(Slides 7-13)

What are the Gonads of the male reproductive system?

Testes

What is the system of ducts in the male reproductive system?

• Epididymis

• Ductus deferens

• Ejaculatory ducts

• Urethra

What are the accessory sex glands of the male reproductive system?

• Seminal

• Vesicles

• Prostate

• Bulbourethral glands

What are the supporting structures of the male reproductive system?

• Scrotum

• Penis

What is the scrotum?

A sac of loose skin, fascia, and smooth muscle that supports the testes

What divides the scrotum into two compartments?

The scrotal septum (externally seen as the raphe).

Why are the testes located outside the body?

To keep them 2–3°C below core body temperature, which is required for spermatogenesis.

Which muscles regulate testicular position?

• Cremaster (skeletal)

• Dartos (smooth)

They contract to move testes further or closer to the body

The cremaster muscle is made of?

Skeletal and Smooth Muscle

The Dartos muscle is made of?

Smooth

What does the cremaster muscle do?

Raises the testes

• During cold and arousal

What does the dartos muscle do?

Wrinkles scrotal skin to reduce surface area and conserve heat.

What are paired, oval glands in the scrotum?

Testes

What are the two tunics surrounding the testis?

• Tunica vaginalis (outer)

• Tunica albuginea (inner)

What is the outer tunic or the outer serous membrane of the testes?

Tunica vaginalis

What is the inner tunic or the inner fibrous capsule of the testes?

Tunica albuginea

What is the tunica vaginalis?

A serous membrane with parietal & visceral layers.

The Tunica vaginalis is an extension of the?

Peritoneal Cavity

• peritoneum

What is the tunica albuginea?

A dense fibrous capsule that forms septa dividing the testis into lobules.

How many lobules are in each testis?

About 250

What is inside each lobule?

1–4 seminiferous tubules

• the site of spermatogenesis.

What is the the site of spermatogenesis?

Seminiferous tubules

What is the rete testis?

A network of tubules that collects sperm from seminiferous tubules.

What houses the rete testis?

Mediastinum testis

Where do sperm go after the rete testis?

Efferent ductules → epididymis.

What are the three regions of the epididymis?

• Head

• Body

• Tail

What are the functions of the epididymis?

• Sperm maturation

• Storage

• Transport.

What are efferent ductules?

Tubes that carry sperm from the rete testis → epididymis.

What is the ligamentous remnant of the processus vaginalis?

The leftover structure from the fetal processus vaginalis after it closes.

What structure connects the epididymis to the ejaculatory pathway?

The vas (ductus) deferens

What is a hydrocele?

Fluid accumulation around the testis due to a patent processus vaginalis.

10% of newborns have hydrocele, which often?

Clears up without treatment within the first two years

What is the Processus vaginalis?

fetal peritoneal tunnel that guides testis descent

• If it stays open → hydrocele

• If it closes → leaves a small ligamentous remnant.

Where do the testes develop?

Near the kidneys

When do the testes descend?

Around the 7th fetal month

The testes descend through the?

Inguinal Canals

What guides testicular descent?

The processus vaginalis.

What is cryptorchidism?

Failure of one or both testes to descend

Occurs in:

• 3% of full‑term infants

• 30% of preterm infants.

Why is cryptorchidism dangerous?

Higher temperature → impaired spermatogenesis + increased cancer risk.

What are the support cells of the Seminiferous Tubules?

• Sertoli (sustentacular) cells

• Leydig (Intestitial) cells

What do Sertoli cells do?

• Form blood‑testis barrier

• Support, nourish, protect germ cells

• Secrete fluid

• Assist spermiation

• Secrete inhibin

What hormone stimulates Sertoli cells?

FSH

Where are Leydig cells located?

In the interstitial space between seminiferous tubules.

What do Leydig cells produce?

Androgens

• Mainly Testosterone

What hormone stimulates Leydig cells?

LH

Sertoli cells secrete inhibin when?

Sperm production is high

What does inhibin do?

Regulate the effect of FSH and Testosterone

• decreases FSH

• decreases LH

Leydig cells arise from?

Dividing stem cells

What is something important we need to know about sperm cells compared to the rest of the bodied cells?

They are antigenic and different from other body cells

• this means they can be attacked by our immune system because they are foreign compared to bodied cells

When does spermatogenesis begin?

At puberty

• takes ~ 2.5 months

What stimulates spermatogenesis?

FSH + LH (via testosterone).

What is the pathway of spermatogenesis?

Spermatogonia (2n) → Primary spermatocyte (2n) → Secondary spermatocyte (n) → Spermatid (n) → Spermatozoa (n)

What is spermiogenesis?

The transformation of Spermatids → spermatozoa (sperm cells) (morphological maturation)

What is spermiation?

Release of sperm from Sertoli cells into the lumen.

Where does spermatogenesis happen?

Inside the Seminiferous Tubules

What is the starting cell of spermatogenesis?

Spermatogonium (2n)

What division does a spermatogonium undergo?

Mitosis

What cell is formed after mitosis of a spermatogonium?

Primary spermatocyte (2n)

What division does a primary spermatocyte undergo?

Meiosis l

What cells are produced after Meiosis I?

Secondary Spermatocyte (n)

What division do secondary spermatocytes undergo?

Meiosis ll

What cells are produced after Meiosis II?

Spermatids (n)

2N represents a?

Diploid (Spermatogonia and Primary Spermatocytes)

• 2 sets of chromosomes = 46 chromosomes

• 23 pairs of chromosomes

• One from mom + one from dad

• Homologous pairs

N represents a?

Haploid (Secondary Spermatocyte; Spermatids; Spermatozoa)

• 1 set of chromosomes = 23 chromosomes

• No pairs

• Just one copy of each chromosome

• This is required for fertilization (23 + 23 = 46)