Recording-2025-05-14T14:35:26.405Z

Gametogenesis

• Males (Spermatogenesis):

  • Sperm cell production begins at puberty and continues throughout life.

• Females (Oogenesis):

  • Egg production starts before birth, pauses before birth, resumes at puberty, and pauses again before each ovulation.
  • Fertile period: From puberty to around age 51 in the US.
  • Menopause: Permanent cessation of reproductive cycle.

Hormonal Regulation & Menstrual Cycle

• Luteinizing Hormone (LH) Surge:

  • Triggers ovulation (release of a mature egg from the ovary).

• Ovulation:

  • The process of releasing a mature egg from the ovary.
  • Linked to the LH surge.

• Menarche:

  • The first occurrence of menstruation (menses) at puberty.

Fertilization

• Fertilization Definition:

  • The successful fusion of a sperm cell with an egg.

• Zygote Formation:

  • A fertilized egg is called a zygote.
  • Fertilization is involved in the formation of a zygote.

• Location of Fertilization:

  • Most commonly occurs in the ampulla of the fallopian tube.
  • The ampulla is the most common, but not the only site of fertilization.

• Post-Fertilization:

  • The zygote travels to the uterus for implantation and gestation.

Amenorrhea

• Amenorrhea Definition:

  • The absence of menstruation (missed period).

• Common Cause:

  • The most common cause is pregnancy, unless proven otherwise.

• Other Causes:

  • Stress can cause amenorrhea, but it is not the most common cause.

Menopause

• Menopause Definition:
  • Cessation of the reproductive cycle, typically around age 51 in the US.

Male Reproductive System - Testes

• Dual Functions of Testes:
  • Exocrine: Production of sperm cells (spermatogenesis).
  • Endocrine: Production of testosterone.

Sperm Path and Structures Involved

• Epididymis:

  • Sperm cells acquire motility (learn to swim).
  • Think of it as sperm "swim school."

• Ductus Deferens (Vas Deferens):

  • Transports sperm cells out of the scrotum and into the pelvic cavity.
  • Passes medial to the ureter and posterior/inferior to the urinary bladder.

• Seminal Vesicle:

  • Gland located lateral to the vas deferens.

• Ejaculatory Duct:

  • Formed by the merging of the vas deferens and the duct of the seminal vesicle.
  • Pierces the prostate gland.

• Location of Ejaculatory Duct:

  • Found within the prostate gland.

• Urethra:

  • Prostatic Urethra: Portion of the urethra that passes through the prostate gland.
  • Membranous Urethra: The middle portion of the urethra.
  • Spongy (Penile) Urethra: The final portion of the urethra.

• Bulbourethral Gland (Cowper's Gland):

  • Produces a slightly alkaline secretion to neutralize residual urine in the urethra, facilitating safe passage of sperm cells.
  • Contributes about 5% of ejaculate volume.

Ejaculate Composition

• Source of Ejaculate:
  • Fluids from the seminal vesicle, prostate gland, and bulbourethral gland.

Flow of Sperm Cells Out of the Body

1. Testes
2. Epididymis
3. Vas Deferens
4. Ejaculatory Duct
5. Prostatic Urethra
6. Membranous Urethra
7. Spongy Urethra

Testicular Temperature Regulation

• Scrotum:

  • Sac outside the body that contains the testes.

• Dartos and Cremaster Muscles:

  • Smooth muscles that regulate testicular temperature.

• Cold Conditions:

  • Dartos and cremaster muscles contract.
  • Testes are elevated closer to the body for warmth.

• Hot Conditions:

  • Dartos and cremaster muscles relax.
  • Testes move further away from the body.

Spermatic Cord

• Contents:

  • Vas Deferens (Ductus Deferens)
  • Testicular Artery
  • Testicular Vein
  • Testicular Nerve
  • Lymphatics

• Note:

  • The epididymis is NOT पार्ट of the spermatic cord.

Penis Anatomy

• Erectile Tissues: