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
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
