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  • Question 1 - What percentage of cardiac output is delivered to the skin? ...

    Correct

    • What percentage of cardiac output is delivered to the skin?

      Your Answer: 2%

      Explanation:

      Making up 4-5% of total body weight, the skin receives approximately 2% of cardiac output.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      4
      Seconds
  • Question 2 - A 69 Year old lady presented to the emergency department following a massive...

    Incorrect

    • A 69 Year old lady presented to the emergency department following a massive myocardial infarction. She was found to be in hypotensive shock with focal neurological signs. Unfortunately the patient demised. What would be the expected findings on the brain biopsy?

      Your Answer: Acute haemorrhagic change

      Correct Answer: Liquefactive necrosis

      Explanation:

      Liquefactive necrosis is often associated with bacterial or fungal infections. However, hypoxic death of cells within the central nervous system can also result in liquefactive necrosis. The focal area is soft with a liquefied centre containing necrotic debris and dead white cells. This may later be enclosed by a cystic wall

    • This question is part of the following fields:

      • Cell Injury & Wound Healing; Neurology
      • Pathology
      25.1
      Seconds
  • Question 3 - Which of the following is the most likely cause of prolonged thrombin clotting...

    Incorrect

    • Which of the following is the most likely cause of prolonged thrombin clotting time?

      Your Answer: von Willebrand factor deficiency

      Correct Answer: Hypofibrinogenemia

      Explanation:

      Thrombin clotting time, also called thrombin time (TT), is test used for the investigation of possible bleeding or clotting disorders. TT reflects the conversion of fibrinogen to fibrin and it’s also very sensitive to the presence of the anticoagulant heparin. A prolonged thrombin time may indicate the presence of hypofibrinogenemia (decreased fibrinogen level ), dysfibrinogenaemia, disseminated intravascular coagulation (DIC), end stage liver disease or malnutrition.

    • This question is part of the following fields:

      • Haematology
      • Pathology
      15
      Seconds
  • Question 4 - A 13-year-old boy's mother notices he has a lump in his arm, near...

    Correct

    • A 13-year-old boy's mother notices he has a lump in his arm, near his right shoulder. An X-ray reveals a lateral projection in the metaphyseal region of his humerus. The lesion is removed and it is found to be composed of bony cortex, capped by cartilage. What's the most likely diagnosis in this case?

      Your Answer: Osteochondroma

      Explanation:

      Osteochondromas, or osteocartilaginous exostoses, are the most common benign bone tumours, and tend to appear near the ends of long bones. The overgrowth can occur in any bone where cartilage forms bone, and they are capped by cartilage. They are most common in people between the ages of 10-20 years old.

    • This question is part of the following fields:

      • Orthopaedics
      • Pathology
      28.1
      Seconds
  • Question 5 - Extracellular body fluid as compared with intracellular body fluid: ...

    Incorrect

    • Extracellular body fluid as compared with intracellular body fluid:

      Your Answer: Contains more amino acids

      Correct Answer: Is relatively rich in glucose

      Explanation:

      The percentages of body water contained in various fluid compartments add up to total body water (TBW). This water makes up a significant fraction of the human body, both by weight and by volume. Ensuring the right amount of body water is part of fluid balance, an aspect of homeostasis. The extracellular fluid (ECF) includes all fluids outside the cells. This fluid can be divided into three fluid departments: interstitial (in the tissue spaces) fluid, blood plasma and lymph, and specialised compartments called transcellular fluid. The extracellular fluid surrounds all the cells in the body and is in equilibrium with the intracellular fluid. So, its composition must remain fairly constant even though substances are passing into and out of the cells. The interstitial fluid, though called a fluid, is in a reality a gel-like composition made up of: water, proteoglycan molecules and collagen. The extracellular fluid constitutes 40% of total body water, with intracellular fluid making up the remaining 60%. It is relatively rich in glucose.

    • This question is part of the following fields:

      • Fluids & Electrolytes
      • Physiology
      25.3
      Seconds
  • Question 6 - A diabetic 58-year-old man, after the injection of radiographic contrast, has a decreased...

    Correct

    • A diabetic 58-year-old man, after the injection of radiographic contrast, has a decreased urine output and decreased level of consciousness. Which of the following conditions has he most likely developed

      Your Answer: Acute tubular necrosis

      Explanation:

      Acute tubular necrosis (ATN) involves damage to the tubule cells of the kidneys and is the most common cause of acute kidney injury. ATN in the majority of the cases is caused by ischaemia of the kidneys due to lack of perfusion and oxygenation but it may also occur due to poison or harmful substance. Contrast used for radiology may cause ATN in patients with several risk factors e.g. diabetic nephropathy. Symptoms may include oliguria, nausea, fluid retention, fatigue and decreased consciousness.

    • This question is part of the following fields:

      • Pathology
      • Renal
      14.5
      Seconds
  • Question 7 - A 60-year-old female has sudden onset of high-grade fever associated with cough with...

    Correct

    • A 60-year-old female has sudden onset of high-grade fever associated with cough with productive rusty-coloured sputum. Chest x-ray showed left-sided consolidation. What is the most accurate test for the diagnosis of this patient?

      Your Answer: Sputum culture

      Explanation:

      Sputum culture is used to detect and identify the organism that are infecting the lungs or breathing passages.

    • This question is part of the following fields:

      • Microbiology
      • Pathology
      16.1
      Seconds
  • Question 8 - Coagulation in the body (in vivo) is a process in which several proteins...

    Incorrect

    • Coagulation in the body (in vivo) is a process in which several proteins known as coagulation factors are activated in a cascade effect to stop bleeding. Which of the following initiates this cascade effect?

      Your Answer: Factor VII

      Correct Answer: Tissue factor

      Explanation:

      Tissue factor (TF), also known as ‘factor III’ or ‘thromboplastin’, is an anti-coagulation protein that initiates the extrinsic coagulation. TF acts as a transmembrane receptor for Factor VII/VIIa . It is expressed by endothelial cells but also certain tissues, such as the heart and brain.

    • This question is part of the following fields:

      • Haematology
      • Pathology
      17.2
      Seconds
  • Question 9 - Under normal conditions, what is the major source of energy of cardiac muscles?...

    Correct

    • Under normal conditions, what is the major source of energy of cardiac muscles?

      Your Answer: Fatty acids

      Explanation:

      Under basal conditions, most of the energy needed by cardiac muscle for metabolism is derived from fats (60%), 35% by carbohydrates, and 5% by ketones and amino acids. However, after intake of large amounts of glucose, lactate and pyruvate are mainly used. During prolonged starvation, fat acts as the primary source. 50% of the used lipids are sourced from circulating fatty acids.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      11
      Seconds
  • Question 10 - If a tumour is found in both lobes of the prostate, without nodal...

    Incorrect

    • If a tumour is found in both lobes of the prostate, without nodal involvement or metastases, a histological grade of G2 and elevated PSA, what is the overall prostatic cancer stage?

      Your Answer: Stage I

      Correct Answer: Stage II

      Explanation:

      The AJCC uses the TNM, Gleason score and PSA levels to determine the overall stage of prostatic cancer. This staging is as follows:

      Stage I: T1, N0, M0, Gleason score 6 or less, PSA less than 10; or T2a, N0, M0, Gleason score 6 or less, PSA less than 10

      Stage IIa: T1, N0, M0, Gleason score of 7, PSA less than 20; or T1, N0, M0, Gleason score of 6 or less, PSA at least 10 but less than 20; or T2a or T2b, N0, M0, Gleason score of 7 or less, PSA less than 20

      Stage IIb: T2c, N0, M0, any Gleason score, any PSA; or T1 or T2, N0, M0, any Gleason score PSA of 20 or more; or T1 or T2, N0, M0, Gleason score of 8 or higher, any PSA

      Stage III: T3, N0, M0, any Gleason score, any PSA Stage IV: T4, N0, M0,any Gleason score, any PSA; or any T, N1, M0,any Gleason score, any PSA; or Any T, any N, M1, any Gleason score, any PSA.

      The patient in this case has a T2 N0 M0 G2 tumour, meaning it belongs in stage II

    • This question is part of the following fields:

      • Pathology
      • Urology
      41.3
      Seconds
  • Question 11 - Which tumour occurs in young adults, affecting the epiphyses of the bones and...

    Incorrect

    • Which tumour occurs in young adults, affecting the epiphyses of the bones and sometimes extending to the soft tissues?

      Your Answer: Chondroblastoma

      Correct Answer: Benign giant-cell tumour

      Explanation:

      Benign giant-cell tumours tend to affect adults in their twenties and thirties, occur in the epiphyses and can erode the bone and extend into the soft tissues. These tumours have a strong tendency to recur.

    • This question is part of the following fields:

      • Orthopaedics
      • Pathology
      18.8
      Seconds
  • Question 12 - Which of the following factors will not affect the wound healing process in...

    Correct

    • Which of the following factors will not affect the wound healing process in a young women who suffered serious burns to her chest and hands?

      Your Answer: Vitamin A deficiency

      Explanation:

      Healing can be sped-up or slowed down due to various reasons: 1. blood supply, 2. infection, 3. denervation, 4. collection of blood/hematoma, 5. mechanical stress, 6. foreign body, 7. techniques used during surgery and 8. dressing of the wound. Other systemic factors include 1. nutrition e.g. deficiency of zinc, vitamin C, protein deficiency, 2. metabolic status, 3. circulatory status and 4. hormonal influence

    • This question is part of the following fields:

      • Cell Injury & Wound Healing
      • Pathology
      15.9
      Seconds
  • Question 13 - Which of these conditions causes haematuria, hypertension and proteinuria in children, usually after...

    Correct

    • Which of these conditions causes haematuria, hypertension and proteinuria in children, usually after a streptococcal infection?

      Your Answer: Acute nephritic syndrome

      Explanation:

      Nephritic syndrome (or acute nephritic syndrome) is a syndrome comprising of signs of nephritis. Children between 2 and 12 are most commonly affected, but it may occur at any age. Predisposing factors/causes include:

      Infections with group A streptococcal bacteria (acute post-streptococcal glomerulonephritis).

      Primary renal diseases: immunoglobulin A nephropathy, membranoproliferative glomerulonephritis, idiopathic rapidly progressive crescentic glomerulonephritis.

      Secondary renal diseases: subacute bacterial endocarditis, infected ventriculo–peritoneal shunt, glomerulonephritis with visceral abscess, glomerulonephritis with bacterial, viral or parasitic infections.

      Multisystem diseases.

      By contrast, nephrotic syndrome is characterized by only proteins moving into the urine.

    • This question is part of the following fields:

      • Physiology
      • Renal
      11.4
      Seconds
  • Question 14 - A 48-year-old man smoker presented to the doctor complaining of a persistent cough...

    Incorrect

    • A 48-year-old man smoker presented to the doctor complaining of a persistent cough and shortness of breath. A chest X-ray indicated the presence of a right upper lung mass. Biopsy of the mass revealed the presence of pink cells with large, irregular nuclei. What is the most probable diagnosis?

      Your Answer: Small cell anaplastic carcinoma

      Correct Answer: Squamous cell carcinoma

      Explanation:

      Squamous cell carcinoma, is a type of non-small cell lung cancer that accounts for approximately 30% of all lung cancers. The presence of squamous cell carcinoma is often related with a long history of smoking and the presence of persistent respiratory symptoms. Chest radiography usually shows the presence of a proximal airway lesion. Histological findings include keratinisation that takes the form of keratin pearls with pink cytoplasm and cells with large, irregular nuclei.

    • This question is part of the following fields:

      • Pathology
      • Respiratory
      110.6
      Seconds
  • Question 15 - A 45-year old lady underwent biopsy of a soft, fleshy mass involving her...

    Incorrect

    • A 45-year old lady underwent biopsy of a soft, fleshy mass involving her left breast. The biopsy showed lymphoid stroma with minimal fibrosis, surrounding sheets of large vesicular cells with frequent mitoses. Which condition is she most likely suffering from?

      Your Answer: Infiltrating ductal carcinoma

      Correct Answer: Medullary carcinoma of breast

      Explanation:

      Medullary carcinoma is a malignant tumour of the breast with well-defined boundaries and accounts for 5% of all breast cancers. Other special features include a larger size of the neoplastic cells and presence of lymphoid cells at tumour edge. Differential diagnosis includes invasive ductal carcinoma. Prognosis is usually good.

    • This question is part of the following fields:

      • Pathology
      • Women's Health
      26.2
      Seconds
  • Question 16 - Glucose is the most important source of energy for cellular respiration. The transport...

    Correct

    • Glucose is the most important source of energy for cellular respiration. The transport of glucose in the renal tubular cells occurs via:

      Your Answer: Secondary active transport with sodium

      Explanation:

      In 1960, Robert K. Crane presented for the first time his discovery of the sodium-glucose cotransport as the mechanism for glucose absorption. Glucose transport through biological membranes requires specific transport proteins. Transport of glucose through the apical membrane of renal tubular as well as intestinal epithelial cells depends on the presence of secondary active Na+–glucose symporters, SGLT-1 and SGLT-2, which concentrate glucose inside the cells, using the energy provided by co-transport of Na+ ions down their electrochemical gradient.

    • This question is part of the following fields:

      • Physiology
      • Renal
      178.7
      Seconds
  • Question 17 - A 78-year-old diabetic man undergoes renal function tests. Which of the following substances...

    Incorrect

    • A 78-year-old diabetic man undergoes renal function tests. Which of the following substances will be the most accurate for measuring glomerular filtration rate (GFR)?

      Your Answer: Urea

      Correct Answer: Inulin

      Explanation:

      Glomerular filtration rate (GFR) is the volume of fluid filtered from the renal glomerular capillaries into the Bowman’s capsule per unit time. Clinically, this is often measured to determine renal function. Inulin was originally used as it is not reabsorbed by the kidney after glomerular filtration, therefore its rate of excretion is directly proportional to the rate of filtration of water and solutes across the glomerular filter. However, in clinical practice, creatinine clearance is used to measure GFR. Creatinine is an endogenous molecule, synthesised in the body, that is freely filtered by the glomerulus (but also secreted by the renal tubules in very small amounts). Creatinine clearance exceeds GFR due to creatinine secretion, and is therefore a close approximation of the GFR.

    • This question is part of the following fields:

      • Physiology
      • Renal
      12.8
      Seconds
  • Question 18 - A 55-year-old woman complains of pain in the proximal and distal interphalangeal joins,...

    Incorrect

    • A 55-year-old woman complains of pain in the proximal and distal interphalangeal joins, and back pain which has increased over the last 4 years and worsens after activity. X-rays reveal Heberden’s and Bouchard’s nodes in her interphalangeal joints and the presence of osteophytes in her spine. What is the most likely diagnosis?

      Your Answer: Rheumatoid arthritis

      Correct Answer: Osteoarthritis

      Explanation:

      Osteoarthritis is most common in older adults, predominating in women between the ages of 40 and 70; after this age, men and women are affected equally. It affects an entire joint, with disruption and potential loss of joint cartilage, along with other joint changes, including bone hypertrophy (osteophyte formation). The pain is usually gradual and is worse after activity, with occasional joint swelling. X-ray findings include marginal osteophytes, narrowing of the joint space, increased density of the subchondral bone, subchondral cyst formation, bony remodelling and joint effusions.

    • This question is part of the following fields:

      • Orthopaedics
      • Pathology
      70.6
      Seconds
  • Question 19 - A 24-year old, lactating mother presents to the clinic with a tender, 1.5cm...

    Correct

    • A 24-year old, lactating mother presents to the clinic with a tender, 1.5cm mass just below the right nipple, which shows multiple fissures. What finding is likely associated with her condition?

      Your Answer: Staphylococcus aureus infection

      Explanation:

      Breast abscess occur commonly in lactating mothers in the postpartum period due to cracking of the nipple. It is commonly caused due to Staphylococcus aureus infection. Fat necrosis usually results from trauma wherein an ill-defined mass is formed. Ductal carcinomas are malignant masses which are not tender usually, and rare in the young age group. Plasma cell mastitis affect women in an older age group. Sclerosing adenosis is a type of fibrocystic disease which can lead to a tender, cystic mass but no fissuring or cracks are seen in the nipple. Fibroadenoma and lipomas are non-tender, well-defined masses.

    • This question is part of the following fields:

      • Pathology
      • Women's Health
      14.7
      Seconds
  • Question 20 - Gram positive bacteria differ from gram negative bacteria due to the presence of...

    Correct

    • Gram positive bacteria differ from gram negative bacteria due to the presence of which of the following structures?

      Your Answer: Outer membrane

      Explanation:

      The reason bacteria are either Gram-positive or Gram-negative is due to the structure of their cell envelope (the cell envelope is defined as the cell membrane and cell wall plus an outer membrane, if one is present.) Gram-positive bacteria, for example, retain the crystal violet due to the amount of peptidoglycan in the cell wall. It can be said therefore that the Gram-stain procedure separates bacteria into two broad categories based on structural differences in the cell envelope.

    • This question is part of the following fields:

      • Microbiology
      • Pathology
      6.3
      Seconds
  • Question 21 - If a 68-year-old man is diagnosed with a testicular seminoma that reaches the...

    Correct

    • If a 68-year-old man is diagnosed with a testicular seminoma that reaches the tunica albuginea and involves the tunica vaginalis, with retroperitoneal lymph nodes greater than 5cm, LDH 1.4 times the reference levels, β-hCG 4250 mIU/ml and AFP 780 ng/ml, what's the clinical stage in this case?

      Your Answer: Stage IIC

      Explanation:

      According to the AJCC, the clinical staging for testicular seminoma is:
      Stage IA: T1 N0 M0 S0
      Stage IB: T2/3/4 N0 M0 S0
      Stage IC: any T N0 M0 S1/2/3
      Stage IIA: any T N1 M0 S0/1
      Stage IIB: any T N2 M0 S0/1
      Stage IIC: any T N3 M0 S0/1
      Stage IIIA: any T any N M1a S0/1
      Stage IIIB: any T any N M0/1a S2
      Stage IIIC: any T any N M1a/1b S3.
      The patient in this case has IIC stage

    • This question is part of the following fields:

      • Pathology
      • Urology
      75.9
      Seconds
  • Question 22 - Fine-needle aspiration is a type of biopsy procedure. When performing a fine-needle aspiration...

    Correct

    • Fine-needle aspiration is a type of biopsy procedure. When performing a fine-needle aspiration of the lungs, which is the most common complication of the procedure?

      Your Answer: Pneumothorax

      Explanation:

      Pneumothorax is the most common complication of a fine-needle aspiration procedure. Various factors, such as lesion size, have been associated with increased risk of pneumothorax .

    • This question is part of the following fields:

      • Pathology
      • Respiratory
      7.3
      Seconds
  • Question 23 - A 32-year-old man presents to the doctor complaining of pain in his left...

    Incorrect

    • A 32-year-old man presents to the doctor complaining of pain in his left calf whilst walking. He says that the pain goes away after a short period of rest but starts again during exercise or walking. The man reveals he has been a smoker for the last 15 years. His blood pressure, blood sugar and cholesterol level are normal. Artery biopsy shows intraluminal thrombosis and vasculitis. What's is the most likely cause of these findings?

      Your Answer: Giant-cell arteritis

      Correct Answer: Buerger's disease

      Explanation:

      Thromboangiitis obliterans, also known as Buerger’s disease, is a rare type of occlusive peripheral arterial disease, usually seen in smokers, most commonly in men aged 20 to 40. Symptoms most often include intermittent claudication, skin changes, painful ulcers on extremities, pain in the extremities during rest and gangrene. Diagnosis is based on clinical findings, arteriography, echocardiography, and computed tomography angiography. A difference in blood pressure between arms, or between the arms and legs is a common finding. Electrocardiographic findings include nonspecific abnormality or normal results.

    • This question is part of the following fields:

      • Cardiovascular
      • Pathology
      30.1
      Seconds
  • Question 24 - A 53 year old women with a history of atrial fibrillation developed an...

    Incorrect

    • A 53 year old women with a history of atrial fibrillation developed an acute abdomen. On laparoscopic examination her bowels appeared to be dusky to red-purple in colour and her mesenteric veins appeared to be patent. Which of the following is most likely to occur in this situation?

      Your Answer: Gas gangrene

      Correct Answer: Wet gangrene

      Explanation:

      Infarction of the small bowel following a sudden and complete occlusion of the mesenteric artery can involve any portion of the bowel, whether small or a large. The splenic flexure is at most risk for infarction as it is the watershed area between the superior and inferior mesenteric vessels. Regardless of whether the arterial or the venous blood vessels are occluded, because of the blood reflow into the damaged portion, it will appear haemorrhagic. The bowel appearing congested at first and then becoming oedematous. If the artery is occluded then there will be a clear cut demarcation and in venous occlusion the dusky colour fades with the rest of the normal bowel. Wet gangrene is characteristic of ischaemic injury to the gut.

    • This question is part of the following fields:

      • Cell Injury & Wound Healing; Gastrointestinal
      • Pathology
      26.2
      Seconds
  • Question 25 - Vincristine is a chemotherapy agent used to treat a number of types of...

    Incorrect

    • Vincristine is a chemotherapy agent used to treat a number of types of cancer. Which of the following is a recognised major side-effect of vincristine?

      Your Answer: Myelosuppression

      Correct Answer: Peripheral neuropathy

      Explanation:

      Vincristine is an alkaloid chemotherapeutic agent. It is used to treat a number of types of cancer including acute lymphocytic leukaemia, acute myeloid leukaemia, Hodgkin’s disease, neuroblastoma, and small cell lung cancer among others. The main side-effects of vincristine are peripheral neuropathy and constipation.

    • This question is part of the following fields:

      • Pathology
      • Pharmacology
      9.6
      Seconds
  • Question 26 - Which of the following substances is most likely to cause pulmonary vasodilatation? ...

    Incorrect

    • Which of the following substances is most likely to cause pulmonary vasodilatation?

      Your Answer: Histamine

      Correct Answer: Nitric oxide

      Explanation:

      In the body, nitric oxide is synthesised from arginine and oxygen by various nitric oxide synthase (NOS) enzymes and by sequential reduction of inorganic nitrate. The endothelium of blood vessels uses nitric oxide to signal the surrounding smooth muscle to relax, so dilating the artery and increasing blood flow. Nitric oxide/oxygen blends are used in critical care to promote capillary and pulmonary dilation to treat primary pulmonary hypertension in neonatal patients post-meconium aspiration and related to birth defects.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
      19.3
      Seconds
  • Question 27 - What is the primary function of the Kupffer cells found in the liver?...

    Correct

    • What is the primary function of the Kupffer cells found in the liver?

      Your Answer: Recycling of old red blood cells

      Explanation:

      Kupffer cells found in the liver are part of the monocyte-reticular system. They are specialised macrophages and primarily function to recycle old and damaged RBCs. The RBCs are phagocytosed and the haemoglobin is broken down into haem and globin. The haem is further broken down into iron that is recycled and bilirubin that is conjugated with glucuronic acid and excreted in the bile.

    • This question is part of the following fields:

      • Inflammation & Immunology; Hepatobiliary
      • Pathology
      119.1
      Seconds
  • Question 28 - A 56 year old gentleman, who is a chronic smoker presents to the...

    Incorrect

    • A 56 year old gentleman, who is a chronic smoker presents to the clinic with dyspnoea. His Chest X-ray shows intercostal space widening with increased blackening bilaterally. What is the most likely finding on his pulmonary function test?

      Your Answer: Increased FEV1/FVC

      Correct Answer: Increased total lung capacity

      Explanation:

      In patients suspected of having chronic obstructive pulmonary disease, pulmonary function testing (PFT) is useful to confirm airway obstruction, to quantify its severity and reversibility, for following disease progression and monitoring response to treatment. These tests include:

      FEV1 – volume of air forcefully expired during the first second after a full breath

      Forced vital capacity (FVC) – total volume of air expired with maximal force and flow-volume loops. The hallmark of airway obstruction is reduction of FEV1, FVC and the ratio of FEV1/FVC, with a concave pattern in expiratory tracing on the flow-volume loop. FEV1 and forced vital capacity (FVC) are easily measured with office spirometry and are useful to assess the severity of disease. Other parameters include increased total lung capacity, functional residual capacity and residual volume, which can help distinguish chronic obstructive pulmonary disease (COPD) from restrictive pulmonary disease where these values are lower than normal. Along with these, other tests are decreased vital capacity; and decreased diffusing capacity for carbon monoxide (DLCO). DLCO is non-specific and can be low in other disorders that affect the pulmonary vascular bed, such as interstitial lung disease. DLCO is however useful to distinguish COPD from asthma, in which DLCO is normal or elevated.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
      34.4
      Seconds
  • Question 29 - The Henderson–Hasselbalch equation describes the derivation of pH as a measure of acidity. According to this equation,...

    Correct

    • The Henderson–Hasselbalch equation describes the derivation of pH as a measure of acidity. According to this equation, the buffering capacity of the system is at maximum when the number of free anions compared with undissociated acid is:

      Your Answer: Equal

      Explanation:

      In 1908, Lawrence Joseph Henderson wrote an equation describing the use of carbonic acid as a buffer solution. Later, Karl Albert Hasselbalch re-expressed that formula in logarithmic terms, resulting in the Henderson–Hasselbalch equation. The equation is also useful for estimating the pH of a buffer solution and finding the equilibrium pH in acid–base reactions. Two equivalent forms of the equation are: pH = pKa + log10 [A–]/[HA] or pH = pKa + log10 [base]/[acid]. Here, pKa is − log10(Ka) where Ka is the acid dissociation constant, that is: pKa = –log10(Ka) = –log10 ([H3 O+][A–]/[HA]) for the reaction: HA + H2 O ≈ A– + H3 O+ In these equations, A– denotes the ionic form of the relevant acid. Bracketed quantities such as [base] and [acid] denote the molar concentration of the quantity enclosed. Maximum buffering capacity is found when pH = pKa or when the number of free anions to undissociated acid is equal and buffer range is considered to be at a pH = pKa ± 1.

    • This question is part of the following fields:

      • Fluids & Electrolytes
      • Physiology
      20.8
      Seconds
  • Question 30 - Which of the following conditions causes an elevation of the pH in the...

    Incorrect

    • Which of the following conditions causes an elevation of the pH in the tissues with elevated arterial CO2 content?

      Your Answer:

      Correct Answer: Metabolic alkalosis

      Explanation:

      Metabolic alkalosis is a metabolic condition in which the pH of tissue is elevated beyond the normal range (7.35-7.45). This is the result of decreased hydrogen ion concentration, leading to increased bicarbonate, or alternatively a direct result of increased bicarbonate concentrations. Normally, arterial pa(CO2) increases by 0.5–0.7 mmHg for every 1 mEq/l increase in plasma bicarbonate concentration, a compensatory response that is very quick. If the change in pa(CO2) is not within this range, then a mixed acid–base disturbance occurs.

    • This question is part of the following fields:

      • Fluids & Electrolytes
      • Physiology
      0
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Cardiovascular (2/2) 100%
Physiology (6/10) 60%
Cell Injury & Wound Healing; Neurology (0/1) 0%
Pathology (9/19) 47%
Haematology (0/2) 0%
Orthopaedics (1/3) 33%
Fluids & Electrolytes (2/3) 67%
Renal (3/4) 75%
Microbiology (2/2) 100%
Urology (1/2) 50%
Cell Injury & Wound Healing (1/1) 100%
Respiratory (1/4) 25%
Women's Health (1/2) 50%
Cell Injury & Wound Healing; Gastrointestinal (0/1) 0%
Pharmacology (1/1) 100%
Inflammation & Immunology; Hepatobiliary (0/1) 0%
Passmed