2026/2027 | 100% Correct Answers with Complete Solutions |
Hematology | Blood Composition | Hemostasis | Clinical
Correlations | Pass Guaranteed - A+ Graded
Domain 1: Blood Composition & Functions (8 Questions)
Q1: A patient has a total blood volume of 5 liters. Approximately what volume
represents plasma, and what percentage of plasma consists of proteins?
A. 2.5 L plasma; 1% protein
B. 3.5 L plasma; 7-9% protein [CORRECT]
C. 4.5 L plasma; 15% protein
D. 2.0 L plasma; 3% protein
Correct Answer: B
Rationale: Blood volume (~5L in 70kg male) consists of 55% plasma (~2.75L) and 45%
formed elements. However, hematocrit (packed cell volume) is ~45%, meaning plasma
is ~55% of total blood volume (~2.75L, typically rounded to 3-3.5L in clinical contexts).
Plasma is 91-93% water and 7-9% solutes, with proteins comprising most of the solute
fraction (albumin ~60%, globulins ~35%, fibrinogen ~4%). Option A underestimates
plasma volume and protein percentage. Option C overestimates both. Option D
underestimates both.
Q2: A patient with liver cirrhosis develops peripheral edema and ascites. Which plasma
protein deficiency primarily contributes to this fluid imbalance?
,A. Albumin deficiency; decreased colloid osmotic pressure (oncotic pressure) allows
fluid filtration from capillaries into interstitial spaces [CORRECT]
B. Fibrinogen deficiency; impaired clotting causes bleeding and fluid loss
C. Globulin deficiency; impaired immune function causes inflammation
D. Transferrin deficiency; iron transport abnormalities
Correct Answer: A
Rationale: Albumin is the most abundant plasma protein (3.5-5.0 g/dL) and primary
determinant of plasma oncotic pressure (~75-80% of total). It maintains the
transcapillary fluid exchange gradient by holding water in the vascular space via
osmotic pressure. Liver cirrhosis reduces albumin synthesis, decreasing oncotic
pressure, leading to edema and ascites (Starling forces altered). Option B (fibrinogen)
affects coagulation. Option C (globulins) affects immunity but not oncotic pressure
significantly. Option D (transferrin) affects iron transport.
Q3: Which blood component is responsible for transporting lipids, steroid hormones,
and fat-soluble vitamins that are insoluble in aqueous plasma?
A. Albumin and specific globulins (lipoproteins, steroid-binding globulins); albumin
carries free fatty acids, lipoproteins transport cholesterol and triglycerides, specific
globulins bind steroid hormones [CORRECT]
B. Fibrinogen primarily carries all lipids
C. Erythrocytes transport lipids in their membranes only
D. Water-soluble plasma transports lipids directly
Correct Answer: A
Rationale: Lipid transport requires protein carriers due to insolubility: Albumin carries
free fatty acids and unconjugated bilirubin; Lipoproteins (chylomicrons, VLDL, LDL,
HDL—classified by density) transport dietary and endogenous lipids; Steroid-binding
globulins (SHBG, CBG) transport steroid hormones (cortisol, aldosterone, sex steroids);
Transferrin carries iron. Option B is incorrect—fibrinogen is for coagulation. Option C is
,incomplete—RBCs don't transport plasma lipids. Option D is impossible—lipids are
hydrophobic.
Q4: A patient has polycythemia with hematocrit of 60%. Which physical property of
blood is most significantly altered, and what clinical consequence results?
A. Blood viscosity increases exponentially with hematocrit; increased resistance to flow,
elevated cardiac workload, risk of thrombosis and hypertension [CORRECT]
B. Blood viscosity decreases, improving flow
C. Blood pH decreases dramatically
D. Plasma oncotic pressure decreases significantly
Correct Answer: A
Rationale: Blood viscosity increases exponentially (not linearly) with hematocrit due to
increased cell-cell interactions and internal friction. Normal Hct ~45%; at 60%, viscosity
approximately doubles. Clinical consequences: increased peripheral resistance,
hypertension, increased cardiac workload, reduced tissue perfusion, and thrombosis
risk (stasis and hypercoagulability). Option B is opposite. Option C (pH) is buffered.
Option D (oncotic pressure) is unrelated to cell concentration.
Q5: Which blood function is demonstrated when leukocytes migrate to a site of
bacterial infection and release antimicrobial substances?
A. Protection (defense against pathogens); specific function of leukocytes in immune
surveillance and inflammatory response [CORRECT]
B. Transport of oxygen to tissues
C. Regulation of body temperature only
D. Maintenance of blood volume
Correct Answer: A
, Rationale: Blood functions include: Transport (O2, CO2, nutrients, hormones, wastes),
Regulation (pH, temperature, osmotic pressure), and Protection (clotting, immune
defense). Leukocyte migration (chemotaxis) to infection sites, phagocytosis, and
antimicrobial release represent the protective/immune function. Option B describes
erythrocyte function. Option C is incomplete—temperature regulation involves blood
distribution but not leukocyte migration specifically. Option D is a physical property, not
a function demonstrated.
Q6: A patient's blood sample shows elevated plasma potassium (hyperkalemia). Which
blood component maintains potassium distribution between plasma and intracellular
fluid?
A. The Na+-K+ ATPase pump in erythrocyte and other cell membranes; maintains high
intracellular K+ and low intracellular Na+ [CORRECT]
B. Plasma proteins bind potassium to reduce free levels
C. Platelets sequester potassium in granules
D. Leukocytes consume potassium as energy source
Correct Answer: A
Rationale: The Na+-K+ ATPase (sodium-potassium pump) maintains the
electrochemical gradient: 3 Na+ out, 2 K+ in, using ATP. This keeps intracellular K+ high
(~140 mEq/L) and extracellular K+ low (~4 mEq/L). Erythrocytes have high Na+-K+
ATPase activity to maintain this gradient. Hyperkalemia occurs when this balance fails
(acidosis, cell lysis, renal failure). Option B is incorrect—plasma proteins don't bind K+
significantly. Option C is incorrect—platelet granules don't sequester K+. Option D is
incorrect—leukocytes don't consume K+ as fuel.
Q7: Which plasma protein is the primary carrier for thyroid hormones (T3, T4) and
retinol (vitamin A)?