All MCAT Biology Resources
Example Questions
Example Question #701 : Mcat Biological Sciences
Which of the following hormones secreted by the pituitary directly acts on the adrenal cortex as its target?
ADH
ACTH
TSH
FSH
LH
ACTH
The only hormone listed that directly stimulates that adrenal cortex is ACTH, which stands for Adrenocorticotropic Hormone. This anterior pituitary-secreted hormone stimulates the adrenal cortex to release cortisol.
The other hormones listed are also secreted by the pituitary gland, but do not act on the adrenal cortex directly.
Example Question #28 : Hormones
Passage:
In a fictional universe, a new life form is discovered that appears to have a number of similarities to humans. Since its discovery by humans, it has been studied with x-ray imaging, magnetic resonance imaging (MRI), computed tomography imaging (CT), as well as with blood chemistries and laboratory studies. Based upon such analyses, scientists have found that both structurally and functionally, this fictional species, called Lorempis marengis, is highly similar to humans. It has structures that appear similar to lungs that are active during respiration. It has a structure that is highly active at all times, especially so in different parts during different activities (similar to the human brain). It also appears to have a digestive tract with a mouth, esophagus, stomach, small intestine, large intestine, and anus that is assumed to carry out the same functions at the cellular level as the parts of the human digestive tract. Scientists are now hoping to continue studying the organism at the cellular level to confirm their assumption that the cellular functions are indeed similar to those of human tissues.
If we assume that the endocrine anatomy, structure, and function in Lorempis marengis is identical to that of humans, which of the following choices correctly lists two hormones secreted by the posterior pituitary gland in Lorempis marengis?
FSH and LH
ADH and ACTH
Oxytocin and ACTH
Oxytocin and Vasopressin
ACTH and TSH
Oxytocin and Vasopressin
The only answer choice that correctly lists two hormones secreted by the posterior pituitary gland in Lorempis marengis is the choice that includes Oxytocin and Vasopressin. This answer choice is correct because we are told in the question stem to assume that the endocrine anatomy, structure, and function in Lorempis marengis is identical to that of humans, and in humans, both Oxytocin and Vasopressin are secreted by the posterior pituitary gland.
Oxytocin and Vasopressin (also known as Anti-diuretic hormone, or ADH) are the two hormones secreted by the posterior pituitary gland.
Each of the other choices contains either a posterior pituitary and an anterior pituitary secreted hormone, or two hormones secreted by the anterior pituitary.
The hormones secreted by the anterior pituitary can be remembered by the mnemonic, FLATPEG (FSH, LH, ACTH, TSH, Prolactin, Endorphin, and Growth Hormone).
Example Question #702 : Mcat Biological Sciences
All of the following are expected to increase after a meal has been consumed except __________.
glucagon
secretin
cholecystokinin
GLUT-4 receptors
insulin
glucagon
When an a meal is consumed, the digestive system is stimulated. This causes the release of secretin and cholecystokinin, hormones that are involved in digestion. Once glucose is in the bloodstream, it interacts with beta cells and causes the release of insulin. Insulin enters the bloodstream and stimulates widespread expression of the GLUT-4 receptor. Glucagon, on the other hand, counters the effects of insulin in a negative feedback loop and would not be expected to increase after a meal is consumed.
Example Question #703 : Mcat Biological Sciences
A lack of which of the following hormones could cause high plasma calcium levels?
Glucagon
Aldosterone
Calcitriol
Parathyroid hormone
Calcitonin
Calcitonin
If the lack of a certain hormone can cause high calcium levels, that means the hormone acts to lower plasma calcium when it is present. Only one of the choices, calcitonin, decreases blood calcium. Parathyroid hormone (PTH) and calcitriol increase plasma calcium levels. Aldosterone and glucagon are unrelated to calcium regulation—aldosterone regulates kidney activity to increase blood pressure and glucagon increases blood sugar levels.
Example Question #61 : Endocrine System
John goes to the doctor and is told that his anterior pituitary is not functioning. Which of the following hormones is likely at lower levels than normal?
Melatonin
Thyroid-stimulating hormone (TSH)
Parathyroid hormone
Atrial natriuretic hormone
Glucagon
Thyroid-stimulating hormone (TSH)
Of all the choices, the only one released by the anterior pituitary is TSH (thyroid-stimulating hormone). Glucagon is released from the pancreas, parathyroid hormone is released from the parathyroid glands, melatonin comes from the pineal gland, and atrial natriuretic hormone is a heart hormone.
Example Question #4 : Hormone Mechanisms And Effects
Which hormone is most responsible for decreased levels of blood calcium?
Glucagon
Calcitonin
Parathyroid hormone (PTH)
Insulin
Calcitonin
Calcitonin lowers plasma calcium, while parathyroid hormone (PTH) increases it. Insulin and glucagon are responsible for blood glucose, not calcium.
Example Question #704 : Mcat Biological Sciences
After ingesting a meal heavy in polysaccharides, an individual has their blood drawn. Levels of which hormone would you expect to be higher than normal?
Insulin
Gastrin
Glucagon
Oxytocin
Insulin
The polysaccharides from the meal will be digested down into glucose by various enzymes in the digestive track. That glucose will be absorbed in the small intestine and travel into the bloodstream. This increase in blood glucose will cause a release of insulin to allow for tissue to take up the glucose and use it for energy. In this individual's blood, we would expect insulin to be higher than normal.
Conversely, when little blood glucose is present, glucagon is released to break down glycogen and fat into glucose that is needed for energy. Gastrin, while also involved in digestion, is closely linked to the release of hydrochloric acid, which activates pepsin to digest proteins. Gastrin is not linked to the digestion of carbohydrates and polysaccharides.
Oxytocin is not involved in digestion.
Example Question #705 : Mcat Biological Sciences
The endocrine system regulates many aspects of human physiology through the release of hormones, which are chemical messengers that act on target organs and are generally transported via the bloodstream. The following are statements about one of these hormones, aldosterone. Which statement is incorrect?
Aldosterone is released by the anterior pituitary
Though their mechanisms of regulation are different, both aldosterone and antidiuretic hormone (ADH) act to increase blood volume
Administration of an angiotensin-converting enzyme (ACE) inhibitor will decrease aldosterone secretion
Aldosterone is a steroid hormone
Aldosterone is released by the anterior pituitary
Aldosterone is a mineralcorticoid, meaning that it is released by the adrenal cortex, not the anterior pituitary.
Mineralcorticoids are also steroids, and are able to cross the cell membrane due to their lipophilic nature. Both aldosterone and antidiuretic hormone (ADH) increase blood volume by acting on different regions of the nephrons in the kidney. Finally, angiotensin-converting enzyme (ACE) inhibitors do decrease the secretion of aldosterone, since aldosterone is activated by the renin-angiotensin system and the inhibitors block a vital conversion step in this chain.
Example Question #706 : Mcat Biological Sciences
Which steroid hormone, produced in the ovaries, is responsible for preparing and maintaining the uterus for pregnancy?
Estrogen
Progesterone
Luteinizing hormone
Follicle-stimulating hormone
Progesterone
Progesterone is responsible for maintaining the uterine environment during pregnancy. In contrast, estrogen is responsible for the development of female secondary sex characteristics, and luteinizing hormone and follicle-stimulating hormone help stimulate follicle growth, ovulation, and estrogen production.
Example Question #707 : Mcat Biological Sciences
Which steroid hormone, produced in the ovaries, is responsible for the growth of female sex organs and is responsible for causing a surge in luteinizing hormone through positive feedback?
Progesterone
Androstenedione
Testosterone
Estrogen
Estrogen
Estrogen is produced by the combination of luteinizing hormone and follicle-stimulating hormone in the ovaries. Estrogen is responsible for causing the luteinizing hormone surge through positive feedback (one of the only examples of positive feedback in endocrine biology) and the growth of the female sex organs.
Progesterone is responsible for preparing and maintaining the uterus for pregnancy.
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