python3 -c " from docx import Document doc = Document('/tmp/workspace/attachments/99110f5c-97ac-4c47-b65c-65c9925092e8/Unit Test-II 2025-26.docx') for p in doc.paragraphs: style = p.style.name if p.style else 'None' if p.text.strip(): print(f'[{style}] {p.text}') "

mkdir -p /tmp/workspace/unit-test-answers && ls /tmp/workspace/unit-test-answers/

cat << 'PYEOF' > /tmp/workspace/unit-test-answers/create_answers.py from docx import Document from docx.shared import Pt, Inches, RGBColor from docx.enum.text import WD_ALIGN_PARAGRAPH from docx.oxml.ns import qn from docx.oxml import OxmlElement import copy doc = Document() # Set margins from docx.shared import Inches sections = doc.sections for section in sections: section.top_margin = Inches(1) section.bottom_margin = Inches(1) section.left_margin = Inches(1.2) section.right_margin = Inches(1.2) # Set default font style = doc.styles['Normal'] style.font.name = 'Times New Roman' style.font.size = Pt(12) def add_heading(doc, text, level=1, color=None): p = doc.add_paragraph() p.alignment = WD_ALIGN_PARAGRAPH.LEFT run = p.add_run(text) run.bold = True if level == 1: run.font.size = Pt(14) if color: run.font.color.rgb = RGBColor(*color) else: run.font.color.rgb = RGBColor(0x1F, 0x49, 0x7D) elif level == 2: run.font.size = Pt(12) run.font.color.rgb = RGBColor(0x2E, 0x74, 0xB5) else: run.font.size = Pt(12) run.font.color.rgb = RGBColor(0, 0, 0) run.font.name = 'Times New Roman' return p def add_subheading(doc, text): p = doc.add_paragraph() run = p.add_run(text) run.bold = True run.underline = True run.font.size = Pt(12) run.font.name = 'Times New Roman' return p def add_para(doc, text, bold_prefix=None): p = doc.add_paragraph() if bold_prefix: run = p.add_run(bold_prefix + " ") run.bold = True run.font.name = 'Times New Roman' run.font.size = Pt(12) run2 = p.add_run(text) run2.font.name = 'Times New Roman' run2.font.size = Pt(12) return p def add_bullet(doc, text, bold_prefix=None): p = doc.add_paragraph(style='List Bullet') if bold_prefix: run = p.add_run(bold_prefix + ": ") run.bold = True run.font.name = 'Times New Roman' run.font.size = Pt(12) run2 = p.add_run(text) run2.font.name = 'Times New Roman' run2.font.size = Pt(12) else: run = p.add_run(text) run.font.name = 'Times New Roman' run.font.size = Pt(12) return p def add_marks_note(doc, text): p = doc.add_paragraph() p.alignment = WD_ALIGN_PARAGRAPH.RIGHT run = p.add_run(text) run.bold = True run.font.size = Pt(11) run.font.color.rgb = RGBColor(0xC0, 0x00, 0x00) run.font.name = 'Times New Roman' return p def add_divider(doc): p = doc.add_paragraph() p.paragraph_format.space_before = Pt(4) p.paragraph_format.space_after = Pt(4) run = p.add_run("_" * 80) run.font.size = Pt(8) run.font.color.rgb = RGBColor(0xCC, 0xCC, 0xCC) # ===== HEADER ===== header_p = doc.add_paragraph() header_p.alignment = WD_ALIGN_PARAGRAPH.CENTER r = header_p.add_run("DEPARTMENT OF PHYSIOLOGY") r.bold = True r.font.size = Pt(14) r.font.name = 'Times New Roman' sub_p = doc.add_paragraph() sub_p.alignment = WD_ALIGN_PARAGRAPH.CENTER r2 = sub_p.add_run("Unit Test – II | MBBS Batch 2025–26 | Time: 1.30 Hrs | Max. Marks: 60") r2.font.size = Pt(11) r2.font.name = 'Times New Roman' title_p = doc.add_paragraph() title_p.alignment = WD_ALIGN_PARAGRAPH.CENTER r3 = title_p.add_run("MODEL ANSWERS WITH MARKS DISTRIBUTION") r3.bold = True r3.font.size = Pt(13) r3.font.color.rgb = RGBColor(0x1F, 0x49, 0x7D) r3.font.name = 'Times New Roman' doc.add_paragraph() add_divider(doc) # =================================================================== # Q1 – ESSAY (2+3+6+4 = 15 marks) # =================================================================== add_heading(doc, "Q.1 Essay Type Question [2+3+6+4 = 15 Marks]") add_para(doc, "Define haemostasis. Discuss briefly different steps of haemostasis. Describe the different mechanisms of coagulation with the help of flow charts. Why blood does not clot in circulation.") doc.add_paragraph() # Part (a) – 2 marks add_subheading(doc, "(a) Definition of Haemostasis [2 Marks]") add_para(doc, "Haemostasis is defined as a precisely orchestrated physiological process that stops bleeding following vascular injury. It involves three major components working in concert: the blood vessel wall (endothelium and vascular smooth muscle), platelets, and the coagulation cascade, ultimately leading to the formation of a stable blood clot at the site of injury while maintaining blood fluidity elsewhere.") doc.add_paragraph() # Part (b) – 3 marks add_subheading(doc, "(b) Steps of Haemostasis [3 Marks]") add_para(doc, "Haemostasis occurs in four sequential steps:") add_bullet(doc, "Immediate reflex vasoconstriction of the injured vessel reduces blood flow to the area. This is mediated by neurogenic reflexes and local release of endothelin from injured endothelium.", "Step 1 – Vascular Spasm") add_bullet(doc, "Disruption of endothelium exposes subendothelial collagen and von Willebrand factor (vWF). Platelet glycoprotein GpIb receptors bind to vWF, causing platelet adhesion. Activated platelets change shape, release ADP and thromboxane A2 (TXA2), and aggregate via GpIIb-IIIa receptors and fibrinogen, forming the primary haemostatic plug.", "Step 2 – Primary Haemostasis (Platelet Plug Formation)") add_bullet(doc, "Vascular injury exposes tissue factor (TF), triggering the coagulation cascade. Thrombin generated cleaves fibrinogen to fibrin, which reinforces the platelet plug, forming the secondary haemostatic plug.", "Step 3 – Secondary Haemostasis (Coagulation / Fibrin Clot)") add_bullet(doc, "Factor XIII cross-links fibrin polymers; platelets contract via actomyosin, compacting the clot. Eventually, fibrinolysis dissolves the clot once healing occurs.", "Step 4 – Clot Stabilisation and Fibrinolysis") doc.add_paragraph() # Part (c) – 6 marks add_subheading(doc, "(c) Mechanisms of Coagulation (with Flow Charts) [6 Marks]") add_para(doc, "The coagulation cascade involves a series of proenzyme (zymogen) activations. Two pathways converge on a common pathway. The key concept: each activated factor acts as a serine protease to activate the next factor.") doc.add_paragraph() add_para(doc, "EXTRINSIC PATHWAY (Tissue Factor Pathway):", None) p_flow = doc.add_paragraph() p_flow.paragraph_format.left_indent = Inches(0.5) r = p_flow.add_run( "Tissue factor (TF) exposed at injury site\n" " ↓\n" "TF binds Factor VII → TF-VIIa complex formed\n" " ↓\n" "TF-VIIa activates Factor X → Xa\n" " (also activates Factor IX → IXa)\n" " ↓\n" "Factor Xa + Factor Va (prothrombinase complex)\n" " ↓\n" "Prothrombin (II) → Thrombin (IIa)\n" " ↓\n" "Fibrinogen (I) → Fibrin (Ia) → Cross-linked fibrin (by XIIIa)" ) r.font.name = 'Courier New' r.font.size = Pt(10) doc.add_paragraph() add_para(doc, "INTRINSIC PATHWAY (Contact Activation Pathway):", None) p_flow2 = doc.add_paragraph() p_flow2.paragraph_format.left_indent = Inches(0.5) r2 = p_flow2.add_run( "Contact activation: Factor XII → XIIa\n" " ↓\n" "XIIa activates Factor XI → XIa\n" " ↓\n" "XIa activates Factor IX → IXa\n" " ↓\n" "IXa + Factor VIIIa + Ca²⁺ + Phospholipid (tenase complex)\n" " ↓\n" "Factor X → Xa\n" " ↓\n" "→ COMMON PATHWAY (see above)" ) r2.font.name = 'Courier New' r2.font.size = Pt(10) doc.add_paragraph() add_para(doc, "COMMON PATHWAY:", None) p_flow3 = doc.add_paragraph() p_flow3.paragraph_format.left_indent = Inches(0.5) r3_f = p_flow3.add_run( "Factor Xa + Factor Va + Ca²⁺ + Phospholipid\n" " ↓ (Prothrombinase complex)\n" "Prothrombin (II) → Thrombin (IIa)\n" " ↓\n" "Fibrinogen → Fibrin monomers → Fibrin polymer\n" " ↓ (Factor XIIIa, Ca²⁺)\n" "Cross-linked, stable fibrin clot" ) r3_f.font.name = 'Courier New' r3_f.font.size = Pt(10) doc.add_paragraph() add_para(doc, "Role of Thrombin (central amplifier):") add_bullet(doc, "Converts fibrinogen → fibrin") add_bullet(doc, "Activates Factors V, VIII, XI (positive feedback)") add_bullet(doc, "Activates Factor XIII (cross-linking)") add_bullet(doc, "Activates platelets") add_bullet(doc, "Activates Protein C (negative feedback via thrombomodulin)") doc.add_paragraph() # Part (d) – 4 marks add_subheading(doc, "(d) Why Blood Does Not Clot in Normal Circulation [4 Marks]") add_para(doc, "Blood remains fluid in circulation due to several natural anticoagulant mechanisms:") add_bullet(doc, "Intact endothelium expresses prostacyclin (PGI2) and nitric oxide (NO), which inhibit platelet aggregation. Endothelium also expresses thrombomodulin, which binds thrombin and activates Protein C, a potent anticoagulant.", "1. Endothelial Anticoagulant Properties") add_bullet(doc, "Activated Protein C (with Protein S as cofactor) degrades Factors Va and VIIIa, shutting down coagulation amplification.", "2. Protein C – Protein S System") add_bullet(doc, "ATIII is the major serine protease inhibitor. It neutralises thrombin, Factors IXa, Xa, XIa, and XIIa. Its activity is greatly potentiated by heparan sulphate on endothelial surfaces.", "3. Antithrombin III (ATIII)") add_bullet(doc, "TFPI is released by endothelium and inhibits the TF-VIIa-Xa complex, limiting the extrinsic pathway.", "4. Tissue Factor Pathway Inhibitor (TFPI)") add_bullet(doc, "Blood flow dilutes and washes away activated clotting factors; the liver rapidly removes and inactivates them.", "5. Dilution and Hepatic Clearance") add_bullet(doc, "Coagulation reactions require negatively charged phospholipid surfaces (exposed only on activated platelets). In circulating blood these surfaces are absent, so coagulation cannot proceed.", "6. Requirement for Phospholipid Surfaces") add_bullet(doc, "Plasminogen is converted to plasmin by tPA, which dissolves any micro-thrombi that form spontaneously.", "7. Fibrinolytic System") doc.add_paragraph() add_divider(doc) # =================================================================== # Q2 – CLINICAL CASE (2+3+5+5 = 15 marks) # =================================================================== doc.add_paragraph() add_heading(doc, "Q.2 Clinical Case Scenario [2+3+5+5 = 15 Marks]") add_para(doc, "Case: A middle-aged man with extreme muscle weakness worsened by evening, difficulty in speech and swallowing, and drooping of eyelids.") doc.add_paragraph() # 2(i) – 2 marks add_subheading(doc, "(i) Probable Diagnosis [2 Marks]") add_para(doc, "Diagnosis: Myasthenia Gravis (MG)") add_para(doc, "Justification:") add_bullet(doc, "Fatigable muscle weakness worsening toward evening (hallmark feature)") add_bullet(doc, "Ptosis (drooping eyelids) – ocular muscles are most commonly affected early") add_bullet(doc, "Bulbar symptoms (dysarthria – difficulty in speech, dysphagia – difficulty in swallowing)") add_bullet(doc, "Middle-aged man (second peak incidence in older males)") doc.add_paragraph() # 2(ii) – 3 marks add_subheading(doc, "(ii) Pathophysiology of Myasthenia Gravis [3 Marks]") add_para(doc, "Myasthenia Gravis is an acquired autoimmune disorder of the neuromuscular junction (NMJ).") add_para(doc, "Mechanism:") add_bullet(doc, "B-lymphocytes (often triggered by thymic abnormalities – thymoma or thymic hyperplasia) produce IgG autoantibodies directed against nicotinic acetylcholine receptors (nAChR) on the postsynaptic motor endplate. The major target is the Main Immunogenic Region (MIR) on the α-subunit of the AChR.") add_bullet(doc, "These antibodies cause: (a) Complement-mediated destruction of postjunctional folds and AChR degradation. (b) Direct blockade of acetylcholine binding. (c) Cross-linking and accelerated internalization of receptors.") add_bullet(doc, "Result: Reduced density of functional AChRs at motor end plate → reduced miniature endplate potential (MEPP) amplitude → insufficient depolarisation to reach threshold → muscle fibre fails to generate action potential → muscle weakness.") add_bullet(doc, "With repeated activity (or as day progresses), ACh stores get depleted and fewer AChRs are available → fatiguability and worsening by evening.") add_bullet(doc, "~10–15% of patients have a thymoma; thymectomy produces clinical improvement in ~75% of these cases.") doc.add_paragraph() # 2(iii) – 5 marks add_subheading(doc, "(iii) Structure of Neuromuscular Junction (with Labelled Diagram) [5 Marks]") add_para(doc, "The neuromuscular junction (NMJ) is the synapse between the terminal branch of a motor neuron and a skeletal muscle fibre.") doc.add_paragraph() add_subheading(doc, "Components:") add_bullet(doc, "A large myelinated motor nerve (α-motor neuron) from the anterior horn of spinal cord. It loses its myelin sheath just before reaching the muscle fibre. The terminal expands into a bulb containing ~300,000 synaptic vesicles, each loaded with approximately 10,000 ACh molecules. Mitochondria are abundant (for ACh synthesis via ATP).", "1. Presynaptic Terminal (Nerve Terminal / Axon Terminal)") add_bullet(doc, "A 20–30 nm gap separating the nerve terminal from the muscle membrane. It contains acetylcholinesterase (AChE), which rapidly hydrolyses ACh after it acts.", "2. Synaptic Cleft") add_bullet(doc, "A specialised region of the muscle cell membrane called the motor end plate. It has primary synaptic gutters (grooves that the nerve terminal sits in) and secondary synaptic clefts (junctional folds) that greatly increase the surface area. Nicotinic AChRs (nAChRs) are densely packed at the crests of these folds (~10,000 receptors/μm²). Voltage-gated Na⁺ channels are concentrated at the depths of the folds.", "3. Postsynaptic Membrane (Motor End Plate)") add_bullet(doc, "Schwann cells cover and insulate the entire junction.", "4. Schwann Cells (Perisynaptic)") doc.add_paragraph() add_para(doc, "LABELLED DIAGRAM OF NEUROMUSCULAR JUNCTION:") p_diag = doc.add_paragraph() p_diag.paragraph_format.left_indent = Inches(0.3) r_diag = p_diag.add_run( """ MYELINATED NERVE FIBRE | [Schwann Cell sheath] | AXON TERMINAL (bulb) ┌──────────────────────────────┐ │ Mitochondria Dense bars │ │ ●●● Synaptic vesicles ●●● │ ← ACh stored here │ (each ~10,000 ACh) │ └──────┬───────────────┬──────┘ │ Synaptic │ │ Cleft │ ← AChE here (20–30 nm) ───────┴───────────────┴────────── ~~~~ PRIMARY SYNAPTIC GUTTER ~~~~ ▼▼▼▼ JUNCTIONAL FOLDS ▼▼▼▼ (nAChR at crests; Na⁺ channels at depths) ────────────────────────────────── MUSCLE FIBRE MEMBRANE (Motor End Plate) """ ) r_diag.font.name = 'Courier New' r_diag.font.size = Pt(9) doc.add_paragraph() # 2(iv) – 5 marks add_subheading(doc, "(iv) Mechanism of Neuromuscular Transmission of Nerve Impulse [5 Marks]") add_para(doc, "The transmission of a nerve impulse across the NMJ occurs in the following steps:") add_bullet(doc, "An action potential travels along the motor nerve fibre and reaches the axon terminal.", "Step 1 – Nerve Action Potential Arrival") add_bullet(doc, "Depolarisation of the terminal opens voltage-gated Ca²⁺ channels in the presynaptic membrane. Ca²⁺ flows from the synaptic cleft into the nerve terminal down its concentration gradient.", "Step 2 – Calcium Influx") add_bullet(doc, "Ca²⁺ binds to calmodulin and activates Ca²⁺-calmodulin-dependent protein kinase, which phosphorylates synapsin proteins anchoring vesicles to the cytoskeleton. This frees the vesicles, which dock at active zones (adjacent to dense bars) and fuse with the presynaptic membrane (exocytosis). Each action potential releases ~125 vesicles (~1.25 × 10⁶ molecules of ACh).", "Step 3 – Acetylcholine Vesicle Release (Exocytosis)") add_bullet(doc, "ACh diffuses across the 20–30 nm synaptic cleft and binds to nicotinic AChRs (ligand-gated ion channels, pentameric – 2α, 1β, 1γ/ε, 1δ subunits) on the postsynaptic membrane. Binding of two ACh molecules (one to each α-subunit) opens the channel, allowing Na⁺ influx and K⁺ efflux → net depolarisation of end plate → End Plate Potential (EPP).", "Step 4 – ACh Binding to Postsynaptic Receptors") add_bullet(doc, "The EPP (which is much larger than threshold) triggers the opening of voltage-gated Na⁺ channels in the perijunctional muscle membrane, generating a muscle action potential that propagates along the entire sarcolemma → triggers excitation-contraction coupling → muscle contraction.", "Step 5 – Generation of Muscle Action Potential") add_bullet(doc, "Acetylcholinesterase (AChE) in the synaptic cleft rapidly hydrolyses ACh into acetate and choline within milliseconds, terminating the signal. Choline is taken back up into the nerve terminal and re-used to synthesise new ACh (with acetyl-CoA from mitochondria).", "Step 6 – Termination – Hydrolysis of ACh") doc.add_paragraph() add_divider(doc) # =================================================================== # Q3 – SHORT NOTES (6 × 5 = 30 marks) # =================================================================== doc.add_paragraph() add_heading(doc, "Q.3 Short Notes [6 × 5 = 30 Marks]") doc.add_paragraph() # ---- 3(a) Erythropoiesis ---- add_subheading(doc, "(a) Steps of Erythropoiesis with Labelled Diagram [5 Marks]") add_para(doc, "Erythropoiesis is the process of formation of mature red blood cells (erythrocytes) from pluripotent haematopoietic stem cells in the red bone marrow.") doc.add_paragraph() add_para(doc, "Developmental Sequence (Committed Progenitors → Mature RBC):") add_bullet(doc, "Pluripotent haematopoietic stem cell (PHSC)") add_bullet(doc, "→ Common Myeloid Progenitor (CMP)") add_bullet(doc, "→ BFU-E (Burst Forming Unit–Erythroid) – first committed erythroid progenitor; responds to SCF, IL-3") add_bullet(doc, "→ CFU-E (Colony Forming Unit–Erythroid) – sensitive to erythropoietin (EPO)") add_bullet(doc, "→ Pronormoblast (Proerythroblast): large cell, basophilic cytoplasm, large nucleus with prominent nucleoli") add_bullet(doc, "→ Basophilic Normoblast (Early Erythroblast): deep blue cytoplasm (ribosome-rich), starts synthesising haemoglobin") add_bullet(doc, "→ Polychromatophilic Normoblast (Intermediate Erythroblast): pink + blue cytoplasm (Hb increasing + ribosomes decreasing), nucleus condensing") add_bullet(doc, "→ Orthochromatic Normoblast (Late Erythroblast): predominantly pink cytoplasm, pyknotic nucleus; nucleus extruded here") add_bullet(doc, "→ Reticulocyte: anucleate; still contains residual mRNA and ribosomes (appear as reticulum with supravital staining); released into circulation; takes 1–2 days to mature fully") add_bullet(doc, "→ Mature Erythrocyte (RBC): biconcave disc, ~7–8 μm diameter, no nucleus, no mitochondria, rich in haemoglobin (~280–340 million molecules/cell)") doc.add_paragraph() add_para(doc, "Regulation: Erythropoietin (EPO) – produced by peritubular interstitial cells of kidney in response to hypoxia. EPO acts on CFU-E → promotes survival, proliferation, and differentiation.") doc.add_paragraph() add_para(doc, "DIAGRAM – Stages of Erythropoiesis:") p_ery = doc.add_paragraph() p_ery.paragraph_format.left_indent = Inches(0.3) r_ery = p_ery.add_run( """ PHSC → CMP → BFU-E → CFU-E ↓ [PRONORMOBLAST] Large, basophilic Prominent nucleoli ↓ [BASOPHILIC NORMOBLAST] Deep blue cytoplasm Hb synthesis begins ↓ [POLYCHROMATOPHILIC NORMOBLAST] Mixed pink+blue cytoplasm Nucleus condensing ↓ [ORTHOCHROMATIC NORMOBLAST] Mainly pink, pyknotic nucleus ★ Nucleus extruded here ★ ↓ [RETICULOCYTE] No nucleus, residual ribosomes Released into blood ↓ [MATURE ERYTHROCYTE] Biconcave disc, no nucleus Full of Haemoglobin """ ) r_ery.font.name = 'Courier New' r_ery.font.size = Pt(9) doc.add_paragraph() # ---- 3(b) AV Nodal Delay ---- add_subheading(doc, "(b) AV Nodal Delay and Its Significance [5 Marks]") add_para(doc, "The AV node (atrioventricular node) is located in the lower interatrial septum, at the junction of the right atrium, interventricular septum, and tricuspid valve – in the region known as the Triangle of Koch.") doc.add_paragraph() add_para(doc, "AV Nodal Delay:") add_para(doc, "The impulse from the SA node travels through the atrial myocardium at ~1 m/s. However, when it reaches the AV node, the conduction velocity slows dramatically to approximately 0.02–0.05 m/s, creating a delay of approximately 0.12–0.20 seconds (about 120–200 ms). This constitutes the PR interval on the ECG.") doc.add_paragraph() add_para(doc, "Mechanism of AV Nodal Delay:") add_bullet(doc, "AV nodal cells are small with fewer gap junctions → slow cell-to-cell conduction") add_bullet(doc, "Cells are Ca²⁺-dependent action potentials (slow response fibres) rather than fast Na⁺-dependent fibres") add_bullet(doc, "Smaller cell diameter → higher internal resistance → slower conduction") add_bullet(doc, "Resting membrane potential is less negative (−60 mV vs −90 mV) → more Na⁺ channels inactivated at rest") doc.add_paragraph() add_para(doc, "Significance of AV Nodal Delay:") add_bullet(doc, "Allows atrial systole to be completed before ventricular systole begins, ensuring optimum ventricular filling (atrial kick).") add_bullet(doc, "Acts as a gatekeeper – protects the ventricles from excessively rapid atrial rates (e.g., atrial flutter/fibrillation).") add_bullet(doc, "Maintains cardiac output by optimising diastolic filling time.") add_bullet(doc, "Allows coordinated AV contraction sequence, making the heart an efficient pump.") add_bullet(doc, "The AV node serves as the secondary pacemaker (escape rate 40–60/min) if the SA node fails.") doc.add_paragraph() # ---- 3(c) Innate Immunity ---- add_subheading(doc, "(c) Innate Immunity [5 Marks]") add_para(doc, "Innate immunity is the non-specific, immediate (within minutes to hours) first line of defence against pathogens. It is present from birth, does not require prior exposure, and does not produce immunological memory.") doc.add_paragraph() add_para(doc, "Components of Innate Immunity:") add_bullet(doc, "Skin (keratinised epithelium), mucous membranes, cilia, cough reflex, acid pH of stomach, lysozyme in tears/saliva", "1. Physical and Chemical Barriers") add_bullet(doc, "Neutrophils (first responders, phagocytosis and NETs), Macrophages (phagocytosis, cytokine secretion, antigen presentation), NK cells (kill virus-infected and tumour cells without prior sensitisation), Dendritic cells (pattern recognition, bridge innate and adaptive immunity), Mast cells, Basophils, Eosinophils.", "2. Cellular Components") add_bullet(doc, "Pattern Recognition Receptors (PRRs): Toll-like receptors (TLRs), NOD-like receptors (NLRs), RIG-I-like receptors recognise Pathogen-Associated Molecular Patterns (PAMPs) on microbes and Damage-Associated Molecular Patterns (DAMPs) from damaged host cells.", "3. Pattern Recognition") add_bullet(doc, "Complement system (classical, lectin, alternative pathways) → opsonisation, direct lysis (MAC), inflammation. Acute phase proteins: C-reactive protein (CRP), fibrinogen, serum amyloid A, mannose-binding lectin.", "4. Humoral Components") add_bullet(doc, "Type I Interferons (IFN-α, IFN-β) – antiviral defence; Pro-inflammatory cytokines (TNF-α, IL-1, IL-6, IL-8/CXCL8 – neutrophil chemoattractant); Anti-inflammatory cytokines (IL-10, TGF-β).", "5. Cytokines") add_bullet(doc, "Vasodilation and increased vascular permeability → swelling, redness, heat. Recruit leukocytes to site of infection. The cardinal signs: Rubor (redness), Calor (heat), Tumor (swelling), Dolor (pain), Functio laesa (loss of function).", "6. Inflammatory Response") doc.add_paragraph() # ---- 3(d) Wallerian Degeneration ---- add_subheading(doc, "(d) Wallerian Degeneration [5 Marks]") add_para(doc, "Wallerian degeneration (also called anterograde or orthograde degeneration) refers to the degenerative changes that occur in the distal segment of a nerve fibre (axon + myelin) following transection or crushing injury. It was described by Augustus Waller in 1850.") doc.add_paragraph() add_para(doc, "Sequence of Events (Timeline):") add_bullet(doc, "The segment of the axon distal to the site of injury – separated from the nerve cell body (which provides metabolic support) – undergoes degeneration. The proximal stump also degenerates back a few nodes of Ranvier.", "Day 1–2: Axon Separation") add_bullet(doc, "The axon becomes granular and fragmented (Wallerian fragmentation). Axoplasm disintegrates. This begins within 12–24 hours of injury.", "Day 2–3: Axon Fragmentation") add_bullet(doc, "Myelin sheath breaks down into lipid droplets and debris. Schwann cells dedifferentiate, proliferate, and phagocytose myelin debris.", "Day 3–7: Myelin Breakdown") add_bullet(doc, "Macrophages (haematogenous) are recruited and collaborate with Schwann cells to phagocytose axon and myelin debris. This is the main clearance phase.", "Day 7 onwards: Macrophage infiltration and clearance") add_bullet(doc, "Schwann cells proliferate and form linear cords (bands of Büngner) within the basal lamina tubes. These serve as scaffolding tracks guiding regenerating axon sprouts from the proximal stump.", "Weeks: Formation of Bands of Büngner") add_bullet(doc, "If continuity is restored (by suture or proximity), regenerating axon sprouts from the proximal stump grow along the Schwann cell columns at a rate of ~1–3 mm/day. Remyelination follows axon maturation.", "Regeneration Phase") doc.add_paragraph() add_para(doc, "Clinical Significance:") add_bullet(doc, "EMG/NCS: Wallerian degeneration produces fibrillation potentials on EMG (3+ weeks after injury) and absent/reduced SNAPs/CMAPs distally.") add_bullet(doc, "Prognostic importance: Neuropraxia (no Wallerian degeneration) has the best prognosis; axonotmesis (WD occurs but endoneurium intact) can fully recover; neurotmesis (complete cut) requires surgical repair.") doc.add_paragraph() # ---- 3(e) Functions of Plasma Proteins ---- add_subheading(doc, "(e) Functions of Plasma Proteins [5 Marks]") add_para(doc, "Plasma proteins are present in blood plasma at a total concentration of 6.0–8.0 g/dL. They are mostly synthesised by the liver (except immunoglobulins – plasma cells, and von Willebrand factor – endothelium).") doc.add_paragraph() add_para(doc, "Major Groups and Functions:") add_bullet(doc, "Albumin (3.5–5.0 g/dL, produced by liver): (i) Maintains colloid osmotic (oncotic) pressure – accounts for ~80% of total oncotic pressure. (ii) Transport: carries fatty acids, bilirubin, drugs (warfarin, aspirin), hormones (cortisol, T3/T4), Ca²⁺. (iii) Buffer: acts as a protein buffer (acidbase balance). (iv) Nutritional reserve of amino acids.", "1. Albumin") add_bullet(doc, "Fibrinogen → converted to fibrin by thrombin (coagulation). Other clotting factors (II, V, VII, VIII, IX, X, XI, XII, XIII, Protein C, Protein S) – essential for haemostasis.", "2. Coagulation Proteins") add_bullet(doc, "IgG, IgA, IgM, IgD, IgE – produced by plasma cells. Functions: neutralisation of toxins and viruses, opsonisation (IgG), complement activation (IgG, IgM), mucosal immunity (IgA), mast cell activation (IgE).", "3. Immunoglobulins (Antibodies)") add_bullet(doc, "Transferrin (iron transport), Caeruloplasmin (copper transport, ferroxidase), Haptoglobin (binds free Hb, prevents renal loss), Haemopexin (binds free haem), Transthyretin (T4/retinol transport).", "4. Transport Proteins") add_bullet(doc, "CRP, serum amyloid A, fibrinogen, complement proteins – rise in response to inflammation/infection (positive APR); albumin and transthyretin fall (negative APR).", "5. Acute Phase Proteins") add_bullet(doc, "Complement proteins (C1–C9): opsonisation, lysis via MAC, chemotaxis, inflammation.", "6. Complement Proteins") add_bullet(doc, "α1-antitrypsin (inhibits neutrophil elastase), antithrombin III, α2-macroglobulin – protect tissues from proteolysis.", "7. Protease Inhibitors") doc.add_paragraph() # ---- 3(f) Latch Bridge Mechanism ---- add_subheading(doc, "(f) Latch Bridge Mechanism [5 Marks]") add_para(doc, "The latch bridge mechanism is a unique property of smooth muscle that allows it to maintain sustained, tonic contraction with very low ATP consumption and minimal fatigue. It was proposed by Hai and Murphy (1988).") doc.add_paragraph() add_para(doc, "Background – Normal Smooth Muscle Contraction:") add_para(doc, "Smooth muscle contraction is regulated by phosphorylation of myosin light chains (MLC) by myosin light chain kinase (MLCK). MLCK is activated when Ca²⁺ binds to calmodulin → Ca²⁺-calmodulin complex → activates MLCK → phosphorylates MLC (at Ser19) → cross-bridge cycling → force generation.") doc.add_paragraph() add_para(doc, "The Latch State:") add_para(doc, "As cytosolic Ca²⁺ levels decline (after initial stimulus), MLCK activity falls. Myosin light chain phosphatase (MLCP) dephosphorylates MLC. However, cross-bridges do NOT detach immediately — they enter a 'latch' state (dephosphorylated, attached cross-bridges = latch bridges).") doc.add_paragraph() add_para(doc, "Key Features of Latch Bridge:") add_bullet(doc, "Cross-bridges are dephosphorylated by MLCP but remain attached to actin in a slowly cycling or non-cycling state.", "1. Dephosphorylated but attached") add_bullet(doc, "Latch bridges cycle very slowly (low ATPase activity) → force is maintained at low metabolic cost.", "2. Very slow cross-bridge cycling") add_bullet(doc, "Smooth muscle can maintain tone for hours (e.g., vascular smooth muscle, urinary bladder) without fatigue.", "3. Sustained force maintenance") add_bullet(doc, "Latch state is favoured at lower levels of Ca²⁺ and lower phosphorylation. At higher Ca²⁺: more phosphorylated bridges → faster cycling → shortening velocity increases. As Ca²⁺ falls: latch bridges predominate → force maintained, velocity decreases.", "4. Force-velocity relationship") doc.add_paragraph() add_para(doc, "FLOW DIAGRAM:") p_latch = doc.add_paragraph() p_latch.paragraph_format.left_indent = Inches(0.3) r_latch = p_latch.add_run( """ ↑ Ca²⁺ → Ca-Calmodulin → MLCK active → MLC phosphorylated ↓ Phospho-myosin (cycling cross-bridge) [Fast cycling, high ATP, force + shortening] ↓ ↓ Ca²⁺ → MLCK less active → MLCP dephosphorylates MLC ↓ Dephospho-myosin (ATTACHED) = LATCH BRIDGE [Very slow or no cycling, low ATP, force MAINTAINED → "Latch State"] ↓ Further MLCP action → cross-bridge detachment → Relaxation """ ) r_latch.font.name = 'Courier New' r_latch.font.size = Pt(9) doc.add_paragraph() add_para(doc, "Physiological significance: The latch mechanism explains sustained tone in blood vessels, airways, gut, and urinary bladder without energy exhaustion – important for maintaining blood pressure and visceral organ function continuously.") doc.add_paragraph() add_divider(doc) # Footer note p_end = doc.add_paragraph() p_end.alignment = WD_ALIGN_PARAGRAPH.CENTER r_end = p_end.add_run("— End of Answers | Physiology Unit Test-II 2025–26 —") r_end.italic = True r_end.font.size = Pt(10) r_end.font.name = 'Times New Roman' r_end.font.color.rgb = RGBColor(0x77, 0x77, 0x77) # Save doc.save('/tmp/workspace/unit-test-answers/Unit_Test_II_Answers_2025-26.docx') print("Saved successfully!") PYEOF python3 /tmp/workspace/unit-test-answers/create_answers.py

python3 -c " from docx import Document doc = Document('/tmp/workspace/unit-test-answers/Unit_Test_II_Answers_2025-26.docx') count = 0 for p in doc.paragraphs: if p.text.strip(): count += 1 print(f'Total non-empty paragraphs: {count}') # Print first 30 to verify structure for i, p in enumerate(doc.paragraphs[:60]): if p.text.strip(): print(f' [{p.style.name}] {p.text[:80]}') "