Hormones in Humans

Section: Understanding Hormones

Hormones are chemical messengers produced by endocrine glands in the body.
They travel around the body in the bloodstream and affect specific target cells.
Each hormone has a unique function and acts on specific cells with the appropriate receptors.
Hormones control a wide range of functions in the body, such as growth, metabolism, mood and reproduction.

Section: Key Hormonal Systems

The hypothalamus produces hormones that control the pituitary gland.
The pituitary gland, often called the ‘master gland’, controls other glands such as the thyroid, adrenal glands and ovaries/testes.
The thyroid gland produces hormones that regulate metabolic rate, heart rate and growth.
The adrenal glands produce adrenaline, which prepares the body for a ‘fight or flight’ response.
The pancreas regulates blood glucose levels by producing insulin and glucagon.
The ovaries in females and the testes in males produce sex hormones which control puberty and fertility.

Section: Examples of Hormones and Their Functions

Insulin reduces blood glucose levels, while glucagon raises blood glucose levels.
Thyroxine regulates metabolic rate, growth and development.
Adrenaline prepares the body for ‘fight or flight’ by increasing heart rate and boosting energy supplies.
Testosterone is a male sex hormone that influences development and maintenance of male secondary sexual characteristics.
Oestrogen and progesterone are female sex hormones which control the menstrual cycle and pregnancy.

Section: Hormones and Homeostasis

Hormones play a crucial role in the maintenance of homeostasis, a stable internal environment.
They respond to changes in the body and regulate physiological processes to keep the body’s internal environment constant.
For instance, insulin and glucagon work together to maintain stable blood glucose levels.

Section: Disorders of the Hormonal System

Any imbalance in hormone production can lead to a variety of disorders.
Hypothyroidism results from too little thyroxine, leading to fatigue and weight gain among other symptoms.
Hyperthyroidism occurs with excess thyroxine, causing rapid heartbeat and weight loss.
Diabetes is a result of failure of the pancreas to produce enough insulin, causing high blood sugar levels.

Section: Key Hormones in Humans Takeaways

Hormones are vital chemical messengers in the body, regulating various physiological processes.
They play a crucial role in the functioning of the body’s systems, including the immune, reproductive, and metabolic systems.
Disorders arise when the body fails to produce the correct amount of specific hormones.