UNIT

3The interaction function

Natural Science 2. Secondary Education

THE ENDOCRINE SYSTEM OF A VERTEBRATE

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3

Natural Science2. Secondary Education

UNIT

3The endocrine system of a vertebrate

• Many vertebrates, including human beings, have a complex chemical coordination system called the endocrine system.

• The human endocrine system is made up of a number of glands that release hormones into the blood.

Pancreas

Ovaries

Testicles

Thyroid gland

Adrenal glands

Pituitary gland

• Each hormone is a chemical messenger that reaches a particular effector organ and triggers a response.

UNIDAD

3

Natural Science2. Secondary Education

UNIT

3The endocrine system of a vertebrate

Pancreas

Ovaries

Testicles

Thyroid gland

Adrenal glands

Click on the gland names to find out how their hormones work.

• Many vertebrates including human beings, have a complex chemical coordination system called the endocrine system.

• The human endocrine system is made up of a number of glands that release hormones into the blood.

• Each hormone is a chemical messenger that reaches a particular effector organ and triggers a response.

Pituitary gland

UNIDAD

3

Natural Science2. Secondary Education

UNIT

3The endocrine system of a vertebrate

PITUITARY GLAND

A small gland found at the base of the brain.

• Prolactin. Stimulates the production of milk in the mammary glands after women give birth.

• TSH (thyroid-stimulating hormone). Regulates the production of hormones in the thyroid.

• Growth hormone. Stimulates the growth of bones and muscles until maturity.

Hormones it produces:

• FSH (follicle-stimulating hormone). Stimulates the production of eggs in the ovaries.

• LH (luteinizing hormone). Stimulates ovulation in women and production of testosterone (the male sex hormone) in men.

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UNIDAD

3

Natural Science2. Secondary Education

UNIT

3The endocrine system of a vertebrate

THYROID GLAND

An H-shaped gland found in the neck (at the top of the windpipe).

• Thyroxine. This hormone causes an increase in the chemical activity of the cells in many of organs. It stimulates our bodies’ metabolism of carbohydrates and fats, consuming oxygen and breaking down proteins inside cells.

Hormones it produces:

Thyroid gland

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UNIDAD

3

Natural Science2. Secondary Education

UNIT

3The endocrine system of a vertebrate

ADRENAL GLANDS

The adrenal glands sit on top of the kidneys.

• Cortisol. This hormone is produced as a response to stress. It regulates the processes of producing and breaking down proteins and sugars in cells.

Hormones they produce:

• Adrenalin. It increases blood sugar levels, blood pressure and heart rate, preparing our bodies for action in situations in which we are alert or in danger.

Adrenal glands

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UNIDAD

3

Natural Science2. Secondary Education

UNIT

3The endocrine system of a vertebrate

PANCREAS

This is a mixed gland: It is both an exocrine and an endocrine gland.

• Glucagon. This hormone causes an increase in blood sugar levels, making cells release glucose into the bloodstream.

• Insulin. This hormone causes a drop in blood sugar levels, making cells take up glucose from the blood.

Hormones it produces:

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UNIDAD

3

Natural Science2. Secondary Education

UNIT

3The endocrine system of a vertebrate

TESTICLES

• Testosterone. This is the male sex hormone, which promotes male sexual characteristics and triggers sperm development.

Hormones they produce:

Testicles

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UNIDAD

3

Natural Science2. Secondary Education

UNIT

3The endocrine system of a vertebrate

OVARIES

• Estrogen and progesterone. These are female sex hormones that cause the development of secondary female characteristics and prepare a woman’s body for possible pregnancy.

Hormones they produce:Ovaries

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