Unit 03 — Blood · Question Bank

TMU Physiology · Blood (Prof. Zhao) · Guyton 14e Ch 32–36
← Notes All Units
0 / 20 answered
0
Score — click each question to reveal the answer
Q1
The haemoglobin concentration in normal blood is about:
TMU 题-blood
A. 15 g/dL
B. 10 g/dL
C. 20 g/dL
D. 25 g/dL
✅ Answer: A. 15 g/dL
Normal adult male Hb ≈ 150 g/L = 15 g/dL (female ~110–150 g/L).
Q2
The main raw materials for erythropoiesis are:
TMU 题-blood
A. calcium and protein
B. iron and protein
C. vitamin B₁₂ and folic acid
D. iron and vitamin B₁₂
✅ Answer: B. iron and protein
Iron + protein build haemoglobin. B₁₂ and folate are maturation factors (DNA synthesis), not the bulk raw materials.
Q3
Which cell plays the most important role in haemostasis?
TMU 题-blood
A. erythrocytes
B. neutrophils
C. platelets
D. monocytes
✅ Answer: C. platelets
Platelets form the platelet plug and provide the phospholipid surface for coagulation.
Q4
Which leukocytes are mainly connected with the immune system?
TMU 题-blood
A. neutrophils
B. eosinophils
C. monocytes
D. lymphocytes
✅ Answer: D. lymphocytes
Lymphocytes (B and T) and plasma cells mediate specific immunity; neutrophils/monocytes mainly phagocytose.
Q5
Which clotting factor is activated by both the intrinsic and the extrinsic pathways?
TMU 题-blood
A. factor X
B. factor V
C. factor VII
D. factor VIII
✅ Answer: A. factor X
Factor X is the convergence point — the start of the common pathway, activated by either route.
Q6
Which factor is the enzyme that converts fibrinogen into fibrin?
TMU 题-blood
A. factor IXa
B. factor IIa (thrombin)
C. factor Xa
D. factor XIIa
✅ Answer: B. factor IIa (thrombin)
Thrombin (factor IIa) cleaves soluble fibrinogen (I) into insoluble fibrin, which is then cross-linked by XIII.
Q7
In the ABO system, type O blood contains:
TMU 题-blood
A. type A agglutinogens
B. type B agglutinogens
C. no agglutinogens but both anti-A and anti-B agglutinins
D. both A and B agglutinogens but no agglutinins
✅ Answer: C. no agglutinogens but both anti-A and anti-B agglutinins
Type O red cells carry no A/B antigens but the plasma has both anti-A and anti-B antibodies — the universal-donor red cell.
Q8
Plasma colloid osmotic pressure is generated mainly by:
A. NaCl
B. glucose
C. urea
D. albumin
✅ Answer: D. albumin
Albumin (the most abundant plasma protein) generates colloid osmotic pressure, which keeps fluid in the capillaries; its fall causes oedema.
Q9
The normal haematocrit in an adult male is about:
A. 40–50%
B. 20–30%
C. 55–65%
D. 70–80%
✅ Answer: A. 40–50%
Haematocrit (% blood volume occupied by red cells): ♂ 40–50%, ♀ 37–48%, neonate ~55%.
Q10
Plasma osmotic pressure is determined by the:
TMU 题-blood
A. chemical nature of the solutes
B. number of solute particles
C. size of the particles
D. valence of the ions
✅ Answer: B. number of solute particles
Osmotic pressure depends only on the NUMBER of dissolved particles, not their chemical nature or size.
Q11
Crystalloid osmotic pressure of plasma is mainly produced by electrolytes and chiefly maintains:
A. intra- vs extra-capillary water balance
B. blood pressure
C. intra- vs extra-cellular water balance
D. plasma pH
✅ Answer: C. intra- vs extra-cellular water balance
Crystalloid OP (mostly NaCl) is large and governs water movement across the cell membrane (intra-/extra-cellular). Colloid OP (albumin) governs capillary fluid balance.
Q12
A 0.9% NaCl solution and a 1.9% urea solution are both iso-osmotic to plasma, yet red cells haemolyse in urea because:
A. urea is hypertonic
B. NaCl is hypotonic
C. urea raises the pH
D. urea penetrates the cell membrane, so the solution is not isotonic
✅ Answer: D. urea penetrates the cell membrane, so the solution is not isotonic
Tonicity counts only non-penetrating particles. Urea crosses the membrane, so the cell still takes up water and lyses — iso-osmotic but not isotonic.
Q13
Rouleaux formation (stacking of red cells) will:
TMU 题-blood
A. increase the ESR
B. decrease the ESR
C. not change the ESR
D. cause haemolysis
✅ Answer: A. increase the ESR
Rouleaux make larger aggregates that settle faster → higher erythrocyte sedimentation rate. Driven by ↑fibrinogen/globulins.
Q14
The ESR is increased mainly by raised plasma levels of:
A. albumin
B. fibrinogen and globulins
C. lecithin
D. glucose
✅ Answer: B. fibrinogen and globulins
Fibrinogen, globulins and cholesterol promote rouleaux → ↑ESR; albumin and lecithin lower it. ESR rises in inflammation/pregnancy/TB.
Q15
Vitamin B₁₂ requires which gastric factor for its absorption in the ileum?
A. gastrin
B. pepsin
C. intrinsic factor
D. HCl
✅ Answer: C. intrinsic factor
Intrinsic factor (from gastric parietal cells) binds B₁₂ for ileal absorption. Its loss → pernicious (megaloblastic) anaemia.
Q16
Erythropoietin (EPO), which stimulates red-cell production, is secreted mainly by the:
A. liver
B. spleen
C. bone marrow
D. kidney
✅ Answer: D. kidney
The kidney senses low blood O₂ (hypoxia) and releases EPO → ↑erythropoiesis — a negative-feedback loop. CKD → anaemia.
Q17
The average lifespan of a circulating red blood cell is about:
A. 120 days
B. 7–14 days
C. 30 days
D. 1 year
✅ Answer: A. 120 days
Red cells live ~120 days, then are removed mainly in the spleen and liver; Hb → bilirubin + recycled iron.
Q18
Iron-deficiency anaemia is typically:
A. macrocytic
B. microcytic and hypochromic
C. megaloblastic
D. haemolytic
✅ Answer: B. microcytic and hypochromic
Too little iron → too little Hb per cell → small (microcytic), pale (hypochromic) cells. B₁₂/folate deficiency → megaloblastic (macrocytic).
Q19
The first step of physiological haemostasis after vessel injury is:
A. fibrin formation
B. clot retraction
C. vascular spasm (vasoconstriction)
D. fibrinolysis
✅ Answer: C. vascular spasm (vasoconstriction)
Order: vascular spasm → platelet plug → blood coagulation (fibrin) → clot retraction. Spasm immediately reduces blood loss.
Q20
Why does an Rh-negative mother's second Rh-positive baby risk haemolytic disease, but rarely the first?
A. anti-D is naturally present
B. the first baby is always Rh-negative
C. Rh antigens disappear after one pregnancy
D. the first pregnancy sensitises her, so anti-D forms and attacks the next Rh⁺ fetus
✅ Answer: D. the first pregnancy sensitises her, so anti-D forms and attacks the next Rh⁺ fetus
Anti-D is not natural; the first Rh⁺ delivery sensitises the mother. Pre-formed anti-D then crosses the placenta in a later Rh⁺ pregnancy. Prevented by anti-D immunoglobulin.
1Haematocrit+
The percentage of whole-blood volume occupied by erythrocytes (packed cell volume). Normal ♂ 40–50%, ♀ 37–48%. It rises in polycythaemia/dehydration and falls in anaemia.
TMU 题-blood
2Blood groups+
The classification of blood by the antigens (agglutinogens) present on the red-cell membrane, with the corresponding antibodies (agglutinins) in the plasma — e.g. the ABO and Rh systems. They determine transfusion compatibility.
TMU 题-blood
3Physiological haemostasis+
The body's process to stop bleeding from a damaged vessel: vascular spasm → platelet plug (primary haemostasis) → blood coagulation laying down fibrin (secondary haemostasis), followed by clot retraction.
TMU 题-blood
4Blood coagulation+
The conversion of liquid blood into a solid gel through a cascade of clotting factors; its fundamental reaction is the conversion of soluble fibrinogen into insoluble fibrin by thrombin, requiring Ca²⁺ and a platelet phospholipid surface.
TMU 题-blood
5Erythrocyte sedimentation rate (ESR)+
The distance (mm) red cells settle in a vertical tube of anticoagulated blood in 1 hour — a measure of suspension stability. Normal ♂ 0–15, ♀ 0–20 mm/h. Raised by fibrinogen/globulins (rouleaux) and in inflammation.
TMU Blood slide
6Colloid osmotic pressure+
The osmotic pressure generated by the plasma proteins (chiefly albumin), ~25 mmHg. Because proteins cannot cross the capillary wall, it pulls fluid back into the capillaries and maintains the plasma–interstitial water balance; its fall causes oedema.
TMU Blood slide
Essay 1
Describe the basic process of blood coagulation briefly.
10 marks

Overview

Coagulation is a cascade of plasma clotting factors (mostly liver-made; II, VII, IX, X are vitamin-K-dependent) needing Ca²⁺ and a platelet phospholipid surface. Two initiating pathways converge on a common pathway.

Intrinsic pathway

Triggered by contact with a damaged (collagen) surface: factor XII → XI → IX → VIII.

Extrinsic pathway

Triggered by tissue factor (III) released from injured tissue + factor VII (faster).

Common pathway

Both routes activate factor X → Xa. Xa converts prothrombin (II) into thrombin (IIa). Thrombin converts fibrinogen (I) into fibrin; factor XIII cross-links the fibrin into a stable clot that traps platelets and cells.

Marking guide (10 marks): intrinsic pathway (contact, XII→XI→IX→VIII) 2 · extrinsic pathway (tissue factor + VII) 2 · convergence at factor X → Xa 2 · prothrombin → thrombin 2 · fibrinogen → fibrin (+ XIII cross-link, Ca²⁺/phospholipid) 2
Essay 2
Describe the composition of plasma osmotic pressure and its physiological significance.
10 marks

Total

Total plasma osmotic pressure ≈ 313 mOsm and depends on the NUMBER of solute particles, not their nature. It has two components:

Crystalloid osmotic pressure

Generated by electrolytes (mainly NaCl) — small and numerous, so it is the LARGE component (~99%). Because these solutes are kept out of cells by the membrane, crystalloid OP governs water movement across the cell membrane and so maintains cell volume / intra- vs extra-cellular water balance.

Colloid osmotic pressure

Generated by plasma proteins, chiefly albumin — large and few, so it is SMALL (~25 mmHg). Because proteins cannot cross the capillary wall, colloid OP governs water movement across the capillary wall and maintains the plasma vs interstitial fluid balance.

Significance

A fall in colloid OP (low albumin — liver/renal disease, malnutrition) → fluid leaks into the interstitium → oedema.

Marking guide (10 marks): total ≈ 313 mOsm + particle-number rule 1 · crystalloid OP (electrolytes, large, cell-membrane/cell volume) 3 · colloid OP (albumin, small, capillary balance) 3 · significance/oedema 3
Essay 3
Describe the characteristics of red blood cells.
10 marks

Morphology

Biconcave, anucleate disc (~7–8 µm), no organelles, packed with haemoglobin; large surface-area:volume ratio favours gas exchange and deformability; lifespan ~120 days.

Plastic deformation

Red cells deform to squeeze through capillaries and splenic sinusoid pores <1 µm.

Osmotic fragility

Sensitivity to osmotic change: in HYPOtonic solution the cell swells and bursts (haemolysis); in HYPERtonic it shrinks (crenation). Normal haemolysis begins at ~0.42–0.45% NaCl and is complete at ~0.30–0.33% NaCl.

Suspension stability (ESR)

Red cells stay evenly suspended in plasma; the ESR measures how fast they settle in 1 h (♂ 0–15, ♀ 0–20 mm/h). Rouleaux formation (↑fibrinogen/globulins) raises the ESR.

Marking guide (10 marks): morphology + functions (biconcave, anucleate, O₂/CO₂, 120 d) 2.5 · plastic deformation 2 · osmotic fragility + haemolysis ranges 3 · suspension stability/ESR + rouleaux 2.5
Essay 4
Describe erythropoiesis and its regulation.
10 marks

Site and stages

Red cells arise in red bone marrow from a pluripotent haematopoietic stem cell → proerythroblast → normoblast → reticulocyte → erythrocyte (fetal sequence: yolk sac → liver/spleen → marrow).

Raw materials and maturation factors

  • Iron + protein → build haemoglobin; deficiency → microcytic hypochromic anaemia.
  • Vitamin B₁₂ + folic acid → DNA synthesis/nuclear maturation; deficiency → megaloblastic anaemia. B₁₂ absorption needs gastric intrinsic factor.

Regulation

Chiefly by erythropoietin (EPO) from the kidney: low blood O₂ (hypoxia) → ↑EPO → ↑proerythroblast production and faster maturation — a negative-feedback loop. Androgen, thyroid hormone and growth hormone also stimulate it.

Marking guide (10 marks): site + stem cell → reticulocyte → RBC 2 · iron + protein (Hb) 2 · B₁₂/folate + intrinsic factor 2 · EPO from kidney, hypoxia-driven, negative feedback 3 · other hormones 1
Essay 5
Describe the ABO blood group system and the principles of safe blood transfusion.
10 marks

ABO antigens and antibodies

  • Group A: A antigen on red cells, anti-B in plasma.
  • Group B: B antigen, anti-A.
  • Group AB: A and B antigens, no antibody — universal recipient.
  • Group O: no antigen, both anti-A and anti-B — universal-donor red cell.

Transfusion reaction

If a recipient's antibody meets the matching donor antigen → agglutination and haemolysis of the transfused red cells.

Principles

Give ABO- and Rh-identical blood; always cross-match before transfusion. The Rh(D) system matters because an Rh-negative recipient can be sensitised to form anti-D, important in transfusion and in haemolytic disease of the newborn (prevented by anti-D immunoglobulin).

Marking guide (10 marks): A/B/AB/O antigens + antibodies 4 · universal donor/recipient 1.5 · cause of transfusion reaction (agglutination/haemolysis) 2 · cross-matching + same ABO/Rh 1.5 · Rh significance/HDN 1