This document discusses how hormones act as mediators in development. It describes how hormones secreted by glands like the pituitary, thyroid, and sex organs play an important role in growth. The pituitary gland secretes growth hormone and controls other glands. Thyroid hormone is necessary for normal growth and brain development. Sex hormones like testosterone and estrogens influence sexual development and characteristics during puberty. The brain controls the pituitary and the timing of sexual maturity.

1. HORMNOES AS MEDIATOR
DEVELOPMENT
By
M.THILAKAR
LS1154
M.SC IN LIFE SCIENCES
SECOND YEAR
BHARATHIDASAN UNIVERSITY,
TIRUCHIRAPALLI

2. What is the Hormone…???
 A hormone is a chemical released by a cell or a
gland in one part of the body that sends out
messages that affect cells in other parts of the
organism.
 Like messenger molecules in the body.
 Hormones secreted by Glands.
 They play Important role in Growth and other
functions.

3. What are the Hormones play in
Growth..???
 Pituitary gland Hormones
 Growth hormones
 Thyroid hormones
 Sex hormones
 Estrogens and
 Progesterones

4. Pituitary gland Hormones
 The pituitary gland is a controlling gland, and the
hormones that it secretes into the blood stream will
control the actions of many other glands within the
body. For this reason the pituitary is also known as
the “master gland”
 Adult function is not clear.
 But in the child it is necessary for growth; without it
dwarfism results.
 Secretion by the Pituitary is controlled by a
substance sent to it from an adjacent part of the
brain.
 Children who lack it are fat as well as small

5. Growth Hormone
 Human growth hormone (somatotropin) is the
pituitary released hormone that is essential for
the normal growth and development of a child to
an adult.
 Without sufficient levels of the hormone, a child
will never reach their full growth potential.
 Adults also produce GH, and the hormone
continues to play an important regulatory role
throughout our lives.
 GH is produced from the pituitary, which is found
within the hypothalamus in the brain.
 With insufficient levels of GH, the crucial
metabolic processes within the body will not work
well.

6. Thyroid hormones
 Thyroid hormone from the thyroid gland in the
neck is necessary for normal growth.
 Without thyroid hormone, however, cells do not
develop and function properly, especially in
the brain.
 Babies who lack thyroid hormone at birth are
small and have insufficiently developed brains.
they are known as cretins.
 if the condition is diagnosed and they are treated
with thyroid hormone at once, they recover
completely.

7. Thyroid hormones cntd….
 Thyroid lack may also develop later in childhood,
when it causes a slowing of growth rate.
 If longer they go without treatment, the more
likely it is that the brain damage will be
permanent.

8. Testosterone
 Testosterone, secreted by the interstitial cells of
the testis, is important not only at puberty but
before.
 Its secretion by the fetal testis cells is responsible
for the development of certain parts of the male
genital apparatus.
 If testosterone is not secreted at a particular and
circumscribed time, the genitalia develop into the
female form.

9. Estrogens
 The female sex hormones, collectively
called estrogens are first secreted in quantity at
puberty by cells in the ovary.
 They cause growth of the uterus, vagina,
and breast.
 They act also on the bones of the hip, causing the
specifically female widening.

10. Sex Hormones
 The pituitary secretes two other hormones
concerned in development of Sex Hormones.
 Follicle-stimulating hormone (FSH), causes
growth of the main portions of the ovary in the
female and the sperm-producing cells in the testis
of the male.
 Luteinizing hormone (LH), causes growth and
secretion of the testosterone-secreting cells of the
male and has an action in controlling the
menstrual cycle in the female.

11. Brain in Sex Hormone
 The signal to start the sequence of events is
given by the brain, not the pituitary.
 Just as the brain holds the information on sex, so
it holds information on maturity.

12. Thank you..