Female Reproduction System Worksheet
THE HUMAN FEMALE REPRODUCTIVE SYSTEM
THE PATH THE EGG TRAVELS
Ovary _______ Oviduct or Fallopian Tube __ Uterus or Womb______Cervix______ Vagina
PARTS OF THE FEMALE REPRODUCTIVE SYSTEM
¨ There are ovaries (female gonads)
¨ Produces eggs or ova (female gametes), female sex (oestrogen and progesterone) that regulate the menstrual cycle, pregnancy, and the secondary sexual characteristics (e.g. )
¨ Puberty is the time during teenage years when females start to release eggs. Puberty occurs a couple of years for females than males usually
¨ Menopause is the time when females releasing eggs. This usually occurs between 45 to 55 years of age.
¨ At birth, females have all their eggs formed, but in an immature state
¨ After puberty and before menopause, one egg is released about every days from each ovary
Oviduct or Fallopian Tube
¨ Connects between ovary and
¨ Place where conception or fertilisation of an egg by a occurs
Uterus or Womb
¨ Strong muscular and elastic organ where an unborn develops
¨ After an egg is released from the ovary, a blood-filled lining develops on the walls of the uterus in preparation for the nourishment of the unborn baby. If no fertilisation of the egg occurs, then this lining passes out through the vagina over several days as ‘periods’ or
¨ The opening between the uterus and the vagina
¨ During pregnancy, a mucous plug forms across the cervix separating the uterus from the outside to prevent of the unborn baby.
¨ Place where the is inserted during sexual intercourse
¨ An elastic and muscular organ that during birth to allow for the passage of the baby
THE FEMALE MENSTRUAL CYCLE
¨ The menstrual cycle begins at and ceases at menopause.
¨ It takes about days.
¨ Menstruation is regulated by the female sex hormones, oestrogen and
¨ Menstruation – Menstruation or ‘periods’ is the release of the blood-filled lining of the uterus if a woman is not pregnant. It begins on Day 1 when menstruation or ‘periods’ begin, and lasts about days.
¨ Ovulation is the release of the egg from the ovary between about Days 12 to 16.
¨ A woman will become pregnant if fertilisation (the of the egg and the sperm) occurs several days after ovulation when the egg is in the fallopian tube. During pregnancy, menstruation
¨ Role of hormones in the menstrual cycle – The Hypothalamus in the brain stimulates the pituitary gland in the brain to produce the hormone FSH (Follicle-Stimulating Hormone). FSH stimulates the growth of an egg in the ovary. The follicle in the ovary secretes oestrogen which stimulates the repair of the uterus wall after and it also stimulates the pituitary gland to produce LH (Lutinizing Hormone). This prevents more than one follicle from developing. LH induces ovulation (release of the ) and the development of the follicle into the corpus . The corpus luteum secretes progesterone. If a female becomes pregnant, the corpus luteum will secrete gonadotrophin which allows the corpus luteum to continue producing progesterone which stimulates the growth of the uterus wall, by inhibiting LH and FSH. If the woman does not become pregnant, the corpus luteum , which leads to less production of progesterone and oestrogen, and menstruation will occur, and another menstrual cycle begins because the lower progesterone and oestrogen levels will stimulate the gland in the brain to produce FSH.
OESTRUS CYCLE IN OTHER ANIMALS
¨ Oestrus is a time when a female animal demonstrates the intensity of the sexual urge. She is said to be ‘in ’. Changes in the lining of the vagina and uterus also prepare for the fertilised egg. Oestrus occurs about the time of ovulation. Female cats and dogs have 2 oestrus periods per year, whereas rats can have them every 5 days.
FERTILISATION OR CONCEPTION
¨ After sexual intercourse, the sperm travels up to join with the egg in the fallopian tube.
¨ The single-celled fertilised egg is called a
¨ 23 chromosomes of the sperm and 23 chromosomes of the egg combine in the zygote’s nucleus, so that the developing baby has chromosomes.
INTERNAL AND EXTERNAL FERTILISATION IN ANIMALS
¨ Internal Fertilisation occurs when the male gamete joins with the female gamete inside an organism (e.g.in ). An advantage is that the survival rate is higher, but the number of offspring is
¨ External Fertilisation occurs when the male gamete joins with the female gamete outside the organism (e.g. fish). This often occurs in a environment, many offspring are produced, but there is a low survival rate.
GESTATION OR PREGNANCY
¨ Gestation in humans lasts about 40 weeks or months
¨ The first sign that a woman is pregnant is usually of menstruation (‘no periods’)
¨ After fertilisation in the fallopian tube, the zygote multiplies to form a ball of cells which travels down to the uterus
¨ The ball of cells (embryo) implants into the wall of the
¨ At the place where occurs, an organ called the placenta develops
¨ The umbilical cord grows between the and the unborn baby’s navel
¨ Inside the umbilical cord are blood vessels which provide nutrients and oxygen to the baby, and return wastes such as back to the mother’s bloodstream
¨ As the baby grows, it is called a foetus
¨ The foetus is by amniotic fluid inside an amniotic sac
¨ In the ninth month of pregnancy, the foetus turns upside down, and the mother’s breasts enlarge ready for production
¨ At about 9 months, the ‘plug’ at the cervix releases, the sac breaks and fluid comes out through the vagina (‘breaking of the waters’)
¨ Muscular contractions occur to both dilate the and ‘push’ out the baby first from the uterus
¨ Further muscular contractions expel the (‘afterbirth’)
¨ The umbilical cord is cut close to the baby’s navel
¨ The mother begins breast milk production
¨ The mother begins the cycle again after the lining of the uterus from the pregnancy has been expelled over several days
¨ Breech Birth occurs when the baby is born legs first
¨ Caesarean Birth is the removal of the baby from the mother’s uterus
¨ Twins – Identical Twins (i.e. 2 sisters or 2 ) form when one egg and one sperm join, but as the zygote multiplies to form a ball of cells, the ball . Non-identical or Fraternal Twins are formed when eggs are fertilised by 2 sperm.