Page 68 - Genius Kidz Prudence Learning Sc-8

Glands Location Functions Major hormones
produced

Pituitary Base of the brain Base of the brain Prolation, oxytocin,
growth hormone
Thyroid Near the larynx Controls many activities of the Thyroxin
body including the rate at which
energy is produced. Also controls
the balance of calcium in the
body

Adrenals (2 glands) Attached to each kidney Regulate heart beat, respiration Adrenalin
rate and blood pressure.

Pancreas Below the stomach Controls glucose level in blood. Insulin
Testes Outside abdominal cavity Promotes development of Testosterone
secondary sexual characters.

Ovaries Lower part of abdominal Controls secondary sexual Oestrogen
cavity characters and changes related
to pregnancy.

REPRODUCTIVE PHASE After fusion of male and female gametes inside

Reproductive phase begins in the case of the fertilised egg or zygote the sex of the child
males at the age of 13-14 years and in the case is determined by the thread like structures
of females at the age of 10-12 years. Most called chromosomes. All human beings have
females become sexually inactive at the age of 23 pairs of chromosomes in the nuclei of their
45-50 years. cells. Two chromosomes out of these are sex
chromosomes namely X and Y. A female has
OVULATION AND MENSTRUATION
two X chromosomes while a male has one X
Ovulation is the process of release of egg or and one Y chromosome. The gametes
ovum from the ovary. Before ovulation, the produced (egg and sperm) have only one set of

body prepares itself for fertilization and chromosomes. The unfertilised egg always has
embryo development. If fertilization occurs one X chromosome since it comes from the
then zygote is developed into foetus but if female. But a sperm may have an X
fertilization doesn't occur then thickened
chromosome or a Y chromosome. On
uterine wall breaks off together with blood
fertilisation if both the chromosomes match
vessels and ova and sheds off through vaginal
(i.e X and X) then the zygote develops into a
opening in form of bleeding called
female child while if the sperm contributes the
menstruation or menstrual cycle. The cycle
Y chromosome to the egg then the zygote
repeats itself after every 28 days for the
develops into a male child. So, now you very
formation and release of new ova.
well know that it is the sex chromosome of the
BOY OR GIRL father that determines the sex of an unborn

baby.

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