CLINICAL EMBRYOLOGY OF THE KIDNEYS, URINARY BLADDER AND URETERS Flashcards
Structures of the Renal (Urogenital) System are derived from two germ layers:
mesoderm
endoderm
what 3 layers is the mesodermal germ layer divided into
paraxial mesoderm
intermediate mesoderm
lateral plate mesoderm ( subdivided into somatic and splanchnic mesoderm)
IDENTIFY THE PRIMARY EMBRYONIC GERM LAYERS THAT GIVE RISE TO THE FOLLOWING REPRODUCTIVE SYSTEM STRUCTURES:
uterine tube
mesoderm
IDENTIFY THE PRIMARY EMBRYONIC GERM LAYERS THAT GIVE RISE TO THE FOLLOWING REPRODUCTIVE SYSTEM STRUCTURES:
uterus and uterine canal
mesoderm
IDENTIFY THE PRIMARY EMBRYONIC GERM LAYERS THAT GIVE RISE TO THE FOLLOWING REPRODUCTIVE SYSTEM STRUCTURES:
vagina
mesoderm and endoderm
IDENTIFY THE PRIMARY EMBRYONIC GERM LAYERS THAT GIVE RISE TO THE FOLLOWING REPRODUCTIVE SYSTEM STRUCTURES:
urethra
endoderm
IDENTIFY THE PRIMARY EMBRYONIC GERM LAYERS THAT GIVE RISE TO THE FOLLOWING REPRODUCTIVE SYSTEM STRUCTURES:
external genitalia
endoderm
what is the renal collecting ductal system made of
Ureters
Renal pelvis
Major calyces
Minor calyces
Collecting tubules.
what is the renal excretory ductal system made of
the nephron renal corpuscle - glomerulus , bowman capsule PCT loop on henle DCT
what is the mesonephric duct
connects primitive kidney ( mesonephros) to the cloaca and serves as the anlage(the rudimentary basis of a particular organ or other part, especially in an embryo) for certain male reproductive organs
what is the cloaca
The term describing the common cavity into which the intestinal, genital, and urinary tracts open in vertebrates. Located at the caudal end of the embryo it is located on the surface by the cloacal membrane
the mesonephric system is made from the mesodermal germ layer structure and contributes to formation of what
renal tubules ureter reproductive ductal system uterine canal vagina
the cloaca is part of the distal portion of the embryonic hindgut and is part of the endodermal germ layer structure and contributes to the formation of what
urinary bladder
urethra
vagina
external genitalia
Haeckel’s Biogenetic Law: “Ontogeny recapitulates Phylogeny”.
what is meant by this
an example of this is the Development of the urinary system
Pronephros - functional kidney in primitive fish
Mesonephros - functional kidney in advanced fish such as aquatic vertebrates
Metanephros - functional kidney in humans
The theory of recapitulation, also called the biogenetic law or embryological parallelism—often expressed using Ernst Haeckel’s phrase “ontogeny recapitulates phylogeny”—is a historical hypothesis that the development of the embryo of an animal, from fertilization to gestation or hatching (ontogeny), goes through stages resembling or representing successive adult stages in the evolution of the animal’s remote ancestors (phylogeny)
wiki
In the embryo, the kidneys develop from three overlapping sequential systems; the pronephros, the mesonephros, and the metanephros. They are all derived from what
urogenital ridge
the pronephros
A transient vestigial excretory unit – nephrotomes, derived from the intermediate mesoderm.
Appear at the beginning of the 4th week and regress by the end of the 4th week.
when does this start and regress
what germ layer does it derive from
what duct is formed and where is this duct found and connected by
appears in the 4th week of development
begins in the cervical region of the embryo - segmented divisions of intermediate mesoderm from tubules known as nephrotomes( 6-10 formed)
These join into the pronephric duct which is the duct that cervical region to the cloaca ( distal end) of the embryo.
Because this is an early system and therefore cannot be functional it regresses completely by the end of week 4
Derived from the intermediate mesoderm which also gives rise to the mesonephric (Wolffian or nephric) ducts.
The mesonephric ducts give rise to primitive excretory tubules with tuft of glomerular capillaries around which it forms the primitive Bowman’s capsule.
These structures together constitute a primitive renal corpuscle that drain into the mesonephric or Wolffian or nephric ducts.
The mesonephric ducts also give rise to the ureteric buds.
The developing gonad lies on the medial side of each developing Mesonephros, both of them form a common ridge called Urogenital Ridge.
the mesonephros develops caudually ( inferior) to the pronephros. Its formation induced by the pronephric duct ( intermediate mesoderm- this is in the thoracolumbar region to form the mesonephric tubules).
mesospheric duct is a continuation of the pronephric duct
most of these tubules regress by the end 8 week mark
additionally the mesonephric duct sprouts the ureteric bud caudally, which induces the development of the definitive kidney.
Metanephros.
when does a permanent kidney arise?
when does the kidney become functional ?
A permanent kidney, appears in the fifth week of development.
Gives rise to the definitive excretory units in the same manner as the mesonephric system.
This constitute the permanent kidney ductal system.
the metanephros forms the definitive kidney - appears at 5th week and becomes functional at around the 12th week
the uteric bud from the mesonephric duct makes contact with caudal region of metanephric
what is the collecting system derived from
what do the collecting tubules converge on forming what
uteric bud
dilates to create ureter , renal pelvis , major and minor calyces and 1-3mill collecting tubules terminating at the DCT
collecting tubules converge on the minor calyces forming renal pyramids
what is the excretory system derived from
metanephric blastema
each collecting tube gives rise to excretory tubules
nephron
proximal end from the bowman capsule around the glomerulus with the distal end elongating to from the PCT, loop of henle and DCT
s shaped
at 1 end of each of the renal tubules - surround the caps diff to form glomerulus
the glomerulus indents that end of renal tubule to from bowman
other end forms stuff mentioned above
where does the definitive kidney initially develop
in the pelvic region before ascending into the abdomen
the kidney receives its blood supply from a pelvic branch of hat
abdominal aorta
these pelvic arteries regress but can resist as accessory renal arteries