18/04/2026
LESSON NOTE
Basic Science • Junior Secondary School 1 (JSS 1)
Subject: Basic Science
Class: Junior Secondary School 1 (JSS 1)
Topic: Human Reproduction
Duration: 80 Minutes (Double Period)
Term: Third Term
Week: Week 2
Date: ___________________________
LEARNING OBJECTIVES
By the end of this lesson, students should be able to:
1. Define human reproduction and explain its importance.
2. Explain the meaning of menstruation and describe the menstrual cycle.
3. Practise proper menstrual hygiene.
4. Define ovulation and identify the signs of ovulation.
5. Explain the processes of fertilization, implantation, and conception.
INSTRUCTIONAL MATERIALS
• Textbook: Basic Science for Junior Secondary Schools
• Charts showing the male and female reproductive systems
• Diagrams of the menstrual cycle and fertilization process
• Whiteboard and markers
• Printed handouts for students
PREVIOUS KNOWLEDGE
Students have previously learned about the human body systems, including the skeletal, muscular, and digestive systems. They have basic knowledge of how living things grow and develop.
INTRODUCTION
The teacher begins the lesson by asking students the following questions to arouse their interest:
• "How do you think babies come into the world?"
• "Have you heard the word 'puberty'? What changes happen to boys and girls as they grow older?"
Allow students to respond freely. Then introduce the lesson by explaining that today they will learn about human reproduction — a natural and important process in human life.
HUMAN REPRODUCTION
Meaning of Human Reproduction
Human reproduction is the biological process by which human beings produce offspring (new babies). It is how the human species continues to exist from one generation to the next.
Reproduction in humans is sexual, meaning it requires two parents — a male (father) and a female (mother). The male and female reproductive systems each play an important role in this process.
The Male Reproductive System
The major organs of the male reproductive system include:
• Te**es – produce s***m cells and the hormone testosterone.
• P***s – used to pass urine and to transfer s***m to the female.
• Sc***um – the sac that holds and protects the te**es.
• S***m duct (vas deferens) – carries s***m from the te**es.
The Female Reproductive System
The major organs of the female reproductive system include:
• Ovaries – produce egg cells (ova) and female hormones (oestrogen and progesterone).
• Fallopian tubes – tubes that carry the egg from the o***y to the uterus.
• Uterus (womb) – where the baby grows and develops during pregnancy.
• Va**na – the birth canal through which the baby is born.
• Cervix – the lower narrow part of the uterus.
MENSTRUATION
Meaning of Menstruation
Menstruation (also called a period or monthly flow) is the monthly shedding of the lining of the uterus (womb) through the va**na. It occurs when a released egg is not fertilised by a s***m cell.
Menstruation usually begins between the ages of 10 and 16 years in girls — this is called menarche (the first menstrual period). It continues until around the age of 45–50 years, when it stops permanently (a stage called menopause).
The Menstrual Cycle
The menstrual cycle is the monthly series of changes in the female body that prepares it for pregnancy. The average cycle lasts about 28 days, though it can range from 21 to 35 days.
The four phases of the menstrual cycle are:
Phase Days (approx.) Name What Happens
1 Days 1–5 Menstrual Phase The uterus lining is shed and flows out as blood.
2 Days 6–13 Follicular Phase The uterus lining thickens and an egg matures in the o***y.
3 Day 14 Ovulation Phase A mature egg is released from the o***y.
4 Days 15–28 Luteal Phase If no fertilization, the lining breaks down and the cycle starts again.
MENSTRUAL HYGIENE
Menstrual hygiene means keeping the body clean and healthy during menstruation. Good menstrual hygiene is very important to prevent infections and to help girls feel comfortable during their period.
Good Menstrual Hygiene Practices
i. Change your sanitary pad, tampon, or cloth regularly (every 4–6 hours) to prevent odour and infection.
ii. Wash the ge***al area (private part) with clean water and mild soap at least twice a day.
iii. Always wash your hands before and after changing a pad.
iv. Dispose of used pads properly by wrapping them in paper or a bag and placing them in a dustbin — never flush them in the toilet.
v. Drink plenty of water and eat healthy food to manage cramps and maintain energy.
vi. Rest when needed — mild exercise like walking can also help reduce pain.
vii. Track your cycle by writing down the date your period starts each month.
viii. Do not be ashamed — menstruation is a natural, healthy process.
Sanitary Materials Available
• Disposable sanitary pads (most common in Nigeria)
• Reusable cloth pads
• Tampons
• Menstrual cups
Note to teacher: Emphasise that students should use whatever is available and affordable, and that cleanliness is what matters most.
OVULATION
Meaning of Ovulation
Ovulation is the process by which a mature egg (o**m) is released from one of the two ovaries into the fallopian tube. This typically occurs around Day 14 of a 28-day menstrual cycle, though it can vary.
The released egg travels through the fallopian tube towards the uterus. If it meets a s***m cell during this journey, fertilisation can occur. The egg lives for only about 12–24 hours after release, while s***m can survive inside the female body for up to 5 days.
Signs of Ovulation
A girl or woman may experience some of these signs when ovulation is occurring:
• Mild pain or cramping on one side of the lower abdomen (called mittelschmerz — a German word meaning 'middle pain').
• A change in va**nal discharge — it becomes clear, stretchy, and slippery, similar to raw egg white.
• A slight rise in body temperature (basal body temperature increases by about 0.2°C after ovulation).
• Increased sexual desire.
• Tender or slightly swollen breasts.
• Light spotting (a very small amount of blood) in some cases.
• A feeling of fullness or bloating in the abdomen.
Note to teacher: Remind students that not everyone experiences these signs, and that ovulation can only be confirmed medically.
FERTILIZATION
Meaning of Fertilization
Fertilization is the fusion (joining together) of a male s***m cell and a female egg cell (o**m) to form a single cell called a zygote. This usually takes place in the fallopian tube.
The process of fertilization:
1. During sexual in*******se, millions of s***m cells are released into the female reproductive tract.
2. The s***m cells swim through the uterus into the fallopian tubes.
3. If an egg is present in the fallopian tube, one s***m cell may pe*****te and fuse with the egg.
4. The nuclei of the s***m and the egg merge, combining their genetic material (DNA).
5. A new cell — the zygote — is formed. This zygote contains 46 chromosomes: 23 from the mother and 23 from the father.
IMPLANTATION AND CONCEPTION
Meaning of Implantation
Implantation is the process by which the fertilized egg (now called a blastocyst after several cell divisions) attaches itself to the thick lining of the uterus (endometrium) and begins to grow.
Steps in implantation:
1. After fertilization, the zygote starts dividing rapidly as it travels down the fallopian tube.
2. Within 3–4 days, the zygote becomes a ball of cells called a morula.
3. By about Day 5–6 after fertilization, it develops into a blastocyst.
4. The blastocyst arrives in the uterus and burrows into the uterine lining — this is implantation.
5. Implantation is complete by about Day 9–10 after fertilization.
Once implantation is successful, the body begins to produce the pregnancy hormone (hCG — human chorionic gonadotropin), which causes the menstrual period to stop. This is often the first sign a woman notices that she may be pregnant.
Meaning of Conception
Conception refers to the successful beginning of a pregnancy. In simple terms, conception happens when a s***m fertilizes an egg AND the fertilized egg successfully implants in the uterus.
Some scientists use the word 'conception' to mean the same as fertilization, while others use it to refer to implantation. For our purposes at this level, conception = fertilization + successful implantation.
After conception:
• The zygote/blastocyst develops into an embryo (weeks 2–8 of pregnancy).
• From week 9 onwards, it is called a foetus.
• After about 40 weeks (9 months) of development in the uterus, a baby is born.
LESSON SUMMARY
Term Simple Definition
Human Reproduction The biological process by which human beings produce new offspring.
Menstruation The monthly shedding of the uterine lining through the va**na when a released egg is not fertilized.
Menstrual Hygiene Keeping the body clean and healthy during menstruation to prevent infections.
Ovulation The release of a mature egg from the o***y into the fallopian tube, usually around Day 14 of the cycle.
Signs of Ovulation Include mild abdominal pain, stretchy discharge, slight rise in body temperature, and breast tenderness.
Fertilization The fusion of a s***m cell and an egg cell in the fallopian tube to form a zygote.
Implantation The embedding of the fertilized egg (blastocyst) into the uterine lining, about 9-10 days after fertilization.
Conception The successful beginning of pregnancy — fertilization + successful implantation.
EVALUATION / CLASS EXERCISE
Answer the following questions in your exercise book:
Section A: Fill in the Blanks
1. Human reproduction requires two parents — a ____________ and a ____________.
2. The monthly shedding of the uterine lining is called ____________.
3. Ovulation usually occurs on Day ____________ of a 28-day cycle.
4. The fusion of s***m and egg to form a zygote is called ____________.
5. After implantation, the fertilized egg is called an ____________ (weeks 2–8).
Section B: Short Answer Questions
6. List THREE signs of ovulation.
7. Mention FOUR good menstrual hygiene practices.
8. Explain the difference between fertilization and implantation.
9. What is the function of the uterus in reproduction?
10. At what age does menstruation typically begin in girls? What is this called?
Section C: True or False
11. The egg cell is produced in the uterus. (True / False)
12. Menstruation occurs when a released egg is not fertilized. (True / False)
13. Implantation takes place in the fallopian tube. (True / False)
14. A zygote is formed after fertilization. (True / False)
HOME ASSIGNMENT
Write a short paragraph (5–8 sentences) explaining the journey from fertilization to implantation. Include the following key words: s***m, egg, fallopian tube, zygote, blastocyst, uterus, and implantation.
