Medical Science Test 1 Nddc Scholarship

Hepatitis C is a viral infection that primarily causes inflammation of the liver. Unlike Hepatitis A and B, there is currently no vaccine available for Hepatitis C. It is primarily transmitted through blood-to-blood contact, though transmission via sexual contact is possible, albeit less common than with Hepatitis B. A significant percentage of those infected (75%–85%) become chronic or 'lifetime' carriers, which can eventually lead to cirrhosis or liver cancer if left untreated with modern antiviral medications.

The liver stores fat-soluble vitamins (A, D, E, and K) and certain water-soluble vitamins like Vitamin B12. Vitamin C (ascorbic acid), however, is a highly water-soluble vitamin that is not stored in any significant quantity in the body; any excess intake is generally excreted through the urine. Because the body cannot store Vitamin C, it must be consumed regularly through the diet to prevent deficiency conditions like scurvy.

Ascites is often caused by liver cirrhosis leading to portal hypertension (increased pressure in the portal vein). This pressure, combined with low levels of albumin (which reduces oncotic pressure), allows fluid to leak into the abdomen. This triggers the Renin-Angiotensin-Aldosterone System (RAAS). While elevated aldosterone causes sodium and water retention, the mere elevation of 'angiotensin I' is not a direct contributor; it is the conversion of angiotensin I to 'angiotensin II' (a potent vasoconstrictor and stimulator of aldosterone) that drives the pathology.

Cimetidine is a classic H2-receptor antagonist. It works by blocking histamine from binding to the H2 receptors on the parietal cells in the stomach, which is one of the key signals for acid secretion. Omeprazole is a Proton Pump Inhibitor (PPI), which works further down the line of acid production. Cimetidine is used to treat conditions like GERD and peptic ulcers by significantly lowering the acidity of the stomach environment.

Magnesium Hydroxide is an antacid. Unlike H2 blockers or PPIs that stop the 'production' of acid, antacids are basic (alkaline) compounds that react chemically with existing stomach acid to neutralise it, forming water and salts. This provides rapid, short-term relief from symptoms like heartburn and indigestion. Maalox is a common brand name for a combination of magnesium hydroxide and aluminium hydroxide.

Metoclopramide is a dopamine D2 receptor antagonist. By blocking dopamine in the gut, it enhances the response to acetylcholine, which increases upper gastrointestinal motility (prokinetic effect) and accelerates gastric emptying. It also works in the brain's chemoreceptor trigger zone to prevent nausea and vomiting. It is frequently used for diabetic gastroparesis and severe acid reflux that doesn't respond to other treatments.

A Pancreatoduodenectomy involves the surgical removal of the head of the pancreas, the duodenum (the first part of the small intestine), a portion of the common bile duct, and sometimes part of the stomach. It is a complex procedure designed to remove tumours located in the head of the pancreas or the biliary system. Cholangiopancreatography is an imaging technique (like ERCP), and a cholecystogram is an X-ray of the gallbladder.

Acute bacterial parotitis is most frequently caused by *Staphylococcus aureus*. This occurs when bacteria from the mouth travel up the parotid duct into the gland, often due to reduced salivary flow (dehydration). While 'mumps' is a famous viral cause of parotitis, *S. aureus* is the primary culprit in bacterial cases, leading to painful swelling, fever, and sometimes purulent discharge from the duct. The other options are parasites associated with different diseases like Elephantiasis or Chagas disease.

Somatostatin is produced and secreted by Delta (D) cells located in the Islets of Langerhans in the pancreas and the mucous membrane of the stomach and intestines. Somatostatin acts as a powerful inhibitory hormone; it inhibits the secretion of both insulin (from beta cells) and glucagon (from alpha cells), as well as reducing gastrointestinal motility and the secretion of digestive enzymes and stomach acid.

The maxillary nerve (the second branch of the trigeminal nerve) passes from the pterygopalatine fossa into the orbit through the inferior orbital fissure. From there, it continues as the infraorbital nerve. The Stylomastoid foramen transmits the facial nerve, the Foramen ovale transmits the mandibular nerve (V3), and the Carotid canal transmits the internal carotid artery. The inferior orbital fissure is the key pathway for the maxillary nerve to reach the face.