Human endocrine system: pituitary gland

The idea

The pituitary gland is a small endocrine gland located at the base of the brain. It is often called the master gland because it secretes several hormones into the blood in response to body conditions. These hormones in turn act on other endocrine glands, stimulating them to release different hormones that bring about specific effects. For example, the pituitary secretes thyroid-stimulating hormone (TSH), which travels in the blood to the thyroid gland and stimulates it to release thyroxine. Similarly, it releases FSH to stimulate the ovaries. In exams, students may be asked to name the pituitary gland, identify its position, or explain why it is referred to as the master gland using a valid example.

What earns the marks

• Names the pituitary gland as a gland located in the brain that secretes hormones directly into the bloodstream.
• States that pituitary hormones travel in the blood plasma to specific target organs.
• Explains that the pituitary is called the master gland because its hormones control the activity of other endocrine glands.
• Uses a named example, such as TSH stimulating the thyroid gland to release thyroxine, or FSH acting on the ovaries.
• Describes the difference between nervous and hormonal coordination, noting that hormonal responses are carried by blood and are generally slower but longer lasting.

Common mistakes and how to put them right

• Thinking the pituitary gland is in the abdomen.

  Put it right by locating it at the base of the brain.

• Saying pituitary hormones travel along nerves.

  Put it right by stating that hormones are secreted into the blood and carried to target organs.

• Confusing the pituitary with the pancreas or thyroid.

  Put it right by linking the pituitary to the control of other glands, rather than direct control of blood glucose or metabolic rate.

Exam tips

• Use the phrase master gland only with a reason, specifically that its hormones stimulate other endocrine glands to release their own hormones.
• When describing pituitary action, clearly distinguish between the hormone released by the pituitary (e.g. TSH) and the hormone released by the target gland (e.g. thyroxine).