Adolescence and Fetal Development Overview

Adolescence

• Adolescence is the transitional period from childhood to adulthood, marked by significant emotional and physical changes.
• Emotional changes might include mood swings, irritability, and experimentation with risky behaviors like alcohol.
• Puberty, the physical changes, occurs between ages 9 and 14, with girls typically starting earlier than boys.
• Puberty primarily affects the reproductive system, allowing for future reproduction.
• Sex hormones (chemical messengers) trigger these changes, produced in the ovaries (female) and testes (male).
• Common physical changes include: hair growth (underarms, pubic), height increase, body odor, emotional changes. For girls: breast development, vaginal hair growth, egg cell production, menstruation, widened hips, female hormone production. For boys: increased muscularity, penis and testicle growth, sperm and male hormone production, wider shoulders, deeper voice, facial hair, and body hair.

Fetal Development

• Fertilization: Sperm and egg unite 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 position/health.
• Sperm transport: Ejaculated sperm travel through the vagina, uterus, and oviduct to reach the egg.
• Embryonic development (key milestones):
• 1 week: Cell specialization begins.
• 4 weeks: Spine, brain, and heart form.
• 9 weeks: Movement, touch, eyes, and ears develop.
• 12 weeks: Muscle activity (kicking, swallowing), and practice breathing.

Fetal support structures:

• Placenta: Facilitates nutrient and waste exchange between mother and fetus, acting as a barrier against infectious agents.
• Umbilical cord: Connects the fetus to the placenta.
• Amniotic fluid: Acts as a shock absorber, protecting the fetus.

Factors affecting fetal development:

• Negative factors: Smoking, alcohol consumption, and drug use can negatively impact fetal growth and development.

Birth Process:

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

Fertilization and Germination

• Pollination: Transfer of pollen from anther to stigma.
• Methods of pollination: Wind and insects differing in methods.
• Insect pollination characteristics: Often scented, with nectar, large/brightly colored flowers, sticky/spiky pollen grains.
• Wind pollination characteristics: Small, often dull-colored flowers, no scent/nectar, smooth/light pollen grains.
• Plant reproduction: Pollen (male gamete) is transferred to stigma, fertilizes ovum (female gamete) in ovary.
• Germination: Process where seed grows into new plant requiring water, oxygen and warmth.

Fertilization and Implantation

• Fertilization: Fusion of sperm and egg nuclei.

• Gametes: Sperm (male) and egg (female) reproductive cells.

• Cilia: Tiny hairs that guide the egg in the oviduct.

• Ejaculation: Release of semen containing sperm into vagina.

• Implantation: Embryo attaches to the uterine wall and begins to develop.

• Sexual intercourse: Allows for sperm to fertilize the egg.

• Female reproductive system: Oviducts, ovaries, uterus, vagina (transport).

• Male reproductive system: Testes (sperm production), sperm ducts, penis (semen delivery).

Menstrual Cycle

• Menstruation: Shedding of the uterine lining when pregnancy fails.
• Menstrual cycle phases (approx. 28 days):
• Days 1-5: Period (uterine lining shed).
• Days 5-13: Uterus lining thickens, egg matures, prepares for pregnancy.
• Day 14: Ovulation (egg released).
• Days 14-21: Egg travels, uterus lining stays thick and spongy.
• Days 22-28: If egg not fertilized, lining breaks down, cycle repeats.
• Pregnancy: If fertilized, egg implants in the uterine lining.
• Contraception: Methods to prevent pregnancy (e.g., condoms, pills).
• Condoms: Barrier method preventing semen entry, also protects against STIs.
• Contraceptive pill: Contains hormones preventing ovulation.

Seed Dispersal

• Importance of seed dispersal: Preventing resource competition.
• Methods: Wind, animals, water, and explosion.

Reproductive Systems

• Male reproductive system features: Testes (sperm production), glands (nutrients), sperm ducts, urethra, penis. 

• Female reproductive system features: Ovaries (egg production), oviducts, uterus, vagina (transport).

This quiz covers the key concepts of adolescence, including emotional and physical changes that occur during this transitional period. It also touches on aspects of fetal development and the significance of puberty. Understand the impact of hormones and the differences in physical changes between boys and girls.