This figure shows the stages of hemoglobin breakdown and disposal. What should go in the yellow box labeled 1?
Heme
Globin
Erythropoietin
The Correct Answer is A
A. Heme: When hemoglobin from old red blood cells is broken down, it first separates into heme and globin. The yellow box leads to the pathway that forms biliverdin, then bilirubin, which is excreted in bile and leaves the body in feces. This sequence occurs only from the heme portion of hemoglobin. During heme breakdown, iron is removed for storage or reuse, and the remaining heme ring is converted to biliverdin and then bilirubin. Therefore, the structure in box 1 must be heme.
B. Globin is incorrect because globin is the protein portion of hemoglobin. It does not form bilirubin. Instead, globin is broken down into amino acids, which are reused by the body to make new proteins. This pathway does not involve bile pigments or fecal excretion.
C. Erythropoietin is incorrect because erythropoietin is a hormone produced by the kidneys that stimulates red blood cell production in the bone marrow. It is not a component of hemoglobin and does not play any role in hemoglobin breakdown or bilirubin formation.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
A. Subject 1: Because Subject 1 lacks both A and B surface antigens, the individual is classified as having blood type O. In the ABO system, type O is characterized by the absence of these specific glycoproteins. This phenotype results in the presence of both anti-A and anti-B antibodies in the plasma.
B. Subject 2: The sample demonstrates visible agglutination in the presence of Anti-A antiserum while remaining smooth in Anti-B antiserum. This indicates the presence of A antigens and the absence of B antigens on the erythrocyte membranes. Consequently, the ABO blood group for this individual is Type A.
C. Subject 3: There is a clear lack of agglutination in the Anti-A antiserum, but distinct clumping is present in the Anti-B antiserum. The reaction confirms that the red blood cells possess B antigens but lack A antigens. This specific reactivity pattern identifies the individual as having Type B blood.
D. Subject 4: Agglutination is prominently visible in both the Anti-A and Anti-B antiserum wells for this individual. This positive reaction in both tests proves the simultaneous presence of both A and B surface antigens. Therefore, Subject 4 is classified as having blood type AB.
Correct Answer is D
Explanation
A. oblique fissure: This is the anatomical groove that separates the superior and inferior lobes of the left lung. While it is a prominent surface feature, it does not represent the specific indentation created by the heart. It facilitates the sliding of lung lobes during the respiratory cycle.
B. hilum: The hilum is the triangular depression on the medial surface of the lung where primary bronchi and pulmonary vessels enter and exit. It serves as the "root" of the lung rather than a space-occupying indentation for the heart. It is located posterior to the cardiac impression.
C. apex: The apex is the superior, blunt tip of the lung that projects above the level of the first rib into the neck. It is located far above the anatomical position of the mediastinal heart. It does not interface with the cardiac apex or ventricular mass.
D. cardiac notch: This is a distinct medial indentation on the anterior border of the superior lobe of the left lung. It accommodates the lateral projection of the heart's apex within the thoracic cavity. This anatomical feature explains why the left lung is smaller than the right lung.
E. base: The base is the broad, concave inferior surface of the lung that rests upon the convex surface of the diaphragm. While the heart sits superior to the central tendon of the diaphragm, it does not indent the diaphragmatic base. The base primarily conforms to the abdominal dome.
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