Puberty summary IEB

PUBERTY AND THE MENSTRUAL CYCLE


Puberty (General Overview)
Process of physical and physiological changes
Leads to:
-​ Development of secondary sexual characteristics
Reproductive maturity Starts:
-​ Girls: 10-14 years
-​ Boys: 12-16 years
• Controlled by the pituitary gland (hypophysis)
• Releases LH and FSH
• Triggers hormone production and gamete formation


Puberty in Males
• Hormone: Testosterone (stimulated by LH and Leydig cells)
• FSH + Testosterone → Spermatogenesis (sperm production)
Primary Changes:
-​ Testes enlarge
-​ Penis enlarges
-​ Sperm production begins
Secondary Changes:
-​ Increased muscle mass
-​ Voice deepens
-​ Facial and body hair (moustache, beard, chest, armpits, pubic area)
-​ Oily skin, sweat, acne
-​ Mood swings and sleep pattern changes
-​ Increased sex drive


Puberty in Females
• Hormone: Oestrogen (stimulated by FSH)
• FSH + Oestrogen → Oogenesis (egg production)

, Primary Changes:
-​ Ovaries mature
-​ Eggs develop
-​ Menstruation begins
Secondary Changes:
-​ Breast development
-​ Wider hips
-​ Growth in height
-​ Body hair (armpits, pubic area, legs)
-​ Oily skin, sweat, acne
-​ Fat deposit under skin


Gametogenesis - Summary
• Formation of mature gametes (sperm in males, eggs in females) in gonads
• Involves meiosis, reducing chromosome number from 46
→ 23
• Ensures zygote has 46 chromosomes after fertilization
Two types:
-​ Spermatogenesis - production of male gametes (sperm)
-​ Oogenesis - production of female gametes (eggs)


Spermatogenesis (in testes)
• Occurs in seminiferous tubules
• Diploid cells undergo meiosis - haploid sperm
• One diploid cell produces 4 non-identical sperm cells
• Continuous production from puberty to death
• Takes 9-10 weeks per sperm to develop
• Millions produced at a time
Structure of sperm:
• Head: Contains nucleus (haploid genetic material)
• Acrosome: enzymes to penetrate ovum