PROMETRIC EXAM QUESTIONS WITH EXPLANATION
Q: Which of following play a role in calcium homeostasis ?
- 1,25-dihydrocycholecalciferol and calcitonin
- 1,25-dihydrocycholecalciferol and insulin
- Parathyroid hormone and glucagon
- Insulin and lipase
Explanation:
Calcium homeostasis refers to the body's ability to maintain a balanced level of calcium in the blood. The three primary hormones involved in this regulation are 1,25-dihydroxycholecalciferol (also known as active vitamin D), parathyroid hormone (PTH), and calcitonin. Calcitonin lowers calcium levels by inhibiting bone resorption (breakdown) while 1,25-dihydroxyvitamin D3 promotes calcium absorption in the intestines and kidneys.
The parathyroid glands release parathyroid hormone (PTH) in response to a decrease in serum calcium. PTH acts on the kidneys to increase calcium reabsorption in the ascending loop of Henle, the distal convoluted tubule, and the collecting duct. The kidney also responds to PTH by increasing secretion of Vitamin D3, which in turn stimulates calcium absorption through the gut. PTH acts on the bones to stimulate osteoclasts involved in bone reabsorption and the release of free calcium. All of these processes contribute to the rise in serum calcium. (NIH Physiology, Calcium)
While insulin plays a crucial role in glucose metabolism, it is not directly involved in calcium homeostasis.
Glucagon is a hormone that raises blood glucose levels. While parathyroid hormone (PTH) is a key player in calcium regulation, it has no direct relationship with glucagon.
Insulin is primarily involved in regulating blood glucose levels and lipase is responsible for breaking down fats. Neither of these hormones have a significant role in calcium homeostasis.
So the correct answer is 1,25-dihydrocycholecalciferol and calcitonin.
Q: Which of following studies are more susceptible to recall bias?
- Retrospective cohort
- Prospective cohort study
- Randomized controlled trial
- Non-randomized controlled trial
Explanation:
Recall bias is a type of bias that occurs when participants in a research study or clinical trial do not accurately remember a past event or experience or leave out details when reporting about them. Recall bias can lead to wrong conclusions about what the study showed. This type of information bias is common in studies using self‐reporting, such as case‐control studies, or retrospective cohort studies where subjects are asked to provide information on exposure only after the disease has or has not occurred.
So the correct answer is Retrospective cohort.
A retrospective cohort study, also known as a historical cohort study, is an observational study that looks back in time to examine the relationship between past exposures and health outcomes.
Prospective cohort study is a research study that follows over time groups of individuals who are alike in many ways but differ by a certain characteristic (for example, female nurses who smoke and those who do not smoke) and compares them for a particular outcome (such as lung cancer).
A randomized controlled trial (RCT) is a scientific experiment where participants are randomly assigned to an experimental group, which receives a specific intervention, or a control group, which receives a placebo or standard treatment.
A non-randomized controlled trial (non-RCT) is a type of study where participants are placed in different groups for testing interventions, but the groups are not randomly assigned. This type of trial is often used when randomization isn’t practical or possible.
Q: Which of the following micro-organisms causes typhoid fever ?
- Shigella
- Flavivirus
- Salmonella
- Treponema pallidum
Explanation:
Typhoid fever is a life-threatening infection caused by the bacterium Salmonella Typhi. It is usually spread through contaminated food or water. Once Salmonella Typhi bacteria are ingested, they multiply and spread into the bloodstream. Salmonella Typhi lives only in humans. Persons with typhoid fever carry the bacteria in their bloodstream and intestinal tract. Symptoms include prolonged high fever, fatigue, headache, nausea, abdominal pain, and constipation or diarrhoea. Some patients may have a rash. Severe cases may lead to serious complications or even death. Typhoid fever can be confirmed through blood testing.
So the correct answer is Samlonella.
Q: Which of the following is an inhibitory neurotransmitter?
- Aspartate
- Serotonin
- Glutamate
- Gama aminobutyric acid (GABA)
Explanation:
GABA is the primary inhibitory neurotransmitter in the central nervous system, meaning it slows down neuronal activity by hyperpolarizing the neuron membrane, making it less likely to fire an action potential.
Aspartate is an excitatory neurotransmitter. It works opposite to GABA, promoting neuronal excitation.
Serotonin is a complex neurotransmitter involved in mood regulation, sleep, appetite, and other functions. While it doesn't directly have excitatory or inhibitory effects, its role is generally considered modulatory.
Glutamate is the most common excitatory neurotransmitter in the CNS. It plays a crucial role in learning and memory but also contributes to overstimulation of neurons.
So the correct answer is GABA.
Q: Which of the following is the main feature of celiac disease?
- Malabsorption of proteins
- Increased protein degradation
- Decreased excretion of proteins
- Decreased breakdown of protein
Explanation:
Celiac disease is a digestive disorder where the body cannot properly absorb nutrients from food, including proteins. This malabsorption is caused by an autoimmune reaction to gluten, a protein found in wheat, barley, and rye. The damage to the small intestine lining prevents the body from breaking down and absorbing nutrients, leading to malnutrition and various symptoms like diarrhea, weight loss, and nutrient deficiencies.
While there might be some increased degradation of proteins in the damaged small intestine of celiac disease patients, this is not the primary feature. The main issue is the inability to absorb the properly digested proteins.
Celiac disease primarily affects absorption, not excretion. The body may attempt to compensate for malabsorption by decreasing protein excretion, but this is a secondary consequence.
Although gluten breakdown is impaired in celiac disease due to the damaged intestinal lining, the decreased breakdown of proteins is not the defining characteristic. The more fundamental issue is the body's inability to absorb the digested proteins.
So the correct answer is option Malabsorption of proteins.
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