1.
Your girlfriend left you yesterday, and today you learn that you failed your biochemistry exam and will most likely have to repeat the semester. Next, you find that your roommate left the island after stealing your credit card and using it to empty your bank account. As a result of all these disasters, your pituitary gland will most likely release increased amounts of _________, which will stimulate the enzyme _________ in your adrenal cortex.
Correct Answer
A. ACTH; desmolase
Explanation
When faced with stressful situations, the body's pituitary gland releases increased amounts of adrenocorticotropic hormone (ACTH). ACTH then stimulates the enzyme desmolase in the adrenal cortex. Desmolase is responsible for the conversion of cholesterol into pregnenolone, a precursor molecule for the production of various steroid hormones, including cortisol. Therefore, in response to the series of disasters mentioned, the pituitary gland is likely to release increased amounts of ACTH, which will stimulate the enzyme desmolase in the adrenal cortex.
2.
A 72-year-old male patient with average blood pressure readings of 210/120 is found to have renal artery stenosis caused by atherosclerotic plaques. This patient will probably have:
Correct Answer
A. Elevated renin in the blood
Explanation
In this scenario, the patient has renal artery stenosis caused by atherosclerotic plaques. Renal artery stenosis leads to a decreased blood flow to the kidneys, which triggers the juxtaglomerular cells in the kidney to release renin. Renin is an enzyme that plays a crucial role in the renin-angiotensin-aldosterone system, which regulates blood pressure. The release of renin leads to the conversion of angiotensinogen to angiotensin I, initiating a cascade that eventually results in the production of angiotensin II, a potent vasoconstrictor. Therefore, in this case, the patient is likely to have elevated renin levels in the blood.
3.
Most patients with Graves disease have an enlarged thyroid gland. Which is the most immediate cause of thyroid enlargement in these patients?
Correct Answer
C. An antibody that stimulates the TSH receptor
Explanation
In Graves disease, the most immediate cause of thyroid enlargement is an antibody that stimulates the TSH receptor. This antibody, known as TSH receptor antibody (TRAb), binds to the TSH receptor on the surface of thyroid cells and mimics the action of TSH. This leads to increased production and release of thyroid hormones, causing the thyroid gland to enlarge. Elevated TSH levels, enhanced activity of thyroperoxidase, increased plasma levels of T4 and T3, and reduced levels of cAMP in the thyroid follicular cells are all consequences of this antibody stimulation rather than the immediate cause of thyroid enlargement.
4.
Dr. Sands
An overweight 54-year-old male becomes a new patient of yours. You decide that you need to do some blood work to obtain “baseline” information to help you manage this person’s health issues. One of the serum blood markers that you ask to be measured is adiponectin. The lab report indicates that his adiponectin level is half of the normal value. Which of the following statements are likely to be also correct about his patient’s health?
Correct Answer
E. His serum free fatty acids are elevated.
Explanation
Adiponectin is a hormone secreted by adipose tissue that helps regulate glucose and lipid metabolism. Low levels of adiponectin are associated with insulin resistance and obesity. One of the functions of adiponectin is to increase fatty acid oxidation in the liver, so if the patient has low levels of adiponectin, it is likely that his liver fatty acid oxidation is decreased. Additionally, low adiponectin levels are associated with elevated serum free fatty acids, as the body is unable to properly regulate lipid metabolism. Therefore, the correct statement is that his serum free fatty acids are elevated.
5.
Dr Grogan
A patient in your care has a 5 year history of Type II diabetes. In controlling the condition, the patient admits to fasting as a means of controlling weight gain (the patient is obese). After one recent day-long fast, the patient experienced fatigue and light-headedness after taking the drug metformin – which works in part by suppressing the liver’s gluconeogenesis pathway enzymes. Given your extensive knowledge of hepatic metabolism – what advice should be given to the patient about future behavior?
Correct Answer
C. Don’t do the double whammy of diet and drug again, they both reduce blood glucose.
Explanation
The correct answer advises the patient to avoid combining fasting with the drug metformin because both can reduce blood glucose levels. This is because metformin works by suppressing the liver's gluconeogenesis pathway enzymes, which can lower blood glucose levels. Fasting also contributes to lower blood glucose levels. Combining the two can lead to excessive reduction in blood glucose, resulting in symptoms like fatigue and light-headedness. Therefore, it is recommended to avoid the double whammy of diet and drug to prevent these symptoms.
6.
A blood test reveals that a 20-year-old, non-obese male patient has high circulating glucose. You suggest a C-peptide test and it reveals that the values are very low compared with normal post-prandial (after meal) values. You make a diagnosis of Type I diabetes based on this low C-peptide value and other tests. Compared to a normal non-diabetic patient, what is your expectation for flux of glucose through the glycogen synthesis (glycogenesis) pathway after a meal in your patient’s muscle cells?
Correct Answer
D. Low insulin will result in lower rates of glycogen production.
Explanation
Based on the information provided, the patient has Type I diabetes which is characterized by low C-peptide values. C-peptide is a marker of insulin production, and in Type I diabetes, there is a deficiency of insulin. Insulin plays a crucial role in promoting glycogen synthesis (glycogenesis) after a meal. Therefore, in this patient, with low insulin levels, the expectation would be for lower rates of glycogen production compared to a normal non-diabetic patient.
7.
Dr Martin
An infant develops a small blind sinus at the middle of the anterior border of the right sternocleidomastoid muscle. Mucus drips intermittently from its opening. Persistence of the opening of which of the following is the embryological basis of this congenital anomaly?
Correct Answer
A. Second pHaryngeal groove and cervical sinus
Explanation
The correct answer is "Second pharyngeal groove and cervical sinus". During embryological development, the second pharyngeal groove and cervical sinus normally close off to form the cervical sinus. However, if the opening persists, it can lead to the development of a congenital anomaly known as a blind sinus. This blind sinus can cause mucus to intermittently drip from its opening, as described in the question.
8.
Dr Kalliecharan
Which of the following statements is characteristic of the pituitary gland?
Correct Answer
A. Herring bodies store oxytocin and vasopressin
Explanation
Herring bodies are storage sites within the pituitary gland that store and release oxytocin and vasopressin. These hormones are produced by the hypothalamus and transported to the pituitary gland for storage in the herring bodies. The other statements in the options are incorrect. CRH is derived from the hypothalamus, not the adenohypophysis. TSH is stored in the pars distalis of the pituitary gland, not the pars nervosa. Basophils produce adrenocorticotropic hormone (ACTH), not growth hormone (GH). Chromophils do not secrete oxytocin and vasopressin, they secrete other hormones like GH, adrenocorticotropic hormone (ACTH), and thyroid-stimulating hormone (TSH).
9.
Which of the following structures is responsible for the development of the pars nervosa?
Correct Answer
C. Infundibular stem
Explanation
The infundibular stem is responsible for the development of the pars nervosa. The pars nervosa is a part of the posterior pituitary gland, which is derived from the neuroectoderm. The infundibular stem connects the hypothalamus to the posterior pituitary gland and serves as a pathway for the transport of hormones produced in the hypothalamus to the pars nervosa. It plays a crucial role in the regulation and release of hormones such as oxytocin and vasopressin.
10.
Which of the following statements is true regarding the thyroid gland?
Correct Answer
B. Thyroid follicular cells contain lots of lysosomes and mitochondria
Explanation
Thyroid follicular cells contain lots of lysosomes and mitochondria. This statement is true because lysosomes are responsible for the breakdown of waste materials and mitochondria are responsible for energy production. These organelles are abundant in thyroid follicular cells because they play a crucial role in the synthesis and secretion of thyroid hormones.
11.
Which group of cells is responsible for secreting the hormone that is produced as a result of angiotensin II stimulation?
Correct Answer
B. Zona glomerulosa cells
Explanation
Zona glomerulosa cells are responsible for secreting the hormone that is produced as a result of angiotensin II stimulation.
12.
Picture 1 shows a Lashley cup used for collecting saliva from the parotid gland. Picture 2 shows that the Lashley cup is placed over the opening of Stensen's duct to collect the saliva for saliva sample testing. Which of the following is the most ideal site for placing the cup?
Correct Answer
D. Opposite the second maxillary molar
Explanation
The most ideal site for placing the Lashley cup is opposite the second maxillary molar. This is because the parotid gland, which produces saliva, is located in the cheek area near the upper second molar. Placing the cup opposite this molar ensures that it is positioned correctly over the opening of Stensen's duct, which drains saliva from the parotid gland.
13.
A 22-year-old woman presents to her physician with swelling in the neck. She said the swelling started growing suddenly in the past 1 week, and it started to hurt and she can’t breathe. On inspection, the physician identified it as a solitary swelling which moved up on deglutition. On palpation, he found the swelling was firm in consistency and it was not attached to the skin. Which of the following statements concerning this swelling would LEAST LIKELY suggest a diagnosis of a thyroid gland swelling?
Correct Answer
B. The swelling is located superficial to the sternothyroid muscle
Explanation
The swelling being located superficial to the sternothyroid muscle would least likely suggest a diagnosis of a thyroid gland swelling because the thyroid gland is located deep to the sternothyroid muscle. Therefore, if the swelling is superficial to this muscle, it is less likely to be related to the thyroid gland.
14.
Dr Thomas
A 26-year-old man reports to his physician that he is thirsty all the time and has been drinking a lot of water, which results in his having to urinate so frequently that it is disruptive to his daily activities. In addition, he has to get up frequently during the night to urinate. History reveals that the man sustained a head injury in a motorcycle accident one week earlier. Which of the following drugs is most likely to relieve his symptoms of thirst and diuresis?
Correct Answer
E. Desmopressin
Explanation
Desmopressin is the most likely drug to relieve the man's symptoms of thirst and diuresis. The man's symptoms, such as excessive thirst and frequent urination, are indicative of diabetes insipidus, which can be caused by a head injury. Desmopressin is a synthetic form of vasopressin, a hormone that helps regulate water balance in the body. By replacing the deficient vasopressin, desmopressin can reduce excessive thirst and urine production, providing relief for the man's symptoms.
15.
A 46-year-old woman is diagnosed with type 2 diabetes mellitus. Her mother also has type 2 diabetes. The woman is found to have a BMI of 32. In addition to receiving nutritional counseling and being referred to an educational support group focused on lifestyle changes to address type 2 diabetes, the woman is prescribed an antihyperglycemic drug with the primary mechanism of action to decrease hepatic synthesis of both glucose and glycogen. Which of the following drugs was most likely prescribed?
Correct Answer
C. Metformin
Explanation
The woman is diagnosed with type 2 diabetes mellitus and has a high BMI, indicating that she is overweight or obese. Metformin is commonly prescribed as a first-line treatment for type 2 diabetes in individuals who are overweight or obese. It works by decreasing hepatic synthesis of both glucose and glycogen, helping to lower blood sugar levels. Therefore, Metformin is the most likely drug prescribed in this case.
16.
Dr White
A 26-year-old man developed polyuria 48 hours after surgical removal of a non-hormone pituitary tumor. Prior to the surgery, he had been taking lithium as part of his treatment for bipolar disorder. Now his urine production is in excess of 4 litres per day and he feels thirsty all of the time, so is drinking large volumes of water. He is administered desmopressin intranasally, which has no effect on his urine flow rate. From what condition is this patient likely suffering?
Correct Answer
D. NepHrogenic diabetes insipidus
Explanation
The patient is likely suffering from nephrogenic diabetes insipidus. This is indicated by the fact that his urine production is in excess of 4 liters per day and he feels thirsty all the time, despite the administration of desmopressin intranasally, which has no effect on his urine flow rate. Nephrogenic diabetes insipidus is a condition where the kidneys are unable to respond to the antidiuretic hormone (ADH), resulting in excessive urine production and persistent thirst. The use of lithium, which is known to cause nephrogenic diabetes insipidus, further supports this diagnosis.
17.
A 58-year old woman visits her physician complaining of persistent headaches. The physician notices that she has a prominent forehead and wide jaw, and that when she speaks her voice is unusually deep and husky. She has large hands and feet. When questioned she says both her shoe and glove sizes have gotten 1 – 2 sizes larger over the past 3-4 years. Which of the following metabolic abnormalities would you expect to observe in this patient?
Correct Answer
C. Increased blood glucose concentration
Explanation
The patient's symptoms, such as a prominent forehead, wide jaw, deep voice, large hands and feet, and an increase in shoe and glove sizes, suggest acromegaly, a condition caused by excessive growth hormone (GH) production. GH stimulates the liver to produce insulin-like growth factor 1 (IGF-1), which leads to increased blood glucose concentration. This occurs because GH inhibits the uptake of glucose into skeletal muscle and adipose tissue, while promoting gluconeogenesis in the liver. Therefore, the correct answer is increased blood glucose concentration.
18.
Dr Selfridge
A 22 year old female patient presents to your office with recurrent vaginal itching diagnosed as a yeast vaginal infection repeatedly over the last 6 months. It responds briefly to topical vaginal antifungal treatment, but seems to come right back. She is obese with a BMI of 32. Her fasting blood sugar was 110 when taken at a community health screening clinic and is 122 in your office today. Which of the following are most true about her condition?
Correct Answer
E. Weight loss of just 10% of her total body weight may improve her metabolic problem.
Explanation
The patient's elevated fasting blood sugar levels and obesity indicate that she may have insulin resistance, which is commonly associated with type II diabetes. However, the question does not provide enough information to definitively diagnose her with diabetes or determine if she will require lifelong insulin therapy. Lifestyle changes, such as weight loss, can help improve insulin resistance and metabolic problems. Therefore, the most true statement about her condition is that weight loss of just 10% of her total body weight may improve her metabolic problem.
19.
Dr Kalliecharan
Which cell type is involved in secreting a substance in response to decreased blood sugar levels?
Correct Answer
E. AlpHa (A) cell
Explanation
Alpha (A) cells are involved in secreting a substance in response to decreased blood sugar levels. These cells are found in the pancreas and are responsible for producing and releasing the hormone glucagon. Glucagon helps to increase blood sugar levels by stimulating the liver to convert stored glycogen into glucose and release it into the bloodstream. This response occurs when blood sugar levels are low and helps to maintain a stable blood sugar balance in the body.
20.
Dr Meisenberg
Deficiency of 21-hydroxylase makes the patient unable to synthesize _________ and leads to __________
Correct Answer
C. Glucocorticoids and mineralocorticoids only; virilization
Explanation
Deficiency of 21-hydroxylase leads to the inability to synthesize glucocorticoids and mineralocorticoids, which in turn causes virilization.