HORMONES

Hormones are chemical messengers that are secreted directly into the blood, which carries them to organs and Tissues of the body to exert their functions. There are many types of hormones that act on different aspects of bodily functions and processes. Some of these include:

Development and Growth
Metabolism of food items
Sexual function and reproductive growth and Health
Cognitive function
Mood Maintenance of body temperature and thirst

Animal hormones

Endocrine System is the system formed by ductless glands which secrete chemical substances called as hormones. Endocrine Glands release hormones directly into the blood.

Endocrine glands Different types of endocrine glands present in our body are the pituitary gland, the pineal gland, the hypothalamus, the thyroid, the parathyroid, the thymus, the adrenal gland, the pancreas, the testes and the ovary.

The pituitary gland

It is a pea-shaped gland located at the base of the brain.
It is considered to be master gland as it secretes many hormones to regulate the organs as well as the other glands.
Different hormones secreted by this gland include Growth hormone, TSH, FSH, LH, ACTH, MSH, Vasopressin and Oxytocin.

The hypothalamus

It is a neuro-endocrine part of the brain.
It links the nervous system and the endocrine system through the pituitary gland.
Different hormones secreted by this gland include TRH, GnRH, GHRH, CRH, Stomatostatin, Dopamine.

The thyroid gland

It is located in the neck, ventral to the larynx.
It is the one of the largest endocrine glands.
The principal hormones produced by this gland are triiodothyronine and thyroxine.

Thyroxine is a hormone that regulates the metabolism of Carbohydrates, proteins and fats in the body. Hyposecretion of thyroxine leads to cretinin in children, and myxoedema in adults. Hypersecretion of thyroxine leads to exopthalmic goitre in adults. Goitre is caused due to deficiency of iodine in food. Iodine is essential for the synthesis of thyroxine.

Parathyroid glands

These are two pairs of small, oval-shaped glands embedded on the dorsal surface of the thyroid gland present in the neck.
They secrete parathormone.
Parathormone helps in regulation of calcium and phosphate ions in the bones and blood.
Hyposecretion leads to parathyroid tetany and hypersecretion causes osteoporosis.

The adrenal glands

These are located above the kidneys and hence are called as suprarenal glands.
Two regions of the adrenal gland are adrenal cortex and adrenal medulla.
Adrenal cortex secretes the hormones like cortisol, aldosterone and androgens.
Adrenal medulla secretes the hormones like adrenaline and noradrenaline.
Adrenaline is also called the “hormone of fight or flight,” or the emergency hormone.
It prepares the body to face an emergency condition of physical Stress, like danger, anger and excitement.

The pancreas

It is located just below the stomach within the curve of the duodenum.
It is both exocrine and endocrine in function.
It secretes hormones such as insulin, glucagon, somatostatin and pancreatic polypeptide.
Insulin regulates the sugar level in our blood. Insulin secreted in small amounts increases the sugar level in our blood which in turn causes a disease called diabetes mellitus.

Gonads

Two types of gonads present in human beings are female gonads and male gonads. Female gonads
A pair of ovaries forms the gonads in female.
Ovaries are the female sex organs that lie one on either side of the abdominal cavity. Ovaries produce two hormones, namely, oestrogen and progesterone.
Oestrogen controls the changes that occur during puberty, like feminine voice, soft skin and development in mammary glands.
Progesterone controls the uterine changes in the menstrual cycle, and helps in the maintenance of pregnancy.

Male gonads

A pair of testes forms the gonads in males.
A pair of testes is the male sex organ located in the scrotum, which is outside the abdomen.
Testes produce the hormone testosterone.
Testosterone controls the changes, which occur during puberty, like deeper voice, development of penis, facial and body hair.

The pineal gland

It is located near the centre of the brain, dorsal to the diencephalon.
It produces the hormone melatonin.
Melatonin affects reproductive development, modulation of wake and sleep patterns, and seasonal functions.

The thymus gland

It is located in front of the heart, in the upper part of the sternum.
It produces the hormone thymosine.
It helps in the maturation of T-lymphocytes.

Plant hormones

Plant hormones are signal Molecules produced within the plant, and occur in extremely low concentrations. Hormones regulate cellular processes in targeted cells locally and, moved to other locations, in other functional parts of the plant. Hormones also determine the formation of flowers, stems, leaves, the shedding of leaves, and the development and ripening of fruit.

There are five major types of plant hormones: auxin, gibberellin, cytokinin, ethylene, and abscisic acid.

Auxins

Auxins are a powerful growth hormone produced naturally by Plants. They are found in shoot and root tips and promote cell division, stem and root growth. They can also drastically affect plant orientation by promoting cell division to one side of the plant in response to sunlight and gravity.

Auxins have four key effects on plant growth:

Stimulating shoot elongation: Auxins positively influence gibberlins that promote cell elongation. This increases plant length. Essentially, gibberlins and thereby auxins, increase the distance between nodes, spacing the branch points further apart.
Controlling seedling orientation: It was the infamous Charles Darwin and his son Francis who first noticed that seedlings bend toward the Light. However, whether a new shoot grows into the Soil or towards light, depends on where auxins are located and how they influence cells within the plant. Auxins will move downward due to gravity and laterally, away from light. Cells grow more in areas of the plant where auxins are highly concentrated.
Stimulating root branching : When an auxin is applied to a cut stem, the stem will initiate roots at the cut.
Promoting fruit development: Auxins in the flower promote maturation of the ovary wall and promote steps in the full development of the fruit.

Auxins can be produced naturally (by the plant) or synthetically (in a lab). When produced synthetically, they can be used in high concentrations as a pesticide, causing drastic growth. The herbicide, 2-4-D, is an example of an auxin-based pesticide, specifically engineered to cause dicots (plants like dandelions) to grow quickly and uncontrollably, ultimately killing the plant.

Gibberellin: Gibberellin causes some similar effects in plants as auxin, but it is a very different hormone. Gibberellins were discovered originally in Japan. A fungus called Gibberella fujikuroi infected rice plants and caused them to grow too tall and fall over. The infectious fungus produced a chemical that stimulated the growth in rice plants. The chemical was isolated and named Gibberellin after the fungus. It was later found that plants naturally produce variations of these chemicals! Gibberellins play an important role in several developmental stages in plants, but their claim to fame is making stems longer. Gibberellins promote stem elongation between nodes on the stem. A node is a place on a stem where a leaf attaches, so gibberellins elongate the internodes. It is easiest to see the absence of gibberellin in dwarf plants and rosette plants – there is very little space between nodes on a stem and the leaves are clustered toward the base of the plant. What’s the big deal about knowing how to control stem elongation in plants? Well, when would it be beneficial to know how to make a plant stem shorter or longer? Biologists can prevent plants in a greenhouse from making gibberellins to keep them a manageable size. That’s handy. Or what if you’re a farmer and your business is something that comes from the stem of a plant? Longer stems would mean more profit for you, right? Gibberellins sprayed on sugar cane in Hawaii elongate the stem between the nodes. Longer stems mean more stored sugar. More sugar to sell means more coin! Knowing about plant hormones just makes cents.

Cytokinins: Cytokinins are a group of hormones that promote cell division in plant roots and shoots and the growth of buds. These hormones have been found in all complex plants as well as mosses, Fungi, and bacteria. There are about 200 different natural and synthetic cytokinins known to botanists today. Most cytokinins are produced in the meristem of the roots. Meristem is the name for a region of tissue within the plant that actively promotes cell division. In other words, the meristem is any place that’s still growing (like the tip of the roots or the top of the stem). Once the cytokinin has been produced in the roots, it travels up the xylem, or vascular tissue, to other parts of the plant where continued growth takes place (such as young leaves, developing fruits, and seeds).

Cytokinins increase cell division by stimulating the production of proteins needed for mitosis. Mitosis is non-sexual cell division that occurs in all living things producing additional cells for body growth. In your body, mitosis is occurring every day, replacing dead and damaged cells and allowing for growth. If you skin your knee, it’s mitosis that grows back the cells you lost. In plants, mitosis creates additional cells that make the plants grow. If you have ever played with building blocks that snap together, you can think of them like plant cells. Every time the process of mitosis occurs, a new cell is formed and moved to the end of the plant making it longer or taller (just like adding a building block to your structure).

Ethylene: Ethylene serves as a hormone in plants. It acts at trace levels throughout the life of the plant by stimulating or regulating the ripening of fruit, the opening of flowers, and the abscission (or shedding) of leaves. Commercial ripening rooms use “catalytic generators” to make ethylene gas from a liquid supply of ethanol. Typically, a gassing level of 500 to 2,000 ppm is used, for 24 to 48 hours. Care must be taken to control carbon dioxide levels in ripening rooms when gassing, as high temperature ripening (20 °C; 68 °F) has been seen to produce CO2 levels of 10% in 24 hours.

Ethylene is produced from essentially all parts of higher plants, including leaves, stems, roots, flowers, fruits, tubers, and seeds. Ethylene production is regulated by a variety of developmental and environmental factors. During the life of the plant, ethylene production is induced during certain stages of growth such as germination, ripening of fruits, abscission of leaves, and senescence of flowers. Ethylene production can also be induced by a variety of external aspects such as mechanical wounding, environmental stresses, and certain chemicals including auxin and other regulators. The pathway for ethylene biosynthesis is named the Yang cycle after the scientist Shang Fa Yang who made key contributions to elucidating this pathway.

Abscisic acid: Abscisic acid, is involved in many developmental plant processes, including leaf abscission, responding to environmental stress, and inhibiting fruit ripening. Abscisic acid is produced in the roots of the plant as well as the terminal buds at the top of the plant.

Functions of Abscisic Acid: The following are some of the physiological responses known to be associated with abscisic acid:

Stimulates the closure of stomata (water stress brings about an increase in ABA synthesis).
Inhibits shoot growth but will not have as much affect on roots or may even promote growth of roots. Induces seeds to synthesize storage proteins.
Inhibits the affect of gibberellins on stimulating de novo synthesis of a-amylase.
It Has some effect on induction and maintanance of dormancy.
It Induces gene transcription especially for proteinase inhibitors in response to wounding which may explain an apparent role in pathogen defense.

Hormones are chemical messengers that are produced by glands in the body and travel through the bloodstream to reach their target tissues. They regulate a wide range of physiological processes, including growth, development, metabolism, Reproduction, and mood.

There are many different types of hormones, each with its own specific function. Some of the most important hormones include:

Adrenal glands: The adrenal glands are located on top of the kidneys. They produce a variety of hormones, including cortisol, epinephrine (adrenaline), and norepinephrine. Cortisol is a stress hormone that helps the body to respond to stress. Epinephrine and norepinephrine are also stress hormones that help the body to prepare for “fight or flight.”
Androgens: Androgens are hormones that are responsible for the development of male secondary sexual characteristics, such as facial hair, a deep voice, and muscle mass. Testosterone is the most important androgen.
Antidiuretic hormone (ADH): ADH is a hormone that is produced by the pituitary gland. It helps to regulate the body’s water balance by increasing the reabsorption of water in the kidneys.
Atrial natriuretic peptide (ANP): ANP is a hormone that is produced by the heart. It helps to regulate the body’s water balance by decreasing the reabsorption of sodium in the kidneys.
Calcitonin: Calcitonin is a hormone that is produced by the thyroid gland. It helps to regulate the body’s calcium levels by decreasing the absorption of calcium from the intestines and increasing the Excretion of calcium in the urine.
Cortisol: Cortisol is a hormone that is produced by the adrenal glands. It is a stress hormone that helps the body to respond to stress. Cortisol also helps to regulate the body’s metabolism, immune system, and blood sugar levels.
Epinephrine (adrenaline): Epinephrine is a hormone that is produced by the adrenal glands. It is a stress hormone that helps the body to prepare for “fight or flight.” Epinephrine increases heart rate, blood pressure, and blood sugar levels.
Follicle-stimulating hormone (FSH): FSH is a hormone that is produced by the pituitary gland. It helps to regulate the production of eggs in the ovaries and sperm in the testes.
Growth hormone (GH): GH is a hormone that is produced by the pituitary gland. It helps to regulate growth and development. GH also helps to regulate the body’s metabolism.
Insulin: Insulin is a hormone that is produced by the pancreas. It helps the body to use glucose for energy. Insulin also helps to regulate the body’s blood sugar levels.
Luteinizing hormone (LH): LH is a hormone that is produced by the pituitary gland. It helps to regulate the production of eggs in the ovaries and sperm in the testes.
Melatonin: Melatonin is a hormone that is produced by the pineal gland. It helps to regulate the body’s sleep-wake cycle.
Oxytocin: Oxytocin is a hormone that is produced by the hypothalamus and released by the pituitary gland. It helps to regulate childbirth and breastfeeding. Oxytocin also plays a role in social bonding and sexual reproduction.
Parathyroid hormone (PTH): PTH is a hormone that is produced by the parathyroid glands. It helps to regulate the body’s calcium levels by increasing the absorption of calcium from the intestines and decreasing the excretion of calcium in the urine.
Progesterone: Progesterone is a hormone that is produced by the ovaries and placenta. It helps to prepare the uterus for pregnancy and maintain pregnancy. Progesterone also helps to regulate the menstrual cycle.
Prolactin: Prolactin is a hormone that is produced by the pituitary gland. It helps to stimulate the production of milk in the breasts. Prolactin also plays a role in sexual reproduction.
Thyroid hormones: Thyroid hormones are produced by the thyroid gland. They help to regulate the body’s metabolism, growth, and development.
Testosterone: Testosterone is a hormone that is produced by the testes. It is responsible for the development of male secondary sexual characteristics, such as facial hair, a deep voice, and muscle mass. Testosterone also plays a role in sexual reproduction.

Hormones are essential for life. They regulate a wide range of physiological processes, and without them, the body would not be able to function properly.

What are the different types of hormones?

Hormones are chemical messengers that are produced by glands in the body and travel through the bloodstream to target cells. They regulate many important bodily functions, including growth, metabolism, reproduction, and mood.

There are many different types of hormones, each with its own specific function. Some of the most important hormones include:

Insulin: This hormone helps the body to use glucose for energy.
Testosterone: This hormone is responsible for male sexual development and function.
Estrogen: This hormone is responsible for female sexual development and function.
Thyroid hormone: This hormone helps to regulate metabolism.
Cortisol: This hormone helps the body to respond to stress.

How do hormones work?

Hormones work by binding to receptors on target cells. When a hormone binds to its receptor, it triggers a series of events inside the cell that ultimately lead to the desired effect. For example, when insulin binds to its receptor on a muscle cell, it causes the cell to take up glucose from the bloodstream.

What are the effects of hormones on the body?

Hormones have a wide range of effects on the body. Some of the most important effects of hormones include:

Regulating growth and development
Regulating metabolism
Regulating reproduction
Regulating mood
Regulating sleep
Regulating blood pressure
Regulating heart rate

What are some disorders of the endocrine system?

The endocrine system is the system of glands in the body that produce hormones. Disorders of the endocrine system can occur when the glands produce too much or too little of a hormone. Some common disorders of the endocrine system include:

Diabetes: This is a condition in which the body does not produce enough insulin.
Hypothyroidism: This is a condition in which the thyroid gland does not produce enough thyroid hormone.
Hyperthyroidism: This is a condition in which the thyroid gland produces too much thyroid hormone.
Cushing’s syndrome: This is a condition in which the body produces too much cortisol.
Addison’s disease: This is a condition in which the adrenal glands do not produce enough cortisol.

How are hormones regulated?

Hormones are regulated by a complex system of feedback loops. In a feedback loop, the level of a hormone in the blood affects the production of that hormone by the glands. For example, when the level of blood sugar rises, the pancreas produces more insulin. This causes the level of blood sugar to fall, which in turn causes the pancreas to produce less insulin.

What are some ways to manage hormone levels?

There are a number of ways to manage hormone levels. Some of the most common methods include:

Medication: Medication can be used to increase or decrease the production of hormones.
Surgery: Surgery can be used to remove or repair glands that are not functioning properly.
Lifestyle changes: Lifestyle changes, such as diet and exercise, can also help to manage hormone levels.

What are some of the latest research findings on hormones?

Research on hormones is constantly evolving. Some of the latest research findings on hormones include:

The discovery of new hormones
The development of new medications to treat hormone disorders
A better understanding of how hormones interact with each other
A better understanding of how hormones affect the body

What are some of the most common myths about hormones?

There are a number of common myths about hormones. Some of the most common myths include:

Hormones are only for Women.
Hormones are only for people who are sexually active.
Hormones are only for people who are overweight or obese.
Hormones are only for people who are over the age of 40.

What are some Resources for Learning more about hormones?

There are a number of resources available for learning more about hormones. Some of the most helpful resources include:

Books
Websites
Magazines
Newspapers
Talk to your doctor

Which of the following is not a hormone?
(A) Insulin
(B) Estrogen
(C) Testosterone
(D) Adrenaline
Which of the following is not a function of the endocrine system?
(A) Regulating metabolism
(B) Controlling growth and development
(C) Regulating reproduction
(D) Producing energy
Which of the following is not a gland of the endocrine system?
(A) Pituitary gland
(B) Thyroid gland
(C) Adrenal gland
(D) Liver
Which of the following is not a hormone produced by the pituitary gland?
(A) Growth hormone
(B) Thyroid-stimulating hormone
(C) Adrenocorticotropic hormone
(D) Insulin
Which of the following is not a hormone produced by the thyroid gland?
(A) Thyroxine
(B) Triiodothyronine
(C) Calcitonin
(D) Insulin
Which of the following is not a hormone produced by the adrenal glands?
(A) Cortisol
(B) Aldosterone
(C) Adrenaline
(D) Insulin
Which of the following is not a function of growth hormone?
(A) Stimulating the growth of bones and tissues
(B) Regulating metabolism
(C) Promoting the development of secondary sex characteristics
(D) Regulating blood sugar levels
Which of the following is not a function of thyroid hormones?
(A) Regulating metabolism
(B) Promoting the development of secondary sex characteristics
(C) Regulating growth and development
(D) Stimulating the production of heat
Which of the following is not a function of calcitonin?
(A) Regulating blood calcium levels
(B) Promoting the absorption of calcium from the intestines
(C) Stimulating the release of calcium from the bones
(D) Inhibiting the release of calcium from the bones
Which of the following is not a function of cortisol?
(A) Regulating blood sugar levels
(B) Promoting the breakdown of carbohydrates, fats, and proteins
(C) Inhibiting the immune system
(D) Regulating blood pressure
Which of the following is not a function of aldosterone?
(A) Regulating blood pressure
(B) Regulating blood volume
(C) Promoting the reabsorption of sodium in the kidneys
(D) Promoting the excretion of potassium in the kidneys
Which of the following is not a function of adrenaline?
(A) Increasing heart rate
(B) Increasing blood pressure
(C) Dilating the pupils
(D) Slowing down the Digestive System
Which of the following is not a disorder of the endocrine system?
(A) Diabetes mellitus
(B) Hyperthyroidism
(C) Hypothyroidism
(D) Insulinoma
Which of the following is not a symptom of diabetes mellitus?
(A) High blood sugar levels
(B) Frequent urination
(C) Extreme thirst
(D) Weight loss
Which of the following is not a symptom of hyperthyroidism?
(A) Weight loss
(B) Increased heart rate
(C) Sweating
(D) Constipation
Which of the following is not a symptom of hypothyroidism?
(A) Weight gain
(B) Fatigue
(C) Dry skin
(D) Constipation
Which of the following is not a treatment for diabetes mellitus?
(A) Insulin injections
(B) Oral medications
(C) Diet and exercise
(D) Surgery
Which of the following is not a treatment for hyperthyroidism?
(A) Antithyroid medications
(B) Radioactive iodine therapy
(C) Surgery
(D) Thyroid hormone replacement therapy
Which of the following is not a treatment for hypothyroidism?
(A) Thyroid hormone replacement therapy
(B) Iodine supplements
(C) Surgery
(D) Radioactive iodine therapy
Which of the following is not a risk factor for diabetes mellitus?
(A) Family history
(B) Obesity
(C) Age
(D) Gender