Page 221 - Physiology and Pathophysiology MNU 2024-2025 نظرى

Clinical pharmacy 2024/2025 Level 2 Pharm D Physiology and Pathophysiology (MD303)
Reproductive Physiology

Female and Male Gonads

Gonads form oocytes in females & sperm in males to signal the body for
Main role
reproduction
Role of
Gonadal 1. oogenesis and spermatogenesis (formation and development of sperm)

hormones 2. supporting conception, pregnancy, and lactation.
1. under hypothalamic–pituitary axis control, using the same hypothalamic

Control signaling hormone (gonadotropin-releasing hormone [GnRH])
2. pituitary hormones, including (LH) and (FSH).

Secretion of gonadotropin-releasing hormone (GnRH),

• The hypothalamic hormone begins at gestational week 4, but its levels remain low
until puberty.

• Secretion of (FSH) and (LH), the anterior pituitary hormones, begins between
gestational weeks 10 and 12. Like GnRH, the levels of FSH and LH remain low until
puberty.

• During childhood, FSH levels are relatively higher than LH levels.

• At puberty and throughout the reproductive years, the secretory pattern changes:
Secretion of GnRH, FSH, and LH increases and becomes pulsatile.
• The relative levels of FSH and LH reverse, with LH levels becoming higher than FSH

levels.
• In addition, in females, there is a 28-day cycle of gonadotropin secretion called the

menstrual cycle.
• Finally, in senescence, gonadotropin secretion rates increase further, with FSH levels

becoming higher than LH levels, as they were in childhood.

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