13:Reproduction [The Endocrine System]

Pituitary Gland

"Releasing hormones" from the hypothalamus signal the release of hormones from a pea-sized endocrine gland in the brain, called the pituitary gland (pih TOO ih tehr ee). The pituitary controls many of your body's functions. These functions include growth, reproduction, and metabolism. Metabolism is the process by which you obtain energy from food. Some pituitary hormones act as "on" switches for other endocrine glands. For example, one pituitary hormone signals the thyroid gland to release hormones essential for normal metabolism. Other pituitary hormones control body activities directly. For example, growth hormone released by the pituitary gland regulates growth throughout your body from infancy to adulthood.

*THE ENDOCRINE SYSTEM*

*QUIZ*

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Hormones

A chemical substance produced by an endocrine gland is known as a hormone. You can think of a hormone as a chemical messenger. Each hormone has a specific function and specific "targets" in the body. Once released into the bloodstream, a hormone travels to its target cells, where it turns on, turns off, speeds up, or slows down the activities of those cells. For example, targets of the hormone adrenaline include cells in your heart, muscles, and brain. Adrenaline causes a faster heartbeat, tensing of the muscles, and increased alertness—your "fight-or-flight" response The endocrine system is kept in balance by the coordinated action of various hormones. For example, a hormone from one gland may turn on the production of a different hormone by a second gland. In turn, the hormone from the second gland signals the first gland to stop releasing its hormone. By this system of checks and balances, the endocrine system keeps the body's activities functioning smoothly.

What is puberty?

A period in adolescence wen a person becomes sexually mature

Which is not an endocrine gland?

A sweet gland

Where do endocrine glands release hormones?

Directly into the bloodstream

*Functions of Endocrine Glands*

Each of your endocrine glands plays a specific, important role in your body. The endocrine glands include the hypothalamus, pituitary gland, thyroid gland, parathyroid glands, thymus gland, adrenal glands, pancreas, and reproductive glands.

Other Endocrine Glands

Endocrine glands are found throughout the body.

How do endocrine glands differ from other body glands, such as sweat glands?

Endocrine glands release chemicals into the bloodstream

How do endocrine glands differ from other body grands, such as sweat glands?

Endocrine glands release chemicals into the bloodstream

Parathyroid Glands

Four tiny parathyroid glands regulate levels of calcium and phosphorus-minerals that necessary for proper bone and tooth formation and for muscle and nerve activity

Thymus Gland

Hormones released by the thymus gland help the immune system develop during childhood. By adolescence, this gland has shrunk considerably in size

*What Is the Endocrine System?*

How much have you grown in the past year? When will you reach your adult height? Your growth rate is one of the many functions controlled by your body's endocrine system. The endocrine system regulates long-term changes in the body such as growth and development. It also controls many of your body's daily activities. Two examples of daily activities include your body's use of energy from a meal and its response to stress.

Where is the pituitary gland located?

In the brain

Which term is the name for the period of sexual development during which a person becomes physically able to reproduce?

Puberty

How is the onset of puberty related to the endocrine system?

Puberty starts when the hypothalamus signals the pituitary gland to begin producing two hormones, which in turn signal the reproductive glands to produce sex hormones.

The reproductive glands are an important part of the endocrine system. In males, the reproductive glands consist of two testes, and in females, two ovaries. The reproductive glands work at low levels in both boys and girls until about the age of ten, when puberty typically begins. Puberty is the period of sexual development during which a person becomes sexually mature and physically able to reproduce.

Puberty starts when the hypothalamus signals the pituitary gland to begin producing two hormones. Those hormones in turn signal the reproductive glands to produce sex hormones. Sex hormones activate several changes in your outward appearance during puberty. Sex hormones also control reproductive functions inside your body. You will learn more about the reproductive glands and their hormones in the next two lessons.

What does the thyroid gland control?

The body's metabolism

Which statement about the endocrine system is true?

The endocrine system controls growth system

Ovaries (Females only)

The female reproductive glands release sex hormones that regulate egg maturation and control changes in a female's body at puberty

Which endocrine gland is part of both the nervous and the endocrine systems?

The hypotalamus

Which gland links the nervous system and the endocrine system, controls many of the pituitary gland functions, and controls the body's water levels?

The hypotalamus

Hypothalamus

The hypothalamus (hy poh THAL uh mus), an endocrine gland located in the brain, is actually part of both the nervous and the endocrine systems. For example, nerve signals from the hypothalamus control body temperature and feelings of sleep and hunger, and hormones from the hypothalamus control the body's water levels. The hypothalamus also produces a class of hormones called "releasing hormones" that signal the release of hormones from another region of the brain.

What is the hypothalamus?

The hypothalamus is an endocrine gland in the brain that is part of both the nervous and endocrine systems

Hypotalamus

The hypothalamus links the nervous system and the endocrine system and controls many of the pituitary gland functions

Testes (Males only)

The male reproductive gland release a sex hormone that regulates sperm production and controls changes in a male's body at puberty

Pancreas

The pancreas is a large gland, located behind the stomach, that controls sugar in the blood

Pituitary Gland

The pituitary gland controls other endocrine glands and regulates growth rate, reproduction, and metabolism

A person feels tired, gains weight, and notices changes in metabolism. Which gland could be the cause?

The thyroid

Thyroid Gland

The thyroid gland regulates the body's overall metabolic rate and controls calcium levels in the bloodstream

Adrenal Glands

These glands release several hormones. Adrenaline triggers the body's response to sudden stress. Other hormones affect salt and water balance in the kidneys and general metabolism

How do hormones reach target cells?

They are carried by blood

What are hormones?

They are substances released by endocrine glands

How do hormones reach the cells they affect?

They travel through the bloodstream

What are the main functions of the pituitary gland?

To control growth, reproduction, metabolism, and other endocrine glands

Endocrine Glands

Your endocrine system is made up of a group of organs, called endocrine glands (EN duh krin). An endocrine gland produces and releases chemical substances that signal changes in other parts of the body. Some of your body's glands, such as sweat glands, release their chemicals into tiny tubes called ducts. The ducts carry the chemicals to the place where they will be used. Endocrine glands, on the other hand, do not have ducts. Instead, they release substances directly into the bloodstream. The blood then carries those substances throughout the body.