Đề thi, bài tập trắc nghiệm online Sinh lý nội tiết – Đề 2

Antidiuretic hormone (ADH), also known as vasopressin, is secreted by the posterior pituitary gland. The anterior pituitary gland secretes GH, TSH, ACTH, prolactin, follicle-stimulating hormone (FSH), and luteinizing hormone (LH).

Diabetes mellitus is characterized by hyperglycemia (high blood sugar) due to either insufficient insulin production (Type 1) or insulin resistance (Type 2), highlighting insulin′s crucial role in glucose regulation.

Oxytocin is synthesized in the hypothalamus and then stored and released by the posterior pituitary gland. It plays a significant role in social bonding, sexual reproduction, childbirth, and the period after childbirth. It stimulates uterine contractions during labor and lactation after birth.

Growth hormone (GH) stimulates growth, cell reproduction, and regeneration in humans and other animals. It is particularly important for the growth of bones and muscles during childhood and adolescence, and continues to play a role in tissue maintenance in adulthood.

Insulin is a peptide hormone, making it water-soluble. Steroid hormones like testosterone, estrogen, and aldosterone are derived from cholesterol and are lipid-soluble, not water-soluble.

The adrenal medulla, part of the adrenal gland, is responsible for producing catecholamines, mainly epinephrine (adrenaline) and norepinephrine (noradrenaline), in response to acute stress, triggering 'fight-or-flight′ responses.

Aldosterone acts primarily in the kidneys to regulate sodium and potassium levels, leading to sodium retention and potassium excretion. This process is essential for maintaining blood volume, electrolyte balance, and blood pressure.

Salivary glands are exocrine glands, secreting saliva through ducts into the oral cavity, not directly into the bloodstream like endocrine glands. Pituitary, thyroid, and adrenal glands are major endocrine glands.

Due to their lipid-soluble nature, steroid hormones can pass through the plasma membrane and bind to receptors located in the cytoplasm or nucleus of target cells, forming hormone-receptor complexes that then influence gene expression.

The nervous system uses electrical and chemical signals for rapid, localized responses. The endocrine system uses hormones transported via the bloodstream, resulting in slower, more widespread, and longer-lasting effects on target cells throughout the body.

Negative feedback mechanisms work to restore a physiological variable back to its normal range. In hormone regulation, when a hormone′s level rises or its effect is achieved, it triggers responses that inhibit further secretion of that hormone, preventing excessive hormone action.

The hypothalamus is a brain region that directly regulates the pituitary gland by secreting releasing and inhibiting hormones, which control the anterior pituitary, and by directly connecting to the posterior pituitary via neurons.

Cortisol is a stress hormone that increases blood glucose through gluconeogenesis, has anti-inflammatory effects, and suppresses the immune system. It also plays a role in metabolism, blood pressure regulation, and stress response.

Cushing′s syndrome, or hypercortisolism, occurs when the body is exposed to high levels of cortisol for a long time. This can be due to various factors, including adrenal tumors, pituitary tumors secreting ACTH, or prolonged use of glucocorticoid medications.

Glucagon, secreted by the pancreas, works antagonistically to insulin. When blood glucose levels are low, glucagon stimulates the liver to break down glycogen (glycogenolysis) and synthesize new glucose from non-carbohydrate sources (gluconeogenesis), thereby increasing blood glucose.

Acromegaly is a disorder resulting from excessive growth hormone (GH) secretion by the pituitary gland in adults. This leads to the enlargement of bones in the hands, feet, and face, as well as other tissues and organs.

Hashimoto′s thyroiditis is an autoimmune disease in which the immune system attacks the thyroid gland. This chronic inflammation often leads to hypothyroidism (underactive thyroid).

The thyroid gland primarily synthesizes and secretes thyroxine (T4) and triiodothyronine (T3), which are iodine-containing hormones essential for regulating metabolic rate, growth, and development.

Hormones act as signaling molecules that travel through the bloodstream to target cells and tissues, where they bind to receptors and initiate specific physiological responses, thereby coordinating bodily functions.

The pineal gland, located in the brain, is the primary site of melatonin production. Melatonin secretion is influenced by light exposure and darkness, and it helps regulate circadian rhythms, including sleep-wake cycles.

Epinephrine (adrenaline), released from the adrenal medulla during stress, is the key hormone mediating the 'fight-or-flight′ response. It increases heart rate, blood pressure, diverts blood to muscles, and raises blood glucose to provide energy for rapid action.

Prolactin, secreted by the anterior pituitary, is essential for lactation. Its primary role is to stimulate milk production (lactogenesis) in the mammary glands after childbirth, enabling breastfeeding.

Peptide hormones and catecholamines, like insulin, are typically water-soluble and cannot directly cross the cell membrane. They bind to cell surface receptors, activating intracellular second messenger systems (e.g., cAMP, calcium ions) to relay the hormonal signal inside the cell. Steroid and thyroid hormones (Estrogen, Cortisol, Thyroxine) generally bind to intracellular receptors.

Insulin, secreted by the pancreas, is the main hormone that lowers blood glucose. It facilitates glucose entry into cells for energy and promotes glycogen synthesis in the liver, converting glucose into storage form.

Endocrine glands are ductless and release hormones directly into the bloodstream to reach target cells throughout the body. Exocrine glands have ducts and secrete substances like sweat, saliva, or enzymes onto epithelial surfaces or into cavities.

Antidiuretic hormone (ADH), released from the posterior pituitary, acts on the kidneys to increase water reabsorption back into the bloodstream. This reduces urine volume and helps to concentrate urine, thus conserving body water and maintaining blood osmolarity.

Parathyroid hormone (PTH), secreted by the parathyroid glands, plays a critical role in calcium homeostasis by increasing blood calcium levels. It achieves this by stimulating calcium release from bones, increasing calcium absorption in the intestines, and promoting calcium reabsorption in the kidneys.

Follicle-stimulating hormone (FSH), secreted by the anterior pituitary, is crucial for reproductive function. In females, FSH stimulates ovarian follicle development and estrogen production. In males, FSH promotes spermatogenesis (sperm production) in the testes.

Graves′ disease is an autoimmune disorder that causes hyperthyroidism. In Graves′ disease, the immune system produces antibodies that stimulate the thyroid gland to produce excessive amounts of thyroid hormones, leading to an overactive thyroid.

In females, luteinizing hormone (LH) surge triggers ovulation, the release of an egg from the ovary. After ovulation, LH stimulates the corpus luteum to develop and secrete progesterone, which is essential for maintaining pregnancy.