Pathophysiology (D236)

Correct Answer

C. Draws water into blood vessels

Explanation

Oncotic pressure, also known as colloid osmotic pressure, is exerted by plasma proteins (mainly albumin) in the blood. This pressure helps draw water from the interstitial fluid back into the capillaries, preventing excessive fluid accumulation in tissues (edema). It plays a crucial role in maintaining blood volume and circulation.

Why other options are wrong

A. Pushes water out of blood vessels

This describes hydrostatic pressure, not oncotic pressure. Hydrostatic pressure is generated by the pumping action of the heart and tends to push fluid out of capillaries.

B. Controls electrolyte balance

Oncotic pressure does not directly control electrolyte balance. Electrolyte balance is primarily maintained by the kidneys and various transport mechanisms across cell membranes.

D. Regulates blood pressure

Although oncotic pressure indirectly affects blood pressure by influencing blood volume, blood pressure is primarily regulated by the heart, blood vessel tone, and kidney function through mechanisms like the renin-angiotensin-aldosterone system.

Correct Answer

D. It is a disorder of the lower respiratory tract.

Explanation

Tuberculosis (TB) is a bacterial infection caused by Mycobacterium tuberculosis, primarily affecting the lower respiratory tract, particularly the lungs. TB leads to granuloma formation and lung tissue destruction, often resulting in chronic cough, hemoptysis, fever, and weight loss. If left untreated, it can spread to other organs, becoming a systemic infection. The disease is primarily transmitted through airborne droplets from an infected person.

Why other options are wrong

A. It is a disorder of the upper respiratory tract. – The upper respiratory tract includes the nose, sinuses, pharynx, and larynx, whereas TB primarily affects the lungs, which belong to the lower respiratory tract. TB can spread to other areas, but its main site of infection is the lungs.

B. It is an obstructive disorder. – Obstructive lung diseases, such as asthma and COPD, are characterized by airflow limitation due to bronchoconstriction or mucus buildup. TB does not primarily cause obstruction but rather leads to lung tissue destruction and fibrosis.

C. It is a non-infectious disorder. – TB is an infectious disease caused by bacteria. Non-infectious lung diseases include conditions like pulmonary fibrosis or lung cancer, which do not result from pathogens.

Correct Answer

D. Hematuria (blood in urine)

Explanation

Hematuria, or blood in the urine, is the primary and most common sign associated with renal cancer. As the tumor grows, it can cause bleeding within the kidney, which results in the presence of blood in the urine. This symptom is a key diagnostic indicator and often leads to further testing to confirm the presence of kidney cancer.

Why other options are wrong

A. Dysuria (painful urination) – Dysuria is often associated with urinary tract infections (UTIs) or bladder conditions, not renal cancer. While some renal cancer patients may experience pain, dysuria is not the primary symptom.

B. Oliguria (low urine output) – Oliguria, or low urine output, can be caused by a variety of renal conditions, including acute kidney injury, but it is not a hallmark of renal cancer. Hematuria is the primary symptom associated with renal cancer.

C. Proteinuria (excess protein in urine) – Proteinuria can occur in kidney disease but is not a specific sign of renal cancer. Hematuria is more directly related to the presence of tumors in the kidneys.

Correct Answer

A. Pyelonephritis (UTI)

Explanation

Patients with multiple sclerosis (MS) are at increased risk for urinary tract infections (UTIs), including pyelonephritis, due to bladder dysfunction. MS can cause neurogenic bladder, leading to urinary retention and incomplete emptying of the bladder, creating an environment for bacterial growth. Symptoms of a UTI in MS patients may include fever, pain, and changes in urinary habits, which can lead to pyelonephritis if untreated.

Why other options are wrong

B. Acute pancreatitis – Acute pancreatitis is characterized by sudden severe abdominal pain, often due to gallstones or alcohol consumption. While MS can cause a variety of neurological symptoms, pancreatitis is not typically associated with MS.

C. Cholecystitis – Cholecystitis, or inflammation of the gallbladder, usually presents with right upper quadrant abdominal pain, nausea, and vomiting. It is not commonly linked to multiple sclerosis.

D. Appendicitis – Appendicitis is characterized by sharp abdominal pain, typically starting near the belly button and moving to the lower right abdomen. While it is a common cause of abdominal pain, it is not typically related to multiple sclerosis.

Correct Answer

B. Cigarette smoking

Explanation

Cigarette smoking is the most significant risk factor for bladder cancer, responsible for approximately 50% of all cases. The chemicals in tobacco smoke are absorbed into the bloodstream, filtered by the kidneys, and then excreted into the urine, where they can damage the bladder lining. This increases the risk of cancerous changes in the bladder cells over time.

Why other options are wrong

A. Obesity – While obesity is a risk factor for various cancers, it is not as strongly linked to bladder cancer as smoking. Obesity may increase the risk of some cancers but is not the primary cause of bladder cancer.

C. Diabetes – Diabetes does not directly cause bladder cancer. However, patients with diabetes may be at a higher risk for other complications like urinary tract infections or kidney disease. It is not considered the strongest risk factor for bladder cancer.

D. High blood pressure – Although high blood pressure may contribute to overall health issues like kidney disease, it is not a significant risk factor for bladder cancer. Other factors, like smoking, have a much stronger correlation with the development of bladder cancer.

Correct Answer

A. Obesity.

Explanation

Obesity is a major risk factor for the development of a hernia. Excess body weight increases the pressure on the abdominal wall, making it more likely for a portion of the intestine or tissue to protrude through a weak area. This increased pressure can lead to hernia formation, particularly in areas where there are natural openings, such as the inguinal or umbilical regions.

Why other options are wrong

B. High physical activity levels. – While heavy lifting or strain during physical activities can increase the risk of a hernia, high physical activity alone, especially when performed with proper technique, is not a significant risk factor. In fact, regular exercise can help strengthen muscles and prevent hernias.

C. Age under 30. – Age under 30 is not a risk factor for hernias. Hernias are more common in older adults, particularly those over the age of 40, due to the weakening of muscles and connective tissue over time.

D. Low protein diet. – A low protein diet may contribute to overall muscle weakness but is not a direct risk factor for developing a hernia. Muscle weakness can increase the risk, but this is more commonly associated with aging or other factors rather than diet alone.

Correct Answer

D. Calluses

Explanation

A callus is a thickened area of skin that forms due to repeated friction or pressure, often seen on the feet, including the heel. It is typically hard and may cause discomfort or pain when walking. Calluses are generally not harmful but may need to be managed if they become painful or too thick.

Why other options are wrong

A. Plantar warts

Plantar warts are caused by a viral infection (HPV) and appear as small, rough growths on the bottom of the feet. They are different from calluses because they are typically painful when touched directly, rather than from pressure while walking.

B. Fungal infection

Fungal infections, such as athlete's feet, cause itching, redness, and peeling skin, but they do not typically form thick, hard patches of skin like calluses. Fungal infections are more likely to cause irritation and discomfort due to inflammation and skin breakdown.

C. Corns

Corns are similar to calluses but are smaller and have a distinct central core. They form on areas of the foot subjected to pressure, like the toes. Unlike calluses, corns tend to be more painful and focused on specific areas, such as the toe joints, rather than the heel.

Correct Answer

A. Oxygen moves across the alveolar membrane into the bloodstream.

Explanation

During gas exchange in the lungs, oxygen from the air in the alveoli moves across the alveolar membrane into the bloodstream, where it binds to hemoglobin in red blood cells. At the same time, carbon dioxide from the blood moves into the alveoli to be exhaled. This process allows the body to obtain oxygen for cellular functions and remove excess carbon dioxide.

Why other options are wrong

B. Oxygen is produced in the alveoli from carbon dioxide.

This is incorrect because oxygen is not produced in the alveoli. Oxygen from the air moves into the bloodstream during gas exchange, while carbon dioxide moves in the opposite direction, from the blood into the alveoli for exhalation.

C. Carbon dioxide moves from the bloodstream into the alveoli.

This is only partially correct. While it is true that carbon dioxide moves from the bloodstream into the alveoli, the key focus of the question is about oxygen moving into the bloodstream, which is why option A is the correct answer.

D. Oxygen is released from hemoglobin into the alveoli.

This is incorrect because oxygen is released from hemoglobin in the bloodstream, not in the alveoli. Oxygen is transported by hemoglobin to the tissues, where it is used, while carbon dioxide is transported from tissues to the lungs for exhalation.

Correct Answer

A. Asthma

Explanation

Asthma primarily affects the lower respiratory tract, especially the bronchi and bronchioles. It is a chronic condition that causes inflammation and narrowing of the airways, making breathing difficult. Although asthma can also involve the upper respiratory tract, its primary effects are on the lower respiratory system.

Why other options are wrong

B. Renal disease

Renal disease refers to conditions affecting the kidneys and has no direct impact on the respiratory tract, whether upper or lower.

C. Cushing syndrome

Cushing syndrome is a disorder caused by excessive cortisol levels in the body and affects many systems, but it does not directly affect the lower respiratory tract.

D. Cholelithiasis

Cholelithiasis is the presence of gallstones in the gallbladder, and it does not affect the respiratory tract at all. It is a digestive system issue.