Embryology: Urinary System Flashcards
When does the development of the urinary system being
At week 4
From what structure is early development of the urinary system
From intermediate mesodermal on each side of embryo that condense to form urogenital ridges that is cylindrical structures
What is the 2 portions of the urogenital ridge & what they form
- Genital ridge forming gonads
- Nephrogenic cord urinary structures
What is the 3 structures that form from the nephrogenic cord
- Pronephro
- Mesonephro
- Metanephro
When & where does the pronephros form
Beginning of week4 arise from cervical region but also regress at end of week 4
What is the 2 structures of the pronephros & what they are
- Pronephric duct: tube that runs lengths of nephrogenic cord & give rise to mesonephric duct
- Nephrotomes: chucks of tissue that breaks off from nephrogenic cord
Where does the mesonephros form
In thoracic/upper lumbar region of nephrogenic cord
What are the 2 structures mesonephros consists of
- Mesonephric duct: develops from pronephric duct & extends to cloaca
- Mesonephric tubules: hollow, S-shaped tubules which connect to mesonephric duct on one & end form a cup (Bowman’s capsule) around a clump of capillaries (glomerulus) on the other end
When does the mesonephros regress & why
Week 10 as permanent kidneys take over
What does the glomerulus of the mesonephros do
Extract fluid from capillaries & flow down duct into cloaca forming urine
When & where does the metanephros form
Week 5 in pelvic region
What does the metanephros form & from what
The permanent kidneys
Intermediate mesoderm ear mesonephric duct
What is the metanephric blastema
Intermediate mesoderm that differentiate into metanephric mesoderm
What does the metanephric blastema induce
The mesonephric duct to sprout a ureteric bud that is connected to mesonephric duct via ureteric stalk
What does the ureteric secrete & what is the effect
As ureteric bud lengthens it secretes growth factor that cause metanephric mesoderm to grow
Ureteric bud grows into metanephric mesoderm surrounding ureteric bud
What does the ureteric stalk form & when
Ureter & at week 6
What does the ureteric bud form & when
Ureteric bud divides & form renal pelvis & division continue to form 2 major calyces, minor calyces & collecting tubules
Week 7 & 8
When does nephron form & from where
Week 8
Cells in collecting tubule signals adjacent metanephric mesoderm to form metanephric vesicles (round cells cluster)