Endocrine System

What is the endocrine system?

A system of glands that release hormones into the blood to control slow, long‑lasting responses.

What are hormones?

Chemical messengers produced by glands and transported in the blood to target organs.

Name three endocrine glands.

Pituitary gland, pancreas, adrenal glands.

What is the role of the pituitary gland?

It is the 'master gland' that releases hormones that control other endocrine glands.

How are hormones different from nervous responses?

Hormones are slower, longer‑lasting, and travel in the blood; nerve impulses are fast and short‑lived.

What is the role of the hypothalamus in the endocrine system?

It links the nervous and endocrine systems, controlling the pituitary gland and releasing some hormones itself.

What is negative feedback in hormone control?

A response that reverses a change once the desired level is reached, helping to keep conditions stable.

How does adrenaline prepare the body for 'fight or flight'?

It increases heart rate, blood pressure, breathing rate, and blood glucose, supplying more oxygen and energy.

Where is insulin produced?

In the pancreas (specifically in the islet cells).

Where is glucagon produced?

Also in the pancreas (islet cells).

What is the role of thyroxine?

To increase metabolic rate and control growth and development.

What is the role of growth hormone?

To stimulate growth of bones and tissues, especially in children and teenagers.

What is diabetes insipidus?

A rare condition where there is too little ADH, causing the kidneys to produce large amounts of dilute urine.

What is ADH?

Antidiuretic hormone, which controls how much water is re‑absorbed in the kidneys.

What is the role of the adrenal glands?

To produce hormones such as adrenaline and cortisol, which help the body respond to stress.

How do hormones reach their target organs?

They are secreted into the blood and travel throughout the body, but only affect cells with specific receptors.

Why are endocrine responses slower than nervous responses?

Hormones must be transported in the blood and can take seconds to minutes or even hours to act.

What is meant by a hormone's target organ?

The organ or tissue that has specific receptors for that hormone and responds to it.

How does the endocrine system control the menstrual cycle?

Through hormones such as FSH, LH, oestrogen, and progesterone released by the pituitary and ovaries.

What is the role of the pancreas in the endocrine system?

It releases insulin and glucagon to control blood glucose concentration.