AP Biology : Endocrine System

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #51 : Endocrine System

__________ causes testosterone production in males and triggers ovulation in females.

Possible Answers:

Follicle-stimulating hormone (FSH)

Luteinizing hormone (LH)

Estrogen

Testosterone

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.

Example Question #52 : Endocrine System

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:

Parathyroid hormone

Calcitriol

Calcitonin

Calmodulin

Growth hormone

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. 

Example Question #53 : Endocrine System

What is the hormone responsible for decreasing blood levels of calcium?

Possible Answers:

Calcitonin

Parathyroid hormone (PTH)

Melatonin

Triiodothyronine

Thyroxine

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.

Example Question #54 : Endocrine System

Which of the following hormones is produced in the posterior pituitary gland?

Possible Answers:

Prolactin

Epinephrine

Oxytocin

Growth hormone

Melatonin

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.

Example Question #55 : Endocrine System

Where is the hormone melatonin produced?

Possible Answers:

Pineal gland

Posterior pituitary

Anterior pituitary

Pancreas

Adrenal 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.

Example Question #51 : Endocrine System

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 reduce blood sugar levels

It will reduce glucagon levels

It will have little to no effect

It will increase blood sugar levels

Correct answer:

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.

Example Question #52 : Endocrine System

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:

Adrenal cortex

Adrenal medulla

Anterior pituitary

Pineal gland

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.

Example Question #53 : Endocrine System

Which of the following hormones is not released by the anterior pituitary gland?

Possible Answers:

Thyroid-stimulating hormone (TSH)

Growth hormone (GH)

Prolactin

Oxytocin

Correct answer:

Oxytocin

Explanation:

The anterior pituitary is responsible for releasing a large number of hormones; however, oxytocin is released by the posterior pituitary. Two of oxytocin's most important functions include stimulating uterus contractions and stimulating milk production by the mammary glands. 

Prolactin stimulates milk release from the mammary glands.

Thyroid-stimulating hormone stimulates the release of hormones from the thyroid gland.

Growth hormone stimulates the growth of bones and stimulates the liver to release insulin-like growth factors.

It is important to note that at least one hormone from the hypothalamus is used to regulate each of the hormones released by the anterior pituitary—for example, the anterior pituitary gland will only release prolactin if the hypothalamus releases prolactin-releasing hormone. 

Example Question #54 : Endocrine System

Chemical messengers released in the blood to stimulate or inhibit the function of another organs are known as __________.

Possible Answers:

second messengers

platelets

hormones

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.

Example Question #51 : Endocrine System

Which of the following is produced by the pituitary gland?

Possible Answers:

Estrogen

Epinephrine

Testosterone

Insulin

Follicle-stimulating hormone

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.

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