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45 Cards in this Set
- Front
- Back
both the urinary and the repro systems develop from _____ which forms a ___ |
intermediate mesoderm, urogenital ridge |
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urinary system consists of (4) |
kidneys (produce urine), ueters (convey urine from the kidneys to the bladder), the bladder, urethra |
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what are the functional units of the kidney ? |
nephrons |
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what are the three kidneys that form in the human embryos |
pronephroi, mesonephroi, metanephroi |
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what week do the pronephrois appear and are arranged where? |
4th, segmentally arranged cell and pronephric tubuli structures in the cervical region of the intermediate mesoderm |
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___ run caudally and open into the cloaca |
pronephric ducts |
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the pronephroi degenerate but the __ persist and are used by the next set of kidneys |
pronephric ducts |
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what week do the meonephroi appear and how do they arrise |
4th, arise from cell clusters-->vesicles-->tubules |
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tubules contact pronephric duct which is now called ___ |
mesonephric duct |
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mesonephric kidneys consist of __ and ___ |
glomeruli and tubules, |
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the mesonephric tubules open into bilateral ___ which were originally the ___ |
mesonephric ducts, pronephric ducts |
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the mesonephric ducts open into the ___. When do the meonephroi degenerate? what do their tubules become? |
cloaca, toward end of the first trimester, the efferent ductules of the testes |
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what are the permanent kidneys called ? |
Metanephroi |
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when do the permanent kidneys develop and when do they start functioning |
5th, 10th |
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urine is produced and excreted into ___. The fetus drinks this and wastes are absorbed and removed via the ___ |
amniotic fluid, placenta |
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metanephroi develop from 2 sources both of mesodermal origin what are they ? |
metanephric diverticulum and metanephric blastema |
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metanephric diverticulum begins as an outgrowth from the ___ near the ___. What does it give rise to (6)? |
mesonephric duct, cloaca
ureter, renal pelvis, major and minor calices and collecting ducts and tubules |
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where is the metanephric blastema located?
as collecting tubules form, they induce the mesoderm to do what? |
caudal part of the nephrogenic cord
form clusters--->vesicles-->tubules-->nephrons |
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the stalk of the metanephric diverticulum becomes the? |
ureter |
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the __ portion of the diverticulum undergoes repetitive ___ events forming the __ which differentiate into the collecting tubules of the ___ |
cranial, branching, branches, metanephros |
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____ generation tubules become confluent and form major calices
___ generation coalesce and form minor calices |
1st four, 2nd four |
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the end of the ___ induces clusters of ___ cells to form small metanephric vesicles that elongate to form ___ . the promixmal ends of these are invaginated by ? |
collecting tubules, mesenchymal, metanephric tubules, glomeruli |
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__ and __ have reciprocal inductive influence.
the differentiation of ___ depends on inductive signals from the other. |
metanephric diverticulum and mesoderm
both primordia |
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what is reciprocal induction? |
branching of the metanephric diverticulum is dependent on induction by the metanephric mesenchyme. The metanephric diverticulum and the metanephrogenic blastema interact and induce eachother to form the permanent kidneys |
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differentiation of the nephrons depends on indcution by the ___ |
collecting tubules |
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how are the uriniferous tubules formed? |
the metanephric tubules,the primordia of the nephrons, become continuous with the collecting tubules and form uriniferous tubules |
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the uriniferous ubules consists of two embryologically different parts, what are they? |
1. a nephron derived from the metanephrogenic blastema 2. a collecting tubules derviced from the metanephric diverticulum (ureteric bud) |
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what are the abnormalities (4) of the kidneys and ureter and what % of pop. |
3-4% Renal agenesis-unilateral or bilateral ectopic kidneys (abnormal position) horseshoe kidney (inferior poles are fused) duplications of upper urinary tract |
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the cloaca is divided by ___ into ___ and ___ |
urorectal septum, dorsal rectum and ventral urogenital sinus |
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bladder and urethra are derived from ___ and ___ |
UG sinus and adjacent mesoderm |
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as bladder enlarges, ___ parts of ___ are incorporated into the wall and therefore __ enter bladder directly |
caudal, mesonephric ducts, ureters |
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initially the bladder is continuous with ___.
What becomes the median umbilical ligament |
allantois, urachus |
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The early genital systems in the 2 sexes are similar; therefore, the initial period of genital development is referred to as? |
the indifferent stage of sexual development |
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when is genetic sex of an embryo determined? and what does this depend on? |
at fertilization
depending on the type of sperm that fertilizes the secondary oocyte |
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The gonads (testes and ovaries) are derived from 3 sources what are they |
1) mesothelium (meodermal epithelium), lining the posterior abdominal wall 2) underlying mesenchyme (embryonic connective tissue) 3) primordial germ cells |
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with an XX sex chromosome complex: the __ of the ___ differentiates into an ovary.
with an XY sex chromosome complex: the __ differentiates into__, and the ___ regresses, except for vestigial remnants |
cortex, indifferent
medulla, testis, cortex |
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___ cells are visible in the __week among the __ cells fo the umbilical vesicle (yolk sac) near the origin of the ___.
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primordial germ cells, 4th, endodermal, allantois |
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The primordial germ cells migrate along the __ of the hindgut to the ____ |
dorsal mesentery, gonadal ridges |
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during the __ week, the primordial germ cells enter the underlying mesenchyme and are incorporated in the ____.
The migration of the promordial germ cells is regulated by the genes __, __, and ___ |
6th , gonadal cords
stella, fragilis and BMP-4 |
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before the __ week gonads of 2 sexes are identical in appearance and are called ___ |
7th, indifferent gonads |
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what determines testicular differentiation
what results in the formation of an ovary? |
testis-determining factor (TDF): a SRY gene product localized in the Y chromosome
absence of Y chromosome (absence of TDF) |
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what do Gonadal sex cords become (3)? and under the involvement of what 2 genes? |
seminiferous tubules (Sox9 and FGF9), tubuli recti, and rete testes as they branch and anastomose |
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what do the walls of the seminiferous tubules include? (2) |
1) spermatogonia derived from primordial germ cells 2) sertoli cells derived from surface mesothelium |
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what are leydig cells derived from and what do they do? |
mesoderm and lie between seminiferous tubules
secrete testosterone in 8th week which influences development of indifferent ducts and external genitalia |
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explain the development of ovary from indifferent gonad (5) |
1) develops more slowly than testes 2) gonadal sex cord degenerates 3) cortical cords form and incorproate primordial germ cells 4) break up into clusters to form primordial follicles (follicular cells and oogonia) 5) oogonia divide during fetal life producing 200 0000 primary oocytes |