Name___________________________________ per ._________
Hormones
Hormones are chemical substances secreted by glands in the body. These
substances circulate in the blood. Hormones regulate the actions of many organs. The
pituitary gland in the hypothalamus of the brain secretes hormones that signal the
reproductive glands or sex glands or gonads to develop. The pituitary is one of the
ductless glands of the body. All of the ductless glands are a part of the endocrine system.
Other endocrine glands are the thyroid, pancreas, and adrenals. The male reproductive
glands are the testicles or testes. The female reproductive glands are the ovaries.
In the female, estrogen is produced by the ovaries. Estrogen causes the lining of
the uterus (womb) to become thickened early in the menstrual cycle. The menstrual
cycle is usually 28 days, although it may vary from 21 to 35 days. An ovary releases one
egg every other month; the ovaries alternate. The ovaries also produce another hormone,
progesterone, which helps keep the embryo in place in the womb if fertilization has
occurred. Progesterone also prepares the mammary glands to produce milk. If
fertilization does not take place, the amount of progesterone decreases, and menstruation
occurs.
In the male, testosterone is necessary for the development of the male external
genital organs. It presence stimulates the development of secondary sex characteristics
during adolescence.
FILL IN THE BLANKS WITH THE CORRECT TERM TO MATCH THE
DEFINITIONS.
1. _________________
pair of endocrine glands
2. _________________
located in the hypothalamus
3. _________________
an endocrine gland
4. ____________________
capable of reproducing
5. ____________________
process of sperm cell entering egg cell
6. ____________________
male sex hormone
7. ____________________
female hormone that builds uterine lining
8. ____________________
female hormone that protects the embryo
9. Name four endocrine glands.
___________________________
____________________________
___________________________
____________________________
10. The male sex hormone is _______________________________.
11. List two female sex hormones: _________________________ and
_______________________.
12. What is the function of hormones in the body?
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