Test How Deep Your Knowledge Is On Hormones Chapters 14

The pancreas secretes both insulin and glucagon. Insulin is responsible for regulating blood sugar levels by allowing cells to take in glucose from the bloodstream. Glucagon, on the other hand, increases blood sugar levels by stimulating the liver to release stored glucose. The secretion of both hormones by the pancreas helps to maintain a balanced and stable blood sugar level in the body.

Aldosterone is a hormone that belongs to the class of mineralocorticoids, which are secreted by the adrenal cortex. It plays a crucial role in the regulation of electrolyte balance in the body, particularly in the reabsorption of sodium and excretion of potassium by the kidneys. This hormone acts on the distal tubules and collecting ducts of the kidneys, promoting the reabsorption of sodium and water, while increasing the excretion of potassium. By doing so, aldosterone helps maintain blood pressure and fluid balance in the body.

T3 and T4 are thyroid hormones that play a crucial role in regulating the body's metabolism. They increase the basal metabolic rate (BMR), which refers to the amount of energy the body needs to perform basic functions at rest. By increasing the BMR, T3 and T4 help to control the rate at which the body burns calories and converts food into energy. This regulation of BMR is important for maintaining a healthy weight and overall metabolic balance in the body.

Insulin is a hormone produced by the pancreas that plays a crucial role in regulating blood glucose levels. It acts by facilitating the uptake of glucose from the bloodstream into cells, where it can be used as a source of energy or stored for later use. Therefore, insulin lowers blood glucose levels by promoting its utilization and storage.

The hormones cortisol, aldosterone, and testosterone are all related to the body's response to stress and play a role in regulating sugar levels, salt balance, and sex hormone production. Cortisol is involved in regulating blood sugar levels and suppressing the immune system. Aldosterone helps regulate salt and water balance in the body. Testosterone is a sex hormone that plays a role in sexual development and function.

A deficiency of dietary iodine impairs the synthesis of T3 and T4. Iodine is an essential nutrient required for the production of thyroid hormones T3 (triiodothyronine) and T4 (thyroxine). Without adequate iodine, the thyroid gland cannot produce enough of these hormones, leading to impaired synthesis. T3 and T4 play crucial roles in regulating metabolism, growth, and development in the body. Therefore, a deficiency of dietary iodine can have significant negative effects on thyroid function and overall health.

Hypocalcemic tetany is caused by a deficiency of PTH (parathyroid hormone). PTH plays a crucial role in regulating calcium levels in the body. When there is a deficiency of PTH, the calcium levels in the blood decrease, leading to hypocalcemia. Hypocalcemia can cause muscle spasms and tetany, which is characterized by involuntary muscle contractions. Therefore, a deficiency of PTH is the underlying cause of hypocalcemic tetany.

The posterior pituitary gland is responsible for releasing two important hormones: antidiuretic hormone (ADH) and oxytocin. ADH helps regulate water balance in the body by controlling the reabsorption of water in the kidneys, while oxytocin plays a role in childbirth and breastfeeding by stimulating contractions of the uterus and the release of milk. These hormones are released directly into the bloodstream from the posterior pituitary gland, which is connected to the hypothalamus.

Cortisol is a hormone that is secreted by the adrenal cortex in response to ACTH. ACTH, or adrenocorticotropic hormone, is released by the pituitary gland and stimulates the adrenal cortex to produce cortisol. Cortisol plays a crucial role in regulating various bodily processes, including metabolism, immune response, and stress response. Therefore, the statement "Cortisol is secreted by the adrenal cortex in response to ACTH" is correct.

The adrenal medulla is a part of the adrenal gland that is responsible for secreting catecholamines, such as adrenaline and noradrenaline. These hormones are released in response to stress or danger, and they help prepare the body for a "fight or flight" response. Catecholamines increase heart rate, blood pressure, and energy levels, among other effects. The adrenal medulla is not stimulated by ACTH, does not secrete steroids, and overactivity of the adrenal medulla does not cause Cushing's syndrome.

Calcitonin is a hormone that is secreted by the parathyroid gland. Its main function is to lower plasma calcium levels in the blood. It does this by inhibiting the activity of osteoclasts, which are cells responsible for breaking down bone tissue and releasing calcium into the bloodstream. By reducing the breakdown of bone tissue, calcitonin helps to decrease the amount of calcium in the blood. This hormone works in opposition to parathyroid hormone (PTH), which increases plasma calcium levels.

T3 and T4 are hormones that are secreted by the adenohypophysis in response to TSH. These hormones play a crucial role in regulating the body's metabolism. However, the given answer states that T3 and T4 contain iodine. This is correct as iodine is an essential component of these hormones. Without sufficient iodine, the production of T3 and T4 would be impaired, leading to thyroid disorders such as hypothyroidism or goiter. Therefore, it is important to ensure an adequate intake of iodine through diet or supplementation to support the synthesis of T3 and T4.

Epinephrine and norepinephrine are hormones that play a crucial role in the fight-or-flight response, which is the body's reaction to stress or danger. They are catecholamines, a type of neurotransmitter that helps transmit signals in the nervous system. These hormones are secreted by the adrenal medulla, a part of the adrenal glands located on top of the kidneys. Therefore, all of the given statements are correct.

Insulin is a hormone produced by the pancreas that plays a crucial role in regulating blood sugar levels. It helps lower blood glucose levels by promoting the uptake of glucose into cells. Insulin also stimulates the synthesis of protein, which is important for growth and repair. Additionally, it promotes the storage of excess glucose as glycogen in the liver and muscles, preventing hepatic gluconeogenesis or the production of glucose by the liver. Finally, insulin promotes the synthesis of fatty acids, which are stored as triglycerides in adipose tissue. Therefore, the correct answer is hepatic gluconeogenesis, as insulin actually inhibits this process.

Prolactin is a hormone secreted by the anterior pituitary gland. It is also known as the lactogenic hormone because it stimulates the mammary glands to produce milk. However, it is not directly responsible for causing the milk let-down reflex. This reflex is actually triggered by the hormone oxytocin. Therefore, out of the given options, "causes the milk let-down reflex" is the least descriptive of prolactin.

ACTH, TSH, and gonadotropins are hormones that are secreted by the adenohypophysis, which is a part of the pituitary gland. These hormones have specific functions and target different organs or tissues in the body. ACTH stimulates the adrenal cortex to release cortisol and other steroids, TSH stimulates the thyroid gland to produce and release thyroid hormones, and gonadotropins regulate the function of the gonads (testes in males and ovaries in females). Therefore, these hormones are not hypothalamic releasing hormones, but rather hormones secreted by the adenohypophysis.

As plasma levels of calcium decrease, the body responds by secreting parathyroid hormone (PTH). PTH helps to increase plasma calcium levels by stimulating the release of calcium from bones, increasing the absorption of calcium in the intestines, and reducing the excretion of calcium in the kidneys. Therefore, the secretion of PTH is the correct answer as it plays a crucial role in maintaining calcium homeostasis in the body.

The hypothalamus is connected to the neurohypophysis by the hypothalamo-hypophyseal tract, not by the portal capillaries. The hypothalamus does secrete releasing hormones into the portal capillaries, is composed of nervous tissue, and synthesizes ADH and oxytocin.

Growth hormone, cortisol, and epinephrine are all secreted by the adrenal gland. These hormones play a role in raising blood glucose levels. Growth hormone stimulates the liver to release glucose into the bloodstream, cortisol increases the breakdown of proteins and fats to produce glucose, and epinephrine triggers the release of stored glucose from the liver. By raising blood glucose levels, these hormones ensure that the body has enough energy during times of stress or physical activity.