1.
The parvocellular pathway from lateral geniculate nucleus to visual
cortex is most sensitive for the stimulus of:
Correct Answer
A. Color contrast.
Explanation
The parvocellular pathway is responsible for processing detailed visual information, such as color and form. It is most sensitive to color contrast, which refers to the difference in color between two adjacent regions. This pathway allows us to perceive and distinguish different colors and their variations in our visual environment. Luminance contrast, temporal frequency, and saccadic eye movements are not specifically associated with the parvocellular pathway and do not directly relate to its sensitivity.
2.
The fibers from the contralateral nasal hemiretina project to the
following layers of the lateral geniculate nucleus:
Correct Answer
C. Layers 1, 4 & 6
Explanation
The fibers from the contralateral nasal hemiretina project to layers 1, 4, and 6 of the lateral geniculate nucleus.
3.
All endothelial cells produce thrombomodulin except those found in:
Correct Answer
C. Cerebral microcirculation.
Explanation
Thrombomodulin is a protein produced by endothelial cells that plays a crucial role in regulating blood clotting. It acts as a cofactor for the protein C pathway, which inhibits the formation of blood clots. While all endothelial cells produce thrombomodulin, the exception is the endothelial cells found in cerebral microcirculation. This is because the brain has its own unique mechanisms for regulating blood clotting to maintain proper cerebral blood flow and prevent ischemic events.
4.
S.A. node acts as a pacemaker of the heart because of the fact that
it:
Correct Answer
D. Generates impulses at the highest rate.
Explanation
The SA node acts as a pacemaker of the heart because it generates impulses at the highest rate. This means that it initiates the electrical signals that regulate the heartbeat more frequently than any other part of the heart. This high rate of impulse generation allows the SA node to set the rhythm and pace of the heartbeat, making it the natural pacemaker of the heart. The other options, such as being capable of generating impulses spontaneously or having rich sympathetic innervations, may contribute to the function of the SA node but do not directly explain why it acts as the pacemaker.
5.
The first physiological response to high environmental temperature
is:
Correct Answer
B. Vasodilation
Explanation
When the body is exposed to high environmental temperature, the blood vessels near the surface of the skin dilate (vasodilation). This allows more blood to flow near the skin's surface, promoting heat loss through radiation and conduction. Vasodilation helps to dissipate excess heat from the body and regulate its temperature. Sweating is another response to high temperature, but it occurs after vasodilation and helps to further cool the body through evaporation. Decreased heat production and non-shivering thermogenesis are not immediate physiological responses to high environmental temperature.
6.
All of the following factors normally increase the length of the
ventricular
cardiac muscle
fibres except:
Correct Answer
D. Lying-to-standing change in posture.
Explanation
Lying-to-standing change in posture does not increase the length of ventricular cardiac muscle fibers. The other factors listed, such as increased venous tone, increased total blood volume, and increased negative intrathoracic pressure, can all lead to an increase in the length of these muscle fibers.
7.
The vasodilatation produced by carbon dioxide is maximum in one of
the following
Correct Answer
B. Brain
Explanation
The correct answer is Brain. Carbon dioxide causes vasodilation in the brain due to its ability to increase blood flow and oxygen delivery to the brain cells. This helps in maintaining adequate cerebral perfusion and ensuring proper brain function. Vasodilation in the brain is important for regulating blood pressure, maintaining brain metabolism, and supporting cognitive processes.
8.
Which one of the following statements regarding water reabsorption
in the tubules?
Correct Answer
A. The bulk of water reabsorption occurs secondary to Na+ reabsorption.
Explanation
The bulk of water reabsorption occurs secondary to Na+ reabsorption because water reabsorption in the tubules is closely linked to the reabsorption of sodium ions. The reabsorption of sodium creates an osmotic gradient that drives the movement of water across the tubule epithelium. As sodium ions are actively transported out of the tubules, water follows passively due to osmosis. This process allows for efficient reabsorption of water in the kidneys and helps maintain water balance in the body.
9.
Urinary concentrating ability of the kidney is increased by:
Correct Answer
A. ECF volume contraction.
Explanation
ECF volume contraction refers to a decrease in the extracellular fluid volume, which can occur due to various reasons such as dehydration or excessive fluid loss. This condition triggers a compensatory mechanism in the kidney, leading to an increase in the urinary concentrating ability. The kidney responds to ECF volume contraction by conserving water and concentrating the urine, which helps in maintaining fluid balance in the body. In contrast, an increase in RBF (renal blood flow), reduction of medullary hyperosmolarity, or an increase in GFR (glomerular filtration rate) would not directly contribute to an increase in the urinary concentrating ability.
10.
Distribution of blood flow is mainly regulated by the:
Correct Answer
B. Arterioles
Explanation
Arterioles are small blood vessels that connect arteries to capillaries. They play a crucial role in regulating blood flow by constricting or dilating their smooth muscle walls. This constriction or dilation affects the resistance to blood flow and ultimately determines the distribution of blood to different organs and tissues. By adjusting the diameter of arterioles, the body can redirect blood to areas that need it the most, such as during exercise or in response to injury or stress. Therefore, arterioles are the main regulators of blood flow distribution in the body.
11.
In which of the following a reduction in arterial oxygen tension
occurs?
Correct Answer
C. Moderate exercise
Explanation
During moderate exercise, the body's oxygen demand increases as muscles require more oxygen to function properly. This increased demand for oxygen leads to a reduction in arterial oxygen tension, as the oxygen is being utilized by the muscles and may not be fully replenished by the lungs. This reduction in arterial oxygen tension is a normal physiological response to exercise and helps to meet the increased oxygen demands of the body.
12.
Neuronal degeneration is seen in all of the following except:
Correct Answer
D. Neuropraxia
Explanation
Neuropraxia is the correct answer because it refers to a temporary loss of nerve function due to a conduction blockage, without any degeneration of the nerve itself. On the other hand, crush nerve injury, fetal development, and senescence can all lead to neuronal degeneration. Crush nerve injury can cause damage to the nerve fibers, fetal development involves the natural pruning and elimination of excess neurons, and senescence refers to the aging process which can lead to degeneration of neurons.
13.
With which one of the following Lower motor neuron lesions are
associated?
Correct Answer
A. Flaccid paralysis.
Explanation
Lower motor neuron lesions are associated with flaccid paralysis. Flaccid paralysis is characterized by the loss of muscle tone, weakness, and decreased reflexes. This occurs when there is damage to the lower motor neurons, which are responsible for transmitting signals from the spinal cord to the muscles. In contrast, upper motor neuron lesions are associated with spasticity, hyperactive stretch reflexes, and muscular incoordination.
14.
Aspermia is the term used to describe:
Correct Answer
A. Absence of semen.
Explanation
Aspermia is the term used to describe the absence of semen. This means that during ejaculation, no seminal fluid is released. It is different from azoospermia, which refers to the absence of sperm in the ejaculate. In aspermia, the individual may still have sperm production, but the semen is not present during ejaculation. This condition can be caused by various factors, including blockages in the reproductive system or issues with the prostate gland.
15.
Which of the following statements can be regarded as primary action
of Inhibin?
Correct Answer
D. It inhibits secretion of FSH.
Explanation
Inhibin is a hormone primarily secreted by the ovaries and testes. It acts as a negative feedback regulator of the pituitary gland, specifically inhibiting the secretion of follicle-stimulating hormone (FSH). FSH is responsible for the development of ovarian follicles in females and the production of sperm in males. By inhibiting FSH secretion, Inhibin helps regulate the reproductive system and maintain hormonal balance. Therefore, the statement "It inhibits secretion of FSH" can be regarded as the primary action of Inhibin.
16.
A 40 year old male, with history of daily alcohol consumption for the
last 7 years, is brought to the hospital emergency room with acute
onset
of seeing snakes all around him in the room, not recognizing
family members,
violent behavior and tremulousness for few hours. There is history
of his
having missed the alcohol drink since 2 days. Examination reveals
increased
blood pressure, tremors, increased psychomotor activity, fearful
affect,
hallucinatory behavior, disorientation,
impaired judgement and insight. He is most likely to be suffering
from:
Correct Answer
B. Delirium tremens.
Explanation
The patient's symptoms of acute onset of hallucinations, violent behavior, tremulousness, increased blood pressure, tremors, impaired judgment, and disorientation are consistent with delirium tremens. Delirium tremens is a severe form of alcohol withdrawal that typically occurs 48 to 96 hours after the last drink. It is characterized by autonomic hyperactivity, hallucinations, agitation, and altered mental status. Alcoholic hallucinosis is characterized by auditory hallucinations but does not typically involve violent behavior or disorientation. Wernicke encephalopathy and Korsakoff's psychosis are associated with thiamine deficiency and typically present with cognitive deficits and memory impairments.
17.
A 45 year male with a history of alcohol dependence presents
with confusion, nystagmus and ataxia. Examination reveals 6th
cranial nerve
weakness. He is most likely to be suffering from:
Correct Answer
B. Wernicke’s encepHalopathy.
Explanation
The patient's history of alcohol dependence, along with the presenting symptoms of confusion, nystagmus, ataxia, and 6th cranial nerve weakness, are indicative of Wernicke's encephalopathy. This condition is caused by thiamine (vitamin B1) deficiency, which is common in individuals with alcohol dependence. Korsakoff's psychosis is a chronic memory disorder also associated with thiamine deficiency, but it does not typically present with the acute neurological symptoms seen in this case. De Clerambault syndrome is a delusional disorder characterized by erotomanic delusions, which is not consistent with the patient's symptoms. Delirium tremens is a severe alcohol withdrawal syndrome, but it does not typically present with the specific neurological findings described.
18.
A 25year old female presents with 2year history of repetitive,
irresistible thoughts of contamination with dirt associated with
repetitive
hand washing. She reports these thoughts to be her own and
distressing;
but is not able to overcome them along with medications. She is
most likely
to benefit from which of the following therapies:
Correct Answer
A. Exposure and response prevention.
Explanation
The patient's symptoms of repetitive, distressing thoughts of contamination with dirt and repetitive hand washing are characteristic of obsessive-compulsive disorder (OCD). Exposure and response prevention (ERP) is a type of therapy commonly used to treat OCD. It involves gradually exposing the patient to their feared thoughts or situations (exposure) while preventing them from engaging in their usual compulsive behaviors or rituals (response prevention). This therapy helps the patient to gradually tolerate their distress and reduce their reliance on compulsions. Systematic desensitization, assertiveness training, and sensate focusing are not typically used in the treatment of OCD.
19.
An 18 year old boy came to the Psychiatry OPD with a complaint of
feeling
changed from inside. He described himself as feeling strange as if
he is
different from his normal self. He was very tense and anxious yet
could
not point out the precise change in him. This phenomena is best
called as:
Correct Answer
B. Depersonalization.
Explanation
The correct answer is Depersonalization. Depersonalization is a psychological phenomenon where an individual feels detached from their own thoughts, feelings, and body. In this case, the 18-year-old boy describes feeling strange and different from his normal self, indicating a sense of detachment from his own identity. This aligns with the symptoms of depersonalization, making it the most appropriate term to describe his experience.
20.
The major difference between typical and atypical antipsychotics
is that:
Correct Answer
B. The former cause tardive dyskinesia.
Explanation
Typical antipsychotics are known to cause tardive dyskinesia, which is a movement disorder characterized by involuntary repetitive movements of the face, tongue, and limbs. On the other hand, atypical antipsychotics have a lower risk of causing tardive dyskinesia. This is an important distinction between the two types of antipsychotics as tardive dyskinesia can be a long-term and sometimes irreversible side effect.
21.
Dry mouth during antidepressant therapy is caused by blockade of:
Correct Answer
A. Muscarinic acetylcholine receptors.
Explanation
Dry mouth during antidepressant therapy is caused by blockade of muscarinic acetylcholine receptors. Antidepressant medications, particularly those with anticholinergic properties, can inhibit the function of muscarinic acetylcholine receptors, leading to dry mouth as a side effect. These receptors are responsible for regulating the production of saliva, so when they are blocked, saliva production decreases, resulting in dry mouth. This is a common side effect of many antidepressant medications and can be managed with proper hydration and oral care.
22.
All of the following are hallucinogens, except:
Correct Answer
D. MethylpHenidate.
Explanation
Methylphenidate is not a hallucinogen. It is a central nervous system stimulant commonly used to treat attention deficit hyperactivity disorder (ADHD) and narcolepsy. Hallucinogens, on the other hand, are substances that alter perception, thoughts, and feelings, often leading to hallucinations. LSD, phenylcyclidine (PCP), and mescaline are all examples of hallucinogens.
23.
An 18-year-old student complains of lack of interest in studies for
last 6 months. He has frequent quarrels with his parents and has
frequent
headaches. The most appropriate clinical approach would be to:
Correct Answer
A. Leave him as normal adolescent problem.
Explanation
The most appropriate clinical approach would be to leave him as a normal adolescent problem because the symptoms described are common for teenagers experiencing the transition to adulthood. Lack of interest in studies, frequent quarrels with parents, and headaches can all be attributed to the normal challenges and changes that occur during adolescence. It is important to consider these factors before jumping to conclusions about more serious conditions such as depression, migraine, or oppositional defiant disorder.
24.
Preservation is:
Correct Answer
A. Persistent and inappropriate repletion of the same thoughts.
Explanation
The correct answer is "Persistent and inappropriate repletion of the same thoughts." This refers to the concept of preservation, which is the repetitive and continuous fixation on the same thoughts or ideas, even when they are no longer relevant or appropriate. This can be a symptom of various mental health conditions, such as obsessive-compulsive disorder (OCD) or schizophrenia. It is often distressing for the individual experiencing it.
25.
One of the following usually differentiates hysterical symptoms from
hypochondriacal symptoms:
Correct Answer
A. Symptoms do not normally reflect understandable pHysiological or pathological mechanisms.
Explanation
Hysterical symptoms and hypochondriacal symptoms can often be distinguished by the fact that hysterical symptoms do not typically have a clear physiological or pathological explanation. In other words, the symptoms experienced by someone with hysteria cannot be easily attributed to a specific physical cause or illness. This is in contrast to hypochondriacal symptoms, where individuals may have physical symptoms that are not explained by organic factors, but they often have a strong belief that they have a serious medical condition.
26.
Which one of the following is the investigation of choice for evaluation
of suspected Perthe’s disease ?
Correct Answer
D. Magnetic Resonance Imaging.
Explanation
Magnetic Resonance Imaging (MRI) is the investigation of choice for evaluating suspected Perthe's disease. This is because MRI provides detailed images of the bone and soft tissues, allowing for a more accurate diagnosis and assessment of the extent of the disease. Plain X-rays may show changes in the bone later in the disease process, while Ultrasonography and Computed Tomography (CT) have limited utility in evaluating Perthe's disease. Therefore, MRI is the preferred imaging modality for diagnosing and evaluating Perthe's disease.
27.
Eisenmenger syndrome is characterized by all except:
Correct Answer
A. Return of left ventricle and right ventricle to normal size.
Explanation
Eisenmenger syndrome is a condition characterized by a reversal of blood flow within the heart due to a defect in the heart's structure. This leads to increased pressure in the lungs and enlargement of the right side of the heart. The correct answer states that there is no return of the left ventricle and right ventricle to normal size, which is consistent with the condition. In Eisenmenger syndrome, the ventricles do not return to their normal size because of the increased pressure in the lungs.
28.
In which one of the following conditions the Sialography is
contraindicated?
Correct Answer
C. Acute parotitis
Explanation
Sialography is a radiographic procedure used to evaluate the salivary glands. Acute parotitis refers to the sudden inflammation of the parotid gland, which is one of the major salivary glands. During acute parotitis, the gland is swollen and painful. Performing sialography in this condition can exacerbate the inflammation and cause further discomfort to the patient. Therefore, sialography is contraindicated in cases of acute parotitis.
29.
The most common site of leak in CSF rhinorrhea is:
Correct Answer
C. Cribriform plate.
Explanation
The correct answer is Cribriform plate. The cribriform plate is a thin, bony structure that separates the nasal cavity from the brain. It contains small perforations called cribriform foramina through which the olfactory nerve fibers pass. If the cribriform plate is fractured or damaged, it can result in a leak of cerebrospinal fluid (CSF) into the nasal cavity, causing CSF rhinorrhea. This is why the cribriform plate is the most common site of leak in CSF rhinorrhea.
30.
Which of the following is the most common renal cystic disease in
infants
is?
Correct Answer
C. Unilateral renal dysplasia.
Explanation
Unilateral renal dysplasia is the most common renal cystic disease in infants. This condition is characterized by the abnormal development of one kidney, leading to the formation of cysts. Polycystic kidney is a genetic disorder that causes multiple cysts to develop in both kidneys. Simple renal cysts are fluid-filled sacs that form in the kidneys, but they are not typically associated with any specific disease. Calyceal cysts are cysts that form in the calyces, which are part of the renal pelvis. However, they are not as common as unilateral renal dysplasia in infants.
31.
The most common type of total anomalous pulmonary venous connection
is:
Correct Answer
A. Supracardiac.
Explanation
The most common type of total anomalous pulmonary venous connection is supracardiac. In this condition, the pulmonary veins from both lungs drain into a common vein that connects to the superior vena cava, which carries deoxygenated blood back to the heart. This abnormal connection occurs above the heart, hence the term "supracardiac." Other types of total anomalous pulmonary venous connection include infracardiac, where the pulmonary veins drain into the portal vein or the hepatic veins, and mixed, which involves a combination of supracardiac and infracardiac connections. The term "cardiac" is too broad and does not specify a specific type of connection.
32.
Which one of the following is the most common location of hypertensive
bleed in the brain?
Correct Answer
A. Putamen/external capsule.
Explanation
The most common location of hypertensive bleed in the brain is the putamen/external capsule. Hypertensive bleeds, also known as intracerebral hemorrhages, often occur in the deep structures of the brain, such as the basal ganglia, which includes the putamen and external capsule. These bleeds are commonly caused by chronic high blood pressure, which weakens the blood vessels in the brain, leading to rupture and bleeding in this specific location.
33.
Which one of the following is the most preferred route to perform
cerebral
angiography?
Correct Answer
A. Transfemoral route
Explanation
The most preferred route to perform cerebral angiography is the transfemoral route. This is because it is a minimally invasive procedure that involves inserting a catheter through the femoral artery in the groin and guiding it to the blood vessels in the brain. This route allows for better visualization of the blood vessels and reduces the risk of complications compared to other routes such as direct carotid puncture or transmaxillary route. The transfemoral route is commonly used in clinical practice and has proven to be safe and effective for cerebral angiography.
34.
Which one of the following soft tissue sarcomas frequently
metastasizes to lymph nodes?
Correct Answer
C. Embryonal Rhabdomyosarcoma.
Explanation
Embryonal Rhabdomyosarcoma is a soft tissue sarcoma that frequently metastasizes to lymph nodes. This type of sarcoma arises from embryonic skeletal muscle cells and is commonly found in children. It has a high tendency to spread to regional lymph nodes, which is why it is often associated with lymph node metastasis. Fibrosarcoma, Osteosarcoma, and Alveolar soft part sarcoma are other types of soft tissue sarcomas, but they do not have the same propensity to metastasize to lymph nodes as Embryonal Rhabdomyosarcoma.
35.
Which one of the following radioisotope is not used as permanent
implant?
Correct Answer
B. Palladium-103.
Explanation
Palladium-103 is not used as a permanent implant because it has a relatively short half-life of 17 days. This means that it decays quickly and loses its radioactivity within a few weeks. In contrast, Iodine-125, Gold-198, and Caesium-137 have longer half-lives and can provide a more sustained radiation therapy treatment.
36.
Which one of the following tumors shows calcification on CT scan?
Correct Answer
C. Meningioma.
Explanation
Meningioma is the correct answer because it is a type of brain tumor that frequently shows calcification on CT scans. Calcification refers to the deposition of calcium within the tumor, which can be visualized on imaging. Ependymoma, medulloblastoma, and CNS lymphoma are not typically associated with calcification on CT scans.