endocrine system

Endocrine System

The system in the body responsible for regulating metabolism, food intake, digestion, tissue maturation, ion regulation, water balance, heart rate, blood pressure, blood glucose, reproductive functions, uterine contractions, milk letdown, and immune system regulation.

Pituitary Gland

A gland that secretes hormones that regulate various body functions and other endocrine glands.

Hypothalamus

A region of the brain that regulates the activity of the pituitary gland through neurohormones and action potentials.

Posterior Pituitary

The posterior part of the pituitary gland that develops from the floor of the brain and consists of the infundibulum and the neurohypophysis.

Anterior Pituitary

The anterior part of the pituitary gland that develops from the roof of the mouth.

Hypothalamohypophysial Tract

The connection between the hypothalamus and the posterior pituitary, through which neurohormones are produced and secreted.

Hypothalamohypophysial Portal System

The connection between the hypothalamus and the anterior pituitary, through which neurohormones regulate hormone production.

ADH (Antidiuretic Hormone)

A hormone that promotes water retention by the kidneys.

Oxytocin

A hormone that promotes uterine contractions during delivery and causes milk letdown in lactating women.

GH (Growth Hormone)

A hormone that stimulates growth in most tissues, regulates metabolism, and promotes bone and cartilage growth.

TSH (Thyroid-Stimulating Hormone)

A hormone that causes the release of thyroid hormones.

ACTH (Adrenocorticotropic Hormone)

A hormone that stimulates cortisol secretion from the adrenal cortex and increases skin pigmentation.

LH (Luteinizing Hormone) and FSH (Follicle-Stimulating Hormone)

Hormones that regulate the production of gametes and reproductive hormones.

Prolactin

A hormone that stimulates milk production in lactating females.

Thyroid Gland

A gland located just inferior to the larynx that produces thyroid hormones.

T3 and T4

Thyroid hormones that regulate metabolism, growth, and the normal function of many tissues in the body.

Calcitonin

A hormone that decreases blood calcium and phosphate levels by inhibiting osteoclasts.

Parathyroid Glands

Glands embedded in the thyroid gland that secrete PTH (Parathyroid Hormone) to increase blood calcium levels.

Adrenal Glands

Glands near the superior poles of the kidneys that produce hormones involved in the body's response to stress.

Adrenal Medulla

The inner part of the adrenal gland that produces hormones like epinephrine and norepinephrine.

Adrenal Cortex

The outer part of the adrenal gland that produces hormones like cortisol and aldosterone.

Pancreas

A gland located along the small intestine and the stomach that functions as both an exocrine and endocrine gland.

Insulin

A hormone that regulates blood glucose levels by promoting the uptake of glucose by cells.

Glucagon

A hormone that increases blood glucose levels by promoting the breakdown of glycogen and lipids.

Reproductive Hormones

Hormones secreted by the ovaries, testes, placenta, and pituitary gland that regulate reproductive functions.

Pineal Gland

A gland that produces melatonin and arginine vasotocin, which can inhibit reproductive maturation and regulate sleep-wake cycles.

Thymus

A gland that produces thymosin, which is involved in the development of the immune system.

Digestive Tract Hormones

Hormones produced by the digestive tract that regulate digestive functions.

Autocrine and Paracrine Chemical Messengers

Chemical messengers produced by cells that have a local effect on body functions.

Eicosanoids

Chemical messengers derived from fatty acids that mediate inflammation and other functions.

Effects of Aging on the Endocrine System

A gradual decrease in the secretion rate of most hormones with age.

Pituitary Gland

• Location: Located at the base of the brain.

• Function: Often referred to as the "master gland," the pituitary gland secretes hormones that control other endocrine glands. It plays a crucial role in growth, development, and the regulation of other hormonal systems.

Thyroid Gland

• Location: Found in the neck, below the Adam's apple.

• Function: Produces thyroid hormones (T3 and T4) that regulate metabolism, energy production, and overall body growth. It also secretes calcitonin, which helps regulate calcium levels in the blood.

Parathyroid Glands

• Location: Four small glands located on the thyroid gland.

• Function: Secrete parathyroid hormone (PTH), which regulates calcium and phosphorus levels in the blood and bone.

Adrenal Glands

• Location: Sit on top of each kidney.

• Function: Produce hormones such as cortisol (involved in stress response and metabolism), aldosterone (regulates salt and water balance), and adrenaline (involved in the "fight or flight" response).

Pancreas

• Location: Located behind the stomach.

• Function: Has both endocrine and exocrine functions. The endocrine part secretes insulin (lowers blood sugar) and glucagon (raises blood sugar), regulating glucose metabolism.

Pineal Gland

• Location: Located in the brain, deep within the center.

• Function: Produces melatonin, which regulates sleep-wake cycles and circadian rhythms.

Hypothalamus

• Location: Part of the brain.

• Function: While not a gland, it plays a crucial role in endocrine function by producing releasing and inhibiting hormones that control the pituitary gland's secretion of hormones.

Ovaries (in females)

• Location: In the pelvic cavity.

• Function: Produce estrogen and progesterone, which regulate the menstrual cycle and are involved in reproductive processes.

Testes (in males)

• Location: In the scrotum.

• Function: Produce testosterone, which is essential for the development of male reproductive tissues and secondary sexual characteristics.

Insulin

• Produced by: Beta cells in the pancreas.

• Function: Facilitates the uptake of glucose by cells, promoting its conversion into energy. it helps lower blood sugar levels.

Glucagon

• Produced by: Alpha cells in the pancreas.

• Function: Stimulates the liver to convert stored glycogen into glucose, raising blood sugar levels. It works in opposition to insulin to regulate glucose balance.

Thyroid Hormones (T3 and T4):

• Produced by: Thyroid gland.

• Function: Regulate metabolism by influencing the body's energy production and utilization. They also play a crucial role in growth, development, and the maintenance of body temperature.

Calcitonin

• Produced by: Thyroid gland.

• Function: Regulates calcium levels in the blood by inhibiting the release of calcium from bones, helping to lower blood calcium levels.

Parathyroid Hormone (PTH)

• Produced by: Parathyroid glands.

• Function: Increases blood calcium levels by stimulating the release of calcium from bones, enhancing calcium absorption in the intestines, and reducing calcium loss in the kidneys.

Cortisol

• Produced by: Adrenal glands.

• Function: Regulates metabolism, suppresses the immune system, and helps the body respond to stress. It also plays a role in maintaining blood pressure and balancing salt and water.

Aldosterone

• Produced by: Adrenal glands.

• Function: Regulates salt and water balance by promoting the reabsorption of sodium and excretion of potassium in the kidneys, helping to maintain blood pressure

Adrenaline (Epinephrine)

• Produced by: Adrenal glands.

• Function: Triggers the "fight or flight" response, increasing heart rate, dilating airways, and redirecting blood flow to critical organs to prepare the body for immediate action in response to stress.

Melatonin

• Produced by: Pineal gland.

• Function: Regulates the sleep-wake cycle and circadian rhythms, helping to synchronize the body's internal clock with the day-night cycle.

Estrogen and Progesterone

• Produced by: Ovaries (in females).

• Function: Regulate the menstrual cycle, support the development of female reproductive tissues, and play a crucial role in pregnancy and the maintenance of the uterine lining.

Testosterone

• Produced by: Testes (in males).

• Function: Promotes the development of male reproductive tissues, secondary sexual characteristics (such as facial hair and deepening voice), and plays a role in maintaining male reproductive health.