Let's Play Anatomy & Physiology II - Ch. Quiz16

Steroid hormones are able to bind to receptors in the nucleus of their target cells. Unlike proteins, steroid hormones are lipid-based molecules that can easily diffuse through cell membranes. Once inside the target cell, they bind to specific receptors located in the nucleus. This binding activates the receptor, leading to changes in gene expression and ultimately affecting cellular processes. Steroid hormones have a longer duration of action compared to proteins and are transported in the blood dissolved in the plasma.

The hypothalamus controls secretion by the anterior pituitary by secreting releasing and inhibiting factors into a tiny portal system. This system allows the hypothalamus to release specific hormones that either stimulate or inhibit the release of hormones by the anterior pituitary. These releasing and inhibiting factors travel through the portal system directly to the anterior pituitary, where they regulate the secretion of hormones into the bloodstream. This mechanism ensures precise control over the anterior pituitary's hormone secretion and allows the hypothalamus to regulate various physiological processes in the body.

Pinealocytes are cells found in the pineal gland, which is responsible for producing melatonin. Melatonin is a hormone that regulates the sleep-wake cycle and helps in maintaining the body's internal clock. It is released in response to darkness and helps to induce sleep. Therefore, the correct answer is melatonin.

Insulin is the correct answer because it is a pancreatic hormone that helps regulate blood sugar levels by promoting the uptake of glucose from the bloodstream into cells. Insulin stimulates the liver and muscles to store excess glucose as glycogen, reducing blood sugar levels. Cortisol, somatotropin, glucagon, and aldosterone do not have the same effect on blood sugar levels as insulin.

When the ovaries are stimulated by FSH (follicle-stimulating hormone), they secrete estrogen. Estrogen is a hormone responsible for the development and regulation of the female reproductive system. It plays a crucial role in the menstrual cycle, the growth and maturation of the uterine lining, and the development of secondary sexual characteristics in females. Therefore, estrogen is the correct answer in this context.

The hormone labeled "1" in Figure 16-1 is corticotropin (ACTH).

The pituitary gland is divided into two lobes, the anterior and posterior lobes. The anterior lobe produces six hormones: growth hormone, prolactin, adrenocorticotropic hormone, thyroid-stimulating hormone, follicle-stimulating hormone, and luteinizing hormone. The posterior lobe produces two hormones: oxytocin and antidiuretic hormone. Therefore, the two lobes of the pituitary gland together produce a total of eight hormones.

Thyroxine is a hormone produced by the thyroid gland that regulates the body's metabolic rate. It controls the rate at which cells convert nutrients into energy, which in turn affects body temperature. Therefore, thyroxine plays a pivotal role in setting the metabolic rate and impacting body temperature.

Insulin targets various cells in the body, including skeletal, cardiac, and smooth muscle cells, as well as adipocytes and liver cells. Insulin plays a crucial role in regulating glucose metabolism and promoting the uptake of glucose into these cells. It helps skeletal, cardiac, and smooth muscle cells to take up glucose for energy production, promotes the storage of excess glucose as fat in adipocytes, and inhibits glucose production in the liver. Therefore, all of the options mentioned in the question are correct as they represent the different cells targeted by insulin.

Oxytocin is a hormone that plays a crucial role in various reproductive processes. It stimulates contractions of the uterus during childbirth, milk ejection from mammary glands during breastfeeding, and also affects the prostate and ductus deferens in males. Therefore, all of the organs mentioned in the options (prostate, ductus deferens, mammary glands, and uterus) contain target cells for oxytocin.

Insulin is the correct answer because it is a pancreatic hormone that helps regulate blood sugar levels by facilitating the entry of glucose into target cells. Insulin is produced by the beta cells of the pancreas and is released in response to high blood sugar levels. It acts by binding to insulin receptors on the surface of target cells, which triggers the uptake of glucose from the bloodstream into these cells. This process helps to lower blood sugar levels and maintain glucose homeostasis in the body.

Peptide hormones are composed of amino acids because they are chains of amino acids that are linked together by peptide bonds. These hormones are synthesized in various glands and tissues throughout the body and play important roles in regulating physiological processes. Examples of peptide hormones include insulin, glucagon, and growth hormone.

PRL (prolactin) and ACTH (adrenocorticotropic hormone) are both hormones secreted by the pituitary gland. PRL is responsible for stimulating milk production in the mammary glands, while ACTH stimulates the production and release of cortisol from the adrenal glands. Therefore, the correct analogy is that PRL is to prolactin as ACTH is to corticotropin.

The C cells of the thyroid gland produce calcitonin. Calcitonin is a hormone that helps regulate calcium levels in the body. It works by inhibiting the activity of osteoclasts, which are cells responsible for breaking down bone tissue and releasing calcium into the bloodstream. By inhibiting osteoclast activity, calcitonin helps to decrease the amount of calcium in the blood, promoting its deposition in bones and preventing excessive calcium release.

Parathyroid hormone is the hormone that has the opposite effect of calcitonin. Calcitonin helps to regulate calcium levels in the blood by inhibiting the release of calcium from the bones. In contrast, parathyroid hormone stimulates the release of calcium from the bones, increasing calcium levels in the blood. This hormone is produced by the parathyroid glands, which are located in the neck.

The adrenal medulla is responsible for the production of epinephrine, also known as adrenaline. Epinephrine is a hormone that plays a crucial role in the body's "fight or flight" response, increasing heart rate, blood pressure, and blood sugar levels. It is released in response to stress or danger, helping to prepare the body for physical exertion and heightened alertness. Androgens, glucocorticoids, mineralocorticoids, and corticosteroids are produced in other parts of the adrenal glands, but not specifically in the adrenal medulla.

Epinephrine is the correct answer because it is a hormone that increases and prolongs the effects of the sympathetic nervous system. It is released by the adrenal glands in response to stress or danger, and it enhances the body's "fight or flight" response. Epinephrine increases heart rate, blood pressure, and blood flow to muscles, while also dilating the airways and increasing glucose production for energy. This hormone helps prepare the body for immediate action in response to a perceived threat or stressor.

The posterior pituitary gland secretes ADH, also known as antidiuretic hormone. ADH plays a crucial role in regulating water balance in the body by acting on the kidneys to increase water reabsorption. This hormone helps to prevent excessive water loss in urine, conserving water and maintaining the body's fluid balance. It is also involved in regulating blood pressure by constricting blood vessels. FSH, TSH, ACTH, and MSH are all hormones secreted by the anterior pituitary gland, not the posterior pituitary gland.

During the alarm phase of the general adaptation syndrome (GAS), the body undergoes a fight-or-flight response to stress. Epinephrine, also known as adrenaline, is the hormone that dominates during this phase. It is released by the adrenal glands and helps to prepare the body for immediate physical activity by increasing heart rate, blood pressure, and energy levels. Epinephrine also redirects blood flow to the muscles and brain, enhancing physical performance and mental alertness.

During the alarm phase of the general adaptation syndrome (GAS), the body goes into a state of stress response. This response is characterized by the mobilization of energy reserves. The body releases stored glucose and fatty acids into the bloodstream to provide a quick source of energy for the body to respond to the stressor. This allows the body to be prepared for the fight-or-flight response and helps in dealing with the immediate threat or stressor. The other options, such as decreased blood flow to skeletal muscles and skin, decreased mental alertness, increased urine release, and decreased rate of respiration, are not associated with the alarm phase of GAS.

After brain surgery, the patient started passing large volumes of very dilute urine. This indicates a condition called diabetes insipidus, which is caused by a deficiency of antidiuretic hormone (ADH) or vasopressin. ADH is responsible for regulating the water balance in the body by promoting water reabsorption in the kidneys. By administering a medicine that mimics ADH, the nurse aims to compensate for the lack of this hormone and reduce the excessive urine production.

When a patient is administered a powerful glucocorticoid like prednisone to suppress the immune system, it can lead to an increase in insulin levels. Glucocorticoids can cause insulin resistance, which means that the body's cells become less responsive to insulin. As a result, the pancreas produces more insulin to compensate for this resistance. Additionally, glucocorticoids can also increase blood glucose levels. They promote gluconeogenesis, which is the production of glucose from non-carbohydrate sources such as amino acids and fatty acids. This combination of increased insulin and increased blood glucose levels is an unintended effect of glucocorticoid administration.

When a G protein becomes activated and causes an activation of enzymes, it triggers a cascade of intracellular events. One of these events is the consumption of ATP, which provides the necessary energy for the enzymatic reactions to occur. Additionally, the activation of enzymes by the G protein also leads to the formation of cAMP (cyclic adenosine monophosphate), which serves as a secondary messenger in many cellular processes. Therefore, the correct answer is that ATP is consumed and cAMP is formed when a G protein becomes activated and causes an activation of enzymes.

The hormone labeled "5" in Figure 16-1 is thyroxin (thyroid hormones).

The hypophyseal portal system refers to a specialized network of blood vessels in the brain that connects two capillary plexuses with short veins. This system is responsible for carrying neurosecretions, including antidiuretic hormone (ADH) and oxytocin, to the anterior lobe of the pituitary gland. Therefore, the correct answer is "all of the above" as all the statements mentioned are true.

Changes in blood osmotic pressure would most affect the secretion of ADH. ADH, or antidiuretic hormone, is released by the posterior pituitary gland in response to increased blood osmotic pressure. When blood osmotic pressure rises, indicating a higher concentration of solutes in the blood, ADH is released to conserve water by reducing urine production in the kidneys. This helps to maintain the body's water balance and prevent dehydration. Therefore, changes in blood osmotic pressure would have the greatest impact on the secretion of ADH.

The correct answer is parathyroid glands; parathyroid hormone. The parathyroid glands are responsible for producing parathyroid hormone (PTH), which plays a crucial role in regulating calcium levels in the blood. Without PTH, there would be a rapid drop in blood calcium levels, leading to muscle contractions and cardiac arrhythmias. This is why the discovery of the parathyroid glands was important in preventing these complications during thyroid surgery.

Gap junctions are specialized protein channels that connect the cytoplasm of adjacent cells, allowing for direct cell-to-cell communication. These junctions play a crucial role in coordinating various cellular activities. In the case of epithelial cells, gap junctions help coordinate ciliary movement, which is important for processes such as the movement of mucus in the respiratory tract. In cardiac muscle cells, gap junctions coordinate contractions, ensuring synchronized and efficient pumping of blood. Additionally, gap junctions facilitate the propagation of action potentials, allowing for rapid and coordinated communication between electrically coupled cells. Therefore, the correct answer is "all of the above."

In a cell that responds to peptide hormones, the link between a first messenger and a second messenger is usually a G protein. G proteins are involved in signal transduction pathways and act as intermediaries between cell surface receptors and intracellular signaling molecules. When a peptide hormone binds to its receptor on the cell surface, it activates a G protein, which then triggers a cascade of biochemical events leading to the production of a second messenger, such as cAMP or calcium ions. These second messengers then transmit the signal within the cell, ultimately resulting in a cellular response to the hormone.

All target cells have hormone receptors and respond to chemical signals. This means that all cells in the body that are capable of receiving and responding to hormones have specific receptors on their surface that allow them to detect and bind to these chemical signals. Once the hormone binds to the receptor, it triggers a series of cellular responses that ultimately lead to a specific physiological effect. Therefore, it is essential for target cells to have both hormone receptors and the ability to respond to chemical signals in order to regulate various bodily functions.

Calcitonin is a hormone that can lower blood levels of calcium ion. It does this by inhibiting the activity of osteoclasts, which are cells responsible for breaking down bone and releasing calcium into the bloodstream. By reducing osteoclast activity, calcitonin helps to decrease blood calcium levels. This hormone is produced by the thyroid gland and is released in response to high levels of calcium in the blood.

When a catecholamine or peptide hormone binds to receptors on the surface of a cell, it triggers a series of intracellular signaling events. These events often involve the activation of second messengers, which are small molecules that relay the signal from the cell surface to the cytoplasm. The second messenger molecules can then initiate various cellular responses, such as the activation of enzymes or the opening of ion channels. Therefore, the correct answer is that a second messenger appears in the cytoplasm.

An activated G protein can trigger the opening of calcium ion channels in the membrane, allowing calcium ions to enter the cell. It can also cause the release of calcium ions from intracellular stores, increasing the concentration of calcium in the cytoplasm. In addition, G protein activation can lead to a fall in cAMP levels by inhibiting adenylate cyclase, the enzyme responsible for cAMP production. However, it can also result in a rise in cAMP levels by activating adenylate cyclase through a different pathway. Therefore, all of the above options are possible outcomes of G protein activation.

During early childhood, the pars intermedia of the adenohypophysis produces melanocyte-stimulating hormone (MSH). MSH plays a role in the regulation of skin pigmentation by stimulating the production and release of melanin in melanocytes. FSH (follicle-stimulating hormone) is involved in the development of ovarian follicles in females and sperm production in males. ADH (antidiuretic hormone) regulates water reabsorption in the kidneys. TSH (thyroid-stimulating hormone) stimulates the thyroid gland to produce thyroid hormones. ACTH (adrenocorticotropic hormone) stimulates the adrenal glands to produce cortisol.

The exocrine portion of the pancreas is responsible for producing digestive enzymes. These enzymes are essential for breaking down carbohydrates, proteins, and fats in the small intestine, allowing for proper digestion and absorption of nutrients. Insulin and glucagon are hormones produced by the endocrine portion of the pancreas, which regulate blood sugar levels. Somatotropin is a growth hormone produced by the pituitary gland, not the pancreas. Bile is produced by the liver and stored in the gallbladder, not the pancreas. Therefore, the correct answer is digestive enzymes.

The mammary glands are prepared for milk secretion by various hormones, including prolactin, estrogens, progesterone, and placental hormones. Prolactin stimulates milk production, while estrogens and progesterone help in the development of the mammary glands and prepare them for milk production. Placental hormones also play a role in preparing the mammary glands for milk secretion. Therefore, all of the mentioned hormones cooperate together to prepare the mammary glands for milk secretion.

Natriuretic peptides and the renin-angiotensin system have opposite effects on the body. Natriuretic peptides promote the excretion of sodium and water, leading to decreased blood volume and blood pressure. On the other hand, the renin-angiotensin system promotes the retention of sodium and water, leading to increased blood volume and blood pressure. Therefore, the effects of natriuretic peptides and the renin-angiotensin system are antagonistic to each other.

The zona reticularis of the adrenal cortex is responsible for producing androgens. Androgens are a group of hormones that are primarily associated with the development and maintenance of male characteristics. They are also present in females but at lower levels. Glucocorticoids are produced in the zona fasciculata and are involved in regulating metabolism and immune response. Mineralocorticoids are produced in the zona glomerulosa and are responsible for regulating electrolyte and water balance. Epinephrine and norepinephrine are produced in the adrenal medulla and are involved in the body's response to stress.

The zona glomerulosa of the adrenal cortex is responsible for producing mineralocorticoids. Mineralocorticoids are a type of steroid hormone that primarily regulate the balance of water and electrolytes in the body. They play a key role in maintaining blood pressure, sodium and potassium balance, and fluid volume. Examples of mineralocorticoids include aldosterone, which promotes sodium reabsorption and potassium excretion in the kidneys, and helps regulate blood pressure. Therefore, the correct answer is mineralocorticoids.

Aldosterone is a hormone that plays a crucial role in regulating the sodium ion content of the body. It is produced by the adrenal glands and acts on the kidneys to increase the reabsorption of sodium ions and the excretion of potassium ions. This helps to maintain the balance of electrolytes in the body and regulate blood pressure. Cortisol is involved in regulating metabolism and stress response, parathormone regulates calcium and phosphate levels, thymosin is involved in immune function, and somatotropin regulates growth and development. Therefore, aldosterone is the correct answer in this case.

Cushing's disease is a condition caused by the overproduction of glucocorticoids, which are a type of steroid hormone. Glucocorticoids, such as cortisol, play a crucial role in regulating various bodily functions, including metabolism, immune response, and stress response. Excess production of glucocorticoids can lead to a range of symptoms, including weight gain, high blood pressure, muscle weakness, and mood changes. Therefore, the correct answer is glucocorticoids.

The hormone labeled "13" in Figure 16-1 is oxytocin. Oxytocin is a hormone produced by the hypothalamus and released by the pituitary gland. It plays a role in various reproductive functions, such as stimulating contractions during childbirth and promoting the release of milk during breastfeeding.

TSH, or thyroid-stimulating hormone, is responsible for the synthesis and release of thyroid hormones. It stimulates the thyroid gland to produce and release hormones such as thyroxine (T4) and triiodothyronine (T3). These hormones are essential for regulating metabolism, growth, and development in the body. Therefore, TSH plays a crucial role in both the synthesis and release of thyroid hormones.

During the resistance phase of the general adaptation syndrome (GAS), the body's stress response is activated. This phase occurs after the initial alarm reaction and is characterized by the body's attempt to adapt and cope with the stressor. One of the ways the body prepares itself during this phase is by mobilizing lipid reserves. This means that stored fats are broken down and used as a source of energy to support the body's increased metabolic demands. This helps to sustain the body's energy levels and allows it to continue functioning despite the ongoing stress.

The symptoms described, such as a deep voice, extensive body hair growth, and cessation of menstruation, are indicative of an excess production of androgens (male sex hormones). The zona reticularis of the adrenal gland is responsible for the production of these androgens, making it the most likely location of the hormone-secreting tumor in Shelly's case. The other options, such as the zona glomerulosa (involved in the production of aldosterone) or the adrenal medulla (involved in the production of adrenaline), are not associated with the symptoms described.

The supraoptic nucleus of the hypothalamus is responsible for producing and releasing antidiuretic hormone (ADH), also known as vasopressin. ADH plays a crucial role in regulating water balance in the body by promoting water reabsorption in the kidneys. Therefore, if the supraoptic nucleus is destroyed, it would result in a loss of ADH secretion. This would lead to decreased water reabsorption in the kidneys, causing increased urine output and potentially leading to dehydration.

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The zona fasciculata of the adrenal cortex is responsible for producing glucocorticoids. Glucocorticoids are a type of steroid hormone that regulate various metabolic processes in the body, including the metabolism of glucose, proteins, and fats. They also have anti-inflammatory and immunosuppressive effects. Androgens are produced in the zona reticularis, while mineralocorticoids, such as aldosterone, are produced in the zona glomerulosa. Epinephrine and norepinephrine are produced by the adrenal medulla, not the adrenal cortex.

Steroid hormones are derived from cholesterol and are produced by reproductive glands. They are lipids and bind to receptors within the cell. However, they are not produced by the adrenal medulla. The adrenal medulla produces catecholamines, such as adrenaline and noradrenaline, not steroid hormones.

Parathyroid hormone (PTH) is responsible for regulating calcium levels in the body. It stimulates osteoclast activity, which breaks down bone to release calcium into the bloodstream. PTH also inhibits osteoblast activity, which is involved in bone formation. It stimulates the formation and secretion of calcitriol at the kidneys, which is the active form of vitamin D that helps increase calcium absorption in the intestines. Additionally, PTH enhances the reabsorption of calcium at the kidneys, reducing its excretion. However, PTH does not directly build up bone, as that is primarily the role of osteoblasts.

The pineal gland is a small endocrine gland located in the brain. It is a component of the epithalamus, not the hypothalamus. The pineal gland secretes melatonin, a hormone that regulates sleep and wakefulness. It contains pinealocytes, specialized cells that produce and release melatonin. Additionally, the pineal gland responds to light and darkness by adjusting melatonin production accordingly.

Addison's disease is caused by too little secretion of cortisol, which is a hormone produced by the adrenal glands. This condition occurs when the adrenal glands do not produce enough cortisol and sometimes aldosterone. This can lead to various symptoms including fatigue, weight loss, low blood pressure, and darkening of the skin. Goiter is typically caused by an iodine deficiency, while diabetes mellitus and diabetes insipidus are related to issues with insulin production or the body's ability to regulate blood sugar. Cushing's disease, on the other hand, is caused by excessive secretion of cortisol.

TSH (thyroid-stimulating hormone) is produced by the pituitary gland and plays a key role in regulating the thyroid gland. It stimulates T3 and T4 secretion, which are the thyroid hormones. TSH also stimulates iodide trapping by thyroid follicle cells, which is the process of taking up iodine from the blood to synthesize thyroid hormones. Additionally, TSH stimulates pinocytosis of colloid by thyroid follicle cells, which is the process of absorbing the protein-rich colloid from the follicles. TSH increases cyclic AMP concentration within thyroid follicle cells, which is an important signaling molecule for thyroid hormone synthesis. However, TSH does not inhibit T3 and T4 secretion.

Renin is an enzyme that plays a crucial role in the activation of angiotensin. Angiotensin is a hormone that causes blood vessels to constrict, leading to an increase in blood pressure. Renin is released by the kidneys in response to low blood pressure or low blood volume. It acts on angiotensinogen, a protein produced by the liver, and converts it into angiotensin I. Angiotensin I is then converted into angiotensin II by the enzyme angiotensin-converting enzyme (ACE). Angiotensin II is a potent vasoconstrictor and also stimulates the release of aldosterone, which increases sodium reabsorption and water retention, further contributing to an increase in blood pressure.

When a steroid hormone binds to its receptor to form an active complex, it triggers a series of events that ultimately lead to the initiation of gene transcription. This is because the steroid hormone-receptor complex acts as a transcription factor, binding to specific DNA sequences and promoting the assembly of the transcriptional machinery. This results in the synthesis of messenger RNA (mRNA) from the genes that are targeted by the hormone-receptor complex, leading to the production of specific proteins that mediate the hormone's effects on the target cells.

LH, or luteinizing hormone, is the pituitary hormone that promotes ovarian secretion of progesterone and testicular secretion of testosterone. LH is responsible for triggering ovulation in females, leading to the release of an egg from the ovary, and stimulating the production of testosterone in males. This hormone plays a crucial role in the reproductive system and is essential for the regulation of hormonal balance and fertility.

Thyroid hormones are known to increase heart rate and force of contraction, so the correct answer is that they do not result in decreased heart rate and force of contraction.

Cortisol is a hormone secreted by the adrenal glands that plays a crucial role in regulating glucose levels in the body. It promotes glucose formation in the liver through a process called gluconeogenesis. Gluconeogenesis involves converting non-carbohydrate sources, such as amino acids and fatty acids, into glucose. This helps to maintain adequate blood glucose levels, especially during times of stress or fasting. Aldosterone, erythropoietin, thymosin, and parathormone do not have a direct role in promoting glucose formation in the liver.

Inadequate iodine in the diet can lead to various health conditions. Hypothyroidism occurs when the thyroid gland does not produce enough thyroid hormones, which can result from a lack of iodine. Cretinism is a severe form of hypothyroidism that occurs in infants and children, leading to stunted growth and intellectual disabilities. Goiter is the enlargement of the thyroid gland, often caused by iodine deficiency. High blood levels of TSH (thyroid-stimulating hormone) can also be a result of inadequate iodine intake. Therefore, all of the mentioned conditions can occur due to inadequate iodine in the diet.

When blood glucose levels fall, the body releases glucagon. Glucagon is a hormone produced by the pancreas that helps to increase blood glucose levels. It does this by stimulating the liver to convert stored glycogen into glucose and release it into the bloodstream. This release of glucose helps to maintain blood sugar levels within a normal range. Therefore, the correct answer is that glucagon is released when blood glucose levels fall.

MSH is secreted by the human pars intermedia in very young children. This hormone plays a role in regulating skin pigmentation, and its secretion is highest during early childhood. As individuals age, the production of MSH decreases. Additionally, MSH can also be secreted in times of stress or in healthy adults, but the highest levels are found in young children.

FSH, also known as follicle-stimulating hormone, is a pituitary hormone that plays a crucial role in reproductive processes. In females, FSH stimulates the growth and development of ovarian follicles, which contain the eggs. It also helps in the production of estrogen. In males, FSH stimulates the production of sperm in the testes. Therefore, FSH is responsible for promoting egg development in ovaries and sperm development in testes.

Activation of the renin-angiotensin system leads to vasoconstriction, which increases blood pressure. It also stimulates the release of aldosterone, which promotes sodium and water retention in the kidneys, leading to increased blood volume and water retention. However, it does not directly affect urine production.

When stress lasts longer than a few hours, an individual will enter the resistance phase of the general adaptation syndrome (GAS). During this phase, the body tries to adapt to the ongoing stressor and maintain physiological balance. The body's resources are mobilized to cope with the stress, and the individual may experience increased resistance to illness or injury. This phase allows the body to continue functioning despite the presence of stress.

During the resistance phase of the general adaptation syndrome (GAS), the body is under prolonged stress and needs to adapt to the ongoing stressor. Glucocorticoids, such as cortisol, are the hormones that dominate during this phase. They are released by the adrenal glands in response to stress and help regulate various physiological processes, including metabolism, immune function, and the body's response to inflammation. Glucocorticoids play a crucial role in mobilizing energy stores and suppressing inflammation, allowing the body to sustain a prolonged response to stress.

Damage to cells of the zona fasciculata of the adrenal cortex would result in decreased ability to convert amino acids to glucose. The zona fasciculata is responsible for producing glucocorticoids, such as cortisol, which play a key role in glucose metabolism. These hormones stimulate the breakdown of proteins, including amino acids, and promote the conversion of amino acids into glucose through a process called gluconeogenesis. Damage to the zona fasciculata would impair the production of glucocorticoids, leading to a decreased ability to convert amino acids to glucose.

Growth hormone is known to have several functions in the body, including promoting bone and muscle growth, as well as promoting amino acid uptake by cells. Additionally, growth hormone is also known to be glucose sparing, meaning it helps to preserve glucose levels in the body. However, growth hormone does not cause fat accumulation within adipocytes.

The regulatory factors that control secretion of anterior pituitary hormones are released by neurons at the median eminence of the hypothalamus. The median eminence is a specialized region at the base of the hypothalamus where neurosecretory cells release hormones into the hypophyseal portal system. These hormones then travel to the anterior pituitary gland, where they stimulate or inhibit the release of specific hormones. This communication between the hypothalamus and the anterior pituitary is essential for maintaining hormonal balance in the body.

Oxytocin is released due to sensory input and is part of a neuroendocrine reflex. Oxytocin is a hormone that plays a role in various reproductive functions, including labor and lactation. It is released in response to sensory stimuli such as touch, suckling, and sexual activity, and helps facilitate bonding and social interactions.

The cells of the adrenal cortex produce aldosterone. Aldosterone is a hormone that is responsible for regulating the balance of salt and water in the body. It acts on the kidneys to increase the reabsorption of sodium and the excretion of potassium, which helps to maintain blood pressure and electrolyte balance. Epinephrine and norepinephrine are produced by the adrenal medulla and are involved in the body's response to stress. ACTH is a hormone produced by the pituitary gland that stimulates the production of cortisol in the adrenal cortex. Angiotensin is a hormone that is involved in regulating blood pressure.

Exposure to light stimulates the production of melatonin. Melatonin is a hormone that is produced by pinealocytes, which are cells in the pineal gland. It is synthesized from serotonin. Melatonin production is inhibited by exposure to light, not stimulated.

Calmodulin is an intracellular protein that binds to calcium ions and acts as a messenger. It is involved in various cellular processes, including muscle contraction, enzyme regulation, and cell growth. The other options, calcitonin, calcitriol, calcium-binding globulin, and calcitropin, are not directly involved in calcium ion signaling and do not serve as messengers in the same way as calmodulin.

Liver cells respond to growth hormone by releasing hormones called somatomedins. Somatomedins, also known as insulin-like growth factors (IGFs), are produced by the liver in response to growth hormone stimulation. They play a crucial role in promoting growth and development of various tissues and organs in the body. These hormones act locally and systemically to stimulate cell growth, protein synthesis, and bone growth. Therefore, somatomedins are the correct answer in this case.

Parathyroid hormone (PTH) is responsible for regulating calcium levels in the blood. When PTH levels increase, it stimulates the release of calcium from the bones into the bloodstream and enhances the absorption of calcium from the intestines. This leads to increased levels of calcium ions in the blood. Thymosin, calcitonin, aldosterone, and cortisol do not directly affect calcium levels in the blood.

A rise in cortisol, which is a stress hormone, would cause an increase in the rate of glucose synthesis by the liver, the rate of glycogen formation by the liver, and the level of fatty acids in the blood. This is because cortisol promotes the breakdown of stored glycogen and fats to provide energy during stressful situations. However, cortisol would not directly affect the levels of ACTH (adrenocorticotropic hormone), which is responsible for stimulating the release of cortisol from the adrenal glands. Therefore, the correct answer is ACTH levels.

The correct answer is thyroid-stimulating hormone. This hormone is not an amino acid derivative, unlike the other options listed. Epinephrine, norepinephrine, and melatonin are all derived from amino acids. Thyroid hormone, while not directly derived from amino acids, is synthesized from the amino acid tyrosine.

If the median eminence of the hypothalamus is destroyed, the hypothalamus would no longer be able to control the secretion of melanocyte-stimulating hormone. The median eminence is a region in the hypothalamus that serves as a bridge between the hypothalamus and the pituitary gland. It releases hormones called releasing factors into the hypothalamic-pituitary portal system, which then travel to the anterior pituitary gland and stimulate the release of specific hormones. Melanocyte-stimulating hormone is one of the hormones that is regulated by the hypothalamus through this pathway. Therefore, if the median eminence is destroyed, the control over melanocyte-stimulating hormone secretion would be lost.

The exhaustion phase of the general adaptation syndrome (GAS) is characterized by decreased resistance to disease and infection. This is because during the exhaustion phase, the body's resources have been depleted due to prolonged exposure to stress. The body's immune system becomes weakened, making it more susceptible to diseases and infections. Therefore, the correct answer is decreased resistance to disease and infection.