AP Bio Endocrine Quiz
Which anterior pituitary hormone regulates blood glucose control by the pancreas? Possible Answers: None of the answers provided Antidiuretic hormone Glucagon Adrenocorticotropic hormone (ACTH)
Which anterior pituitary hormone regulates blood glucose control by the pancreas? Possible Answers: None of the answers provided Antidiuretic hormone Glucagon Adrenocorticotropic hormone (ACTH)
Which of the following is a hormone that is directly regulated by the nervous system? Possible Answers: Calcitonin Epinephrine Melatonin Estrogen
Which of the following is a hormone that is directly regulated by the nervous system? Possible Answers: Calcitonin Epinephrine Melatonin Estrogen
While walking home from class one afternoon, you take a shortcut that leads you in front of a house that is guarded by a huge, barking dog. Unfortunately, you are terrified of dogs! Though the dog is unable to escape its yard, as you walk past you notice yourself breathing more quickly than normal and you can feel your heart racing and your palms sweating. Which of your glands is most likely responsible for your physiological reaction to the dog? Possible Answers: Pineal gland Adrenal medulla Anterior pituitary Adrenal cortex
Correct answer: Adrenal medulla Explanation: The adrenal gland is almost certainly responsible for your reaction, as this gland contains the adrenal medulla, which is capable of releasing epinephrine. During stressful situations, the sympathetic nervous system triggers the fight-or-flight response. During this response, sympathetic nerves stimulate the adrenal medulla, which then releases epinephrine. Epinephrine raises blood sugar levels and increases blood pressure, brain oxygen consumption, and heart rate. It prepares an individual to either fight a threat (such as a dog), or run away from it. The anterior pituitary is capable of releasing a number of hormones including growth hormone, thyroid-stimulating hormone, and prolactin. The pineal gland is involved in biorhythms and sleep patterns. The adrenal cortex is stimulated by adrenocorticotropic hormone and releases corticosteroids in response to long-term stress, such as sleep or food deprivation.
How might Grave's disease cause hyperthyroidism? (Note: Your mother had grave's disease! but she is fine now but I know about it...) Possible Answers: Antibody binding and activation of thyroid-stimulating hormone receptors A cellular immune response selectively destroys thyroid-stimulating hormone producing cells in the pituitary A cellular immune response selectively destroys cell in the parathyroid glands Antibody binding and inactivation of thyroid-stimulating hormone
Correct answer: Antibody binding and activation of thyroid-stimulating hormone receptors Explanation: Hyperthyroidism is an over-secretion of the thyroid hormones, resulting in an increase in metabolism and energy consumption. Grave's disease is the most common cause of hyperthyroidism. It is an autoimmune disorder in which the body's immune system produces antibodies that bind to the thyroid-stimulating hormone (TSH) receptor. The binding of the antibody to the receptor serves as a non-hormonal activation of the receptor and thyroid hormone continues to be produced, even when TSH is not present. The normal negative feedback mechanism to maintain thyroid hormone levels is bypassed. Inactivation of thyroid-stimulating hormone or its receptors would cause a decrease in the production of thyroid hormone, known as hypothyroidism. The parathyroid glands are not directly involved in regulating thyroid hormone.
Which pituitary hormone is responsible for regulating the water volume in blood? Possible Answers: Glucagon Oxytocin Aldosterone Insulin Antidiuretic hormone
Correct answer: Antidiuretic hormone Explanation: Antidiuretic hormone (ADH) is secreted by the posterior pituitary and acts on the kidney tubules, increasing the water retention in blood and decreasing the water volume in urine. It works by increasing the number of aquaporins (water channels in the plasma membrane) in the collecting duct of the kidney nephrons. Water flows down its osmotic gradient out of tubule, and into the blood for circulation. Aldosterone also functions to regulate water volume in the blood, and is associated with the renin-angiotensin-aldosterone system (RAAS). Aldosterone functions by increasing sodium reabsorption. This increases the solute concentration in the blood, passively causing water to diffuse out of the filtrate and into the blood. Though aldosterone and antidiuretic hormone have similar functions, aldosterone is secreted by the adrenal cortex, not the pituitary. Oxytocin stimulates uterine contractions and milk release in the mammary glands. Glucagon and insulin are involved in the regulation of blood sugar levels.
Glucocorticoid release by the adrenal glands functions to mobilize fuel for the body in what way? Possible Answers: Breakdown of proteins from skeletal muscle Conversion of stored fat to glucose Signaling the pancreas to secrete glucagon Direct stimulation of a feedback loop to the hypothalamus
Correct answer: Breakdown of proteins from skeletal muscle Explanation: Glucocorticoids are produced from the adrenal gland. Their primary effect increases energy and glucose metabolism by making more glucose available from non-carbohydrate sources. Glucocorticoids stimulate gluconeogenesis. One way this is accomplished is through activation of the glucocorticoid receptors within skeletal muscle, which signal the breakdown of muscle proteins to their corresponding amino acids. The amino acids are then transported to the liver and kidneys where they are converted to glucose, which is released into the bloodstream. The ability to make glucose from muscle proteins can provide additional fuel when the body needs more glucose (under stress conditions) than the liver can mobilize from the glycogen it has stored. The process, however, can be detrimental if stimulated for extended periods of time.
Amy has osteoporosis, which is a disease that affects the bone. It occurs in individuals with low calcium levels in their bones. The bones become weak, brittle and may break. Which of the following hormones would she need to produce to help reduce the problems associated with osteoporosis? Possible Answers: Calcitriol Calmodulin Parathyroid hormone Growth hormone Calcitonin
Correct answer: Calcitonin Explanation: Calcitonin is the hormone in charge of taking calcium ions from the bloodstream and incorporating them into the matrix of the bone. This allows the bone to produce hydroxyapatite crystals from the calcium, which can strengthen the matrix of the bone and reduce the effect of osteoporosis. Parathyroid hormone and calcitriol (vitamin D) have opposite effects as calcitonin - they increase the blood calcium levels through breaking down bone and increasing the absorption of calcium in the gut. Growth hormone is responsible for normal growth and development of the body, especially bones and skeletal muscles. It is not involved in regulation of minerals such as calcium. Calmodulin is a calcium binding protein that regulates many intracellular processes.
What is the hormone responsible for decreasing blood levels of calcium? Possible Answers: Thyroxine Parathyroid hormone (PTH) Calcitonin Triiodothyronine Melatonin
Correct answer: Calcitonin Explanation: The hormone responsible for the reduction of calcium in the blood is calcitonin. This hormone promotes the assimilation of calcium ions into the bone matrix from the blood. This reduces the concentration of calcium ions in the blood and increases the concentration found in the bone. Meanwhile, PTH has the opposite effect by taking calcium ions from the bone matrix and releasing them into the blood.
Which hormone is most likely to be produced in order to decrease plasma calcium levels? Possible Answers: Melatonin Oxytocin Parathyroid hormone Antidiuretic hormone Calcitonin
Correct answer: Calcitonin Explanation: The two hormones known for their effect on plasma calcium levels are calcitonin and parathyroid hormone (PTH). When calcium levels are high, calcitonin is released by the thyroid gland to stimulate the uptake of serum calcium into bone. This effectively decreases calcium levels in the blood. PTH has the opposite effect and is released by the parathyroid gland. The three remaining answer choices are not known for their effect on calcium levels in the blood.
Which of the following is most directly regulated by parathyroid hormone (PTH)? Possible Answers: Corticosteroids Glucose Thyroid hormone Calcium ions
Correct answer: Calcium ions Explanation: Calcium ions are essential for normal cellular function. Parathyroid hormone is released when blood calcium levels fall below a threshold of about 10mg per 100mL. Parathyroid hormone acts to raise blood calcium through multiple mechanisms. It works directly to increase blood calcium by causing demineralization of bone and by directly stimulating ion reabsorption in the kidneys. It also acts indirectly by stimulating conversion of vitamin D, which acts on the intestines to stimulate the uptake of calcium ions from food.
The corpus luteum releases progesterone to prevent menstruation from occurring; if an ovum is not fertilized, then menstruation occurs. What happens to progesterone levels if the ovum is not fertilized? Possible Answers: Progesterone levels stay the same Increase Progesterone levels will depend on relative estrogen levels Decrease
Correct answer: Decrease Explanation: In order for menstruation to occur, progesterone levels must decrease. When fertilization does not occur, the corpus luteum ceases progesterone production, initiating menstruation. The corpus luteum then transitions into the corpus albicans and removed from the ovary in preparation for the new menstrual cycle.
_________ is a critical hormone that controls heart rate and constriction of blood vessels. It is crucial in the fight-or-flight response. Possible Answers: Glucagon Insulin Epinephrine Cortisol
Correct answer: Epinephrine Explanation: Epinephrine, released from the adrenal gland, is important for the fight-or-flight response. During moments of stress, heart rate increases, pupils dilate, and blood vessels constrict in order to prepare for danger. All of this is controlled by epinephrine and norepinephrine, and is part of the sympathetic nervous system.
Which of the following is does not describe an endocrine interaction? Possible Answers: Adrenocorticotropic hormone is secreted to stimulate secretion of cortisol Epinephrine is secreted into a synapse to excite a post-synaptic neuron Insulin is secreted by the pancreas to lower blood-glucose levels All of these are endocrine interactions
Correct answer: Epinephrine is secreted into a synapse to excite a post-synaptic neuron Explanation: Endocrine interactions involve a molecule (hormone) being secreted into the bloodstream to trigger a response in target cells in a different location. Reduction of blood-glucose levels by insulin and stimulation of cortisol release by adrenocorticotropic hormone are both examples of endocrine function. Though epinephrine can act as a hormone when secreted by the adrenal medulla, the answer option indicates that it is being secreted by a neuron into a synapse. In this case, epinephrine would be acting as a neurotransmitter, causing an effect on a neighboring post-synaptic neuron. This answer does not describe an endocrine interaction.
Which of the following is produced by the pituitary gland? Possible Answers: Estrogen Follicle-stimulating hormone Insulin Epinephrine Testosterone
Correct answer: Follicle-stimulating hormone Explanation: The hormones secreted by the pituitary gland are FLAT PEG: Follicle-stimulating hormone, luteinizing hormone, adrenocorticotropic hormone, thyroid-stimulating hormone, prolactin, endorphins, and growth hormone. Testosterone is produced in the testes in males, and in the adrenal gland in both males and females. Insulin is produced by the pancreas. Estrogen is produced by the ovaries in females, and in the adrenal gland in both males and females.
Where in the body is core temperature regulated? Possible Answers: Anterior pituitary Posterior pituitary Thalamus Hypothalamus
Correct answer: Hypothalamus Explanation: The hypothalamus is a structure in the brain responsible for homeostatic control over much of the body. It is responsible for maintaining core body temperature within normal levels. There are special neurons located within the hypothalamus that respond to changes in body temperature. The hypothalamus then sends out signals to the result of the body in response to changes in temperature.
Which of the following provides the correct sequence of signaling for a hormone cascade pathway? Possible Answers: Anterior pituitary, endocrine gland, hypothalamus, target cells Hypothalamus, endocrine gland, anterior pituitary, target cells Hypothalamus, anterior pituitary, endocrine gland, target cells Anterior pituitary, hypothalamus, endocrine gland, target cells
Correct answer: Hypothalamus, anterior pituitary, endocrine gland, target cells Explanation: Groups of hormones from the hypothalamus, anterior pituitary, and individual endocrine glands are often organized into a hormone cascade pathway. The flow of such a cascade occurs as follows: 1. Signals or sensory cells in the brain trigger the hypothalamus to secrete a hormone (example: thyroid-releasing hormone) that either stimulates or inhibits release of a particular hormone from the anterior pituitary. 2. The anterior pituitary hormone (example: thyroid-stimulating hormone) acts on a target endocrine tissue (example: thyroid gland) 3. The endocrine tissue secretes a systemic hormone (example: thyroid hormone/T4) that creates a physiological response. 4. The physiological response by the target cells provides negative feedback to the brain to curtail the cascade.
hat key factor distinguishes type 1 diabetes from type 2 diabetes? Possible Answers: Type 2 diabetes is an autoimmune disorder In type 1 diabetes, the body remains responsive to insulin Type 1 diabetes is usually associated with being overweight Type 2 diabetes usually occurs after age 40, when insulin production decreases
Correct answer: In type 1 diabetes, the body remains responsive to insulin Explanation: Type 1 diabetes, also known as insulin-dependent diabetes, is an autoimmune disease in which the body attacks and destroys the beta cells within the islet of Langerhans. These cells produce insulin, which normally works in a regulated feedback mechanism with glucagon to maintain glucose homeostasis. Type 1 diabetes usually occurs in children and is treatable with injectable insulin shots. Glucose levels need to be monitored frequently to know when insulin needs to be given/taken to maintain proper glucose levels. In type 1 diabetes, the determining factor is the inability to produce insulin due to destruction of the beta cells. The body remains responsive to insulin. In type 2 diabetes the body is still capable of producing insulin, but the tissues of the body have become unresponsive and do not remove glucose from the bloodstream. Type 2 diabetes generally begins during adulthood and is not caused by autoimmune interaction.
After a large meal, an individual's blood sugar increases. This signals an increase in which of the following hormones? Possible Answers: Insulin Thyroxine (T4) Glucagon Adrenocorticotropic hormone (ACTH) Epinephrine
Correct answer: Insulin Explanation: After a large meal the body must quickly remove glucose from the blood. Insulin facilitates the entry of glucose into a variety of body cells, particularly hepatocytes in the liver. Once inside the cell, glucose is either stored as a polymer (glycogen) or reduced into carbon dioxide and water to produce a usable form of energy (ATP) for the cell. Glycogen is stored in the liver until blood glucose levels become low, at which point it can be converted back to glucose and released to maintain homeostasis. This process, known as glycogenolysis, is stimulated by the release of glucagon. Together, insulin and glucagon create a negative feedback loop to regulate glucose in the blood. Thyroxine (T4) regulates metabolic rate, and is released from the thyroid. Adrenocorticotropic hormone (ACTH) is released from the anterior pituitary and stimulates the release of glucocorticoids (like cortisol) from the adrenal glands. The release of epinephrine is tightly linked to the sympathetic nervous system, and is involved in the immediate stress response.
ollowing a large meal, which of the following biological changes occurs? Possible Answers: Glycogenolysis begins to occur Insulin levels drop, facilitating the release of glucose from cells Gluconeogenesis activity increases Insulin levels spike, facilitating the storage of glucose into cells Glucagon levels spike, promoting the breakdown of glycogen
Correct answer: Insulin levels spike, facilitating the storage of glucose into cells Explanation: Following a large uptake of glucose, the body will begin to release insulin to facilitate storage of the glucose molecules within the cells of the liver, as well as skeletal muscles. Glucagon is released when blood glucose levels are low and promotes an increase in free blood glucose. The breakdown of glycogen into free blood glucose is a process known as glycogenolysis; this process is stimulated by glucagon and inhibited by insulin. Gluconeogenesis is the generation of glucose from non-carbohydrate carbon substrates; it is also stimulated by glucagon and inhibited by insulin.
Which of the given elements is a component of thyroid hormone? Possible Answers: Iodine Copper Zinc Potassium
Correct answer: Iodine Explanation: There are two types of thyroid hormone: T3 and T4. Both hormones are derived from the amino acid tyrosine, and are created by the addition of iodine atoms to the amino acid structure. The full name of T3 is triiodothyronine (three iodine atoms) and the full name of T4 is tetraiodothyronine (four iodine atoms). Because iodine is specific to the production of thyroid hormone, radioactive iodine is used to gather images of the thyroid gland. If iodine levels are low, the thyroid cannot produce sufficient thyroid hormone. The result is hypothyroidism. Symptoms of hypothyroidism include weight gain, lethargy, and intolerance to cold. In extreme cases, the thyroid will enlarge in an attempt to produce more hormone, resulting in a goiter.
What aspect of growth hormone differentiates it from other anterior pituitary hormones? Possible Answers: It produces both tropic and non-tropic effects It is a steroid hormone It provides negative feedback directly to the hypothalamus It is the only glycoprotein hormone
Correct answer: It produces both tropic and non-tropic effects Explanation: Non-tropic hormones are hormones that directly stimulate target cells to induce effects. For example, aldosterone acts directly on the kidney to promote reabsorption of sodium, which causes an increase in blood pressure. This differs from tropic hormones, which act on other endocrine glands to stimulate (or inhibit) release of a second hormone. For example, thyroid-stimulating hormone is responsible for stimulating the release for thyroid hormone by acting on the thyroid gland. Growth hormone (GH) stimulates growth through both tropic and non-tropic mechanisms. Growth hormone's major tropic effect is to stimulate the release of insulin-like growth factors (IGFs) from the liver, which causes bone growth. Growth hormone also stimulates a number of tissues through non-tropic mechanisms to affect metabolism and raise blood glucose levels.
Which of these hormones is responsible for the secretion of testosterone in males? Possible Answers: Luteinizing hormone (LH) Follicle stimulating hormone (FSH) Oxytocin Human growth hormone (hGH)
Correct answer: Luteinizing hormone (LH) Explanation: Luteinizing hormone is responsible for the secretion of testosterone from leydig cells in the testes. FSH is responsible for the proliferation of sertoli cells, which nurture sperm cell precursors. hGH is responsible for body growth, and is not responsible for testosterone formation. Oxytocin is responsible for increasing uterine contractions during pregnancy.
__________ causes testosterone production in males and triggers ovulation in females. Possible Answers: Luteinizing hormone (LH) Estrogen Testosterone Follicle-stimulating hormone (FSH)
Correct answer: Luteinizing hormone (LH) Explanation: The hormone described in the question is luteinizing hormone (LH). If fertilization occurs, the LH levels will decrease and human chorionic gonadotropin (hCG) is released from the placenta to simulate LH function.
Which of the following hormones is not secreted by the pituitary gland? Possible Answers: Follicle-stimulating hormone Melatonin Adrenocorticotropic hormone Growth hormone Prolactin
Correct answer: Melatonin Explanation: Melatonin is secreted by the pineal gland, which is also in the brain. The function of melatonin is not yet certain, but current research hints that it plays functions in regulation of the circadian rhythm. All other hormones are indeed secreted by the pituitary gland.
Example Question #31 : Endocrine System Which of the following statements is not true of melatonin? Possible Answers: Melatonin affects skin pigmentation Melatonin is structurally similar to corticosteroids Melatonin's main function is to regulate functions related to light and changes in day length Melatonin is produced in the pineal gland
Correct answer: Melatonin is structurally similar to corticosteroids Explanation: Melatonin is a modified amino acid that is secreted by the pineal gland. The pineal gland contains light-sensitive cells and has nervous connections to the eyes that affect its secretory activity. As a result, melatonin regulates functions related to light, circadian rhythm, and seasonal alterations based on the amount of daylight. Melatonin is secreted at night, and the amount released depends on the length of the night. In winter, for example, more melatonin is released. Melatonin is believed to target a group of neurons in the hypothalamus called the suprachiasmatic nucleus (SCN), which functions as a biological clock. Melatonin also affects skin pigmentation in many vertebrates. Since melatonin is a modified amino acid, its structure is very different from that of corticosteroids, which are synthesized from the lipid cholesterol. Melatonin has two rings (similar to tryptophan), a modified ether group (from the carboxylic acid of the amino acid), and an amide group (from the amine group of the amino acid). Corticosteroids have four rings and multiple hydroxyl and ketone groups.
Vasopressin is released when sensory neurons in the hypothalamus detect a rise in the osmolarity of the blood. When secreted, this hormone causes changes in water reabsorption by the kidneys. This is an example of what type of signaling? Possible Answers: Synaptic signaling Neuroendocrine signaling Autocrine signaling Paracrine signaling
Correct answer: Neuroendocrine signaling Explanation: Neuroendocrine signaling describes the process when specialized neural sensors, usually in the brain, detect changes in the body. These sensors stimulate the release of a hormone to help correct deviations. The hormone can travel via the bloodstream to affect distant tissues. In this example, sensor neurons in the hypothalamus trigger the release of the hormone vasopressin to affect the kidney.
Which of the following hormones is produced in the posterior pituitary gland? Possible Answers: Growth hormone Melatonin Prolactin Epinephrine Oxytocin
Correct answer: Oxytocin Explanation: The correct answer is oxytocin because this hormone is produced in the posterior pituitary gland along with antidiuretic hormone (ADH). Oxytocin is responsible for uterine contraction during labor in a positive feedback look mechanism.
Most hormone regulatory signaling is based on negative feedback control mechanisms. What hormone operates through a positive feedback mechanism? Possible Answers: Insulin Calcitonin Vasopressin Oxytocin
Correct answer: Oxytocin Explanation: The oxytocin pathway is an example of a positive feedback mechanism. Unlike negative feedback, which counteracts a stimulation, positive feedback reinforces a stimulus, leading to an even greater response. One key function of oxytocin in mammals is to regulate the release of milk during nursing. In this case, the initial stimulus in the oxytocin pathway is an infant suckling, which stimulates sensory nerve cells in the nipples. The signal is received in the hypothalamus, which signals the posterior pituitary to secrete more oxytocin. Additional oxytocin is released into the bloodstream, signaling the mammary glands to secrete milk and perpetuating the stimulation of the hypothalamus. Oxytocin participates in a similar positive feedback loop when it stimulates uterine contractions during birth. Vasopressin (antidiuretic hormone) is moderated by a negative feedback loop based on blood pressure. Based on pressure sensors in the body, vasopressin will be released or inhibited. Insulin and glucagon work in a negative feedback loop via sensors in the pancreas to moderate blood glucose levels. Calcitonin and parathyroid hormone work in a negative feedback loop to moderate blood calcium.
_________, released from the __________, is the hormone responsible for controlling lactation in nursing women, as well as triggering labor in pregnant women. Oxytocin . . . posterior pituitary Vasopressin . . . posterior pituitary Luteinizing hormone . . . posterior pituitary Follicle-stimulating hormone . . . hypothalamus
Correct answer: Oxytocin . . . posterior pituitary Explanation: Oxytocin is responsible for lactation in nursing women. When the nipple is stimulated, oxytocin is released from the posterior pituitary to cause lactation. During labor, release of oxytocin causes positive feedback on the hypothalamus, which causes further oxytocin release. Luteinizing hormone and follicle-stimulating hormone are released from the anterior pituitary and function to regulate the menstrual cycle. Vasopressin is released from the posterior pituitary and helps to regulate blood pressure and water balance.
Where is the hormone melatonin produced? Possible Answers: Anterior pituitary Adrenal gland Posterior pituitary Pancreas Pineal gland
Correct answer: Pineal gland Explanation: Melatonin is produced in the pineal gland which is a gland in the brain responsible for the body's circadian rhythms and sleep/wake cycle. The concentration of melatonin peaks at night and causes us to fall asleep. Melatonin is degraded while we sleep so that when we wake up in the morning we start to produce it again throughout the day.
Which disorder is correctly matched with a probable cause? Possible Answers: Enlargement of face and extremities: hypersecretion of thyroxine Low blood calcium: hypersecretion of parathyroid hormone Enlargement of face and extremities: hyposecretion of growth hormone Diabetes: hypersecretion of insulin Pituitary dwarfism: hyposecretion of growth hormone
Correct answer: Pituitary dwarfism: hyposecretion of growth hormone Explanation: To answer this question, it is necessary to understand the prefixes "hyper" and "hypo." "Hyper" refers to excessive synthesis, while "hypo" refers to reduced synthesis. Growth hormone is responsible for stimulating cell growth and division throughout the body. Hyposecretion would cause a deficiency and reduce the effectiveness of growth hormone, potentially causing pituitary dwarfism. Hyposecretion of growth hormone in adults leads to poor protein synthesis, which significantly impacts the muscles and skin. Enlargement of the face and extremities is an adult condition known as acromegaly. The underlying cause is hypersecretion of growth hormone. In children, this condition can lead to gigantism if untreated. The hormone thyroxine is not involved. Parathyroid hormone elevates blood calcium levels, so hypersecretion would cause high blood calcium. Insulin functions to reduce blood glucose levels. Since diabetes is classified by high blood glucose, insulin must lose functionality to cause this disease. This means that it would be hyposecreted, rather than hypersecreted.
During pregnancy in mammals, which of the following hormones is directly responsible for maintaining the lining of the uterus? Possible Answers: Prolactin Growth hormone Melatonin Glucocorticoids Progesterone
Correct answer: Progesterone Explanation: Progesterone is a steroid hormone that supports gestation in mammalian pregnancy. After the eighth week of pregnancy, it is produced by the placenta and helps to decrease the maternal immune response to prepare for pregnancy. Melatonin is a hormone used to regulate circadian rhythm and sleep cycles. Glucocorticoids, such as cortisone and cortisol, prepare the body for long term stressors. Prolactin stimulates the production of milk in mammals. Growth hormone promotes the enlargement of various organs and stimulates cell division.
Which of the following in not a tropic hormone? Possible Answers: Adrenocorticotropic hormone (ACTH) Thyroid-stimulating hormone (TSH) Prolactin Follicle-stimulating hormone (FSH)
Correct answer: Prolactin Explanation: A tropic hormone is one that regulates the function of other endocrine cells or glands. Thyroid-stimulating hormone (TSH), follicle-stimulating hormone (FSH), adrenocorticotropic hormone (ACTH), and luteinizing hormone (LH) are the four topic hormones that are produced by the anterior pituitary. Prolactin is also produced by the anterior pituitary, but does not trigger a response from any other endocrine tissues. The stimulation of mammary gland growth and milk production in mammals, regulation of fat metabolism and reproduction in birds, and the regulation of salt and water balance in freshwater fish are all functions of prolactin.
Which of the following hormones is released from the anterior pituitary? Possible Answers: Cortisol Epinephrine Insulin Prolactin Glucagon
Correct answer: Prolactin Explanation: The anterior pituitary gland contains endocrine cells that release hormones through the hypothalamic-hypophyseal axis. Prolactin controls milk production and contributes to regulation of the immune system. Of the listed hormones, prolactin is the only hormone released from the anterior pituitary. Insulin and glucagon are secreted by the pancreas. Cortisol is released by the adrenal cortex; epinephrine is released by the adrenal medulla.
__________ is the hormone responsible for milk production in female mammals. It is released by the __________. Possible Answers: Prolactin . . . anterior pituitary Oxytocin . . . posterior pituitary Prolactin . . . posterior pituitary Prolactin . . . mammary glands Oxytocin . . . anterior pituitary
Correct answer: Prolactin . . . anterior pituitary Explanation: Prolactin is responsible for the production of milk, while oxytocin is responsible for the ejection of milk. The question asks for the hormone that causes production, so the answer is prolactin. Prolactin is released from the anterior pituitary. Oxytocin is released from the posterior pituitary and the mammary glands are responsible for releasing milk.
Insulin helps regulate blood sugar at homeostatic levels by stimulating which of the following processes? Possible Answers: Stimulating the release of glucose from the liver Stimulating the breakdown of glycogen to glucose Promoting the entry of glucose into cells Activating hormone production in the posterior pituitary gland
Correct answer: Promoting the entry of glucose into cells Explanation: Insulin works by stimulating adipocytes (fat cells), hepatocytes (liver cells), and skeletal muscle to translocate glucose transporter-rich vesicles to the cell membrane. This allows the diffusion of glucose from the blood into these tissue types after a carbohydrate-rich meal. Without insulin, even if an individual has high blood glucose levels, these three cell types would essentially be deprived of the circulating glucose. Glucagon works against insulin by increasing blood glucose levels as they decrease via gluconeogenesis and glycogenolysis.
Which of the following physiological responses is not under hormonal control? Possible Answers: An insect larva transitioning to the pupa stage Glucagon effect of increasing blood glucose levels Calcitonin lowering of blood calcium levels Prostaglandin stimulation of uterine smooth muscle contraction
Correct answer: Prostaglandin stimulation of uterine smooth muscle contraction Explanation: In almost all animals, the endocrine and nervous systems are integrated to respond and control physiological responses. In insects, the prothoracic gland releases a hormone called ecdysone at different times to stimulate molting and maturation. Calcitonin and glucagon are hormones that are secreted by the pancreas and thyroid gland, respectively. They produce these hormones in response to ongoing monitoring of blood levels for glucose and calcium. The hormones are secreted to produce physiological responses in order to bring a return to homeostasis. Prostaglandins are local regulators and produce rapid responses that are confined to a small area. In the example, prostaglandins in semen stimulate the smooth muscle of the uterine wall to contract to facilitate sperm reaching an egg.
Which of the following describes paracrine signaling? Possible Answers: Secretion of neurotransmitters that diffuse across synapses and trigger a response in cells of target tissues (neurons, muscles, and glands) Secretion of molecules that diffuse into the bloodstream and trigger a response in target cells anywhere in the body Secretion of molecules that diffuse locally and trigger a response on neighboring cells Secretion of molecules that diffuse locally and trigger a response in the same cells that secreted them
Correct answer: Secretion of molecules that diffuse locally and trigger a response on neighboring cells Explanation: Hormones and other signaling molecules generate physiological responses by binding to specific receptor proteins in or on target cells. Only cells that have receptors for the secreted molecule (hormone, neurotransmitter, neurohormone, etc.) are target cells; other cells are nonresponsive. There are five different classifications for molecular signaling. These are as follow: Endocrine signaling: Secreted molecules diffuse into the bloodstream and trigger responses in target cells throughout the body. Paracrine signaling: Signaling molecules diffuse locally and trigger a response in neighboring cells. Autocrine signaling: Secretion of molecules that diffuse locally and trigger a response on the same cells that secreted them. Synaptic signaling: Secretion of neurotransmitters that diffuse across synapses and trigger a response in cells or target tissues (neurons, glands, and muscles). Neuroendocrine signaling: Secretion of hormones from neuronal cells that diffuse into the bloodstream and trigger a response on cells throughout the body.
Obesity can sometimes be caused by the slowing of the thyroid gland's production of thyroid hormones III and IV (T3 and T4), a condition known as hypothyroidism. Conversely, hyperthyroidism occurs when the thyroid overproduces T3 and T4. If T3 and T4 receptors became insensitive to the hormones, what effect would this have on the body? Possible Answers: Faster metabolism and weight gain Slower metabolism and weight loss Faster metabolism and weight loss Slower metabolism and weight gain
Correct answer: Slower metabolism and weight gain Explanation: The question tells us that slowed output of thyroid hormones can lead to obesity. One can safely assume that receptor insensitivity will have a similar effect. In either scenario, the T3 and T4 hormones are unable to elicit the proper response form the body. Similar to individuals with hypothyroidism, individuals with insensitive receptors would show slowed metabolism and increased weight gain.
How do steroid hormones elicit a response from their target cells? Possible Answers: Steroid hormones enter the nucleus of the target cell and increase the creation of ribosomes by the nucleolus. This results in more proteins being made by the target cell. Steroid hormones attach to a membrane-bound receptor on the cell. This creates an intracellular second messenger which leads to a reaction cascade. Steroid hormones move freely throughout the bloodstream and attach to their target cells. This interaction increases ion permeability in the cell. Steroid hormones enter the target cell and alter the products of the cell at the transcription level.
Correct answer: Steroid hormones enter the target cell and alter the products of the cell at the transcription level. Explanation: Steroids are nonpolar, which means that they are able to pass easily through cell membranes, but require a transport protein through the hydrophilic blood in order to do so. The steroid hormone then enters the nucleus and attaches to the DNA in order to increase the desired product at the level of transcription.
Which of the following is a target of follicle-stimulating hormone (FSH)? Possible Answers: Anterior pituitary Testes Adrenal gland Mammary glands
Correct answer: Testes Explanation: Follicle-stimulating hormone (FSH) is a tropic hormone produced in the anterior pituitary. Its primary functions are to regulate development, growth, pubertal maturation, and reproductive processes of the human body. In males, follicle-stimulating hormone acts on the testes to promote spermatogenesis. In females, follicle-stimulating hormone is an important modulator of the menstrual cycle.
Which of the following is an endocrine organ? Possible Answers: The appendix The stomach The gallbladder The kidney The spleen
Correct answer: The kidney Explanation: Endocrine glands release hormones directly into the circulatory system, where they can act on target effector organs. The kidneys serve both endocrine and exocrine functions. Releasing urine filtrate through ducts is an exocrine function. Kidneys also release the hormone erythropoietin, which promotes the generation of new red blood cells.
A certain molecule is known to signal through an autocrine mechanism. What does this tell us about the hormone's behavior? Possible Answers: The molecule is released by a certain cell, travels through the bloodstream, and acts on receptors on distant cells The molecule is released by a certain cell, travels through the bloodstream, and acts on receptors in the hypothalamus The molecule is released by a certain cell and acts on receptors on that same cell The molecule is released by a certain cell and acts to mediate release of more of the same hormone The molecule is released by a certain cell and acts on receptors on nearby cells
Correct answer: The molecule is released by a certain cell and acts on receptors on that same cell Explanation: To answer this question, you must have an understanding of the differences between endocrine, paracrine, and autocrine functioning. This example, in which a molecule exhibits autocrine behavior, means that a cell releases a hormone that acts on itself. In paracrine signaling, the molecule does not act on the same cell, but does diffuse through tissue to reach nearby target cells. Finally, endocrine signaling refers to hormone molecules that are released and transported through the bloodstream to act on more faraway target cells in distant regions.
Which of the following is not true about water-soluble hormones? Possible Answers: Tyrosine-derivative hormones are water-soluble Their receptors are found on the cell membrane Binding to its receptor can initiate a signal transduction cascade They act as local regulators
Correct answer: They act as local regulators Explanation: Water-soluble hormones can be either polypeptides (proteins) or tyrosine-derivatives. The binding of a water-soluble hormone to a receptor occurs on the cell membrane, and receptor binding triggers a physiological response through a signal transduction cascade. Peptide hormones include insulin, growth hormone, oxytocin, adrenocorticotropic hormone, and many more. Tyrosine-derivative hormones include epinephrine and the thyroid hormones (T3 and T4). Water-soluble hormones, like most hormones, are secreted into the bloodstream and carried throughout the body. As such, they are capable of eliciting responses in non-local regions of the body, and would not be classified as local regulators.
Which one of the following vitamins can be produced by the human body? Possible Answers: Vitamin E Vitamin D Vitamin C Vitamin A
Correct answer: Vitamin D Explanation: Vitamin D is the only vitamin that can be produced endogenously via UV activation of 7-dehydrocholesterol in the skin. All other vitamins must be obtained from outside sources, namely the digestion of other organic matter.
__________ is released in response to low blood sugar levels, while __________ is released in response to high blood sugar levels. Possible Answers: thyroid hormones . . . glucagon insulin . . . thyroid hormones insulin . . . glucagon glucagon . . . insulin
Correct answer: glucagon . . . insulin Explanation: Insulin is responsible for lowering blood sugar levels, and is therefore released when the body's blood sugar levels are too high. Glucagon is released in response to low blood sugar levels, and acts to increase sugar concentrations. Thyroid hormones (T3 and T4) are released to increase the body's metabolic rate, but are not directly influenced by blood sugar levels.
Chemical messengers released in the blood to stimulate or inhibit the function of another organs are known as __________. Possible Answers: hormones platelets second messengers electrolytes enzymes
Correct answer: hormones Explanation: A hormone is a chemical formed in one organ and carried by the blood to stimulate or inhibit the function of another organ. Enzymes are protein molecules that carry out catalytic functions. Electrolytes are simply ions dissolved in solution. Second messengers are relay molecules between a signal and its ultimate effect, such as the molecules that carry signals from the cell membrane to the nucleus to affect transcription. Platelets are cell fragments in the blood that help form clots to heal injuries.
The pancreas is responsible for regulating blood sugar levels through the release of insulin and glucagon. In Type I Diabetic individuals the body has high blood sugar due to the inability to produce insulin, which is responsible for lowering blood sugar. In an individual with Type II Diabetes the body produces insulin, however, the receptors have become insensitive to the presence of insulin. What effect will injecting additional insulin have in an individual with Type II Diabetes? Possible Answers: It will increase blood sugar levels It will reduce blood sugar levels It will have little to no effect It will reduce glucagon levels
It will have little to no effect Explanation: Because insulin receptors have been desensitized to insulin, the addition of more insulin will not have any effect. This is why Type II Diabetes is much more difficult to treat than Type I. The recommended course of action for individuals with Type II diabetes is to eat healthy and exercise.
Parathyroid hormone (PTH) is a peptide hormone responsible for increasing the concentration of calcium in the blood. This is accomplished by stimulating the activity of osteoclasts and removing calcium from the bones. If a person has low blood calcium levels, what would you expect the level of PTH to be in the body? Possible Answers: Parathyroid hormone would be higher than normal in the blood. Parathyroid levels will fluctuate until normal calcium levels are restored. Parathyroid hormone would be lower than normal in the blood. Normal levels of parathyroid hormone would be seen as a different hormone works to restore normal calcium levels. Normal levels of parathyroid hormone would be seen as it works to restore normal calcium levels.
Parathyroid hormone would be higher than normal in the blood. Explanation: A critical concept to understand about hormones in the body is negative feedback. Remember that hormones are not causing the body's condition, but rather, are responding to the body's condition. As a result, parathyroid hormone would be higher than normal in order to increase the concentration of calcium currently in the blood, correcting the existing deficiency.
Which of the following is not true of hormones? Possible Answers: All of these are true of hormones. Hormones are released directly into body fluids and tissues. Hormones affect a wider range of the body compared to neurotransmitters. Hormones are relatively slow acting compared to neurotransmitters. Hormones affect only one specific tissue at a time.
Which of the following is not true of hormones? Possible Answers: All of these are true of hormones. Hormones are released directly into body fluids and tissues. Hormones affect a wider range of the body compared to neurotransmitters. Hormones are relatively slow acting compared to neurotransmitters. Hormones affect only one specific tissue at a time.
The major tropic action of the growth hormone is to signal the __________ to release __________. Possible Answers: hypothalamus . . . thyroid-stimulating hormone pancreas . . . glucagon thyroid . . . T3 and T4 liver . . . insulin-like growth factors adrenal medulla . . . epinephrine
liver . . . insulin-like growth factors Explanation: Growth hormone is released from the anterior pituitary, and has numerous effects on the body. One of its primary effects is to stimulate release of insulin-like growth factors (IGFs) from the liver. These compounds circulate in the blood and directly stimulate bone and cartilage growth. The release of thyroid-stimulating hormone (TSH) causes the release of T3 and T4, which help speed up metabolism. Glucagon serves to increase blood glucose level. Epinephrine is released in response to short term stress, and stimulates the sympathetic nervous system.
