Ch.18 - The Endocrine System

The correct answer is Parathyroid Hormone. The parathyroid gland secretes parathyroid hormone (PTH), which plays a crucial role in maintaining calcium homeostasis in the body. PTH acts on the bones, kidneys, and intestines to increase the levels of calcium in the blood. It stimulates the release of calcium from the bones, enhances the reabsorption of calcium in the kidneys, and promotes the absorption of calcium in the intestines. This hormone is essential for regulating calcium levels and ensuring proper functioning of various physiological processes.

Amino acids are the building blocks of proteins. Proteins are made up of long chains of amino acids that are linked together by peptide bonds. Each amino acid has a unique side chain, which gives it specific properties and functions. Therefore, the correct answer is amino acid derivative as it correctly identifies the building block of proteins.

Endocrine reflexes are controlled by negative feedback loops. In this type of loop, the output of a system inhibits or reduces the activity of the system itself. In the case of endocrine reflexes, the release of hormones is regulated by feedback mechanisms that sense the level of hormones in the bloodstream. When hormone levels reach a certain threshold, the feedback mechanism signals the endocrine glands to reduce or stop hormone production, maintaining homeostasis. This negative feedback loop helps to regulate hormone levels and prevent excessive or inadequate hormone secretion.

The correct answer is hypophysis. The pituitary gland is commonly referred to as the hypophysis. It is a small gland located at the base of the brain and is responsible for producing and releasing various hormones that regulate several bodily functions. The term "hyperphysis" and "hemophysis" are not accurate names for the pituitary gland.

The correct answer is "Abdominal Pelvic Cavity" because the pancreas is an organ that is located in the abdominal region of the body. It is situated behind the stomach and in front of the spine. The abdominal pelvic cavity is the space in the body that contains the abdominal organs, including the pancreas. Therefore, this is the most accurate and appropriate location for the pancreas.

ADH, also known as antidiuretic hormone, is a hormone that is secreted by the pituitary posterior. It plays a crucial role in regulating the balance of water in the body by controlling the amount of water reabsorbed by the kidneys. This hormone helps to prevent excessive urine production and dehydration, especially in situations where water intake is limited.

Melatonin is a hormone that regulates the sleep-wake cycle and is primarily produced by the pinealocytes in the pineal gland. These cells are responsible for the synthesis and secretion of melatonin in response to darkness, which helps to regulate circadian rhythms. Therefore, the correct answer is Pinealocytes & circadian rhythms.

The hypothalamus is considered the main control center of the endocrine system because it plays a crucial role in regulating hormone production and release. It receives signals from various parts of the body and responds by releasing specific hormones that stimulate or inhibit the release of hormones from the pituitary gland. The hypothalamus also controls the release of hormones from other endocrine glands, such as the thyroid gland and adrenal cortex, by producing releasing or inhibiting factors. Therefore, the hypothalamus acts as a coordinator and regulator of the endocrine system, making it the correct answer.

All of the statements given are true. Hormones are released at the capillaries, as they are secreted by endocrine glands into the bloodstream. Hormones bind to target cells when inactivated, as they need to interact with specific receptors on the surface of target cells to exert their effects. Hormones can be broken up by enzymes, which can help regulate their levels in the body. Additionally, hormones can be absorbed or broken down by the liver and kidney, which are important organs involved in the metabolism and elimination of various substances, including hormones. Therefore, all of the statements are correct.

The Adrenal Medulla produces two hormones, adrenaline and noradrenaline, that are controlled by the Sympathetic Nervous System. This system is responsible for the body's "fight or flight" response, which is triggered in response to stress or danger. When the Sympathetic Nervous System is activated, it stimulates the Adrenal Medulla to release adrenaline and noradrenaline into the bloodstream, preparing the body for immediate action. These hormones increase heart rate, blood pressure, and energy levels, and enhance the body's overall response to stress.

Cushing's disease is a hormone disorder characterized by elevated levels of cortisol in the blood. This condition can result in various symptoms, including a rounded face known as "Moon Face." Addison's disease is the opposite of Cushing's disease, as it is caused by low cortisol levels. Aldosteronism and hyperaldosteronism are conditions related to the hormone aldosterone, not cortisol. Therefore, the correct answer is Cushing's disease.

Chief cells are the primary cells of the parathyroid gland. They produce and secrete parathyroid hormone (PTH).

Lipid derivatives, such as steroids, have a longer circulation time because they are highly soluble in lipids and can easily pass through cell membranes. This allows them to be distributed throughout the body and interact with target cells for a longer period of time. Steroids are a specific type of lipid derivative that have various functions in the body, including regulating metabolism, inflammation, and immune responses.

Direct communication occurs between cells of the same type. This type of communication involves direct physical contact between adjacent cells, allowing for the transfer of molecules and signals through gap junctions or plasmodesmata. This direct communication is important for coordinating cellular activities and maintaining tissue integrity.

Paracrine communication is the correct answer because it refers to the mechanism of intercellular communication where cells release chemical messengers that act on nearby cells within the same tissue. These chemical messengers, known as local hormones, transfer information from one cell to another, allowing for coordination and regulation of cellular activities within a specific tissue. This form of communication is distinct from direct communication, synaptic communication, and endocrine communication, which involve different modes of signaling and target different types of cells or tissues.

The hypothalamus controls the posterior pituitary by releasing inhibiting hormones. These inhibiting hormones regulate the release of hormones from the posterior pituitary gland, thereby controlling its function.

Aldosteronism is the correct answer because it is a condition characterized by excess production of aldosterone hormone by the adrenal glands. This hormone is responsible for regulating the balance of potassium (K+) and sodium (Na+) in the body. In aldosteronism, there is an excessive retention of sodium and increased excretion of potassium, leading to low levels of K+. This imbalance can cause cardiac, neural, and kidney failure as potassium is essential for their proper functioning. Addison's disease, Cushing's disease, and hyperaldosteronism are not associated with low levels of K+ and do not cause the same symptoms.

Epinephrine increases glucose availability for ATP production. Epinephrine, also known as adrenaline, is released by the adrenal glands in response to stress or danger. It stimulates the breakdown of glycogen in the liver and muscles, releasing glucose into the bloodstream. This increase in glucose availability allows for the production of ATP, the main energy source for cells. Epinephrine also enhances the breakdown of fats for energy, further supporting ATP production.