স্পেশাল বিসিএস (স্বাস্থ্য)

Sweet-tasting compounds are detected by a combination of two closely related G-protein-coupled taste receptors, T1R2 and T1R3.
The receptors responsible for umami taste is believed to be a complex of T1R1 and T1R3 proteins. Thus, T1R3 appears to function as a co- receptor for sweet and umami tastes.
Bitter taste is sensed by another family (T2R) of approximately 30 different G-protein coupled receptors. Individual bitter-sensing taste receptor cells express multiple T2Rs, each of which recognizes a unique set of bitter compounds.
Sour taste, associated with acidic food or drink, is believed to be sensed by ion channels that are opened by hydrogen ions although the precise mechanisms are not fully understood. Recent studies suggest that an acid- sensitive potassium channel (KIR2.1) and a hydrogen ion-selective ion channel (otopetrin 1) may mediate acid responses in taste receptor cells

Explanation: coagulation screening tests are Platelet count, PT, APTT & Fibrinogen concentration

Tuberculoid leprosy, caused by Mycobacterium leprae, presents with few hypopigmented, anesthetic skin patches with well-defined borders due to a strong cell-mediated immune response. Nodular lesions are seen in lepromatous leprosy, not tuberculoid

Intramembranous ossification, by which most flat bones begin to form, takes place within condensed sheets (“membranes”) of embryonic mesenchymal tissue. Most bones of the skull and jaws, as well as the scapula and clavicle, are formed embryonically by intramembranous ossification.

Cushing’s disease (a pituitary ACTH-secreting adenoma) is the most common endogenous cause. However, overall, iatrogenic (exogenous steroids) is most common.

Answer: C. Keep the patient admitted and initiate psychiatric referral
Justification:

Suicide attempt suggests mental illness → requires mental fitness evaluation.
Doctor has a legal and ethical duty to protect life.
(Reddy Ch. 22; Bangladesh Mental Health Act 2018)

GeneXpert detects M. tuberculosis DNA and rifampicin resistance within 2 hours

Explanation: Secondary pulmonary tuberculosis classically involves the apex of the upper lobes of one or both lungs

Explanation :
Obstructive pulmonary disease -
Asthma
COPD

The left upper lobe contains the cardiac notch, where the left ventricle and pericardial sac lodges. The Lingula (which is the embryologic counterpart to the right middle lobe) lies just beneath the cardiac notch.

Explanation: DNA replication occurs in S(synthesis) phase of cell cycle

Explanation -
Causes of down syndrome -
Non dysjunction ( 94%)
Mosaicism ( 2%)
Robertsonian translocation ( 4%)

The. Content of space of Disse is kupffer cell.

Reference: Davidson 23rd; P-668

TSH receptor antibodies (TRAb), especially thyroid-stimulating immunoglobulins, are highly specific for Graves’ disease, driving hyperthyroidism. Anti-TPO and anti-thyroglobulin antibodies are more common in Hashimoto’s

Chronic liver disease (CLD) is a broad term encompassing various conditions leading to progressive liver damage. Decompensation signifies the failure of the liver to perform its essential functions, often leading to complications like ascites, hepatic encephalopathy, variceal bleeding, and spontaneous bacterial peritonitis (SBP). SBP is an infection of the ascitic fluid and is a serious complication of advanced CLD with ascites.

The hypothalamic hypophyseal tract includes bundles of nerve axons that run from supraoptic nucleus (SON) and paraventricular nucleus (PVN) in the hypothalamus to the posterior pituitary.

Membranous part is the shortest part of male urethra

Reference: Davidson 23rd; P-825
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ADH prevents diuresis. It increases reabsorption of H20.

Section 45 of The Evidence Act, 1872 addresses the relevance of expert opinions in court. When the court needs to form an opinion on a point of foreign law, science, physical or forensic evidence, art, or specific aspects of identity like handwriting or fingerprint, the opinion of a person skilled in that area (an expert) is considered relevant. These experts are called "experts" within the context of the Act. 

Hemophilia- X-linked recessive
Myotonic dystrophy, Osteogenesis imperfecta- Autosomal dominant

Examples of autosomal recessive disorders: 

Metabolic:
1. Homocystinuria/Alpha-1 antitrypsin deficiency
2. Cystic fibrosis
3. Phenylketonuria
4. Alkaptonuria
5. Wilson’s disease
6. Galactosemia
7. Lysosomal storage disease
8. Glycogen storage disease

Haematopoietic:
1. Thalassaemia
2. Sickle cell anaemia

Endocrine:
1. Congenital adrenal hyperplasia

Nervous: 
1. Neurogenic muscular atrophy
2. Friedrich’s ataxia
3. Spinal muscular atrophy

Skeletal: 
1. Some variants of Ehlers-Danlos syndrome

Endogenous pigment that accumulates inside the cell is lipofuscin

Explanation :

Ref : Sembulingam 6th edition (Table- 141.3)

Signet ring is present in P. falciparum

Reference: Davidson 23rd; P-799

Accumulation of excess fluid in tissue is called edema

TSH is most sensitive thyroid function test.

MS is a demyelinating disease

After transfusion of stored blood citrate metabolized in body and Produce HCO3- leads to metabolic alkalosis (Citrate is anticoagulant in blood bag).

Explanation -
A hapten is a substance that can combine with a specific antibody but lacks antigenicity of its own.
Many small molecules of Mr < 1000 such as toxins, drugs and hormones are not capable of invoking immune response when injected directly into animals.
Non protein substance
They are thus not immunogenic by themselves, and are called haptens.

Stem Breakdown:

Recurrent episodes of chest pain, palpitations, and shortness of breath: These symptoms suggest a tachyarrhythmia, such as paroxysmal supraventricular tachycardia (PSVT).
ECG showing PSVT: PSVT is a common type of arrhythmia characterized by sudden onset and termination, often due to reentrant circuits in the atrioventricular (AV) node.
Option Analysis:

A) Beta-blockers: Beta-blockers can be used to control the rate in some arrhythmias, but they are not the first-line treatment for terminating acute PSVT episodes.
B) Adenosine: This is the correct answer. Davidson and Harrison recommend adenosine as the first-line treatment for acute PSVT because it temporarily blocks AV nodal conduction, terminating the reentrant circuit responsible for PSVT. It is highly effective and works within seconds.
C) Calcium channel blockers: Calcium channel blockers (e.g., verapamil, diltiazem) can be used to slow AV nodal conduction in PSVT, but they are typically second-line agents after adenosine.
D) Amiodarone: Amiodarone is used to treat ventricular arrhythmias and atrial fibrillation but is not the first-line treatment for acute PSVT. It has a longer onset of action compared to adenosine.

Generalised cortical atrophy, particularly in the hippocampus and temporal lobes, is the hallmark imaging finding in Alzheimer’s disease. Davidson explains that atrophy reflects the loss of neurons and synapses in affected brain regions. Harrison adds that MRI or CT imaging can help support the clinical diagnosis, but definitive diagnosis still relies on clinical features and histopathology, if available.

Important findings :

1. Bleeding time-Normal
2. Clotting time- prolonged
3. APTT- prolonged
4. Prothrombin time- Normal
5. Platelet count- Normal

Type-1 respiratory failure occurs in lobar collapse

Definite cyanosis appears whenever the arterial blood contains more than 5 grams of deoxygenated hemoglobin in each 100 ml of blood. A person with anemia almost never becomes cyanotic. Conversely, in a person with Polycythemia vera frequently has cyanosis, even under otherwise normal conditions.

Gastrulation is an event of 3rd week of development.

Explanation: Adenocarcinoma is the most common cancers in non-smokers.

HBV is a major cause of HCC, especially in endemic regions. Cirrhosis of any cause increases HCC risk.

Factors That Cause a Hypoeffective Heart
► (1) Increased arterial pressure against which the heart must pump, such as in hypertension.
► (2) Inhibition of nervous excitation of the heart.
► (3) Pathological factors that cause abnormal heart rhythm or rate of heartbeat.
► (4) Coronary artery blockage, causing a "heart attack”.
► (5) Valvular heart disease.
► (6) Congenital heart disease.
► (7) Myocarditis, an inflammation of the heart muscle.

Filiform papillae: They are the most numerous papillae. They are small and conical in shape. The epithelium at the tips of these papillae is keratinised. It may project in the form of threads.

Explanation :
Congenital cyanotic heart disease :
Fallot's tetralogy
Transposition of the great vessels
Severe ebstain anomaly
Tricuspid atresia
Pulmonary atresia
Severe pumonary stenosis

Congenital acyanotic heart disease -
ASD
VSD
PDA
Coarctation of aorta
Congenital aoryuc stenosis

Chronic liver disease can lead to impaired bile production and fat-soluble vitamin (A, D, E, K) malabsorption. Vitamin K deficiency can cause coagulopathy.

Evidence of Plasma Leakage (key differentiating point between Dengue and Dengue Haemorrhagic Fever)
Rise in Hct.: 20% (eg. In children 35 → 42 and in adults 40→48)
• Circulatory failure: Cold/cold clammy skin, CRFT>2 Sec, tachycardia, weak pulse, narrow pulse pressure <20, hypotension.
• Fluid accumulation - Ascites/ Pleural effusions
• Albumin <3.5 gm/dl

The richest source of histamine is mast cell

Explanation: Other causes of Atypical pneumonia are : Psittacosis, Q fever, Legionella, Mycoplasma pneumoniae.

Explanation :
Chronic inflammation is characterized by the
following:
• Infiltration with mononuclear cells, which include macrophages, lymphocytes, and plasma cells.
• Tissue destruction, induced by the persistent offending agent or by the inflammatory cells.
• Attempts at healing by connective tissue replacement of damaged tissue, accomplished by angiogenesis (proliferation of small blood vessels) and, in particular, fibrosis.

Explanation -
LP is essential or extremely useful in the diagnosis of bacterial, fungal, mycobacterial, and viral central nervous system (CNS) infections and, in certain settings, to aid in the diagnosis of subarachnoid hemorrhage (SAH), demyelinating diseases, Guillain-Barré syndrome and other inflammatory disorders,cerebral abscess,Neurosyphilis, Brain tumor,Acute poliomyelitis. 

Explanation: ‘Oligoclonal Band’ in CSF is a typical feature of Multiple sclerosis

Current guidelines for RA emphasize early and aggressive treatment with disease-modifying anti-rheumatic drugs (DMARDs), typically methotrexate, within 3 months of diagnosis. This "treat-to-target" strategy aims to achieve remission or low disease activity to prevent irreversible joint damage and improve long-term outcomes. Delaying DMARDs allows progression of structural damage.

Reference: Davidson 23rd; P-812
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