Hormones are super important for how cells talk to each other in living things. These special messengers are made in certain glands and move through the blood to target cells. There, they help the body keep everything balanced and support growth and development.

Types of Hormones:

1. Peptide Hormones: Made up of amino acids. Some examples are insulin and glucagon.

   • Insulin helps control sugar levels in the blood and is made of 51 amino acids.
   • Glucagon is 29 amino acids long and helps release sugar from the liver.

2. Steroid Hormones: These come from cholesterol. Examples include cortisol and testosterone.

   • Cortisol is involved when we are stressed and affects how our body handles sugar and the immune system.
   • Testosterone is important for male growth and helps build muscles and strength.

3. Amine Hormones: Made from single amino acids. One example is epinephrine, which comes from tyrosine.

   • Epinephrine helps increase heart rate and gives us more energy during stressful times.

How Hormones Work:

Hormones usually work by connecting to special receptors on target cells. There are two main ways they do this:

1. Membrane-bound Receptors:

   • Used by peptide and amine hormones.
   • When these hormones bind, they start a series of signals inside the cell. Often, this involves helpers called secondary messengers, like cyclic AMP (cAMP).
   • For example, when insulin connects to its receptor, it helps cells take in sugar. This is especially important for about 1.5 million Americans who have diabetes and need insulin to manage their sugar levels.

2. Intracellular Receptors:

   • Used by steroid hormones.
   • These hormones can go inside the cell and connect to receptors in the cytoplasm or nucleus. This influences how genes are expressed.
   • For instance, testosterone can activate genes that help muscles grow. This is really important for athletes and bodybuilders who want to improve their performance.

Hormones in Health:

• About 15% of health problems worldwide are connected to hormone imbalances.
• Hormone therapies, like hormone replacement therapy (HRT), can help reduce symptoms of menopause in up to 75% of women who experience them.

In summary, hormones are key players in how cells communicate, helping to manage complex biological functions and keeping our bodies working properly. By understanding what hormones do, we can learn more about biology and how to manage health problems.