Question | Answer |
Primordium appears when & where? | 4th week in floor of pharyngeal gut epithelium |
What descends through the mesenchyme leaving behind the thyroglossal duct? | Thyroid diverticulum |
The developing thyroid descends anterior to what? and when? | Hyoid bone and reaches the front of trachea during the 7th week |
Ultimobranchial body is from what pouch? | From ventral portion of 4th pouch |
What is the ultimobranchial body incorporated into? | Into the thyroid
(forms C-cells -> thyrocalcitonim -> which decrease blood Ca) |
When does thyroid begin to function? | End of 3rd month |
Foramen cecum of posterior adult is located? | At posterior end of median sulcus; sulcus terminalis runs forward and lateral from foramen cecum |
What ANOMALIE can form anywhere along the migratory path of thyroid from remnants of thyroglossal duct? | Thryoglossal cyst |
What ANOMALIE causes the throglossal cyst to open onto anterior surface of neck? | Thryoglossal fistula |
What anomalie is anywhere along the path of thyroid descent, commonly at base of tongue just behind foramen cecum? | Aberrant thyroid tissue |
Hypophysis is derived from what two surfaces? | Rathke's pouch & Infundibular process |
When does Rathke's pouch BEGIN? | 3rd week |
What is Rathke's pouch? | Is an ectodermal evagination from roof of primitive mouth which (Stomodeum) which later loses its connection (loses connection in 8th week) |
What happens in the 5th week in Rathke's pouch? | Makes contact with the infundibular process -> Adenohypophysis |
What is Infundibular process? | Neurorectal evagination of the diencephalon -> Neurohypophysis |
What MALFORMATION is when small portion of Rathke's pouch remains in roof of pharynx? | Pharyngeal hypophysis |
What MALFORMATION is a remnant of pouch is intracrainially located, symptoms usually before age 15. | Craniopharyngioma (Rathke's pouch tumor) |
Components of suprarenal glands? | Medsodermal (CORTEX)
Neuroectodermal (MEDULLA) |
Coelomic mesothelial cells located in groove bw dorsal mesentery & urogenital ridge proliferate and invade underlying mesenchyme during the 5th week, forms what? | Fetal cortex |
What cells invade fetal cortex from adjacent sympathetic ganglia? | Sympathetic cells from chromaffin cells of medulla |
Coelomic mesothelial cells give rise to a 2nd cortex called? | Permanent cortex |
Permanent cortex gives rise in late fetal period to? | Zona glomerulosa (present at birth), zona fasciculate (present at birth), and zona reticularis (postnatal 3rd yr) |
In the cervical region, intermediate mesoderm form? | Nephrotomes (segmented cell clusters) |
The medial part of nephrotomes opens into? | The intraembryonic coelom |
The lateral part of nephrotomes grows? | Grows caudally uniting with successive segments to form pronephric duct |
What does dorsal aorta form? | External & internal glomeruli |
What does glomerulus + pronephric tubule = | = excretory unit of pronephros |
Formation of nephrons in thoracic/lumbar/sacral regions flow chart? | Intermediate mesoderm->nephrotomes->nephrotomes fuse->nephrogenic cord->excretory units of mesonephros and metanephros |
Names of the 3 kidney systems? | Pronephros, mesonephros, metanephros |
When do pronephros develop? | End of 3rd week through 4th week |
Where are pronephros from? | First 7-10 nephrotome segments, primarily in cervical region, from segmented nephrotomes, nonfunctional & transitory |
When to mesonphros develop? | 4th-8th weeks. Develops during: regression of mesonephric system, in lower lumber/scaral regions. |
Where are mesonphros from? | From the nephrogenic cord |
Known as the adult kidney of fishes and amphibians? | Mesonphros |
What is an urogenital ridge? | Longitudinal ridge on posterior abdominal wall formed by gonad & mesonephros |
What is an urogenital mesentery? | A broad based mesentery which attaches UG ridge to posterior abdominal wall |
Regression of mesonephric duct in males? | Remains to form ducts of male reproductive system (ductus epididymis, ejact ducts |
Regression of mesonephric duct in females? | Almost completely disappears |
Regression of mesonephros? | Most degenerates, a few caudal mesonephric tubules persist and are found in association with ovary & testis |
When does metanephros become functional? | During 2nd half of pregnancy |
What does the collecting system of metanephric develop come from? | From ureteric bud |
What does the excretory system of metanephric development come from? | From metanephric blastema |
The cloaca (by urorectal septum) forms? 2 | Anorectal canal & primitive urogenital sinus |
The primitive urogenital sinus (epithelial endoderm lining) forms what 3 parts? | Vesical part, pelvic part, phallic part |
What is developed in the vesicle part from the primitive urogenital sinus? | Urinary bladder - male & female |
What is developed in the pelvic part from the primitive urogenital sinus? | Female urethra, male prostatic & membranous urethra |
What is developed in the phallic part from the primitive urogenital sinus? | Male proximal penile urethra |
The endodermal lined allantois constricts and loses its lumen forming a thick fibrous cord called? | Urachus |
What is the urachus termed in the adult?
? | Median umbilical ligament |
Where is the ureters from? | From mesoderm of ureteric buds |
The portion of the mesodermal mesonephric ducts absorbed into the bladder forms? | Vesical trigone |
In the male, the remaining nonabsorbed parts of mesonephric ducts move? | Medially & descend to enter the prostatic urethra. |
In the female, the remaining nonabsorbed parts of mesonephric? | Regress |
What develops as evaginations & proliferations of endodermal epithelium of the prostatic & penile uretheras in MALE? | Prostate & bulboureahral glands |
What develops as evaginations & proliferations of endodermal epithelium of UG sinus and urethra in FEMALE? | Greater vestibular, urethral, paraurethral glands |
What happens to the primitive (meduallry) sex cords of the indifferent gonad in the FEMALE? | They do NOT remain well defined (as in male) but break up into the IRREGULAR RETE OVARii |
What happens to rete ovarii? | Later disappears and is replaced by stromal CT forming the OVARIAN MEDULLA |
Surface coelomic mesodermal epithelium give rise to? | 2nd generation of sex cords, CORITICAL CORDS (they remain close to surface in cortex of ovary) |
What happens to the cortical cords in the 4th intrauterine month ? | They break up and surround one or more germ cells: germ cells of cords/epithelial cells of cords |
Germ cells of cords route? | Oogoina->primary oocytes |
Epithelial cells of cords route? | ->follicular cells |
When does the indifferent stage occur? | During 6th week |
How many pairs of genital ducts does both male and female have? | 2 |
What occurs in early stage of mesonephric (wolffian) ducts? | They run from mesonephros to cloaca |
What occurs in late stage of mesonephric (wolffian) ducts? | Open into UG sinus lateral to PARAMESONEPHRIC TUBERCLE |
Where does the paramesonephric (Mullerian) ducts arise from? | A longitudinal invagination of the coelomic epithelium on the anterolateral surface of the UG ridge |
Derivative of MALE efferent ducts? | Mesonephric Excretory Tubules- From epigenital tubules (near CENTER pole of testis) |
Derivative of MALE paradidymis? | Mesonephric Excretory Tubules- From paragential tubles (near CAUDAL pole of testis) |
Derivative of MALE appendix testis? | Paramesonephric duct- From very small cranial part of duct |
Derivative of MALE colliculus seminalis? | UG sinus- From paramesonsphric tubercle of sinus wall |
Dervivative of MALE utriculus prostaticus? | UG sinus - Probably develops as an outpocketing from wall of UG sinus |
Derivative of FEMALE epoophoron? | Mesonephric Excretory Tubules- Located in mesosalphinx bw ovary and uterine tube |
Derivative of FEMALE paroophoron? | Mesonephric Excretory Tubules- Located in mesosalphinx bw ovary and uterine tube |
Derivative of FEMALE duct of duct of epoophoron (Gartner's)? | Mesonephric Duct- May sometimes form a Gartner's cyst in wall of vagina or uterus |
Derivative of FEMALE appendix vesiculosa (hydatids of Morgagni)? | Mesonephric Duct- pedunculated vesicle near fimbriae |
Derivatives within the paramesonephric duct? | MUCOSAL PART ONLY: uterine tube, uterus, upper 1/3 of vagina |
What derivatives are in the pelvic portion of the UG sinus? | (1) part of vestibule (2) hymen (3)lower 2/3 of vagina (4)paraurethral & urethral glands (5)urethra |
What derivatives are in the phallic portion of the UG sinus? | (1) part of vestibule (2) greater vestibular glands (Bartholins glands) |
During development of LOWER 2/3 of vagina, solid epithelial evaginations from UG sinus form? | Sinovaginal bulbs->further development produces the VAGINAL PLATE (end of 3rd month) |
During development of LOWER 2/3 of vagina, what happens by the 5th month? | The vaginal plate forms lumen of definitive lower 2/3rds of vagina |
During development of LOWER 2/3 of vagina, the paramesonephric tubercle forms? | The HYMEN, which separates vagina from pelvic portion of UG sinus |
When is the indifferent stage in external genitalia? | 6th week |
In cloacal folds, underlying mesenchyme forms? | Forms CLOACAL FOLDS during 4th week |
Cloacal folds fuse anteriorly to form? | Genital tubercle |
Urorectal septum (superficially forms perineal body) divides cloacal folds into? | (1)Urogenital folds (ANTERIOR to perineal body) and (2)Anal folds (POSTERIOR to perineal body) |
Genital (Labioscrotal) swellings develop from? | Underlying mesenchyme lateral to urogenital folds |
Female genital tubercle forms? | Phallus->CLITORIS |
Female urogenital folds forms? | LABIA MINORA |
Female (labioscrotal) swellings forms? | LABIA MAJORA |
Female urogenital membrane (bw urogenital folds) breaks down forming? | Urogenital groove->VESTIBULE |
Male genital tubercle forms? | Phallus->PENIS |
Development of male urogenital folds into proximal penile urethra? | Urethral folds->urethral groove(urethral groove closes when urethral folds fuse OVER urethral groove -> PROXIMAL PENILE URETHRA |
Male invagination of surface ectoderm at tip of phallus; ectoderm forms solid cord, later cavitates forming ultimately what? | DISTAL TIP PENILE URETHRA |
The skin of penis that grows over glans is called? | PREPUCE (foreskin) |
Male genital (labioscrotal) swellings form scrotal swellings which fuse in middle form? | SCROTUM |
Urogenital mesentery becomes? | Mesentery of gonad as mesonephros disapears |
Urogenital mesentery CRAINIAL part becomes? | Cranial genital ligament- from upper pole of gonad->diaphragm; this ligament disappears in the male |
Urogenital mesentery CAUDAL part becomes? | Caudal genital ligament- from lower pole of gonad->inguinal canal (2nd month) |
Gubernaculum extends from? | Caudal pole of gonad to genital (labioscrotal) swelling |
Gubernaculum is formed from 3 structures? | (1)Caudal genital ligament (2)Mesenchymal band in inguinal canal (3)Mesenchymal Condensation in genital (labioscrotal) swelling |
Gobernaculum forms what in the MALE? | Gubernaculum testis |
Gobernaculum forms what in the FEMALE? | Round ligament of uterus & ovarian ligament |
T/F Gubernaculum does NOT grow in proportion to the trunk and pelvis? | TRUE |
Movement of testis? | Retroperitoneal & primarily relative |
Gubernaculum appears to pull the testis from the posterior abdominal wall to area of? | Deep inguinal ring during 2-3rd month |
What causes the passage of testis through inguinal canal and into scrotum? | Increased pressure (from growth of viscera) and gonadotrophic and androgenic hormones, and probably not by the gubernaculum. **7th month |
What happens to processus vaginalis in 3rd month? | Follows gubernaculum testis (and lies over it) into the scrotum and pulls muscular and fascial layers with it |
Are gubernaculum testis external or internal to the process of vaginalis? | EXTERNAL. |
What eventually happen to the processus vaginalis in MALES? | Components of the process wrap around blood supply, vas deferens, etc of testis thereby forming the coverings of the spermatic cord. |
Descent of ovary- Craninal genital ligament forms? | Suspensory ligament of ovary |
Descent of ovary- Gubernaculum forms? | Ovarian ligament & round ligament of uterus |
Descent of ovary- Broad ligament forms? | Formed by caudal fusion of paramesonephric ducts |