18 



Tne Excretory ana Reproductive Systems 



Introduction 



1. Developmental relationships 



2. Functions of the excretory and reproductive systems 



3. Basic embryonic tissues which contribute to the urogenital structures 

 Development of the excretory system 



1. General description 



a. Types of kidneys formed during embryonic development 



b. Types of nephrons or renal units produced in developing vertebrate embryos 



2. Functional kidneys during embryonic development 



a. Pronephros 



b. Mesonephros 



c. Metanephros and opisthonephros 



3. Development and importance of the pronephric kidney 



a. General considerations 



b. Shark, Squalus acanthias 



c. Frog 



d. Chick 



e. Mammal (human) 



4. Development of the mesonephric kidney 



a. Squalus acanthias 



b. Frog 



c. Chick 



d. Mammal 



5. Development of the metanephric kidney 



a. Chick 



1) Metanephric duct and metanephrogenous tissue 



2) Formation of the metanephric renal units 



b. Mammal (human) 



1) Formation of the pelvis, calyces, collecting ducts, and nephric units 



2) Formation of the capsule 



3) Changes in position of the developing kidney 



6. Urinary ducts and urinary bladders 



a. Types of urinary ducts 



b. Urinary bladders 



c. Cloaca 



768 



