AP Biology : Understanding Hormones
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Example Question #41 : Understanding Hormones
Which of the following is an endocrine organ?
The stomach
The spleen
The appendix
The gallbladder
The kidney
The kidney
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.
Example Question #41 : Understanding Hormones
__________ causes testosterone production in males and triggers ovulation in females.
Testosterone
Luteinizing hormone (LH)
Estrogen
Follicle-stimulating hormone (FSH)
Luteinizing hormone (LH)
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 #42 : Understanding Hormones
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?
Calmodulin
Calcitonin
Parathyroid hormone
Calcitriol
Growth hormone
Calcitonin
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?
Calcitonin
Parathyroid hormone (PTH)
Melatonin
Triiodothyronine
Thyroxine
Calcitonin
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 #42 : Understanding Hormones
Which of the following hormones is produced in the posterior pituitary gland?
Growth hormone
Oxytocin
Epinephrine
Prolactin
Melatonin
Oxytocin
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 #43 : Understanding Hormones
Where is the hormone melatonin produced?
Pancreas
Posterior pituitary
Pineal gland
Adrenal gland
Anterior pituitary
Pineal gland
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.
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