Reproductive System: Introduction and Male Anatomy

Overview

• Sexual reproduction involves production of offspring through germ cells (gametes).
• Organs of reproduction are called gonads (testes in males, ovaries in females).
• Gonads produce gametes (sperm and egg) and secrete sex hormones.
• Gynecology: Focuses on female reproductive system.
• Urology: Focuses on urinary system and male reproductive system.

Male Reproductive System

• Testes: Produce sperm.
• Ducts: Pathways for sperm travel.
• Accessory Sex Glands: Add secretions to sperm.
• Supporting Structures: Includes the penis.

Anatomy of the Male Reproductive System

Testes

• Held in the scrotal sac.
• Epididymis: Stores sperm, allowing them to mature.
• Vas Deferens: Duct that carries sperm and joins the seminal vesicle.
• Seminal Vesicles & Prostate Gland: Add secretions to sperm.
• Pathway: Sperm moves from prostatic urethra -> membranous urethra -> spongy/penile urethra.
• Bulbourethral Gland: Adds secretions before ejaculation.

Penis

• Composed of erectile tissues:
  • Corpora Cavernosa
  • Corpus Spongiosum (surrounds urethra)
• Glans Penis: Head of the penis; has a ridge called the corona and is covered by foreskin.

Scrotum

• Supports the testes; divided into two regions by a septum.
• Contains dartos muscle (wrinkles scrotal skin) and cremaster muscle (controls elevation of testes).
• Rafe: Line dividing the scrotal sac.

Connective Tissue Layers

• External Spermatic Fascia
• Internal Spermatic Fascia
• Tunica Vaginalis: Derived from peritoneum.
• Tunica Albuginea: Inner layer dividing testes into lobules.

Spermatogenesis

• Occurs in seminiferous tubules.
• Sertoli Cells (Sustentacular Cells): Support and nourish developing sperm, form blood-testis barrier.
• Leydig Cells (Interstitial Cells): Produce testosterone.

Blood-Testis Barrier

• Protects sperm from immune system attack.
• Formed by tight junctions between Sertoli cells.

Cryptorchidism

• Condition where testes do not descend into the scrotum.
• Risks: Infertility and increased risk of testicular cancer.
• Surgical correction may be required if testes do not descend naturally.

Key Lecture Goals

• Functions and locations of key male reproductive structures:
  • Cremaster Muscle, Dartos Muscle, Testes
  • Sertoli Cells, Leydig Cells
  • Tunica Albuginea, Tunica Vaginalis, Rafe, Spermatic Cord
  • Blood-Testis Barrier
  • Definition and consequences of cryptorchidism