
- •Symptoms
- •Ureteroceles
- •Congenital Ureteral Obstruction
- •Pipestem Ureter
- •Megaureter-Megacystis Syndrome
- •Prune Belly Syndrome
- •Vascular Ureteral Obstructions
- •Division of the Urogenital Sinus
- •Bladder Development
- •Urachal Anomalies
- •Cloacal Duct Anomalies
- •Other Bladder Anomalies
- •Bladder Diverticula
- •Bladder Extrophy
- •Gonadal Development
- •Testicular Differentiation
- •Ovarian Differentiation
- •Gonadal Anomalies
- •Genital Duct System
- •Disorders of Testicular Function
- •Female Ductal Development
- •Prostatic Urethral Valves
- •Gonadal Duct Anomalies
- •External Genital Development
- •Male External Genital Development
- •Female External Genital Development
- •Anomalies of the External Genitalia
- •References
- •2: Gross and Laparoscopic Anatomy of the Upper Urinary Tract and Retroperitoneum
- •Overview
- •The Kidneys
- •The Renal Vasculature
- •The Renal Collecting System
- •The Ureters
- •Retroperitoneal Lymphatics
- •Retroperitoneal Nerves
- •The Adrenal Glands
- •References
- •3: Gross and Laparoscopic Anatomy of the Lower Urinary Tract and Pelvis
- •Introduction
- •Female Pelvis
- •Male Pelvis
- •Pelvic Floor
- •Urinary Bladder
- •Urethra
- •Male Urethra
- •Female Urethra
- •Sphincter Mechanisms
- •The Bladder Neck Component
- •The Urethral Wall Component
- •The External Urethral Sphincter
- •Summary
- •References
- •4: Anatomy of the Male Reproductive System
- •Testis and Scrotum
- •Spermatogenesis
- •Hormonal Regulation of Spermatogenesis
- •Genetic Regulation of Spermatogenesis
- •Epididymis and Ductus Deferens
- •Accessory Sex Glands
- •Prostate
- •Seminal Vesicles
- •Bulbourethral Glands
- •Penis
- •Erection and Ejaculation
- •References
- •5: Imaging of the Upper Tracts
- •Anatomy of the Upper Tracts and Introduction to Imaging Modalities
- •Introduction
- •Renal Upper Tract Basic Anatomy
- •Modalities Used for Imaging the Upper Tracts
- •Ultrasound
- •Radiation Issues
- •Contrast Issues
- •Renal and Upper Tract Tumors
- •Benign Renal Tumors
- •Transitional Cell Carcinoma
- •Renal Mass Biopsy
- •Renal Stone Disease
- •Ultrasound
- •Plain Radiographs and IVU
- •Renal Cystic Disease
- •Benign Renal Cysts
- •Hereditary Renal Cystic Disease
- •Complex Renal Cysts
- •Renal Trauma
- •References
- •Introduction
- •Pathophysiology
- •Susceptibility and Resistance
- •Epidemiological Breakpoints
- •Clinical Breakpoints
- •Pharmacodynamic Parameters
- •Pharmacokinetic Parameters
- •Fosfomycin
- •Nitrofurantoin
- •Pivmecillinam
- •b-Lactam-Antibiotics
- •Penicillins
- •Cephalosporins
- •Carbapenems
- •Aminoglycosides
- •Fluoroquinolones
- •Trimethoprim, Cotrimoxazole
- •Glycopeptides
- •Linezolid
- •Conclusion
- •References
- •7: An Overview of Renal Physiology
- •Introduction
- •Body Fluid Compartments
- •Regulation of Potassium Balance
- •Regulation of Acid–Base Balance
- •Diuretics
- •Suggested Reading
- •8: Ureteral Physiology and Pharmacology
- •Ureteral Anatomy
- •Modulation of Peristalsis
- •Ureteral Pharmacology
- •Conclusion
- •References
- •Introduction
- •Afferent Signaling Pathways
- •Efferent Signaling
- •Parasympathetic Nerves
- •Sympathetic Nerves
- •Vesico-Spinal-Vesical Micturition Reflex
- •Peripheral Targets
- •Afferent Signaling Mechanisms
- •Urothelium
- •Myocytes
- •Cholinergic Receptors
- •Muscarinic Receptors
- •Nicotinic Receptors
- •Adrenergic Receptors (ARs)
- •a-Adrenoceptors
- •b-Adrenoceptors
- •Transient Receptor Potential (TRP) Receptors
- •Phosphodiesterases (PDEs)
- •CNS Targets
- •Opioid Receptors
- •Serotonin (5-HT) Mechanisms
- •g-Amino Butyric Acid (GABA) Mechanisms
- •Gabapentin
- •Neurokinin and Neurokinin Receptors
- •Summary
- •References
- •10: Pharmacology of Sexual Function
- •Introduction
- •Sexual Desire/Arousal
- •Endocrinology
- •Steroids in the Male
- •Steroids in the Female
- •Neurohormones
- •Neurotransmitters
- •Dopamine
- •Serotonin
- •Pharmacological Strategies
- •CNS Drugs
- •Enzyme-inducing Antiepileptic Drugs
- •Erectile Function
- •Ejaculatory Function
- •Premature Ejaculation
- •Abnormal Ejaculation
- •Conclusions
- •References
- •Epidemiology
- •Calcium-Based Urolithiasis
- •Uric Acid Urolithiasis
- •Infectious Urolithiasis
- •Cystine-Based Urolithiasis
- •Aims
- •Who Deserves Metabolic Evaluation?
- •Metabolic Workup for Stone Producers
- •Medical History and Physical Examination
- •Stone Analysis
- •Serum Chemistry
- •Urine Evaluation
- •Urine Cultures
- •Urinalysis
- •Twenty-Four Hour Urine Collections
- •Radiologic Imaging
- •Medical Management
- •Conservative Management
- •Increased Fluid Intake
- •Citrus Juices
- •Dietary Restrictions
- •Restricted Oxalate Diet
- •Conservative Measures
- •Selective Medical Therapy
- •Absorptive Hypercalciuria
- •Thiazide
- •Orthophosphate
- •Renal Hypercalciuria
- •Primary Hyperparathyroidism
- •Hyperuricosuric Calcium Oxalate Nephrolithiasis
- •Enteric Hyperoxaluria
- •Hypocitraturic Calcium Oxalate Nephrolithiasis
- •Distal Renal Tubular Acidosis
- •Chronic Diarrheal States
- •Thiazide-Induced Hypocitraturia
- •Idiopathic Hypocitraturic Calcium Oxalate Nephrolithiasis
- •Hypomagnesiuric Calcium Nephrolithiasis
- •Gouty Diathesis
- •Cystinuria
- •Infection Lithiasis
- •Summary
- •References
- •12: Molecular Biology for Urologists
- •Introduction
- •Inherited Changes in Cancer Cells
- •VEGR and Cell Signaling
- •Targeting mTOR
- •Conclusion
- •References
- •13: Chemotherapeutic Agents for Urologic Oncology
- •Introduction
- •Bladder Cancer
- •Muscle Invasive Bladder Cancer
- •Metastatic Bladder Cancer
- •Conclusion
- •Prostate Cancer
- •Other Chemotherapeutic Drugs or Combinations for Treating HRPC
- •Conclusion
- •Renal Cell Carcinoma
- •Chemotherapy
- •Immunotherapy
- •Angiogenesis Inhibitor Drugs
- •Conclusion
- •Testicular Cancer
- •Stage I Seminoma
- •Stage I non-seminomatous Germ Cell Tumours (NSGCT)
- •Metastatic Germ Cell Tumours
- •Low-Volume Metastatic Disease (Stage II A/B)
- •Advanced Metastatic Disease
- •Salvage Chemotherapy for Relapsed or Refractory Disease
- •Conclusion
- •Penile Cancer
- •Side Effects of Chemotherapy
- •Conclusion
- •References
- •14: Tumor and Transplant Immunology
- •Antibodies
- •Cytotoxic and T-helper Cells
- •Immunosuppression
- •Induction Therapy
- •Maintenance Therapy
- •Rejection
- •Posttransplant Lymphoproliferative Disease
- •Summary
- •References
- •15: Pathophysiology of Renal Obstruction
- •Causes of Renal Obstruction
- •Effects on Prenatal Development
- •Prenatal Hydronephrosis
- •Spectrum of Renal Abnormalities
- •Renal Functional Changes
- •Renal Growth/Counterbalance
- •Vascular Changes
- •Inflammatory Mediators
- •Glomerular Development Changes
- •Mechanical Stretch of Renal Tubules
- •Unilateral Versus Bilateral
- •Limitations of Animal Models
- •Future Research
- •Issues in Patient Management
- •Diagnostic Imaging
- •Ultrasound
- •Intravenous Urography
- •Antegrade Urography and the Whitaker Test
- •Nuclear Renography
- •Computed Tomography
- •Magnetic Resonance Urography
- •Hypertension
- •Postobstructive Diuresis
- •References
- •Introduction
- •The Normal Lower Urinary Tract
- •Anatomy
- •Storage Function
- •Voiding Function
- •Neural Control
- •Symptoms
- •Flow Rate and Post-void Residual
- •Voiding Cystometry
- •Male
- •Female
- •Neurourology
- •Conclusions
- •References
- •17: Urologic Endocrinology
- •The Testis
- •Normal Androgen Metabolism
- •Epidemiological Aspects
- •Prostate
- •Brain
- •Muscle Mass and Adipose Tissue
- •Bones
- •Ematopoiesis
- •Metabolism
- •Cardiovascular System
- •Clinical Assessment
- •Biochemical Assessment
- •Treatment Modalities
- •Oral Preparations
- •Parenteral Preparations
- •Transdermal Preparations
- •Side Effects and Treatment Monitoring
- •Body Composition
- •Cognitive Decline
- •Bone Metabolism
- •The Kidneys
- •Endocrine Functions of the Kidney
- •Erythropoietin
- •Calcitriol
- •Renin
- •Paraneoplastic Syndromes
- •Hypercalcemia
- •Hypertension
- •Polycythemia
- •Other Endocrine Abnormalities
- •References
- •General Physiology
- •Prostate Innervation
- •Summary
- •References
- •Wound Healing
- •Inflammation
- •Proliferation
- •Remodeling
- •Principles of Plastic Surgery
- •Tissue Characteristics
- •Grafts
- •Flap
- •References
- •Lower Urinary Tract Symptoms
- •Storage Phase
- •Voiding Phase
- •Return to Storage Phase
- •Urodynamic Parameters
- •Urodynamic Techniques
- •Volume Voided Charts
- •Pad Testing
- •Typical Test Schedule
- •Uroflowmetry
- •Post Voiding Residual
- •Further Diagnostic Evaluation of Patients
- •Cystometry with or Without Video
- •Cystometry
- •Videocystometrography (Cystometry + Cystourethrography)
- •Cystometric Findings
- •Comment:
- •Measurements During the Storage Phase:
- •Measurements During the Voiding Phase:
- •Abnormal Function
- •Disorders of Sensation
- •Causes of Hypersensitive Bladder Sensation
- •Causes of Hyposensitive Bladder Sensation
- •Disorders of Detrusor Motor Function
- •Bladder Outflow Tract Dysfunction
- •Detrusor–Urethral Dyssynergia
- •Detrusor–Bladder Neck Dyssynergia
- •Detrusor–Sphincter Dyssynergia
- •Complex Urodynamic Investigation
- •Urethral Pressure Measurement
- •Technique
- •Neurophysiological Evaluation
- •Conclusion
- •References
- •Endoscopy
- •Cystourethroscopy
- •Ureteroscopy and Ureteropyeloscopy
- •Nephroscopy
- •Virtual Reality Simulators
- •Lasers
- •Clinical Application of Lasers
- •Condylomata Acuminata
- •Urolithiasis
- •Benign Prostatic Hyperplasia
- •Ureteral and Urethral Strictures
- •Conclusion
- •References
- •Introduction
- •The Prostatitis Syndromes
- •The Scope of the Problem
- •Category III CP/CPPS
- •The Goal of Treatment
- •Conservative Management
- •Drug Therapy
- •Antibiotics
- •Anti-inflammatories
- •Alpha blockers
- •Hormone Therapies
- •Phytotherapies
- •Analgesics, muscle relaxants and neuromodulators
- •Surgery
- •A Practical Management Plan
- •References
- •Orchitis
- •Definition and Etiology
- •Clinical Signs and Symptoms
- •Diagnostic Evaluation
- •Treatment of Infectious Orchitis
- •Epididymitis
- •Definition and Etiology
- •Clinical Signs and Symptoms
- •Diagnostic Evaluation of Epididymitis
- •Treatment of Acute Epididymitis
- •Treatment of Chronic Epididymitis
- •Treatment of Spermatic Cord Torsion
- •Fournier’s Gangrene
- •Definition and Etiology
- •Risk Factors
- •Clinical Signs and Symptoms
- •Diagnostic Evaluation
- •Treatment
- •References
- •Fungal Infections
- •Candidiasis
- •Aspergillosis
- •Cryptococcosis
- •Blastomycosis
- •Coccidioidomycosis
- •Histoplasmosis
- •Radiographic Findings
- •Treatment
- •Tuberculosis
- •Clinical Manifestations
- •Diagnosis
- •Treatment
- •Schistosomiasis
- •Clinical Manifestations
- •Diagnosis
- •Treatment
- •Filariasis
- •Clinical Manifestations
- •Diagnosis
- •Treatment
- •Onchocerciasis
- •References
- •25: Sexually Transmitted Infections
- •Introduction
- •STIs Associated with Genital Ulcers
- •Herpes Simplex Virus
- •Diagnosis
- •Treatment
- •Chancroid
- •Diagnosis
- •Treatment
- •Syphilis
- •Diagnosis
- •Treatment
- •Lymphogranuloma Venereum
- •Diagnosis
- •Treatment
- •Chlamydia
- •Diagnosis
- •Treatment
- •Gonorrhea
- •Diagnosis
- •Treatment
- •Trichomoniasis
- •Diagnosis
- •Treatment
- •Human Papilloma Virus
- •Diagnosis
- •Treatment
- •Scabies
- •Diagnosis
- •Treatment
- •References
- •26: Hematuria: Evaluation and Management
- •Introduction
- •Classification of Hematuria
- •Macroscopic Hematuria
- •Microscopic Hematuria
- •Dipstick Hematuria
- •Pseudohematuria
- •Factitious Hematuria
- •Menstruation
- •Aetiology
- •Malignancy
- •Urinary Calculi
- •Infection and Inflammation
- •Benign Prostatic Hyperplasia
- •Trauma
- •Drugs
- •Nephrological Causes
- •Assessment
- •History
- •Examination
- •Investigations
- •Dipstick Urinalysis
- •Cytology
- •Molecular Tests
- •Blood Tests
- •Flexible Cystoscopy
- •Upper Urinary Tract Evaluation
- •Renal USS
- •KUB Abdominal X-Ray
- •Intravenous Urography (IVU)
- •Computed Tomography (CT)
- •Retrograde Urogram Studies
- •Magnetic Resonance Imaging (MRI)
- •Additional Tests and Renal Biopsy
- •Intractable Hematuria
- •Loin Pain Hematuria Syndrome
- •References
- •27: Benign Prostatic Hyperplasia (BPH)
- •Historical Background
- •Pathophysiology
- •Patient Assessment
- •Treatment of BPH
- •Watchful Waiting
- •Drug Therapy
- •Interventional Therapies
- •Conclusions
- •References
- •28: Practical Guidelines for the Treatment of Erectile Dysfunction and Peyronie´s Disease
- •Erectile Dysfunction
- •Introduction
- •Diagnosis
- •Basic Evaluation
- •Cardiovascular System and Sexual Activity
- •Optional Tests
- •Treatment
- •Medical Treatment
- •Oral Agents
- •Phosphodiesterase Type 5 (PDE 5) Inhibitors
- •Nonresponders to PDE5 Inhibitors
- •Apomorphine SL
- •Yohimbine
- •Intracavernosal and Intraurethral Therapy
- •Intracavernosal Injection (ICI) Therapy
- •Intraurethral Therapy
- •Vacuum Constriction Devices
- •Surgical Therapy
- •Conclusion
- •Peyronie´s Disease (PD)
- •Introduction
- •Oral Drug Therapy
- •Intralesional Drug Therapy
- •Iontophoresis
- •Radiation Therapy
- •Surgical Therapy
- •References
- •29: Premature Ejaculation
- •Introduction
- •Epidemiology
- •Defining Premature Ejaculation
- •Voluntary Control
- •Sexual Satisfaction
- •Distress
- •Psychosexual Counseling
- •Pharmacological Treatment
- •On-Demand Treatment with Tramadol
- •Topical Anesthetics
- •Phosphodiesterase Inhibitors
- •Surgery
- •Conclusion
- •References
- •30: The Role of Interventional Management for Urinary Tract Calculi
- •Contraindications to ESWL
- •Complications of ESWL
- •PCNL Access
- •Instrumentation for PCNL
- •Nephrostomy Drains Post PCNL
- •Contraindications to PCNL
- •Complications of PCNL
- •Semirigid Ureteroscopy
- •Flexible Ureteroscopy
- •Electrohydraulic Lithotripsy (EHL)
- •Ultrasound
- •Ballistic Lithotripsy
- •Laser Lithotripsy
- •Ureteric Stents
- •Staghorn Calculi
- •Lower Pole Stones
- •Horseshoe Kidneys and Stones
- •Calyceal Diverticula Stones
- •Stones and PUJ Obstruction
- •Treatment of Ureteric Colic
- •Medical Expulsive Therapy (MET)
- •Intervention for Ureteric Stones
- •Stones in Pregnancy
- •Morbid Obesity
- •References
- •Anatomy and Function
- •Pathophysiology
- •Management
- •Optical Urethrotomy/Dilatation
- •Urethral Stents
- •Preoperative Assessment
- •Urethroplasty
- •Anastomotic Urethroplasty
- •Substitution Urethroplasty
- •Grafts Versus Flaps
- •Oral Mucosal Grafts
- •Tissue Engineering
- •Graft Position
- •Conclusion
- •References
- •32: Urinary Incontinence
- •Epidemiology and Risk Factors
- •Pathophysiology
- •Urge Incontinence
- •Conservative Treatments
- •Pharmacotherapy
- •Invasive/ Surgical Therapies
- •Stress Urinary Incontinence
- •Male SUI Therapies
- •Female SUI Therapies
- •Mixed Urinary Incontinence
- •Conclusions
- •References
- •33: Neurogenic Bladder
- •Introduction
- •Examination and Diagnostic Tests
- •History and Physical Examination
- •Imaging
- •Urodynamics (UDS)
- •Evoked Potentials
- •Classifications
- •Somatic Pathways
- •Brain Lesions
- •Cerebrovascular Accident (CVA)
- •Parkinson’s Disease (PD)
- •Multiple Sclerosis
- •Huntington’s Disease
- •Dementias
- •Normal Pressure Hydrocephalus (NPH)
- •Tumors
- •Psychiatric Disorders
- •Spinal Lesions and Pathology
- •Intervertebral Disk Prolapse
- •Spinal Cord Injury (SCI)
- •Transverse Myelitis
- •Peripheral Neuropathies
- •Metabolic Neuropathies
- •Pelvic Surgery
- •Treatment
- •Summary
- •References
- •34: Pelvic Prolapse
- •Introduction
- •Epidemiology
- •Anatomy and Pathophysiology
- •Evaluation and Diagnosis
- •Outcome Measures
- •Imaging
- •Urodynamics
- •Indications for Management
- •Biosynthetics
- •Surgical Management
- •Anterior Compartment Repair
- •Uterine/Apical Prolapse
- •Enterocele Repair
- •Conclusion
- •References
- •35: Urinary Tract Fistula
- •Introduction
- •Urogynecologic Fistula
- •Vesicovaginal Fistula
- •Etiology and Risk Factors
- •Clinical Factors
- •Evaluation and Diagnosis
- •Pelvic Examination
- •Cystoscopy
- •Imaging
- •Treatment
- •Conservative Management
- •Surgical Management
- •Urethrovaginal Fistula
- •Etiology and Presentation
- •Diagnosis and Management
- •Ureterovaginal Fistula
- •Etiology and Presentation
- •Diagnosis and Management
- •Vesicouterine Fistula
- •Etiology and Presentation
- •Diagnosis and Management
- •Uro-Enteric Fistula
- •Vesicoenteric Fistula
- •Pyeloenteric Fistula
- •Urethrorectal Fistula
- •References
- •36: Urologic Trauma
- •Introduction
- •Kidney
- •Expectant Management
- •Endovascular Therapy
- •Operative Intervention
- •Operative Management: Follow-up
- •Reno-Vascular Injuries
- •Pediatric Renal Injuries
- •Adrenal
- •Ureter
- •Diagnosis
- •Treatment
- •Delayed Diagnosis
- •Bladder and Posterior Urethra
- •Bladder Injuries: Initial Management
- •Bladder Injuries: Formal Repair
- •Anterior Urethral Trauma
- •Fractured Penis
- •Penile Amputation
- •Scrotal and Testicular Trauma
- •Imaging
- •CT-IVP (CT with Delayed Images)
- •Technique
- •Cystogram
- •Technique
- •Retrograde Urethrogram (RUG)
- •Technique
- •Retrograde Pyelogram (RPG)
- •Technique
- •One-Shot IVP
- •Technique
- •References
- •37: Bladder Cancer
- •Who Should Be Investigated?
- •Epidemiology
- •Risk Factors
- •Role of Screening
- •Signs and Symptoms
- •Imaging
- •Cystoscopy
- •Urine Tests
- •PDD-Assisted TUR
- •Pathology
- •NMIBC and Risk Groups
- •Intravesical Chemotherapy
- •Intravesical Immunotherapy
- •Immediate Cystectomy and CIS
- •Radical Cystectomy with Pelvic Lymph Node Dissection
- •sexual function-preserving techniques
- •Bladder-Preservation Treatments
- •Neoadjuvant Chemotherapy
- •Adjuvant Chemotherapy
- •Preoperative Radiotherapy
- •Follow-up After TUR in NMIBC
- •References
- •38: Prostate Cancer
- •Introduction
- •Epidemiology
- •Race
- •Geographic Variation
- •Risk Factors and Prevention
- •Family History
- •Diet and Lifestyle
- •Prevention
- •Screening and Diagnosis
- •Current Screening Recommendations
- •Biopsy
- •Pathology
- •Prognosis
- •Treatment of Prostate Cancer
- •Treatment for Localized Prostate Cancer (T1, T2)
- •Radical Prostatectomy
- •EBRT
- •IMRT
- •Brachytherapy
- •Treatment for Locally Advanced Prostate Cancer (T3, T4)
- •EBRT with ADT
- •Radical Prostatectomy
- •Androgen-Deprivation Therapy
- •Summary
- •References
- •39: The Management of Testis Cancer
- •Presentation and Diagnosis
- •Serum Tumor Markers
- •Primary Surgery
- •Testis Preserving Surgery
- •Risk Stratification
- •Surveillance Versus Primary RPLND
- •Primary RPLND
- •Adjuvant Treatment for High Risk
- •Clinical Stage 1 Seminoma
- •Risk-Stratified Adjuvant Treatment
- •Adjuvant Radiotherapy
- •Adjuvant Low Dose Chemotherapy
- •Primary Combination Chemotherapy
- •Late Toxicity
- •Salvage Strategies
- •Conclusion
- •References
- •Index
19
Embryology for Urologists
These diverticula are considered to be congen- |
Gonadal Development |
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ital in origin. |
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While bladder diverticula can be congenital, |
Sexual differentiation in the fetus is bipoten- |
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they are generally acquired. The majority of |
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tial. This is true not only for the gonad and |
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such acquired diverticula are due to some form |
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the external genitalia which are derived from |
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of outlet obstruction. In children, posterior |
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a common primordium but for the ductal |
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urethral valves and congenital urethral stric- |
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structures as well, each sex having its own |
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tures are the most common cause. In adults, |
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primordium. |
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benign prostatic hypertrophy and acquired |
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Formation of the undifferentiated gonad |
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urethral strictures are the general basis for this |
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begins during the fifth week of fetal life when the |
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problem. |
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proliferation of germinal epithelial cells and the |
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However, the classical distinction, between an |
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mesenchyme underlying them produce a prom- |
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acquired and a congenital diverticulum is that |
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inence on the medial side of each mesonephros. |
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the congenital diverticulum displays an adventi- |
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This prominence is then known as the gonadal |
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tial, muscular, and mucosal layer whereas the |
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ridge.While the germinal epithelial cells and the |
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acquired diverticulum has only an adventitial |
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underlying mesenchymal tissue continue to pro- |
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and mucosal layer. Symptomatology is generally |
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liferate, primordial germ cells migrate into this |
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related to stasis with complicating infection, cal- |
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underlying mesenchyme at about the sixth week |
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culus formation or tumor formation. The treat- |
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of fetal life and the undifferentiated or bipoten- |
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ment is surgical if the diverticulum cannot be |
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tial gonad is formed (see Fig. 1.16). |
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cystoscoped, does not empty well, or complica- |
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tions exist. |
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Bladder Extrophy
Extrophy is a severe congenital affliction and is fortunately very rare. It occurs approximately once in 40,000 births and the male is afflicted three times more often than the female. Embryologically, it results from failure of the mesodermal structures of the abdominal wall below the umbilicus to develop normally. Gilles believes that this is due to abnormal forward displacement of the cloacal membrane. On the other hand, Patten believes that it is due to abnormal caudal formation of the paired primordia of the genital tubercle. Other theories exist but whatever the cause, the results are generally devastating.
Varying degrees of bladder extrophy can occur and range from simple epispadias to complete extrophy with epispadias, pubic separation, inguinal hemia, imperforate anus, or persistent cloaca. Testicular maldescent is also frequently associated.In addition,the ureterovesical junction is generally defective with associated reflux.
From a clinical standpoint, it is worthy to note that while urachal remnants can give rise to adenocarcinoma which tends to spread late, bladder extrophy gives rise to adenocarcinoma which spreads early.
Testicular Differentiation
At about the seventh week of fetal life testicular differentiation occurs. Such differentiation of the gonadal primordium occurs through the action of male organizer substance and is thought to be controlled by the Y chromosome. Not until normal testicular development and function has been initiated can development of the male phenotype occur. In the absence of such testicular development, the differentiated gonad will thus develop into an ovary at the 13th to 14th week of fetal life. For normal male fetal development the 7th to 12th week of fetal development are thus essential. If testosterone secretion is delayed for whatever reason, abnormal male development will occur.
When the gonad develops into a testis (see Fig. 1.17)
1.Proliferation of the coelemic epithelium ceases and the sex cords of the undifferentiated stage become the seminiferous tubules. These, with their cellular duality, provide the spermatogonia as well as the Sertoli - or nutritive - support cells.
2.A layer of connective tissue, the tunica albuginea, interposes itself between the coelemic epithelium and the rest of the gland and compartmentalizes the rolled up seminiferous tubules.
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Practical Urology: EssEntial PrinciPlEs and PracticE |
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Primordial germ cells |
Supranenal medulla |
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Suprarenal cortex |
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Mesonephric duct |
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Tubule |
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Medulla |
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Hindgut |
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Cortex |
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Primary sex cord |
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Y |
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(13th |
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14th week) |
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Developing testes |
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Developing ovaries |
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Germinal epithelium |
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sex cord) |
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Mesovarium |
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Seminiferous cord |
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Mesonephric |
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Mesonephric |
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tubule |
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Tunica |
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Germinal epithelium |
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Primordial germ cell |
Paramesonephric duct |
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Cortical cords
Figure 1.16. gonad development based on the presence or absence of the y chromosome.
Appendix epididymis
Appendix testis
Wolffian duct
(Mesonephric duct)
Müllerian duct Interstitial tissue Vasa efferentia
Rete testis Tubuli recti
Seminiferous tubule
Tunica albuginea
Figure 1.17. testicular development.
21
Embryology for Urologists
3. The deep portions of the seminiferous tubules |
about the ninth week of fetal life, a primary cor- |
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narrow to form the tubuli recti, and these |
tex and medulla form.These structures then give |
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converge to form the rete testis. The Sertoli |
rise to a definitive cortex by the fourteenth week |
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of life. In ovarian development, the coelemic ger- |
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cells, seminiferous tubules, tubuli recti, and |
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minal epithelium gives rise to the primary ovar- |
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rete testis thus all originate from the coelemic |
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ian follicles, the underlying mesenchyme to the |
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epithelium. The Sertoli cells produce |
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stromal cells, and the primordial germ cells to |
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Müllerian inhibiting factor (MIF). |
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the ova. Like the testis, the ovary also gains a |
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4. The interstitial cells of Leydig differentiate |
mesentery known as the mesovarium, and set- |
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between the seminiferous tubules. They pro- |
tles into a more caudal position as the fetus |
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duce testosterone, which is the androgenic |
develops. In addition to this early internal |
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hormone which influences male genital tract |
descent,the ovary also becomes attached through |
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the gubernaculum to the tissues of the genital |
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and external genital development and |
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folds, which form the round ligaments of the |
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differentiation. |
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ovary, as well as to the tissues of the uterovaginal |
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5. As the Wolffian body (Genito-urinary ridge) |
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canal which form the broad ligament of the |
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regresses, the rete testes anastomose with the |
uterus. A small processus vaginalis also forms |
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adjacent mesonephric tubules thus establish- |
and passes toward the labial swellings, but this |
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ing the first genito-urinary connection (GU). |
structure is usually obliterated at full term. |
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These connecting mesonephric tubules are |
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known as the vasa deferentia, and that por- |
Gonadal Anomalies |
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tion of the mesonephric duct into which they |
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open becomes the epididymis. |
Gonadal anomalies can simply be broken down |
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As the testicle further develops,it increases in size |
into anomalies of development and anomalies |
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and shortens into a more compact organ while |
of position. |
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achieving a more caudal location. Furthermore, |
Anomalies of development include anomalies |
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its broad attachment to the mesonephros is con- |
in number such as agenesis or anorchism, hypo- |
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verted into a gonadal mesentery known as the |
genesis, supemumerary gonads or polyorchism, |
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mesorchium. By the third month of fetal life, the |
as well as the extremely rare anomaly of gonadal |
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testis has descended and is located retroperitone- |
fusion or synorchism. |
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ally in the false pelvis from where it gradually |
Anomalies of position include cryptorchidism, |
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descends to the abdominal end of the inguinal |
or imperfect descent of the testis, which is by far |
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canal. It remains there until the seventh month of |
the commonest spermatic tract anomaly. The |
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fetal life at which time it passes through the ingui- |
causeof imperfecttesticulardescentisunknown, |
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nal canal behind the processus vaginalis to enter |
but is usually anatomic or hormonal in origin. |
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the scrotum by the end of the eighth month. |
Testicular ectopy is due to faulty testicular |
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Caudal migration of the testes is facilitated by |
descent along one of the subsidiary strains of |
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means of the gubenaculum. This fibromuscular |
the gubemaculum. In such aberrant descent, the |
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band extends from the lower pole of the testis |
testicle may be interstitial, femoral, penile, |
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through the developing muscular layers of the |
perineal, or transverse in its position. |
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anterior abdominal wall to terminate in the sub- |
Failure of union between the rete testes and |
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cutaneous tissue of the scrotal swelling. The |
mesonephros, that is, the mesonephric tubules, |
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gubenaculum also has several subsidiary strands |
results in a testis separate from the male genital |
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that extend to adjacent regions (femoral, inter- |
ducts. |
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stitial, penile, etc.) and these explain testicular |
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maldescent into these regions. |
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Ovarian Differentiation
In the absence of male organizer substance, a factor of the XY chromosome the undifferentiated gonad develops into an ovary. Initially, at
Genital Duct System
Before discussing development of the genital duct system and the external genitalia, it is important to reemphasize that while the Y chromosome and testicular development and
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22 |
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Practical Urology: EssEntial PrinciPlEs and PracticE |
function are absolutely essential in the devel- |
The Müllerian inhibiting factor is secreted by |
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opment of the male fetus, neither the 46 XX |
the Sertoli cells and acts locally (rather than sys- |
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complement nor the ovaries are necessary, for |
temically) to suppress the development of the |
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female fetal development. It has been experi- |
adjacent Müllerian structures in direct contact |
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mentally shown that if a genetic male fetus is |
with the ipsilateral fetal testis. As the testis des- |
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castrated (no testosterone or MIF) before the |
cends it acts sequentially on the adjacent Müllerian |
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genitalia differentiate, a female phenotype will |
structures with the only remnants being the |
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develop. Thus while testicular influence is abso- |
appendix testis at the superior end and the utricle |
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lutely necessary for male development, ovarian |
in the verumontanum at the distal end. |
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influence is of no significance in female devel- |
This action cannot be duplicated by andro- |
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opment since the natural tendency of the fetus |
gens since testosterone, which is secreted by the |
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is to develop into a female. |
Leydig cells, acts systemically rather than locally |
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As alluded to earlier, for normal male pheno- |
and plays the most important role in two other |
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type development in utero, the testes must not |
major facets of male phenotype development. |
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only differentiate normally but also function |
First of all, it permits differentiation of the |
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normally. Two specific substances which are |
mesonephric tubules and ductal structures into |
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critical to the development of the male pheno- |
the epididymis, vas deferens, seminal vesicles, |
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type must be produced by the testes. The first of |
and ejaculatory ducts. Secondly, testosterone |
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these is the hormone testosterone which is |
also acts as a prehormone on the androgen |
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secreted by the Leydig cells. The second is the |
dependent target areas, which include the com- |
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Müllerian inhibiting factor (MIF) which is |
ponents of the urogenital tubercle, the urogeni- |
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thought to be secreted by the Sertoli cells (see |
tal sinus, and that area in the urogenital sinus |
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Fig. 1.18). |
which will eventually develop into the prostate |
Figure 1.18. testosterone and müllerian inhibition factor (mif) influence on gonadal and genital development.
Leydig cells |
Sertoli cell |
Testosterone
Müllerian ducts
Wolffian ducts (Mesonephric ducts)
Vas deferens
Seminal vesicles
Seminiferous tubules
Müllerian
Inhibiting Factor (MIF) impacting on the Mullerian ductal system
Dihydrotestosterone
External genital anlage
tubercle lateral folds
lateral swelling
Epididymis
shaft glans
scrotum