1. Embryology and Anatomy of the testis Flashcards

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.

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2
Q

The germ cells of the testis are derived from

A

the Yolk Sac.

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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)

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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.

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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

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6
Q

The testis reaches the internal ring at

A

the 6th month of intrauterine life.

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7
Q

The testis enters the inguinal canal at

A

the 7th month of intrauterine life.

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8
Q

The testis reaches the external ring at

A

the 8th month of intrauterine life.

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9
Q

The testis reaches the scrotum at

A

the 9th month of intrauterine life.

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10
Q

at the 6th month of intrauterine life, The testis reaches

A

the internal ring

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11
Q

at the 7th month of intrauterine life, The testis reaches

A

the inguinal canal

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12
Q

at the 8th month of intrauterine life, The testis reaches

A

the external ring

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13
Q

at the 9th month of intrauterine life, The testis reaches

A

the scrotum

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14
Q

Factors Responsible for Normal Descent of the Testicles

A
  1. Chorionic gonadotrophin from the maternal circulation
  2. Gubernaculum:
  3. Elongation of upper half of the body
  4. Intra-abdominal pressure
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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

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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.

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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.

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18
Q

in Factors Responsible for Normal Descent of the Testicles, Intra-abdominal pressure

A

squeezing the testes through the ring

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19
Q

Ernbryological origin of the epididymis & vas deferens

A

They arise from the mesonephric ( Wolffian ) duct

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20
Q

The mesonephric tubules embryologically give

A
  • The vasa efferentia
  • Appendix of the epididymis
  • The paradidymis (organ of Giraldes)
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21
Q

Embryological origin of The vasa efferentia

A

The mesonephric tubules

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22
Q

Embryological origin of The appendix of the epididymis

A

The mesonephric tubules

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23
Q

Embryological origin of The paradidymis

A

The mesonephric tubules

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24
Q

Alternative name for The paradidymis

A

organ of Giraldes

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25
Q

Embryological origin of organ of Giraldes

A

The mesonephric tubules

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26
Q

Embryological origin of The appendix of the testis

A

arises from the remnant of the paramesonephric duct ( Mullerian duct).

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27
Q

alternative name for The appendix of the testis

A

Hydatid of Morgagni

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28
Q

Embryological origin of The Hydatid of Morgagni

A

arises from the remnant of the paramesonephric duct ( Mullerian duct).

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29
Q

alternative name for the paramesonephric duct

A

Mullerian duct

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30
Q

Macroscopic structure of the testis :

A

Morphology and size

Place in the space

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31
Q

Morphology of the testis in Macroscopic structure of the testis :

A

It is a flattened ovoid body

It has:
2 surfaces (medial and lateral),
2 borders (anterior and posterior)
2 ends (upper and lower).
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32
Q

Size of the testis in Macroscopic structure of the testis :

A

measuring 2x1x1 inch.

or 4x2x2.5 cm

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33
Q

place of the testis in the space in Macroscopic structure of the testis :

A

It is placed obliquely so that posterior borders are nearer to each other than the anterior borders.

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34
Q

Minute structure of the testis

A

1- Tunica albuginea :

2- Fibrous septa

3- Seminiferous tubules

4- Interstitial cells of Leydig :

5- Vasa efferentia

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35
Q

Tunica albuginea in the Minute structure of the testis

A

a tough fibrous coat which is thickened posteriorly to for the mediastinum testes.

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36
Q

Fibrous septa in the Minute structure of the testis

A

divide the testicle into 200-300 compartments

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37
Q

Seminiferous tubules in the Minute structure of the testis

A

number

Length

Ending

Lining cells

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38
Q

number of Seminiferous tubules in the Minute structure of the testis

A

About 400-600 in number

There are about 2-3 tubules in each compartment.

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39
Q

Length of each of the Seminiferous tubules in the Minute structure of the testis

A

each is 60 cm long,

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40
Q

Ending of the Seminiferous tubules in the Minute structure of the testis

A

As the tubules reach the mediastinum testis, they join one another and open in the rete testis which is a network of seminal channels.

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41
Q

The rete testis

A

a network of seminal channels.

The Seminiferous tubules as they reach the mediastinum testis, they join one another and open in it

42
Q

Lining cells of the Seminiferous tubules in the Minute structure of the testis

A

Lined by spermatocyte - sertoli cells

43
Q

Functions of the Sertoli cells

A
  • Secrete estrogen in small dose essential for spermatogenesis
  • AMH( anti-mullerian hormone) to stop mullerian duct formation intra-uterine
  • Forms blood testicular barrier
44
Q

Interstitial cells of Leydig in the Minute structure of the testis

A

site

function

45
Q

site of Interstitial cells of Leydig in the Minute structure of the testis

A

in between the Seminiferous tubules.

46
Q

function of Interstitial cells of Leydig in the Minute structure of the testis

A

They secrete testosterone.

47
Q

Vasa efferentia in the Minute structure of the testis

A

Beginning

Number

Ending

48
Q

Beginning of Vasa efferentia in the Minute structure of the testis

A

arise from the top part of the testicle from the rete testis.

49
Q

number of Vasa efferentia in the Minute structure of the testis

A

They are 15-20 in number

50
Q

Ending of Vasa efferentia in the Minute structure of the testis

A

They join the head of the epididymis.

51
Q

Coverings of the testis

A

9 coverings from inside outwards

  1. Tunica albuginea

2- Visceral layer of tunica vaginalis.

  1. Parietal layer of tunica vaginalis.
  2. Internal spermatic fascia :
  3. Cremasteric muscle and fascia:
  4. External spermatic fascia :
  5. Colles’ fascia
  6. Dartos muscle
  7. Skin of the scrotum.
52
Q

fibrous capsule of the testis

A

Tunica albuginea

53
Q

origin of Internal spermatic fascia in Coverings of the testis

A

fascia transversalis.

54
Q

Cremasteric muscle and fascia in Coverings of the testis

A

Origin

Nerve supply

Function

The cremasteric reflex

55
Q

origin of Cremasteric muscle and fascia in Coverings of the testis

A

internal oblique muscle.

56
Q

nerve supply of Cremasteric muscle and fascia in Coverings of the testis

A

The genital branch of genito-femoral nerve

“cremasteric nerve” L1

57
Q

Function of Cremasteric muscle and fascia in Coverings of the testis

A

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
Q

The cremasteric reflex

A

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
Q

The cremasteric reflex in infants

A

may be exaggerated leading to retractile testis which is a mistaken diagnosis of undescended testes

60
Q

origin of External spermatic fascia in Coverings of the testis

A

derived from external oblique aponeurosis

61
Q

origin of colles’ fascia in Coverings of the testis

A

is the extension of the deep membranous layer of the superficial fascia of the abdomen “Scarpa’s fascia” to the scrotum

62
Q

Scarpa’s fascia

A

the deep membranous layer of the superficial fascia of the abdomen

63
Q

Dartos muscle in Coverings of the testis

A

Origin

Nerve supply

Function

64
Q

Origin of Dartos muscle in Coverings of the testis

A

replaces the superficial fatty layer of the superficial fascia of the abdomen “Camper’s fascia”.

65
Q

Nerve supply of Dartos muscle in Coverings of the testis

A

supplied by sympathetic fibres

66
Q

Function of Dartos muscle in Coverings of the testis

A

responsible for corrugation of the skin of the scrotum

67
Q

Camper’s fascia

A

the superficial fatty layer of the superficial fascia of the abdomen

68
Q

Nerue supply of Skin of the scrotum in Coverings of the testis

A

Anterior 1/3 (L1) :

Posterior 2/3 (S3) :

69
Q

Nerue supply of Anterior 1/3 of Skin of the scrotum in Coverings of the testis

A
  • The ilioinguinal nerve

* The genital branch of genitofemoral nerve “cremasteric nerve”.

70
Q

Nerue supply of Posterior 2/3 of Skin of the scrotum in Coverings of the testis

A
  • The posterior scrotal nerves

* The perineal branch of posterior cutaneous nerve of thigh.

71
Q

origin of The posterior scrotal nerves in Nerue supply of Posterior 2/3 of Skin of the scrotum in Coverings of the testis

A

arising from the perineal nerve

arising from the pudendal nerve.

72
Q

Blood supply of the testis

A

1- Testicular artery (Main blood supply)

2- Cremasteric artery

3- Artery of the vas

73
Q

Testicular artery in Blood supply of the testis

A

Alternative name

origin

74
Q

Alternative name for Testicular artery in Blood supply of the testis

A

internal spermatic artery

75
Q

origin of Testicular artery in Blood supply of the testis

A

Arises from the abdominal aorta at level of L2 below the renal artery.

76
Q

Main blood supply of the testis

A

Testicular artery

77
Q

Cremasteric artery in Blood supply of the testis

A

Alternative name

origin

anastomosis

78
Q

Alternative name for Cremasteric artery in Blood supply of the testis

A

External spermatic artery

79
Q

origin of Cremasteric artery in Blood supply of the testis

A

Branch of the inferior epigastric artery, which is branch of the external iliac artery.

80
Q

anastomosis of Cremasteric artery in Blood supply of the testis

A

Usually anastomosing with the testicular artery but far from the testis.

81
Q

Surgical importance of the fact that Cremasteric artery usually anastomoses with the testicular artery but far from the testis.

A

Ligation of cresmasteric artery is done in upper part to avoid ligation of testicular artery by mistake in its lower part

82
Q

origin of Artery of the vas in Blood supply of the testis

A

Branch of the inferior vesical artery, which is a branch of the anterior division of the internal iliac artery

83
Q

Alternative name for inferior vesical artery

A

uterine artery

84
Q

Venous Drainage of the terstis

A
  1. Pampiniform plexus of veins :
  2. Cremasteric vein(s)
  3. Vein of the vas :
85
Q

Pampiniform plexus of veins in Venous Drainage of the terstis

A

Number in scrotum, inguinal canal and above the internal ring

Ending

86
Q

In the scrotum, Number of Pampiniform plexus of veins in Venous Drainage of the terstis

A

About 15-25 veins in the scrotum

87
Q

In the inguinal canal, Number of Pampiniform plexus of veins in Venous Drainage of the terstis

A

about 4-6 veins in the inguinal canal.

88
Q

Above the internal ring, Number of Pampiniform plexus of veins in Venous Drainage of the terstis

A

The are 2 veins lying on psoas muscle on either side of the testicular artery.

89
Q

Ending of Pampiniform plexus of veins in Venous Drainage of the terstis

A

The right testicular vein “internal spermatic vein” goes to the inferior vena cava,

The left testicular vein goes to the left renal vein.

90
Q

Alternative name for internal spermatic vein

A

The right testicular vein

91
Q

meaning of pampiniform

A

3an2od el 3enab

92
Q

the reason why the Pampiniform plexus of veins is a plexus

A

To provide:

  • Cooling of testicular artery
  • subnormal temp (35) for spermatogenesis
93
Q

Cremasteric vein(s) in Venous Drainage of the terstis

A

Alternative name

Anastomosis

Ending

94
Q

Alternative name for Cremasteric vein(s) in Venous Drainage of the terstis

A

External spermatic veins

95
Q

Anastomosis of Cremasteric vein(s) in Venous Drainage of the terstis

A

It anastomosis with the pampiniform plexus of veins in the inguinal canal.

96
Q

Ending of Cremasteric vein(s) in Venous Drainage of the terstis

A

Drains into the inferior epigastric vein.

97
Q

Ending of vein of the vas in Venous Drainage of the terstis

A

Drains into the inferior vesical vein.

98
Q

Lymphatic drainage of the testis

A
  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
Q

site of the iliac lymph nodes

A

on the internal iliac arteries

100
Q

Nerve supply of the testis

A

A. Sympathetic supply

B.Sensory supply

101
Q

Sympathetic Nerve supply of the testis

A

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
Q

Sensory Nerve supply of the testis

A

Sensory fibres share the same sympathetic pathway.