Hormones are chemicals synthesized and produced by specialized glands to control and regulate the activity of certain cells and organs. These specialized glands are known as endocrine glands. These endocrine glands are distributed throughout the body. These messengers control many physiological functions as well as psychological health. They are also quite important in maintaining homeostasis in the body.
They are used to communicate between organs and tissues. In vertebrates, They are responsible for the regulation of many physiological processes and behavioral activities such as digestion, metabolism, respiration, sensory perception, sleep, excretion, lactation, stress induction, growth and development, movement, reproduction, and mood manipulation. In plants, hormones modulate almost all aspects of development, from germination to senescence.
Functions of Hormones
- Food metabolism.
- Growth and development.
- Controlling thirst and hunger.
- Maintaining body temperature.
- Regulating mood and cognitive functions.
- Initiating and maintaining sexual development and reproduction.
Types of Hormones
They are classified as follows:
- Peptide Hormones: These are composed of amino acids and are soluble in water. They are unable to pass through the cell membrane as it contains a phospholipid bilayer that stops any fat-insoluble molecules from diffusing into the cell. Insulin is an important peptide hormone produced by the pancreas.
- Steroid Hormones: Unlike peptide hormones, These are fat-soluble and can pass through a cell membrane. Sex hormones such as testosterone, estrogen, and progesterone are examples of steroid hormones.
- Cortisol: It has been named the “stress hormone” as it helps the body in responding to stress. This is done by increasing the heart rate, elevating blood sugar levels, etc.
- Estrogen: This is the main sex hormone present in women which brings about puberty, prepares the uterus and body for pregnancy, and even regulates the menstrual cycle. Estrogen level changes during menopause because of which women experience many uncomfortable symptoms.
- Melatonin: It primarily controls the circadian rhythm or sleep cycles.
- Progesterone: It is a female sex hormone also responsible for the menstrual cycle, pregnancy and embryogenesis.
- Testosterone: This is the most important sex hormone synthesized in men, which causes puberty, muscle mass growth, and strengthens the bones and muscles, increases bone density, and controls facial hair growth.