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Ovaries:
• Females →→ Present inside the pelvic region and secrete estrogen and
progesterone
• Estrogen-This is the main sex hormone present in women which bring about
puberty, prepares the uterus and body for pregnancy and even regulates the
menstrual cycle.
• Progesterone – It is a female sex hormone also responsible for menstrual cycle,
pregnancy and embryo genesis.

Adrenal gland:
• It is present above the kidney.
• Produces adrenaline (fight or flight hormone).
• Functions include →→ increases heartbeat, supplies more oxygen to
muscles, increases breathing rate, lowers blood supply to the digestive
organs and increases supply to the skeletal system.

FEEDBACK MECHANISM
• The prominent role of hormones is that of a messenger.
• Sometimes, hormones act more as a regulator than a messenger.
• Hormone as a regulator maintains the homeostasis of the body. Once the
hormones meet their target, their production needs to be controlled and this is
attained by a mechanism called feedback control mechanism. The feedback
mechanism could either be positive or negative.

Positive feedback mechanism----
• The thyroid gland produces a hormone called thyroxine, and its secretion is
controlled by the Thyrotropin Releasing Hormone (TRH) from the
hypothalamus and the Thyroid Stimulating Hormone (TSH) from the anterior
pituitary.
• When the level of thyroxine in the blood reduces, hypothalamus stimulates the
thyroxine secretion by stimulating TSH secretion.
Negative feedback mechanism-----
Ex 1- If hypothalamus continues to stimulate thyroxine production, it could result in
high level of thyroxine in blood. This sends a negative feedback to the hypothalamus
to reduce or stop the TRH and TSH secretion which regulates the thyroxine level in
the body.
Ex-2-