Presentation on theme: "Objective To be able to…. 3.8 describe the structure and explain the function of the male and female reproductive systems;. 3.12 understand the roles of."— Presentation transcript:
Objective To be able to…. 3.8 describe the structure and explain the function of the male and female reproductive systems;. 3.12 understand the roles of oestrogen and testosterone in the development of secondary sexual characteristics.
When a girl goes through puberty one of the changes that occurs is that she will begin to have periods. This is the female body’s way of preparing to reproduce A woman’s reproductive system works on a 28 day cycle This cycle is known as the menstrual cycle The menstrual cycle consists of A number of stages In this lesson we will learn what those stages are.....
Day 1 – 7 The menstruation cycle starts with the first day of a woman’s period. This is the name given to the time of the month when the lining of the uterus comes away and exits through the vagina as blood.
Day 7 - 13 Around day 7 the blood flow stops. The lining of the uterus begins to build up again. At this time an egg starts to mature in one of the ovaries
Day 14 (The Middle) On the 14 th day which is the middle of the cycle, an egg is released by an ovary into the oviduct.
Day 14 - 17 The egg can last up to 3 days after it is released from the ovary. During this time the egg travels down the oviduct and into the uterus hoping to be fertilised.
Day 18 - 28 If the egg is not fertilised then the lining of the uterus begins to break down.
Day 1 – 7 The cycle starts over again expelling the lining of the uterus and the egg. Remember this is known as a period or menstruation. The cycle starts over again...
You should be able to…. 3.9 understand the roles of oestrogen and progesterone in the menstrual cycle
The cycle is started by a hormone called follicle stimulating hormone (FSH), produced by the pituitary gland. This causes one of the ovaries to form a follicle in which the ovum develops. As the ovum matures, the follicle becomes filled with another hormone, oestrogen. The release of the ovum from the follicle is called ovulation. After ovulation, the follicle becomes yellowish in colour. The follicle is now called a corpus luteum. The development of the corpus luteum is controlled by another hormone from the pituitary gland called luteinising hormone (LH). The corpus luteum now produces a hormone called progesterone. If the ovum is not fertilised, the corpus luteum degenerates and stops producing progesterone. Progesterone maintains the growth of the lining of the uterus. If the ovum is not implanted, no more progesterone is produced, and the inside lining of the uterus detaches and sloughs off. The breakdown and discharge of the soft uterine tissues and the unfertilised egg is called menstruation.
Most should be able to List the main stages in the menstrual cycle Know that the hormones FSH, LH, oestrogen and progesterone control the cycle Some students should be able to Explain the role of FSH as a fertility drug Describe the role of hormones as contraceptives Page 108 question 5a Page 108 question 5b
. 3.10 describe the role of the placenta in the nutrition of the developing embryo. 3.11 understand how the developing embryo is protected by amniotic fluid
An embryo forms a plate-like structure called the placenta. The umbilical cord joins the fetus to the placenta. In the placenta, food and oxygen diffuse from the mother’s blood into the blood of the fetus. Carbon dioxide and waste products diffuse from the blood of the fetus to the mother’s blood. How does an embryo get food and oxygen and how does it get rid of waste? The placenta
In the earliest stages of development, a human baby is called an embryo. After the first eight weeks of pregnancy, a human embryo is then called a fetus. At this stage the fetus has all the main human features. The fetus continues to develop and grow inside its mothers’ uterus for a total of 40 weeks. What happens next? From embryo to fetus