The symptoms of median nerve injury include tingling or numbness in the forearm, thumb, and three adjacent fingers, as well as gripping weakness and the inability to move the thumb across the palm. Because the thenar muscles and the flexor pollicis longus are paralyzed, flexion, abduction, and opposition of the thumb at the MCPJ and IPJ are gone.

Advantages:relatively quickrelatively cheap and easy to performparticularly suitable for studying associations between an exposure and an outcome when the outcome is uncommon or if the outcome occurs decades after exposurea wide range of risk factors can be investigated in each studyDisadvantages:subject to recall biasunlike in a whole population study, absolute risk cannot be quantifiedtemporal relationship between exposure and outcome can be difficult to establishunsuitable for rare risk factorsprone to confounding

Acetazolamide is a non-competitive, reversible inhibitor of carbonic anhydrase found in the cytosol of cells and on the brush border of the proximal convoluted tubule. Bicarbonate and hydrogen ions are converted to carbonic acid by carbonic anhydrase, which then converts carbonic acid to carbon dioxide and water. As a result, acetazolamide reduces the availability of hydrogen ions, causing sodium and bicarbonate ions to accumulate in the renal tubule, resulting in diuresis.The mechanism of action of the various types of diuretics is summarised below:1) Loop diuretics, e.g. furosemide, bumetanideAct on the Na.K.2Cl co-transporters in the ascending loop of Henlé to inhibit sodium, chloride and potassium reabsorption.2) Thiazide diuretics, e.g. Bendroflumethiazide, hydrochlorothiazideAct on the Na.Cl co-transporter in the distal convoluted tubule to inhibit sodium and chloride reabsorption.3) Osmotic diuretics, e.g. mannitolIncreases the osmolality of the glomerular filtrate and tubular fluid, increasing urinary volume by an osmotic effect.4) Aldosterone antagonists, e.g. spironolactoneActs in the distal convoluted tubule as a competitive aldosterone antagonist resulting in inhibition of sodium reabsorption and increasing potassium reabsorption.5) Carbonic anhydrase inhibitors, e.g. acetazolamideInhibit the enzyme carbonic anhydrase preventing the conversion of bicarbonate and hydrogen ions into carbonic acid.

Passive diffusion is a process that describes the movement down a concentration gradient. This process accounts for movement across small distances like within the cytosol or across membranes. Factors that affect the diffusion of a substance across a membrane are the permeability (p) of the membrane, a difference in concentration across the membrane and the membrane area over which diffusion occurs. The membrane thickness and composition, and the diffusion coefficient of the substance also affects the permeability. Fick’s law describes the rate of diffusion of a substance within a solution, which can be modified to describe the rate of diffusion across a membrane.

Acute lymphoblastic leukaemia (ALL) is caused by an accumulation of lymphoblasts in the bone marrow and is the most common malignancy of childhood. The incidence of ALL is highest at 3 – 7 years, with 75% of cases occurring before the age of 6. 85% of cases are of B-cell lineage. Haematological investigations reveal a normochromic normocytic anaemia with thrombocytopenia in most cases. There is great variation in the chance of individual patients achieving a long-term cure based on a number of biological variables. Approximately 25% of children relapse after first-line therapy and need further treatment but overall 90% of children can expect to be cured. The cure rate in adults drops significantly to less than 5% over the age of 70 years.

The anterior triangle is the triangular area of the neck found anteriorly to the sternocleidomastoid muscle. It is formed by the anterior border of sternocleidomastoid laterally, the median line of the neck medially and by the inferior border of the mandible superiorly. The apex of the anterior triangle extends towards the manubrium sterni. The anterior triangle contains:Muscles: thyrohyoid, sternothyroid, sternohyoid musclesOrgans: thyroid gland, parathyroid glands, larynx, trachea, esophagus, submandibular gland, caudal part of the parotid glandArteries: superior and inferior thyroid, common carotid, external carotid, internal carotid artery (and sinus), facial, submental, lingual arteriesVeins: anterior jugular veins, internal jugular, common facial, lingual, superior thyroid, middle thyroid veins, facial vein, submental vein, lingual veinsNerves: vagus nerve (CN X), hypoglossal nerve (CN XII), part of sympathetic trunk, mylohyoid nerveThe posterior triangle is a triangular area found posteriorly to the sternocleidomastoid muscle. It has three borders; anterior, posterior and inferior borders. The anterior border is the posterior margin of the sternocleidomastoid muscle. The posterior border is the anterior margin of the trapezius muscle, while the inferior border is the middle one-third of the clavicle. The investing layer of deep cervical fascia and integument forms the roof of the space, while the floor is covered with the prevertebral fascia along with levator scapulae, splenius capitis and the scalene muscles. The inferior belly of omohyoid subdivides the posterior triangle into a small supraclavicular, and a large occipital, triangle.Contents:Vessels: the third part of the subclavian artery, suprascapular and transverse cervical branches of the thyrocervical trunk, external jugular vein, lymph nodesNerves: accessory nerve (CN XI), the trunks of the brachial plexus, fibers of the cervical plexus

The electron transfer system is responsible for most of the energy produced during respiration. The is a system of hydrogen carriers located in the inner mitochondrial membrane. Hydrogen is transferred to the electron transfer system via the NADH2molecules produced during glycolysis and the Krebs cycle. As a result, a H+ion gradient is generated across the inner membrane which drives ATP synthase. The final hydrogen acceptor is oxygen and the H+ions and O2 combine to form water.

Effects of beta-blockers:Cardiovascular system: Reduce blood pressureReduce heart rate, contractility and cardiac outputIncrease AV conduction time, refractoriness and suppress automaticityEye:Reduce intraocular pressureRespiratory system:Cause bronchoconstriction

Parathyroid hormone (PTH), also called parathormone or parathyrin, is a peptide hormone that is secreted by the parathyroid glands, which lie immediately behind the thyroid gland. In particular, this hormone is made by chief cells. It regulates the serum calcium concentration through its effects on bone, kidney, and intestine. This hormone is primarily released in response to decreasing plasma Ca2+ concentration and it serves to increase plasma calcium levels and decrease plasma phosphate levels.PTH activates Ca2+entry channels in the apical membrane and the Ca2+ATPase pump in the basolateral membrane and as a result, increases calcium reabsorption in the distal tubule of the nephron. It inhibits reabsorption of phosphate and this increases its excretion by in the proximal tubule of the nephron.

Healthcare-associated bacteraemia is most commonly caused by intravenous access. Any intravenous device that is left in place for a long time increases the risk of infection. It allows bacteria like Staphylococcus aureus and Staphylococcus epidermidis to enter the body.