BIO 202L LAB 10 WORKSHEET BLOOD AND THE
HEART 2026/2027 | Comprehensive Lab Assessment |
Complete Answers | Pass Guaranteed - A+ Graded
Section 1: Blood Composition & Formed Elements (Q1-15)
Q1. A student examines a blood smear and observes numerous biconcave disc-
shaped cells lacking nuclei. These cells are approximately 7-8 μm in diameter and
appear pale pink with a central pallor. Which formed element is being described?
A. Lymphocytes
B. Neutrophils
C. Erythrocytes
D. Monocytes
C. Erythrocytes [CORRECT]
Rationale: Erythrocytes (RBCs) are anucleate, biconcave discs approximately 7-8 μm
in diameter with a central pallor of about one-third the cell diameter. The biconcave
shape maximizes surface area for gas exchange. The central pallor is a common
diagnostic feature; students often confuse RBCs with small lymphocytes, but
lymphocytes possess a large, round nucleus occupying most of the cell.
Correct Answer: C
Q2. During a laboratory exercise, a student analyzes a peripheral blood smear and
identifies a leukocyte with a multilobed nucleus (3-5 lobes) and fine, light pink-lilac
granules in the cytoplasm. This cell constitutes what percentage of the normal
leukocyte differential?
A. 20-40%
B. 50-70%
C. 1-4%
D. 0.5-1%
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B. 50-70% [CORRECT]
Rationale: The cell described is a neutrophil, identified by its segmented nucleus (3-
5 lobes) and fine, neutral-staining granules. Neutrophils normally constitute 50-70%
of circulating leukocytes, making them the most abundant WBC. Common lab errors
include confusing neutrophils with eosinophils; eosinophils have bilobed nuclei and
large, bright red-orange granules, while basophils have coarse, dark blue-purple
granules that obscure the nucleus.
Correct Answer: B
Q3. A laboratory report indicates a patient has elevated levels of a plasma protein
responsible for maintaining oncotic pressure and transporting fatty acids, hormones,
and drugs. Which plasma protein is deficient or elevated in this clinical scenario?
A. Fibrinogen
B. Globulin
C. Albumin
D. Transferrin
C. Albumin [CORRECT]
Rationale: Albumin constitutes approximately 60% of plasma proteins and is the
primary determinant of plasma oncotic pressure, drawing water into the vascular
space by osmosis. It also transports hydrophobic substances (fatty acids, steroid
hormones, bilirubin, and certain drugs). Students often confuse albumin with
fibrinogen; fibrinogen is a clotting factor (4% of plasma proteins) converted to fibrin
during coagulation, while albumin is synthesized by the liver and has no role in
clotting.
Correct Answer: C
Q4. A student observes a blood smear under oil immersion and notes a leukocyte
with a large, indented/kidney-bean shaped nucleus and abundant blue-gray
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cytoplasm with a "ground glass" appearance. The cell is approximately 12-20 μm in
diameter. Which cell type is identified, and what is its normal differential percentage?
A. Eosinophil; 1-4%
B. Monocyte; 2-8%
C. Basophil; 0.5-1%
D. Lymphocyte; 20-40%
B. Monocyte; 2-8% [CORRECT]
Rationale: Monocytes are the largest circulating leukocytes (12-20 μm) with
characteristic kidney-bean or horseshoe-shaped nuclei and abundant blue-gray
cytoplasm containing fine azurophilic granules, giving a "ground glass" appearance.
They normally comprise 2-8% of the differential. A common lab error is confusing
monocytes with large lymphocytes or band neutrophils; band neutrophils have C-
shaped or S-shaped non-segmented nuclei, while monocytes have the distinctive
indented nucleus and more abundant cytoplasm.
Correct Answer: B
Q5. In a blood smear identification exercise, a student encounters a cell fragment
measuring 2-4 μm that appears as irregular purple-staining cytoplasmic fragments
with fine granules, often observed in clumps. These cell fragments are critical for
which physiological process?
A. Antibody production
B. Hemostasis and clot formation
C. Phagocytosis of bacteria
D. Allergic response mediation
B. Hemostasis and clot formation [CORRECT]
Rationale: The description identifies thrombocytes (platelets), which are anucleate
cell fragments (2-4 μm) derived from megakaryocyte cytoplasm. They contain alpha
granules and dense granules and are essential for primary hemostasis (platelet plug
formation) and secondary hemostasis (providing phospholipid surface for
coagulation cascade). Students frequently confuse platelet clumps with small
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lymphocyte clusters or debris; platelets lack nuclei and have granular cytoplasm,
distinguishing them from lymphocytes.
Correct Answer: B
Q6. A clinical laboratory reports that a patient's blood contains elevated levels of
carboxyhemoglobin. The patient was found in a closed garage with a running vehicle.
Which gas displaced oxygen from hemoglobin, and what characteristic color change
does this produce in the blood?
A. Carbon dioxide; dark purple
B. Nitrogen; no color change
C. Carbon monoxide; bright cherry-red
D. Hydrogen cyanide; bright red
C. Carbon monoxide; bright cherry-red [CORRECT]
Rationale: Carbon monoxide (CO) binds to hemoglobin with approximately 240
times greater affinity than oxygen, forming carboxyhemoglobin (COHb). This
produces a characteristic bright cherry-red color in blood and tissues. CO binding
prevents oxygen transport and shifts the oxygen-hemoglobin dissociation curve
leftward, further impairing oxygen release. Students often confuse CO with CO₂; CO₂
binds to globin amino groups forming carbaminohemoglobin (normal transport
mechanism), while CO binds to the heme iron, causing toxic hypoxia.
Correct Answer: C
Q7. A student is examining a blood smear and identifies a cell with a bilobed nucleus
and large, bright red-orange refractile granules in the cytoplasm. This leukocyte is
typically elevated in which clinical condition?
A. Bacterial infection
B. Parasitic infection and allergic reactions