Lab 3: Gross anatomy of human reproduction 2

Question 1

What is the clinical significance of the inguinal canal?

Answer 1

Its a potential weakness in the abdominal wall, and thus a common site of herniation e.g. inguinal hernia

Question 2

What structures are transmitted through the inguinal canal?

Answer 2

Transmits:

• The spermatic cord (males)
• The round ligament of the uterus (females)
• ilioingjuinal nerve (male and female)

Question 3

The two openings to the inguinal canal are known as rings. What are the rings of the inguinal canal?

Answer 3

Deep ring- marks the start of the inguinal canal

Superficial ring- marks the end of the inguinal canal

Question 4

Where does the spermatic cord begin and end?

Answer 4

Begins at the opening of the deep inguinal ring of the inguinal canal.

The cord passes through the inguinal canal, entering the scrotum via the superficial inguinal ring.

It continues into the scrotum, ending at the posterior border of the testes.

Question 5

What are the coverings of the spermatic cord?

Answer 5

• External spermatic fascia (outer layer)
• Cremaster muscle and fascia (middle layer)
• Internal spermatic fascia (inner layer)

Question 6

The cremasteric muscle is derived from which muscle of the abdomen?

Answer 6

Derived from the internal oblique muscle and its fascial coverings.

Question 7

Where does the round ligament of the uterus begin and end?

Answer 7

It originates at the uterine horns (the points at which the fallopian tubes enter the uterus), and attaches to the labia majora, passing through the inguinal canal.

Question 8

What are the coverings of the round ligament of the uterus?

Answer 8

The transversalis fascia.

Question 9

The ilio-inguinal nerve is a branch of which spinal nerve?

Answer 9

L1

Question 10

What part of the body is supplied by the ilio-inguinal nerve?

Answer 10

Skin of the scrotum or labia

Adjacent thigh

Question 11

Describe the compensation that occurs in the canal that prevents herniation?

Answer 11

When intra-abdomianl pressure is raised, the muscles of the anterior and posterior wall contract, and ‘clamp down’ on the canal.

Protecting from herination

Question 12

During early development the hindgut ends in which region?

Answer 12

The cloaca

Question 13

What is the difference between a direct and indirect inguinal herina?

Answer 13

Indirect – where the peritoneal sac enters the inguinal canal through the deep inguinal ring.

Direct – where the peritoneal sac enters the inguinal canal though the posterior wall of the inguinal canal.

Question 14

Define the term hernia?

Answer 14

Defined as the protrusion of an organ or fascia through the wall of a cavity that normally contains it

Question 15

What causes indirect inguinal hernia?

Answer 15

The failure of embryonic closure of the processus vaginalis

Question 16

What causes direct inguinal hernia?

Answer 16

Direct inguinal hernias are acquired, usually in adulthood, due to weakening in the abdominal musculature

Question 17

What are the two categories of inguinal hernias?

Answer 17

Direct and indirect

Question 18

The two types of inguinal hernias are direct and indirect. Which type are congenital?

Answer 18

Indirect as its caused by a failure of the closure of the embryological structure, processus vaginalis.

Question 19

The two types of inguinal hernias are direct and indirect. Which type are acquired?

Answer 19

Direct inguinal hernia

Question 20

In fetus, what does the gonads first appear as?

Answer 20

Genital ridges

Question 21

How are genital ridges formed?

Answer 21

Proliferation of the epithelium and condensation of underlying mesenchyme.

Question 22

When does germ cells appear in the genital ridges?

Answer 22

Not until week 6 gestation.

Question 23

Describe the germ cell migration into the genital ridges?

Answer 23

Primordial germ cells originate in the epiblast

Week 3: Migrate through the primitive streak into the endoblast

Week 4: they migrate along the dorsal mesentery of the hindgut.

Week 5: they arrive at the primitive gonads

Week 6: invade and reside in the genital ridges.

Question 24

Describe the development of the primitive sex cords?

Answer 24

Shortly before and during arrival of primordial germ cells, the epithelium of the genital ridge proliferates, and epithelial cells penetrate the underlying mesenchyme forming the primitive sex cords

Question 25

Name these parts of the 6 week embryo?

Answer 25

Question 26

Around the cloacal membrane, in the 3rd week of development, a pair of which folds develop?

Answer 26

Cloacal folds

Question 27

Cranial to the cloacal membrane, the cloacal folds unite to form what?

Answer 27

Genital tubercle

Question 28

Around week 6 of development, the cloacal folds subdivided into two groups.

Name them?

Answer 28

Urethral folds (anteriorly)

Anal folds (posteriorly)

Question 29

The genital swellings appear.

Where are they located in relation to the urethral folds?

Answer 29

Laterally

Question 30

The genital swellings will go on to form which structure in females?

Answer 30

Labia majora

Question 31

The genital swellings will go on to form which structure in males?

Answer 31

Scrotal swellings

Question 32

Name these parts of the embryological development of the external genitalia?

Answer 32

Question 33

The urethral folds will go on to form which structure in females?

Answer 33

Labia minora

Question 34

The urethral folds will go on to form which structure in males?

Answer 34

Scrotal raphe, spongy urethra and ventral aspect of the penis

Question 35

Name these parts of a female external genitalia?

Answer 35