Puberty and The Menstrual Cycle
the stage when sex hormones cause physical changes and the body becomes capable of reproduction.
💡 Key Concept: The main hormones involved are:
- Testosterone (in males) – produced by the testes.
- Oestrogen (in females) – produced by the ovaries.
Changes During Puberty
In Males (Testosterone) | In Females (Oestrogen) |
Voice deepens | Breasts develop |
Facial and body hair grows | Menstrual cycle begins |
Sperm production starts | Hips widen |
The Menstrual Cycle
The menstrual cycle is a monthly process in females that prepares the body for pregnancy.
Overview of the Cycle (approx. 28 days)
Stage | Days | What Happens |
Menstruation | 1–5 | Lining of uterus is shed (period). |
Lining Builds Up | 6–13 | Uterus lining thickens in preparation for fertilised egg. |
Ovulation | ~Day 14 | An egg is released from an ovary. |
Lining Maintained | 15–28 | If no fertilisation, hormone levels fall and the cycle restarts. |
💡 Ovulation = most fertile time.
Hormones Involved in the Menstrual Cycle
Hormone | Produced By | Role |
FSH (Follicle Stimulating Hormone) | Pituitary gland | Causes egg to mature; stimulates oestrogen. |
Oestrogen | Ovaries | Builds up uterus lining; inhibits FSH, stimulates LH. |
LH (Luteinising Hormone) | Pituitary gland | Triggers ovulation. |
Progesterone | Ovaries | Maintains the uterus lining; inhibits FSH and LH. |
Questions
- What is the role of testosterone in males?
- What triggers ovulation?
- Which hormone maintains the uterus lining?
- What does FSH do?
- On which day does ovulation usually occur?
Summary
- Puberty is triggered by sex hormones: testosterone in males and oestrogen in females.
- The menstrual cycle prepares the uterus for pregnancy and involves FSH, LH, oestrogen, and progesterone.
- Ovulation occurs around day 14, and hormone levels rise and fall to control the cycle.