1. Embryology and Anatomy of the testis Flashcards
(102 cards)
1
Q
Embryological origin of the testis
A
It arises in the lumbar region from the Genital ridge at the level of L2 below the developing kidney.
The germ cells are derived from the Yolk Sac.
2
Q
The germ cells of the testis are derived from
A
the Yolk Sac.
3
Q
Migration of the testis
A
It migrates downwards, forwards & medially, passing through the inguinal canal carrying with it a fold of peritoneum (Processus Vaginalis)
4
Q
Processus Vaginalis
A
it’s a fold of peritoneum carried with the testis during passing through the inguinal canal
Normally the processus vaginalis becomes obliterated soon after birth from the level of the internal ring to just above the testis forming the
vestige of processus vaginalis.
5
Q
vestige of processus vaginalis
A
obliteration of the processus vaginalis soon after birth from the level of the internal ring to just above the testis
6
Q
The testis reaches the internal ring at
A
the 6th month of intrauterine life.
7
Q
The testis enters the inguinal canal at
A
the 7th month of intrauterine life.
8
Q
The testis reaches the external ring at
A
the 8th month of intrauterine life.
9
Q
The testis reaches the scrotum at
A
the 9th month of intrauterine life.
10
Q
at the 6th month of intrauterine life, The testis reaches
A
the internal ring
11
Q
at the 7th month of intrauterine life, The testis reaches
A
the inguinal canal
12
Q
at the 8th month of intrauterine life, The testis reaches
A
the external ring
13
Q
at the 9th month of intrauterine life, The testis reaches
A
the scrotum
14
Q
Factors Responsible for Normal Descent of the Testicles
A
- Chorionic gonadotrophin from the maternal circulation
- Gubernaculum:
- Elongation of upper half of the body
- Intra-abdominal pressure
15
Q
in Factors Responsible for Normal Descent of the Testicles, Chorionic gonadotrophin from the maternal circulation
A
stimulates the growth of the testes & may play some part in the migration of the organ
16
Q
in Factors Responsible for Normal Descent of the Testicles, Gubernaculum
A
Fibromuscular band connecting the lower pole of the testis to the bottom of the scrotum guiding the testes into the scrotum.
17
Q
in Factors Responsible for Normal Descent of the Testicles, Elongation of upper half of the body
A
leading to relative caudal shift in position of the testes.
18
Q
in Factors Responsible for Normal Descent of the Testicles, Intra-abdominal pressure
A
squeezing the testes through the ring
19
Q
Ernbryological origin of the epididymis & vas deferens
A
They arise from the mesonephric ( Wolffian ) duct
20
Q
The mesonephric tubules embryologically give
A
- The vasa efferentia
- Appendix of the epididymis
- The paradidymis (organ of Giraldes)
21
Q
Embryological origin of The vasa efferentia
A
The mesonephric tubules
22
Q
Embryological origin of The appendix of the epididymis
A
The mesonephric tubules
23
Q
Embryological origin of The paradidymis
A
The mesonephric tubules
24
Q
Alternative name for The paradidymis
A
organ of Giraldes
25
Embryological origin of organ of Giraldes
The mesonephric tubules
26
Embryological origin of The appendix of the testis
arises from the remnant of the paramesonephric duct ( Mullerian duct).
27
alternative name for The appendix of the testis
Hydatid of Morgagni
28
Embryological origin of The Hydatid of Morgagni
arises from the remnant of the paramesonephric duct ( Mullerian duct).
29
alternative name for the paramesonephric duct
Mullerian duct
30
Macroscopic structure of the testis :
Morphology and size
Place in the space
31
Morphology of the testis in Macroscopic structure of the testis :
It is a flattened ovoid body
```
It has:
2 surfaces (medial and lateral),
2 borders (anterior and posterior)
2 ends (upper and lower).
```
32
Size of the testis in Macroscopic structure of the testis :
measuring 2x1x1 inch.
or 4x2x2.5 cm
33
place of the testis in the space in Macroscopic structure of the testis :
It is placed obliquely so that posterior borders are nearer to each other than the anterior borders.
34
Minute structure of the testis
1- Tunica albuginea :
2- Fibrous septa
3- Seminiferous tubules
4- Interstitial cells of Leydig :
5- Vasa efferentia
35
Tunica albuginea in the Minute structure of the testis
a tough fibrous coat which is thickened posteriorly to for the mediastinum testes.
36
Fibrous septa in the Minute structure of the testis
divide the testicle into 200-300 compartments
37
Seminiferous tubules in the Minute structure of the testis
number
Length
Ending
Lining cells
38
number of Seminiferous tubules in the Minute structure of the testis
About 400-600 in number
There are about 2-3 tubules in each compartment.
39
Length of each of the Seminiferous tubules in the Minute structure of the testis
each is 60 cm long,
40
Ending of the Seminiferous tubules in the Minute structure of the testis
As the tubules reach the mediastinum testis, they join one another and open in the rete testis which is a network of seminal channels.
41
The rete testis
a network of seminal channels.
The Seminiferous tubules as they reach the mediastinum testis, they join one another and open in it
42
Lining cells of the Seminiferous tubules in the Minute structure of the testis
Lined by spermatocyte - sertoli cells
43
Functions of the Sertoli cells
* Secrete estrogen in small dose essential for spermatogenesis
* AMH( anti-mullerian hormone) to stop mullerian duct formation intra-uterine
* Forms blood testicular barrier
44
Interstitial cells of Leydig in the Minute structure of the testis
site
function
45
site of Interstitial cells of Leydig in the Minute structure of the testis
in between the Seminiferous tubules.
46
function of Interstitial cells of Leydig in the Minute structure of the testis
They secrete testosterone.
47
Vasa efferentia in the Minute structure of the testis
Beginning
Number
Ending
48
Beginning of Vasa efferentia in the Minute structure of the testis
arise from the top part of the testicle from the rete testis.
49
number of Vasa efferentia in the Minute structure of the testis
They are 15-20 in number
50
Ending of Vasa efferentia in the Minute structure of the testis
They join the head of the epididymis.
51
Coverings of the testis
9 coverings from inside outwards
1. Tunica albuginea
2- Visceral layer of tunica vaginalis.
3. Parietal layer of tunica vaginalis.
4. Internal spermatic fascia :
5. Cremasteric muscle and fascia:
6. External spermatic fascia :
7. Colles' fascia
8. Dartos muscle
9. Skin of the scrotum.
52
fibrous capsule of the testis
Tunica albuginea
53
origin of Internal spermatic fascia in Coverings of the testis
fascia transversalis.
54
Cremasteric muscle and fascia in Coverings of the testis
Origin
Nerve supply
Function
The cremasteric reflex
55
origin of Cremasteric muscle and fascia in Coverings of the testis
internal oblique muscle.
56
nerve supply of Cremasteric muscle and fascia in Coverings of the testis
The genital branch of genito-femoral nerve
| "cremasteric nerve" L1
57
Function of Cremasteric muscle and fascia in Coverings of the testis
raise and lower the scrotum in order to regulate the
temperature of the testis and promote spermatogenesis
In a cool environment the cremaster draws the testis closer to the body preventing heat loss, while in a warm environment the cremaster relaxes allowing the testis to cool.
58
The cremasteric reflex
is elicited by lightly stroking the superior and medial (inner) part of the thigh.
The normal response is a contraction of the
cremasteric muscle that pulls up the scrotum and testis on the side stroked.
In infants, this reflex may be exaggerated leading to retractile testis which is a mistaken diagnosis of undescended testes
59
The cremasteric reflex in infants
may be exaggerated leading to retractile testis which is a mistaken diagnosis of undescended testes
60
origin of External spermatic fascia in Coverings of the testis
derived from external oblique aponeurosis
61
origin of colles' fascia in Coverings of the testis
is the extension of the deep membranous layer of the superficial fascia of the abdomen "Scarpa's fascia" to the scrotum
62
Scarpa's fascia
the deep membranous layer of the superficial fascia of the abdomen
63
Dartos muscle in Coverings of the testis
Origin
Nerve supply
Function
64
Origin of Dartos muscle in Coverings of the testis
replaces the superficial fatty layer of the superficial fascia of the abdomen "Camper's fascia".
65
Nerve supply of Dartos muscle in Coverings of the testis
supplied by sympathetic fibres
66
Function of Dartos muscle in Coverings of the testis
responsible for corrugation of the skin of the scrotum
67
Camper's fascia
the superficial fatty layer of the superficial fascia of the abdomen
68
Nerue supply of Skin of the scrotum in Coverings of the testis
Anterior 1/3 (L1) :
Posterior 2/3 (S3) :
69
Nerue supply of Anterior 1/3 of Skin of the scrotum in Coverings of the testis
* The ilioinguinal nerve
| * The genital branch of genitofemoral nerve "cremasteric nerve".
70
Nerue supply of Posterior 2/3 of Skin of the scrotum in Coverings of the testis
* The posterior scrotal nerves
| * The perineal branch of posterior cutaneous nerve of thigh.
71
origin of The posterior scrotal nerves in Nerue supply of Posterior 2/3 of Skin of the scrotum in Coverings of the testis
arising from the perineal nerve
arising from the pudendal nerve.
72
Blood supply of the testis
1- Testicular artery (Main blood supply)
2- Cremasteric artery
3- Artery of the vas
73
Testicular artery in Blood supply of the testis
Alternative name
origin
74
Alternative name for Testicular artery in Blood supply of the testis
internal spermatic artery
75
origin of Testicular artery in Blood supply of the testis
Arises from the abdominal aorta at level of L2 below the renal artery.
76
Main blood supply of the testis
Testicular artery
77
Cremasteric artery in Blood supply of the testis
Alternative name
origin
anastomosis
78
Alternative name for Cremasteric artery in Blood supply of the testis
External spermatic artery
79
origin of Cremasteric artery in Blood supply of the testis
Branch of the inferior epigastric artery, which is branch of the external iliac artery.
80
anastomosis of Cremasteric artery in Blood supply of the testis
Usually anastomosing with the testicular artery but far from the testis.
81
Surgical importance of the fact that Cremasteric artery usually anastomoses with the testicular artery but far from the testis.
Ligation of cresmasteric artery is done in upper part to avoid ligation of testicular artery by mistake in its lower part
82
origin of Artery of the vas in Blood supply of the testis
Branch of the inferior vesical artery, which is a branch of the anterior division of the internal iliac artery
83
Alternative name for inferior vesical artery
uterine artery
84
Venous Drainage of the terstis
1. Pampiniform plexus of veins :
2. Cremasteric vein(s)
3. Vein of the vas :
85
Pampiniform plexus of veins in Venous Drainage of the terstis
Number in scrotum, inguinal canal and above the internal ring
Ending
86
In the scrotum, Number of Pampiniform plexus of veins in Venous Drainage of the terstis
About 15-25 veins in the scrotum
87
In the inguinal canal, Number of Pampiniform plexus of veins in Venous Drainage of the terstis
about 4-6 veins in the inguinal canal.
88
Above the internal ring, Number of Pampiniform plexus of veins in Venous Drainage of the terstis
The are 2 veins lying on psoas muscle on either side of the testicular artery.
89
Ending of Pampiniform plexus of veins in Venous Drainage of the terstis
The right testicular vein "internal spermatic vein" goes to the inferior vena cava,
The left testicular vein goes to the left renal vein.
90
Alternative name for internal spermatic vein
The right testicular vein
91
meaning of pampiniform
3an2od el 3enab
92
the reason why the Pampiniform plexus of veins is a plexus
To provide:
* Cooling of testicular artery
* subnormal temp (35) for spermatogenesis
93
Cremasteric vein(s) in Venous Drainage of the terstis
Alternative name
Anastomosis
Ending
94
Alternative name for Cremasteric vein(s) in Venous Drainage of the terstis
External spermatic veins
95
Anastomosis of Cremasteric vein(s) in Venous Drainage of the terstis
It anastomosis with the pampiniform plexus of veins in the inguinal canal.
96
Ending of Cremasteric vein(s) in Venous Drainage of the terstis
Drains into the inferior epigastric vein.
97
Ending of vein of the vas in Venous Drainage of the terstis
Drains into the inferior vesical vein.
98
Lymphatic drainage of the testis
1. To the para-aortic lymph nodes.
2. Some lymphatics from the medial side of the testis may run with the artery of the vas and drain to the iliac lymph nodes.
3. The skin of the scrotum is drained by the inguinal lymph nodes
99
site of the iliac lymph nodes
on the internal iliac arteries
100
Nerve supply of the testis
A. Sympathetic supply
B.Sensory supply
101
Sympathetic Nerve supply of the testis
Fibres arise from T10; pass in the greater or lesser splanchnic nerves to relay in the coeliac ganglion.
Past ganglionic sympathetic fibres reach the testis along the testicular artery
102
Sensory Nerve supply of the testis
Sensory fibres share the same sympathetic pathway.
