Structure of kidney and ureter Flashcards
Muscular cavity where digestive waste and urine leave the embryo
Cloaca
The kidneys present in embryo development
Pronephros, mesonephros and metanephros
Pronephros
First set of kidneys which regress after 4 weeks and are non functional. They are located in the region of the cervical vertebrae.
What is the composition of the pronephros?
Nephric tubules and nephrotomes
Mesonephros
Temporary and first functional kidneys that form urine. Become part of the urogenital system. They drain into the mesonephric duct/Wolffian duct which eventually regresses. Located in the thoracic/lumbar region.
What does the mesonephros composed of?
Forms urogenital ridge.
Where is the mesonephric system derived from?
Segmented intermediate mesoderm
Metanephros
Located in lower sacral/lumbar region. Contains uretic bud and later, the metanephric blastema.
Where does the bladder develop?
From urogenital region with opening to the allantosis.
Mesonephric duct
Contains the uretic bud to forms the minor calcyx, major calcyx, collecting duct, collecting tubules and ureter
Effect of uretic bud?
Induces differentiation of the mesoderm for formation of the metanephric blastema caps
Renal vesicle
First epithelial derivative of the metanephric blastema. It will from the PCT and DCT first, and develop into the glomerulus, bowman’s capsule and DCT.
Metanephric blastema
Cap forms due to signals from the uretic bud. It gives rise to the nephron from the glomerulus to the DCT via formation of renal vesicle
Renal blood supply during development
Branches from the abdominal aorta and as kidney ascends, it comes directly off abdominal aorta.
Renal artery-> interlobar -> arcuate -> interlobular artery -> afferent arteriole
What are abnormalities that can occur to the kidneys during development?
Kidney develops in pelvis because it does not migrate up
Fusion of the kidneys
Aberrant renal arteries (multiple)
Where does the ureter drain into the bladder?
Superior and posterior
Region where urethra crosses the pelvic floor?
Membranous
What is the majority of the spongy urethra lined with?
Pseudostratified columnar epithelia.
Which part of the urethra is lined with stratified squamous epithelia?
End of urethra in glans penis
Location of kidney anatomically
Retroperitoneal organ from T12 to L3. Right side is lower than the left. Hilum opens anteromedially to abdominal aorta. It is divided into the cortex and the medulla. The functional unit of the kidney is the nephron
What are the anatomical coverings of the kidney?
Enveloped in a tough fibrous connective tissue capsule called the renal capsule which contains perirenal fat. The renal capsule is separated from surrounding pararenal fat by the renal fascia.
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Renal capsule
Renal fascia
Pararenal fat
Which vessel does reabsorption take place in the kidney?
Peritubular capillaries, a branch of the efferent arteriole which surround the PCT and DCT. They drain into the interlobular veins. They are therefore located in the cortical regions of the nephron.
What is pararenal fat?
White adipose tissue located anteriorly to renal fascia
Which vessels are a branch of the afferent arteriole?
Vasa recta capillaries that surround the Loop of Henle for reabsorption in the countercurrent mechanisms. They drain into the renal veins.
Which vessels are a branch of the efferent arterioelle?
Peritubular capillaries, surrounding the PCT and DCT in the cortical region for reabsorption of solutes and secretion into the nephron. They drain into the veins.
Renal fascia
Connective tissue sheath which encloses the kidneys and its structures, extending into the pelvis urethra. It has a midline attachment which prevents inward movement of vessels in renal hilum.
What is perinephric fat?
Brown adipose tissue surrounding kidneys and adrenal glands, separated from pararenal fat via the renal fascia.