Scrotum

What are the three major structures contained in the scrotum?

What are the three major structures contained in the scrotum?

1. Spermatic cord

2. Epididymis

3. Testes

What structure separates the scrotum into two sacs?

Median raphe

What is the External Spermatic Fascia?

Fascial layer derived from the external oblique muscle

What is the Cremaster Muscle?

A suspender muscle that arises from the internal oblique muscle of the abdominal wall

What does the Cremaster Muscle consist of?

Bands of skeletal muscle

What wrinkles the scrotal skin?

Dartos Fascia and Dartos Muscle

What elevates the testes?

Cremaster Muscle

What does the Dartos Fascia and Dartos Muscle continue internally to form?

Median raphe (septum)

What is the Cremasteric Fascia derived from?

Fascia of internal oblique muscle

What is the Internal Spermatic Fascia?

Transversalis fascia

How many layers does the Tunica Vaginalis have?

Double-layer extension of peritoneum

What is the serous layer covering the testis?

Tunica Vaginalis

What two structures does the Tunica Vaginalis seperate?

Separates scrotal layers from tunica albuginea

What does the Tunica Vaginalis cover specifically?

The testes except for where the epididymis is attached

What three structures does the Tunica Vaginalis consist of?

1. Parietal (outer) layer

2. Visceral (inner) layer

3. Vaginalis sac

What layer of the Tunica Vaginalis lines the walls of the scrotal sac?

Parietal (outer) layer

What layer of the Tunica Vaginalis covers the testis, epididymis, and lower portion of spermatic cord?

Visceral (inner) layer

What is the potential space between the
two layers of tunica vaginalis? What does it contain?

Vaginalis sac containing fluid

What are the three ducts that deliver sperm to the outside of the body?

1. Epididymis

2. Ductus deferens

3. Urethra

What are the three accessory sex glands that empty into the ducts during ejaculation?

1. Seminal vesicles

2. Prostate gland

3. Bulbourethral glands

What are the testicles?

1. Symmetric

2. Oval shaped glands

What is the Appendix Testis?

Small remnant tissue on the testicle created from the degeneration of paramesonephric ducts

What is the Tunica Albuginea?

Dense, fibrous capsule covering testis

What does the tunica albuginea divide the testicles into?

Divides each testicle into 250-400 lobules

What are lobules?

Internal compartments of the testicle

What do the lobules contain?

1. Seminiferous tubules

2. Interstitial cells (Leydig)

How many Seminiferous Tubules do lobules contain?

1-3

What do Seminiferous Tubules produce? How?

Produce sperm by spermatogenesis

What do Seminiferous Tubules contain?

Sustentacular (Sertoli) cells

What do Sustentacular (Sertoli) cells produce? Why is this important?

The blood-testis barrier needed for immunity

Where do the seminiferous tubules move spermatazoa to?

1. Seminiferous tubules

2. Straight (rectus) tubules

3. Rete testis

What do the seminiferous tubules converge to form?

The rete testis

Where is the rete testis located?

Testicular mediastinum

What is the thickened portion of albuginea along the posterior border of testis?

Mediastinum teste

Where do the Semineferous Tubules converge and exit into the Rete Testis and Efferent Ducts?

Mediastinum teste

What is the Ductus (Vas) Deferens/Seminal Duct?

Muscular cord that ascends along posterior border of testis

What are the functions of the Ductus (Vas) Deferens/Seminal Duct?

1. Pump sperm into prostatic segment of urethra

2. Store sperm for several months

How does the Ductus (Vas) Deferens/Seminal Duct enter the pelvic cavity?

Through inguinal canal

What structure does vas deferens merge into? What does this form?

The Vas Deferens merges with the Seminal Vesicles to form the Ejaculatory Ducts

What is the epididymis?

Comma-shaped structure that curves along posterior
border of testis

What is the appendix epididymis?

The most cranial portion of the mesonephric duct

What is the epididymis head (globus major)?

Most superior portion of epididymis

What does the epididymis head consist of?

First part of efferent ducts that transport sperm out of testes

What does the epididymis body (corpus) contain?

Ductus epididymis

What is the ductus epididymis?

Tightly coiled single tube where efferent ducts drain into

What is the epididymis tail (globus minor)?

Distal part of epididymal ducts

What part of the epididymis exits and continues as ductus (vas) deferens in the spermatic cord?

Epididymis tail

What are the normal measurements for the epididymis?

1. Head = 10-12 mm

2. Body = Less than 4 mm

3. Tail = Less than 4 mm

Where are the efferent ductules located?

From rete testes to enter upper portion of epididymis

What are the normal measurements of a testicle?

1. Length = 4.0-5.0 cm

2. Width = 2.0-3.0 cm

3. AP = 2.0-3.0 cm

4. Weight = 12.5-19 g

Where are each testicle located?

1. Obliquely positioned within scrotum

2. Attached to spermatic cord

Where is the upper pole of the testicle located relative to the scrotum? Lower pole?

1. Upper pole = anterolateral

2. Lower pole = posteromedial

What muscle does the spermatic cord contain?

Cremaster muscle

What is the path of arterial blood flow to the testes?

1. Aorta

2. Testicular Artery

3. Capsular Arteries

4. Centripetal Arteries

What is the arterial blood flow pattern of the testes?

1. Low resistance = high blood flow

2. Broad systolic peaks

3. High diastolic flow

What is the path of arterial blood flow to the scrotum and epididymis?

1. Inferior Epigastic Artery

2. Cremasteric (External Spermatic) Artery

3. Inferior Vesicle Artery

4. Deferential Artery

What artery courses through the epididymis tail and divides into a capillary network?

Deferential Artery

What is the arterial blood flow pattern of the scrotum and epididymis?

1. High resistance = low blood flow

2. Narrow systolic peaks

3. Diminished/absent diastolic flow

What is the path of venous blood flow to the testes?

1. Intratesticular Veins

2. Venous Outflow

3. Pampiniform Plexus

4. Internal Spermatic Vein

5. IVC

Where does the left internal spermatic vein drain into?

1. Left renal vein

2. IVC

Where does the right internal spermatic vein drain into?

Directly into IVC

What is the path of lymphatic drainage of the testes?

1. Lymph plexuses under tunica vaginalis, testis, and epididymis

2. Traverse in spermatic cord

3. Testicular vessels

4. Lumbar (para-aortic) nodes as high as renal veins

What are the chief phases of the male sexual response?

1. Erection

2. Ejaculation

What is spermatogenesis?

Sperm formation

What is a male gamete?

Sperm or spermatozoa

How much sperm does an adult male produce each day?

400 million

What is meiosis?

1. “A lessening”

2. Nuclear division

Where does meiosis occur?

Mostly in gonads

How many divisions does meiosis consist of? What does this produce?

1. Two consecutive nuclear divisions

2. Produces four daughter cells

What does the hormonal regulation of reproductive function involve?

Brain-Testicular Axis

What does hormonal regulation of spermatogenesis and testicular androgen production involve?

1. Interactions between

   1. Hypothalamus

   2. Anterior pituitary gland

   3. Testes

What hormone directly stimulates the testes? What type of cell is this hormone?

1. Gonadotropins (FSH and LH)

2. Pituitary cells

What hormone stimulates spermatogenesis in the testes?

FSH

What hormone indirectly stimulates the testes? How?

GnRH via its effects on the release of FSH and LH

What hormone binds to pituitary cells?

GnRH

What serves as the final trigger for spermatogenesis?

Testosterone

What hormones exert negative feedback?

1. Testosterone

2. Inhibin

How are testosterone and the number of sperm produced related?

1. Directly

   1. More testosterone = more sperm

Why is it important that the testicles are held outside of the body, but within the scrotum?

Temperature is more optimum for sperm maturation

What is the site of sperm maturation?

Epididymis

How do the testicles function as an exocrine gland?

Producing sperm

How do the testicles function as an endocrine gland?

Synthesizing and secreting testosterone

What is human chorionic gonadotropin (HCG) produced by?

Tumors

What structures cause an elevation of human chorionic gonadotropin (HCG) in the blood?

1. Seminoma

2. Embryonic cell tumors of testes

What is the main androgen secreted by Leydig cells?

Testosterone

What hormone induces puberty in males?

Testosterone

What structures cause an elevation of testosterone in the blood?

1. Testicular tumor

2. Adrenal hyperplasia

3. Benign or malignant tumors of testes, adrenal, pituitary

4. Adrenal tumor

What structures cause a decrease in testosterone in the blood?

1. Orchiectomy

2. Testicular or prostate cancer

3. Cirrhosis of liver

4. Primary or secondary hypogonadism

What is the normal ultrasound appearance of the testicles?

1. Homogenous

2. Smooth walls

What is the normal ultrasound appearance of the mediastinum testis?

1. Highly echogenic

2. Parallel to epididymis

What is the normal ultrasound appearance of the appendix testis?

1. Small ovoid

2. Under epididymis head

What is the normal measurement of the scrotal wall?

2-8 mm thick

What is the normal ultrasound appearance of the epididymis head? Body? Tail?

1. Head = Isoechoic or MORE echogenic than testis

2. Body = Isoechoic or LESS echogenic than testis

3. Tail = Thicker than body

What is cryptorchidism?

Undescended testis

What is the normal age for the testes to descend into the scrotal sac?

8 months gestational age

What does cryptorchidism look like in adults?

Small testis with normal echogenicity

Where is cryptorchidism most commonly found?

At or below level of inguinal canal

What are the potential concerns of cryptorchidism?

1. Increased chance of malignancy (seminoma) in
   undescended testicle

2. Infertility

Where can undescended testis appear?

Anywhere along normal track of decent from
retroperitoneum to scrotum

Who is acute painful scrotum commonly found in?

1. Children

2. Adults