3.6-excretory system

• Endocrine system


  A system in the body composed of endocrine glands that produce and release hormones into the bloodstream to regulate various bodily functions
• Hormones


  Chemical messengers produced by endocrine glands that regulate the function of distant organs, each with a specific receptor for its hormone
• Hydrophilic


  Substances that dissolve easily in water; also known as polar
• Hydrophobic


  Substances that tend to be insoluble in water; also known as non-polar
• Receptors


  Proteins located on the surfaces of target cells that bind to specific hormones, enabling the cells to receive and respond to the messages carried by the hormones
• Thyroid Hormones


  Hormones T3 and T4 released by the thyroid gland, requiring the action of other hormones in the process
• Adrenal Glands


  Paired endocrine glands situated on top of the kidneys, consisting of an outer cortex and an inner medulla, producing corticoid hormones like aldosterone and cortisol
• Adrenal Cortex


  The outer part of the adrenal gland that is not uniform in microscopic appearance and is divided into three zones based on the organization of cells producing specific hormones
• Aldosterone


  A steroid hormone produced by the adrenal cortex that regulates blood pressure and the balance of salt and water in the body
• Cortisol


  A steroid hormone produced by the adrenal cortex that plays a role in regulating blood sugar levels and the body's recovery from stress
• Adrenal Medulla


  The central part of the adrenal gland composed of chromaffin cells that produce adrenaline and noradrenaline in response to stressful situations
• Stress Response


  Physiological reactions to stress, also known as the 'fight or flight' response, resulting from the release of adrenaline and noradrenaline from the adrenal medulla
• Thyroid Gland


  An endocrine gland located in the throat that produces hormones like T3 and T4, essential for regulating metabolism
• Parafollicular Cells


  Secretory cells in the thyroid gland that produce calcitonin, another thyroid hormone
• Parathyroid Hormone


  A protein hormone synthesized by the parathyroid glands in response to low blood calcium levels, regulating calcium levels in the body
• Pituitary Gland


  A pea-shaped endocrine gland located at the base of the brain, consisting of anterior and posterior lobes that regulate various hormones and control other endocrine glands
• Control systems


  Mechanisms put in place to maintain the levels of circulating hormones in the blood within narrow limits, often through negative feedback
• Negative feedback


  A regulatory mechanism where a hormone inhibits its own production by blocking the glands that produce it when its concentration exceeds or drops below the normal range
• Adrenal glands


  Pair of organs located on the upper margin of each kidney, composed of the cortex and the medulla which synthesize and secrete different hormones like cortisol, aldosterone, adrenaline, and noradrenaline
• Cortisol


  Steroid hormone produced by the cortex of the adrenal glands, involved in various physiological processes including stress response and metabolism
• Aldosterone


  Steroid hormone produced by the cortex of the adrenal glands, responsible for regulating salt and water balance in the body
• Adrenaline


  Hormone produced by the medulla of the adrenal glands, involved in the fight-or-flight response and increasing heart rate and blood flow to muscles
• Noradrenaline


  Hormone produced by the medulla of the adrenal glands, functioning as a neurotransmitter and involved in the stress response
• Thyroid gland


  Endocrine gland located in the lower neck, secreting hormones like T3, T4, and calcitonin that regulate metabolism, growth, and calcium levels in the blood
• T3 and T4


  Thyroid hormones produced by the follicular cells of the thyroid gland, critical for brain development, metabolism, and overall body function
• Calcitonin


  Hormone produced by the parafollicular cells of the thyroid gland in response to high blood calcium levels, involved in regulating calcium homeostasis
• Parathyroid glands


  Endocrine glands located on the posterior surface of the thyroid gland, producing parathyroid hormone (PTH) to regulate calcium levels in the blood and maintain calcium homeostasis
• Calcium reabsorption


  The process by which cells of the kidney tubules increase the uptake of calcium, leading to decreased loss of calcium in urine
• 1,25-dihydroxy vitamin D


  The active form of vitamin D produced in the kidney, which enhances calcium absorption in the intestine
• Parathyroid hormone


  Hormone that regulates calcium and phosphorus levels in the blood, excessive secretion can lead to bone damage and high blood calcium levels
• Calcitonin


  Hormone that opposes the action of parathyroid hormone, decreases blood calcium levels by inhibiting osteoclast activity and calcium resorption in the kidneys
• Sultan Kösen Turkish man recognized as the world's tallest living man due to excessive growth hormone production from a pituitary gland tumor
• Endocrine system


  A chemical messaging system using hormones to regulate body functions, influenced by hormone production levels which can have negative effects on the body
• Iodine deficiency


  Lack of iodine impacting the production of thyroid hormones T3 and T4, leading to thyroid gland enlargement and various symptoms like low metabolic rate and reduced brain development
• Endocrine system


  A system in the body that produces and secretes hormones to regulate various functions such as growth, development, homeostasis, reproduction, and behavior
• Hormones


  Chemical messengers produced by the endocrine glands that regulate various physiological activities in the body
• Insect endocrine system


  The endocrine system specific to insects that produces hormones to regulate growth, development, and behavior
• PTTH (Prothoracicotropic hormone)


  A hormone produced by neurosecretory cells in the brain that stimulates the prothoracic glands to secrete ecdysone
• Juvenile hormone (JH)


  An insect hormone produced by the corpora allata that regulates growth and development in the nymphal and larval stages
• Ecdysone (20E)


  A steroid hormone produced by the prothoracic glands that controls moulting in insects