Adolescence and Puberty Changes

Adolescence

• Adolescence is the period of growth from childhood to adulthood, marked by emotional and physical changes.
• Mood swings, anger, fatigue, and experimentation with risky behaviors (e.g., alcohol) are common during adolescence.
• Puberty, the period of physical changes, occurs between ages 9-14, typically earlier in girls than boys, varying between individuals.
• Puberty primarily involves changes to the reproductive system, enabling the possibility of parenthood in later life.
• Sex hormones, chemical messengers in the bloodstream, trigger puberty.
• Female hormones are produced in the ovaries, while male hormones are produced in the testes.

Puberty Changes

• Boys and Girls: Hair growth in underarm and pubic areas, height increase, increased body odor, emotional changes.
• Girls: Breast development, vaginal hair growth, egg cell production in ovaries, menstruation, widening hips, ovary production of female hormones.
• Boys: Muscle development, penis and testicle enlargement, testicle production of sperm and male hormones, shoulder broadening, deeper voice, facial, arm, leg, and underarm hair growth.

Fetal Development

• Fertilization: Sperm and egg nuclei join to form a zygote.
• Implantation: Fertilized egg attaches to the uterine lining.
• Gestation: Time from fertilization to birth (approximately 9 months/40 weeks).
• Ultrasound Scans: Used to monitor fetal growth, detect abnormalities, and assess fetal position and health.

Stages of Fetal Development

• 1 Week: Cell specialization begins.
• 4 Weeks: Spine, brain, and heart begin forming.
• 9 Weeks: Movement, sense of touch, eye and ear formation begin.
• 12 Weeks: Muscle activity (kicking, swallowing), lung practice.

Supporting Structures During Pregnancy

• Placenta: Facilitates nutrient and waste exchange between mother and fetus, acts as an immune barrier.
• Umbilical Cord: Connects the fetus to the placenta.
• Amniotic Fluid: Cushions and protects the fetus against shocks.

Factors Affecting Fetal Development

• Smoking: Can lead to premature birth.
• Alcohol Consumption: Can impact brain development.
• Drug Use: Can harm fetal growth and organ formation.

Birth Process

• Uterine contractions expel the baby through the vagina.
• Umbilical cord is cut after birth.
• Placenta is delivered as the afterbirth.

Fertilisation and Germination

• Pollination: Transfer of pollen from anther to stigma (by wind or insects).
• Pollination Methods Differences: Insect-pollinated flowers are often scented, colorful, and produce sticky or spiky pollen, while wind-pollinated flowers are small, dull, have no scent or nectar, and produce smooth, light pollen.
• Germination Factors: Seeds need water, warmth (to speed up reactions) , and oxygen (for respiration).

Fertilisation and Implantation

• Fertilization: The joining of egg and sperm nuclei.
• Gametes: Reproductive cells (egg and sperm).
• Embryo Development: Fertilized egg divides into a ball of cells.
• Implantation: Embryo attaches to the uterine lining.
• Sexual Intercourse: Semen (containing sperm) is released into the woman's vagina.
• Ejaculation: Semen released.
• Sperm Travel: Sperm swim to the egg in the oviduct.
• Cilia: Tiny hairs in the fallopian tubes assist egg movement.

Reproductive Systems

• Male Reproductive System: Testes (produce sperm and hormones), glands (produce nutrients for sperm), sperm ducts (carry sperm), urethra (carries urine or sperm), penis (transfers sperm, carries urine).
• Female Reproductive System: (Details in separate section, but includes ovaries (contain eggs), Fallopian tubes (oviducts))

Seed Dispersal

• Seeds are dispersed to prevent competition. Methods include wind, animals, water, and explosion.

Menstrual Cycle

• Menstruation: Discharge of uterine lining.
• Menstrual cycle: Monthly sequence, typically 28 days.
• Ovulation: Egg release from ovary.
• Contraception: Methods to prevent pregnancy (e.g., condoms, pill).
• Contraception Methods: Condoms (barrier method preventing semen entry) and the pill (hormonal method preventing ovulation).
• Menstrual Cycle Stages Describe the phases of the menstrual cycle (ovulation, menstruation, egg maturation, uterine wall changes)).