Jan31 M2-Embryology - Abdominal wall, gonadal descent and Inguinal canal

Question 1

gonads start and end point in embryo

Answer 1

start: lumbar posterior wall
end: labial scrotal fold

Question 2

two names of mass of mesenchyme supporting the gonads

Answer 2

intermediate mass (of mesenchyme)
OR urogential ridge (UGR)

Question 3

why called urogenital RIDGE and what surrounds it

Answer 3

projects in coelomic cavity and lined by ceolemic epithelium (will become peritoneal cavity)

Question 4

(IMPORTANT) organs (3) and structures formed by UGR (and consequent embryo origin)

Answer 4

kidneys, adrenals and gonads + supporting tissues and ligaments
So all these FROM MESENCHYME

Question 5

gonads initial position and blood supply

Answer 5

L1-L2 near lungs. aorta gives branches

Question 6

how medial umbilical ligaments are formed

Answer 6

aorta gives branches that go through UGR that will become the umbilicar arteries (to umbilicus)

Question 7

site of descent of the UGR and what this is

Answer 7

on both sides of the cloaca (site where external genitalia is in primitive state)

Question 8

gubernaculum definition + intra or retroperitoneal

Answer 8

mesenchyme extending from inferior lobe of gonads to labio-scrotal fold. is retroperitoneal

Question 9

coelomic epithelium will form what

Answer 9

mesothelium lining abd cavity and all sex cords in males and females

Question 10

gubernaculum function

Answer 10

governs and guides the passage of the gonads all the way down to the labio-scrotal fold

Question 11

end site of gonads in female after go through gubernaculum

Answer 11

labium major (homologous to scrotum in males)

Question 12

possible ectopic position of testes and why

Answer 12

upper part of the thigh (or wtv. too high, too low, on the side). bc gubernaculum didn’t end in labio-scrotal fold

Question 13

organ displaced upwards as gonads go downwards

Answer 13

kidneys

Question 14

how gonads reach the labio-scrotal fold

Answer 14

have to pierce through the abdominal wall (muscles)

Question 15

processus vaginalis def

Answer 15

finger-like projection of the peritoneal cavity around the gubernaculum near the labio-scrotal fold

Question 16

processus vaginalis location

Answer 16

lateral to the inferior epigastric artery. (midway between ASIS and pubic tubercle

Question 17

processus vaginalis 2 functions

Answer 17

1. penetrates abd wall (has same muscles and fascia around) to create inguinal canal.
2. has a moist serosa facilitating the passage of the testes and vessels

Question 18

origin of the vas deferens (what formed it)

Answer 18

mesonephric duct

Question 19

structure near the point where gonads pierce the abd wall

Answer 19

inferior epigastric artery

Question 20

structure near the umbilical artery

Answer 20

medial umbilical ligament

Question 21

tube extending from prostatic urethra to gonads and that is always present from start to end point of gonads movement + what it will form

Answer 21

vas deferens. forms the spermatic cord

Question 22

gubernaculum forms what in females after it passes the inguinal canal (out of the pelvis) and connects to what

Answer 22

round ligament of the uterus. will connect to the labia major

Question 23

important substances involved in passage of gonads through abdominal wall (give example of a specific one)

Answer 23

androgens. insulin-like peptide hormone 3 (INSL3) produced by Leydig cells in the testes (binds GR8 receptor in gubernaculum)

Question 24

factors involved in the passage of the gonads through the abdominal wall

Answer 24

• length of the inguinal canal
• androgens
• moist processus vaginalis

Question 25

gubernaculum testis def and what it comes from

Answer 25

made by the gubernaculum. is the short muscular cord attaching gonads to abd wall and pulling them through it

Question 26

consequence of gubernaculum testis being too long

Answer 26

testes too long, can twist, turn around, block vessels, cause ischemia (may lose a testis)

Question 27

where round ligament of the uterus (previously the gubernaculum) stops in females

Answer 27

in the labium major

Question 28

cryptorchidism def

Answer 28

hidden testis because of its failure to descend into the scrotum during postnatal first 3 months

Question 29

cryptorchidism most common in who and possible consequences

Answer 29

premature males. can cause sterility or neoplasia of the testes

Question 30

molecular receptor that is necessary for passage of gonads through abd wall and molecule that binds to it

Answer 30

GR8 (or LGR8) receptor. binds INSL3 (insulin-like 3).

Question 31

what produces INSL3 and where is its receptor

Answer 31

Leydig cells in the gonads. Its receptor is GR8, in the gubernaculum

Question 32

3 layers of abdominal wall muscles around the processus vaginalis (also called tunica vaginalis near the gonads) and name

Answer 32

inside to outside. 1. internal spermatic fascia (from transversalis fascia) 2. cremasteric muscle (from internal oblique) 3. external spermatic fascia (from external oblique aponeurosis)

Question 33

abd wall muscle that is not pierced through when gonads go through abd wall and that doesn't go in inguinal canal

Answer 33

transversus abdominis (also called transverse oblique)

Question 34

name of the plexus where the vas deferens and the arteries and veins near the gonads are (inside the spermatic cord)

Answer 34

pampiniform plexus

Question 35

contents of spermatic cord other than vas deferens and vessels (pampiniform plexus)

Answer 35

1. testicular lymph nodes 2. autonomic nerves 3. remains of processus vaginalis (obliterated) 4. genital branch (MOTOR) of femorogenital nerve supplying cremasteric muscle

Question 36

genital branch of the genitofemoral nerve (L1,L2) function and sensory or motor

Answer 36

(MOTOR) supplies cremasteric muscle for the cremasteric reflex

Question 37

fibers outside spermatic cord necessary for the cremasteric reflex

Answer 37

SENSORY fibers of ilio-inguinal nerve (L1) to the testicle area and inner thigh

Question 38

consequences (2) of partial or total incomplete closure of the processus vaginalis

Answer 38

1. possible indirect hernia is possible (stuff going from abd wall to spermatic cord) 2. if partial closure, cyst (hydrocoele) can form around the spermatic cord

Question 39

name of processus vaginalis in spermatic cord and name near the testes

Answer 39

obliterated processus vaginalis | tunica vaginalis

Question 40

structure supporting the inguinal canal and it extends from where to where

Answer 40

inguinal ligament extends from ASIS to pubic tubercle

Question 41

muscles wrapping around the inguinal canal and which is more involved (3)

Answer 41

lateral to medial on inguinal ligament: transversus abdominis, internal oblique, external oblique aponeurosis forms an arch

Question 42

function of transversus abdominis near spermatic cord

Answer 42

protects entry of inguinal canal

Question 43

what protects the external opening of the spermatic cord and inguinal canal (when go deeper inguinal canal)

Answer 43

conjoint tendon (joining of internal oblique and aponeurosis of TA extending above pubic tubercle)

Question 44

when increase in abd pressure (coughing, straining), what closes the inguinal canal

Answer 44

contraction of TA and internal oblique

Question 45

what forms the anterior wall of the inguinal canal (also called an oblique cleft)

Answer 45

aponeurosis of external oblique

Question 46

what forms roof (superiorly) of inguinal canal

Answer 46

arches of IO and TA

Question 47

(IMPORTANT) what forms the posterior wall of the inguinal canal

Answer 47

transversalis fascia, reinforced by the conjoint tendon

Question 48

what forms the floor (inferiorly) of the inguinal canal

Answer 48

inguinal ligament and lacunar ligament (lacunar = lateral to conjoint, lies on the pubis)

Question 49

3 ligaments visible from interior surf of anterior abd wall and origin

Answer 49

median umb l. : urachus (extending to bladder) medial umb l. : umb. vessels lateral umb l. : inferior epigastric artery

Question 50

cause of indirect inguinal hernias and occur near what structure

Answer 50

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

Question 51

direct inguinal hernia occurs where

Answer 51

medially to inferior epigastric artery, through Hasselbach's triangle

Question 52

Hasselbach's triangle 3 sides

Answer 52

bottom: inguinal ligament medial: side of rectus abdominis lateral: inferior epigastric artery

Question 53

cause of testis torsion, ischemia, etc. other than long gubernaculum testis

Answer 53

long and unclosed tunica vaginalis

Question 54

round ligament of the uterus extending from where to where in females

Answer 54

from ovaries (are near fallopian tubes) to opening of labium major

Question 55

case of ovary riding the inguinal canal or ligament: what's the cause

Answer 55

anomaly of the fallopian tube

Question 56

ectopic testis cause

Answer 56

abnormal gubernaculum attachment, integrity or function.