Endocrine System - Physiology and Pathology

Introduction

The endocrine system comprises of numerous glands that secrete hormones into the blood to be carried to a target cell. Endocrine system hormones function even when the target cells are located far from the endocrine glands. The endocrine system regulates almost every metabolic activity in the body through these actions to produce an integrated response. The endocrine system produces hormones that cause the stress response, regulates the heartbeat or blood pressure, and controls how the cells grow and develop in general.

Endocrine glands are typically vascularized, with a dense network of blood vessels. Hormones are produced and stored in intracellular granules or vesicles within these organs, which fuse with the plasma membrane in reaction to the appropriate signal. This action causes hormones to be released into the extracellular space or the bloodstream. Different inputs activate the endocrine system, allowing responses to various internal and external stimuli.

What Are The Different Endocrine Glands?

The endocrine system's major glands, each of which produces one or more specific hormones, are the

• Hypothalamus.

• Pituitary gland.

• Pineal gland.

• Thyroid gland.

• Parathyroid glands.

• Pancreas.

• Adrenal glands.

• Gonads - Testes (men) and ovaries (women).

What Is the Physiology of the Endocrine Glands?

• HypothalamusThe hypothalamus is at the base of the brain, where the optic nerves behind each eye cross and meet. Apart from controlling water balance, sleep, temperature, appetite, and blood pressure, the hypothalamus secretes hormones that regulate the release of hormones from the pituitary gland.

• Pituitary GlandThis tiny gland is about the size of a pea but performs a critical function. It produces hormones that regulate several other glands, including the thyroid, adrenal glands, ovaries, and testicles. The pituitary gland regulates many different bodily functions, including growth. It is at the bottom of the brain.

• Pineal GlandThe pineal gland is present in the middle of the brain, beneath the corpus callosum. For most of history, it was also referred to as the "third eye" due to its location in the brain and connection with light. It produces melatonin, a hormone that influences the body's internal clock. It influences the body's sleep-wake cycle and is also known as the circadian rhythm. Its effects are minimal unless the individual is sleep-deprived. Since circadian rhythm appears to coincide with the day and night cycle, factors like jet lag or working on a night shift have a more noticeable effect on an individual. That is why people who work at night find it difficult to fall asleep during the day and, as a result, stay awake during the day.

• Thyroid GlandThe thyroid gland is located near the windpipe in the throat. It is brownish red with blood vessels running through it. Thyroid hormones are secreted by the thyroid gland. The most noticeable are T3 and T4, which influence the rate of metabolism in the body.

• Parathyroid GlandThe parathyroid glands are four tiny glands in the neck behind the thyroids. They control calcium levels in the body by producing a parathyroid hormone. When the thyroid gland produces too many parathyroid hormones, it can cause brittle bones and kidney stones.

• PancreasThe pancreas is an exocrine as well as endocrine gland located behind the stomach. It's about 6 inches long and fairly flat. The pancreas serves two primary functions:

  • Secreting digestive enzymes.
  • Secreting hormones like insulin and glucagon.Insulin is produced by pancreatic cells and aids in keeping blood glucose levels in the body from becoming too high. Diabetes type 1 and 2 are both caused by a lack of insulin. The hormone glucagon is produced by pancreatic cells and aids the body in preventing glucose levels from falling too low. Hypoglycemia results from a lack of glucagon. Another significant difference is that insulin becomes active when blood glucose levels are high, whereas glucagon becomes active only when blood glucose levels are low.

• Adrenal GlandEach kidney has an adrenal gland on top of it. The adrenal glands, like many other glands, collaborate with the hypothalamus and pituitary gland. The adrenal glands produce and release corticosteroid hormones and epinephrine, which regulate blood pressure and metabolism.

• OvariesThe ovaries of a woman are situated on both sides of the uterus, underneath the opening of the fallopian tubes. In addition to egg cells, the ovaries produce estrogen and progesterone.

• TestesThe testes of a man are housed in a pouch that hangs suspended outside of the male body. The testes help in the production of testosterone and sperm.

What Are the Conditions and Disorders That Affect the Endocrine System?

Various conditions can disrupt the endocrine system. These conditions can cause health problems throughout the body. The following are among the most common disorders:

• Diabetes: It is an endocrine disorder that affects how the body uses energy from food. Diabetes occurs when the pancreas does not secrete enough insulin or when insulin fails to function properly.

• Thyroid Disorders: A variety of conditions can impair thyroid gland function. Hypothyroidism is when the thyroid produces insufficient hormones. Hyperthyroidism is when the thyroid gland produces excess hormones.

• Hypogonadism: (Low testosterone) can cause erectile dysfunction in men. It can also lead to memory and concentration issues, changes in muscle strength, and decreased sexual drive. It occurs when the testes do not produce enough testosterone, the sex hormone.

• PCOS: Women with PCOS (polycystic ovary syndrome) experience irregular menstrual cycles, abnormal hair growth, excessive acne, and weight gain due to a hormonal imbalance. Diabetes, a higher risk of metabolic syndrome, and infertility are all possible outcomes.

• Osteoporosis: Bones become weak when a woman's ovaries do not produce enough estrogen. Men can develop osteoporosis when their testosterone levels fall too low, even though women are more likely to do so. Weak bones can also occur in people with hyperparathyroidism, an overactive parathyroid gland.

The endocrine system may also be impacted by substances known as endocrine disrupters. Pesticides, cosmetics, plastics, and even our food and water, as well as pesticides themselves, all contain these chemicals. Endocrine disrupters alter the way hormones communicate with the body, which results in a variety of issues.

Conclusion

To stay healthy, the endocrine system requires the same nutrients as the rest of the body. Therefore, exercise, healthy eating, and routine doctor visits are all recommended. In addition, a healthcare provider must be consulted if there is a family history of thyroid problems, PCOS, or diabetes.