Jan31 M2-Embryology - Abdominal wall, gonadal descent and Inguinal canal Flashcards
gonads start and end point in embryo
start: lumbar posterior wall
end: labial scrotal fold
two names of mass of mesenchyme supporting the gonads
intermediate mass (of mesenchyme) OR urogential ridge (UGR)
why called urogenital RIDGE and what surrounds it
projects in coelomic cavity and lined by ceolemic epithelium (will become peritoneal cavity)
(IMPORTANT) organs (3) and structures formed by UGR (and consequent embryo origin)
kidneys, adrenals and gonads + supporting tissues and ligaments
So all these FROM MESENCHYME
gonads initial position and blood supply
L1-L2 near lungs. aorta gives branches
how medial umbilical ligaments are formed
aorta gives branches that go through UGR that will become the umbilicar arteries (to umbilicus)
site of descent of the UGR and what this is
on both sides of the cloaca (site where external genitalia is in primitive state)
gubernaculum definition + intra or retroperitoneal
mesenchyme extending from inferior lobe of gonads to labio-scrotal fold. is retroperitoneal
coelomic epithelium will form what
mesothelium lining abd cavity and all sex cords in males and females
gubernaculum function
governs and guides the passage of the gonads all the way down to the labio-scrotal fold
end site of gonads in female after go through gubernaculum
labium major (homologous to scrotum in males)
possible ectopic position of testes and why
upper part of the thigh (or wtv. too high, too low, on the side). bc gubernaculum didn’t end in labio-scrotal fold
organ displaced upwards as gonads go downwards
kidneys
how gonads reach the labio-scrotal fold
have to pierce through the abdominal wall (muscles)
processus vaginalis def
finger-like projection of the peritoneal cavity around the gubernaculum near the labio-scrotal fold
processus vaginalis location
lateral to the inferior epigastric artery. (midway between ASIS and pubic tubercle
processus vaginalis 2 functions
- penetrates abd wall (has same muscles and fascia around) to create inguinal canal.
- has a moist serosa facilitating the passage of the testes and vessels
origin of the vas deferens (what formed it)
mesonephric duct
structure near the point where gonads pierce the abd wall
inferior epigastric artery
structure near the umbilical artery
medial umbilical ligament
tube extending from prostatic urethra to gonads and that is always present from start to end point of gonads movement + what it will form
vas deferens. forms the spermatic cord
gubernaculum forms what in females after it passes the inguinal canal (out of the pelvis) and connects to what
round ligament of the uterus. will connect to the labia major
important substances involved in passage of gonads through abdominal wall (give example of a specific one)
androgens. insulin-like peptide hormone 3 (INSL3) produced by Leydig cells in the testes (binds GR8 receptor in gubernaculum)
factors involved in the passage of the gonads through the abdominal wall
- length of the inguinal canal
- androgens
- moist processus vaginalis
gubernaculum testis def and what it comes from
made by the gubernaculum. is the short muscular cord attaching gonads to abd wall and pulling them through it
consequence of gubernaculum testis being too long
testes too long, can twist, turn around, block vessels, cause ischemia (may lose a testis)
where round ligament of the uterus (previously the gubernaculum) stops in females
in the labium major
cryptorchidism def
hidden testis because of its failure to descend into the scrotum during postnatal first 3 months
cryptorchidism most common in who and possible consequences
premature males. can cause sterility or neoplasia of the testes
molecular receptor that is necessary for passage of gonads through abd wall and molecule that binds to it
GR8 (or LGR8) receptor. binds INSL3 (insulin-like 3).
what produces INSL3 and where is its receptor
Leydig cells in the gonads. Its receptor is GR8, in the gubernaculum
3 layers of abdominal wall muscles around the processus vaginalis (also called tunica vaginalis near the gonads) and name
inside to outside.
- internal spermatic fascia (from transversalis fascia)
- cremasteric muscle (from internal oblique)
- external spermatic fascia (from external oblique aponeurosis)
abd wall muscle that is not pierced through when gonads go through abd wall and that doesn’t go in inguinal canal
transversus abdominis (also called transverse oblique)
name of the plexus where the vas deferens and the arteries and veins near the gonads are (inside the spermatic cord)
pampiniform plexus
contents of spermatic cord other than vas deferens and vessels (pampiniform plexus)
- testicular lymph nodes
- autonomic nerves
- remains of processus vaginalis (obliterated)
- genital branch (MOTOR) of femorogenital nerve supplying cremasteric muscle
genital branch of the genitofemoral nerve (L1,L2) function and sensory or motor
(MOTOR) supplies cremasteric muscle for the cremasteric reflex
fibers outside spermatic cord necessary for the cremasteric reflex
SENSORY fibers of ilio-inguinal nerve (L1) to the testicle area and inner thigh
consequences (2) of partial or total incomplete closure of the processus vaginalis
- possible indirect hernia is possible (stuff going from abd wall to spermatic cord)
- if partial closure, cyst (hydrocoele) can form around the spermatic cord
name of processus vaginalis in spermatic cord and name near the testes
obliterated processus vaginalis
tunica vaginalis
structure supporting the inguinal canal and it extends from where to where
inguinal ligament extends from ASIS to pubic tubercle
muscles wrapping around the inguinal canal and which is more involved (3)
lateral to medial on inguinal ligament: transversus abdominis, internal oblique, external oblique aponeurosis forms an arch
function of transversus abdominis near spermatic cord
protects entry of inguinal canal
what protects the external opening of the spermatic cord and inguinal canal (when go deeper inguinal canal)
conjoint tendon (joining of internal oblique and aponeurosis of TA extending above pubic tubercle)
when increase in abd pressure (coughing, straining), what closes the inguinal canal
contraction of TA and internal oblique
what forms the anterior wall of the inguinal canal (also called an oblique cleft)
aponeurosis of external oblique
what forms roof (superiorly) of inguinal canal
arches of IO and TA
(IMPORTANT) what forms the posterior wall of the inguinal canal
transversalis fascia, reinforced by the conjoint tendon
what forms the floor (inferiorly) of the inguinal canal
inguinal ligament and lacunar ligament (lacunar = lateral to conjoint, lies on the pubis)
3 ligaments visible from interior surf of anterior abd wall and origin
median umb l. : urachus (extending to bladder)
medial umb l. : umb. vessels
lateral umb l. : inferior epigastric artery
cause of indirect inguinal hernias and occur near what structure
lateral (meaning not medial to but on other side) to inferior epigastric a.
caused by congenital muscle weakness + processus vaginalis takes a while to close
direct inguinal hernia occurs where
medially to inferior epigastric artery, through Hasselbach’s triangle
Hasselbach’s triangle 3 sides
bottom: inguinal ligament
medial: side of rectus abdominis
lateral: inferior epigastric artery
cause of testis torsion, ischemia, etc. other than long gubernaculum testis
long and unclosed tunica vaginalis
round ligament of the uterus extending from where to where in females
from ovaries (are near fallopian tubes) to opening of labium major
case of ovary riding the inguinal canal or ligament: what’s the cause
anomaly of the fallopian tube
ectopic testis cause
abnormal gubernaculum attachment, integrity or function.
