SEXUAL REPRODUCTION IN HUMANS
MALE REPRODUCTIVE SYSTEM
Male reproductive system:
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Functions of the main parts of the male reproductive system.
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FEMALE REPRODUCTIVE SYSTEM
Female reproductive system:
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Functions of the main parts of the female reproductive system.
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COMPARE BETWEEN MALE AND FEMALE GAMETE
- Gametes are sex cells.
- The male gamete is called the sperm develops in testes.
- The female gamete is called the ovum or egg develops in ovary.
MALE GAMETE (SPERM)
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FEMALE GAMETE
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SEXUAL INTERCOURSE
FERTILIZATION
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State exactly what happens at the moment of fertilisation. (Board question)
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EARLY DEVELOPMENT OF ZYGOTE AND IMPLANTATION
- After fertilization in oviduct, the fertilized egg or zygote divides into two cells by mitosis.
- Then it continues to divide to give four cells and then eight.
- After few hours there is a solid ball of cells formed which is known as early embryo.
- This early embryo travels down the oviduct to the uterus due to contraction of oviduct and beating of ciliated epithelial cells lining the oviduct.
- It may take 7-9 days for the embryo to reach the uterus.
- In uterus, it embeds into the soft lining of the uterus. This is called implantation.
- ANIMATION
PREGNANCY (DEVELOPMENT OF FETUS AND PLACENTA)
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PLACENTA AND BLOOD CIRCULATION
ANTE NATAL CARE
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LABOUR AND BIRTH(PARTURITION)
BREASTFEEDING : ADVANTAGES AND DISADVANTAGES
Advantages for breast-feeding
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Advantages of Bottle feeding
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MENSTRUAL CYCLE
Menstrual cycle: The series of events that occur in cyclic manner at every 28-32 days and involve the formation of female gamete with change in structure and function of entire female reproductive system.
Day 1 to day 5 (Menstruation phase)
Day 1 to day 5 (Menstruation phase)
- Day 1 is the first day of menstruation.
- The levels of oestrogen and progesterone declined greatly.
- Low progesterone level leads to the menstruation.
- Menstruation is the breakdown and discharge of the outer layer of the uterine lining.
- Low oestrogen and progesterone levels permit the secretion of FSH (follicle stimulating hormone) by the pituitary gland.
- FSH stimulated the formation and maturation of a Graafian follicle.
- The maturing follicle secretes oestrogen.
- Oestrogen inhibits FSH secretion preventing other follicles maturing.
- Oestrogen also stimulates repair of the uterine lining.
- Oestrogen brings about a surge of LH (luteinising hormone) just before ovulation.
- The surge of LH stimulates ovulation.
- Ovulation is the release of the egg cell from the mature Graafian follicle at the ovary’s surface.
- The egg cell is drawn into the Fallopian tube.
- A corpus luteum (yellow body) develops from the ‘empty’ Graafian follicle.
- The corpus luteum secretes progesterone and oestrogen.
- High levels of theses hormones also inhibit FSH and LH secretion from the pituitary.
- If implantation does not take place by day 26 the corpus luteum disintegrates.
- The degeneration of the corpus luteum causes the levels of oestrogen and progesterone to decline rapidly.
- The degenerated corpus luteum becomes a small scar in the ovary
SEX HORMONES & SECONDARY SEXUAL CHARACTERISTICS
- Sex hormones are responsible for the development of secondary sexual characteristics at puberty.
- Secondary sexual characteristics : Secondary sex characteristics are features that appear during puberty in humans. A person becomes an adolescent when puberty starts.
- Puberty : The stage of development during which sexual maturity reached. In this stage sperm production begins in a boy and ovulation in a girl.
- Sex hormones:
- In male: Testosterone
- In female: Oestrogen
- A drop in hormones level can reduce these features, while a high level of hormone can increase them.
Secondary sexual characteristics in Male :
In male, testosterone secreted by testes causes following changes.
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Secondary sexual characteristics in Female :
In female, Oestrogen secreted by ovaries cause following changes.
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FERTILITY DRUGS & ARTIFICIAL INSEMINATION
- Infertile couples: Couples are regarded as being infertile if they have had regular, unprotected sexual intercourse for 12 months without the women becoming pregnant.
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METHODS OF BIRTH CONTROL
NATURAL METHODS
ARTIFICIAL METHODS
- Chemical methods : contraceptive pill, spermicide
- Mechanical methods :condom, diaphragm, femidom, IUD (Intra-uterine devices)
- Surgical : vasectomy, female sterilisation
SEXUALLY TRANSMITTED DISEASES
GONORRHOEA
Sign & symptoms
In male:
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HIV/AIDS : caused by human immuno virus (HIV)
How HIV affects the immune system..?
- The HIV virus attacks some type of lymphocytes in the bloodstream.
- Lymphocytes produce antibodies, which attacks the antigens present on invading microbes.
- If the body cannot respond to infections through the immune system, it becomes vulnerable to pathogens that might not otherwise be life-threatening.
- As a result, the patient has little or no resistance to a wide range of diseases such as influenza, pneumonia, blood disorders, skin cancer or damage to the nervous system, which the body cannot resist.