BIOD 152 MODULE 4 ACTUAL EXAM 2026/2027 | Portage Learning |
26 Questions with Rationales | Complete Answer Key | Updated
Edition | Pass Guaranteed - A+ Graded
Q1: Which plasma protein is primarily responsible for maintaining colloid osmotic
pressure and preventing fluid loss from capillaries into tissues?
A. Globulins
B. Fibrinogen
C. Albumin [CORRECT]
D. Hemoglobin
Correct Answer: C
Rationale: Albumin constitutes approximately 60% of plasma proteins by weight and is
the primary determinant of colloid osmotic pressure (oncotic pressure), which is
approximately 25 mmHg. Its small molecular size and high concentration create an
osmotic gradient that draws water back into capillaries from interstitial fluid, opposing
hydrostatic pressure. Distractor A (Globulins) include alpha, beta, and gamma globulins;
while they contribute to osmotic pressure, their primary functions are transport
(alpha/beta) and immune defense (gamma/immunoglobulins). Distractor B (Fibrinogen)
is essential for blood clotting (converted to fibrin) but contributes minimally to oncotic
pressure. Distractor D (Hemoglobin) is an intracellular protein within erythrocytes, not a
plasma protein; its presence in plasma indicates hemolysis. Clinical correlation:
Hypoalbuminemia (liver disease, nephrotic syndrome, malnutrition) causes edema due
to reduced oncotic pressure.
,Q2 (Blood Typing Problem): A patient with blood type A- needs an emergency
transfusion. The blood bank has types O-, O+, A-, A+, B-, and AB+ available. Which blood
type(s) can this patient safely receive?
A. A- and A+ only
B. O- and A- [CORRECT]
C. O-, A-, B-, and AB-
D. O-, O+, A-, and A+
Correct Answer: B
Rationale: Blood type A- indicates A antigens on RBCs and anti-B antibodies in plasma,
with no Rh(D) antigen. Transfusion compatibility follows two rules: (1) Recipient
antibodies must not attack donor RBC antigens; (2) Donor plasma antibodies are
usually diluted and less critical. Type A- can receive: Type A- (identical - A antigens
present, no Rh conflict, no antibodies against recipient) and Type O- (universal donor -
no A, B, or Rh antigens to react with recipient's anti-B antibodies). Distractor A is
incorrect because A+ contains Rh(D) antigen, which would cause anti-D antibody
production in the Rh-negative recipient, risking future transfusion reactions or hemolytic
disease of the newborn. Distractor C includes B- and AB-, which have B antigens that
would react with recipient's anti-B antibodies, causing acute hemolytic transfusion
reaction. Distractor D includes O+ and A+, both containing Rh(D) antigen. In
emergencies, O- is the universal donor for RBC transfusions because it lacks all major
antigens.
Q3 (Diagram Labeling): Identify structures 1-5 on the heart diagram below (anterior view,
internal structures visible):
, plainCopy
[Diagram Description: Anterior view of heart with right atrium opened,
showing:
1 - Superior vena cava entry point into chamber
2 - Valve between right atrium and right ventricle
3 - Muscular ridges in ventricular wall
4 - Vessel exiting superiorly from right ventricle
5 - Wall separating right and left ventricles]
Correct Answer:
1. Right Atrium (receives systemic venous return)
2. Tricuspid Valve (right AV valve; prevents backflow into atrium during ventricular
systole) [CORRECT]
3. Trabeculae Carneae (muscular ridges in ventricular walls; prevent adhesion of
papillary muscles) [CORRECT]
4. Pulmonary Trunk (exits right ventricle; carries deoxygenated blood to lungs)
[CORRECT]
5. Interventricular Septum (muscular wall separating ventricles; prevents mixing of
oxygenated/deoxygenated blood) [CORRECT]
Rationale: This diagram shows the right side of the heart and great vessels. Structure 1
is the right atrium, receiving deoxygenated blood via superior and inferior vena cavae; it
contains the fossa ovalis (remnant of foramen ovale). Structure 2 is the tricuspid valve
(three cusps: anterior, posterior, septal), anchored by chordae tendineae to papillary
muscles; it closes during ventricular systole to prevent regurgitation. Structure 3,
trabeculae carneae, are irregular muscular ridges that increase surface area and
contractile force; they include the moderator band (septomarginal trabecula) carrying
right bundle branch fibers. Structure 4, the pulmonary trunk, arises from the conus
arteriosus (infundibulum) of the right ventricle and bifurcates into right and left
pulmonary arteries. Structure 5, the interventricular septum, has membranous (upper)
and muscular (lower) portions; defects here cause ventricular septal defects (VSD), the
most common congenital heart defect.
26 Questions with Rationales | Complete Answer Key | Updated
Edition | Pass Guaranteed - A+ Graded
Q1: Which plasma protein is primarily responsible for maintaining colloid osmotic
pressure and preventing fluid loss from capillaries into tissues?
A. Globulins
B. Fibrinogen
C. Albumin [CORRECT]
D. Hemoglobin
Correct Answer: C
Rationale: Albumin constitutes approximately 60% of plasma proteins by weight and is
the primary determinant of colloid osmotic pressure (oncotic pressure), which is
approximately 25 mmHg. Its small molecular size and high concentration create an
osmotic gradient that draws water back into capillaries from interstitial fluid, opposing
hydrostatic pressure. Distractor A (Globulins) include alpha, beta, and gamma globulins;
while they contribute to osmotic pressure, their primary functions are transport
(alpha/beta) and immune defense (gamma/immunoglobulins). Distractor B (Fibrinogen)
is essential for blood clotting (converted to fibrin) but contributes minimally to oncotic
pressure. Distractor D (Hemoglobin) is an intracellular protein within erythrocytes, not a
plasma protein; its presence in plasma indicates hemolysis. Clinical correlation:
Hypoalbuminemia (liver disease, nephrotic syndrome, malnutrition) causes edema due
to reduced oncotic pressure.
,Q2 (Blood Typing Problem): A patient with blood type A- needs an emergency
transfusion. The blood bank has types O-, O+, A-, A+, B-, and AB+ available. Which blood
type(s) can this patient safely receive?
A. A- and A+ only
B. O- and A- [CORRECT]
C. O-, A-, B-, and AB-
D. O-, O+, A-, and A+
Correct Answer: B
Rationale: Blood type A- indicates A antigens on RBCs and anti-B antibodies in plasma,
with no Rh(D) antigen. Transfusion compatibility follows two rules: (1) Recipient
antibodies must not attack donor RBC antigens; (2) Donor plasma antibodies are
usually diluted and less critical. Type A- can receive: Type A- (identical - A antigens
present, no Rh conflict, no antibodies against recipient) and Type O- (universal donor -
no A, B, or Rh antigens to react with recipient's anti-B antibodies). Distractor A is
incorrect because A+ contains Rh(D) antigen, which would cause anti-D antibody
production in the Rh-negative recipient, risking future transfusion reactions or hemolytic
disease of the newborn. Distractor C includes B- and AB-, which have B antigens that
would react with recipient's anti-B antibodies, causing acute hemolytic transfusion
reaction. Distractor D includes O+ and A+, both containing Rh(D) antigen. In
emergencies, O- is the universal donor for RBC transfusions because it lacks all major
antigens.
Q3 (Diagram Labeling): Identify structures 1-5 on the heart diagram below (anterior view,
internal structures visible):
, plainCopy
[Diagram Description: Anterior view of heart with right atrium opened,
showing:
1 - Superior vena cava entry point into chamber
2 - Valve between right atrium and right ventricle
3 - Muscular ridges in ventricular wall
4 - Vessel exiting superiorly from right ventricle
5 - Wall separating right and left ventricles]
Correct Answer:
1. Right Atrium (receives systemic venous return)
2. Tricuspid Valve (right AV valve; prevents backflow into atrium during ventricular
systole) [CORRECT]
3. Trabeculae Carneae (muscular ridges in ventricular walls; prevent adhesion of
papillary muscles) [CORRECT]
4. Pulmonary Trunk (exits right ventricle; carries deoxygenated blood to lungs)
[CORRECT]
5. Interventricular Septum (muscular wall separating ventricles; prevents mixing of
oxygenated/deoxygenated blood) [CORRECT]
Rationale: This diagram shows the right side of the heart and great vessels. Structure 1
is the right atrium, receiving deoxygenated blood via superior and inferior vena cavae; it
contains the fossa ovalis (remnant of foramen ovale). Structure 2 is the tricuspid valve
(three cusps: anterior, posterior, septal), anchored by chordae tendineae to papillary
muscles; it closes during ventricular systole to prevent regurgitation. Structure 3,
trabeculae carneae, are irregular muscular ridges that increase surface area and
contractile force; they include the moderator band (septomarginal trabecula) carrying
right bundle branch fibers. Structure 4, the pulmonary trunk, arises from the conus
arteriosus (infundibulum) of the right ventricle and bifurcates into right and left
pulmonary arteries. Structure 5, the interventricular septum, has membranous (upper)
and muscular (lower) portions; defects here cause ventricular septal defects (VSD), the
most common congenital heart defect.
