CSS - PMS - CCE - PCS - General Science
Blood System
During fetal life, a major organ of hematopoiesis is the:
A. Liver
B. Stomach
C. Lung
D. Thyroid
Correct Answer: A
The fetal liver is a major hematopoietic organ before bone marrow becomes dominant.
CSS - PMS - CCE - PCS - General Science
Blood System
The earliest major site of blood cell formation in the human embryo is the:
A. Thymus
B. Yolk sac
C. Kidney
D. Pancreas
Correct Answer: B
Early embryonic hematopoiesis begins in the yolk sac before shifting mainly to the liver and later bone marrow.
CSS - PMS - CCE - PCS - General Science
Blood System
The stem cell from which all blood cells ultimately arise is the:
A. Myoblast
B. Hematopoietic stem cell
C. Osteoblast
D. Fibroblast
Correct Answer: B
All formed elements of blood originate from multipotent hematopoietic stem cells in bone marrow.
CSS - PMS - CCE - PCS - General Science
Blood System
Red blood cells are produced primarily in adults in the:
A. Yellow bone marrow
B. Red bone marrow
C. Liver only
D. Spleen only
Correct Answer: B
In adults, erythrocytes are formed mainly in red bone marrow of the axial skeleton and proximal ends of some long bones.
CSS - PMS - CCE - PCS - General Science
Blood System
Which ion is the major intracellular cation of blood cells?
A. Sodium
B. Potassium
C. Chloride
D. Bicarbonate
Correct Answer: B
Potassium is the major intracellular cation, including within blood cells.
CSS - PMS - CCE - PCS - General Science
Blood System
Which ion is the major cation of blood plasma?
A. Potassium
B. Calcium
C. Sodium
D. Magnesium
Correct Answer: C
Sodium is the major extracellular cation and therefore the predominant cation in plasma.
CSS - PMS - CCE - PCS - General Science
Blood System
The principal buffer system of blood plasma is the:
A. Phosphate buffer only
B. Bicarbonate buffer system
C. Ammonia buffer system
D. Lactate buffer system
Correct Answer: B
The carbonic acid-bicarbonate system is the principal extracellular buffer system in blood.
CSS - PMS - CCE - PCS - General Science
Blood System
The normal pH of arterial blood is approximately:
A. 6.8–7.0
B. 7.00–7.20
C. 7.35–7.45
D. 7.60–7.80
Correct Answer: C
Normal arterial blood pH is tightly regulated around 7.35–7.45.
CSS - PMS - CCE - PCS - General Science
Blood System
Antibodies are mainly found in which plasma protein fraction?
A. Alpha globulins
B. Beta globulins
C. Gamma globulins
D. Albumin
Correct Answer: C
Immunoglobulins are concentrated mainly in the gamma-globulin fraction of plasma proteins.
CSS - PMS - CCE - PCS - General Science
Blood System
A major function of plasma albumin is to:
A. Destroy bacteria directly
B. Maintain colloid osmotic pressure
C. Carry oxygen in red cells
D. Produce platelets
Correct Answer: B
Albumin helps retain water within the vascular compartment by maintaining plasma oncotic pressure.
CSS - PMS - CCE - PCS - General Science
Blood System
The most abundant protein in human plasma is:
A. Globulin
B. Albumin
C. Fibrin
D. Hemoglobin
Correct Answer: B
Albumin is the most abundant plasma protein and is a major contributor to plasma colloid osmotic pressure.
CSS - PMS - CCE - PCS - General Science
Blood System
Plasma differs from serum mainly because plasma contains:
A. Glucose
B. Electrolytes
C. Clotting factors such as fibrinogen
D. Antibodies only
Correct Answer: C
Serum is plasma after clotting has occurred, so it lacks fibrinogen and several clotting factors consumed in the clotting process.
CSS - PMS - CCE - PCS - General Science
Blood System
The percentage of blood volume occupied by red blood cells is called:
A. ESR
B. Hematocrit
C. Clotting time
D. Osmotic index
Correct Answer: B
Hematocrit, also called packed cell volume, is the percentage of whole blood occupied by red blood cells.
CSS - PMS - CCE - PCS - General Science
Blood System
Approximately what fraction of whole blood is plasma by volume?
A. About 35%
B. About 45%
C. About 55%
D. About 75%
Correct Answer: C
Plasma normally forms about 55% of whole blood volume, while formed elements account for roughly 45%.
CSS - PMS - CCE - PCS - General Science
Vitamins
Smokers generally have higher requirements for which vitamin because oxidative stress accelerates its turnover?
A. Vitamin C
B. Vitamin K
C. Vitamin B12
D. Vitamin D only
Correct Answer: A
A is correct because smoking increases oxidative stress and lowers vitamin C concentrations, increasing dietary requirements.
CSS - PMS - CCE - PCS - General Science
Vitamins
Which symptom combination most strongly suggests scurvy?
A. Bleeding gums, bruising and poor wound healing
B. Night blindness and dry eyes
C. Bone bowing in a child
D. Dermatitis, diarrhea and dementia
Correct Answer: A
A is correct because scurvy causes capillary fragility, gingival disease and impaired wound healing due to defective collagen.
CSS - PMS - CCE - PCS - General Science
Vitamins
Which vitamin deficiency is especially associated with perifollicular hemorrhages and corkscrew hairs?
A. Vitamin C
B. Vitamin A
C. Vitamin B1
D. Vitamin D
Correct Answer: A
A is correct because fragile connective tissue in scurvy can produce perifollicular bleeding and corkscrew hairs.
CSS - PMS - CCE - PCS - General Science
Vitamins
Vitamin C can help regenerate oxidized:
A. Vitamin E
B. Vitamin K only
C. Vitamin D
D. Vitamin B12
Correct Answer: A
A is correct because ascorbate participates in antioxidant networks and can help regenerate tocopherol from its oxidized radical form.
CSS - PMS - CCE - PCS - General Science
Vitamins
Which vitamin is a major chain-breaking antioxidant in lipid membranes?
A. Vitamin E
B. Vitamin C only
C. Vitamin B12
D. Vitamin K
Correct Answer: A
A is correct because alpha-tocopherol interrupts lipid peroxidation chain reactions in biological membranes.
CSS - PMS - CCE - PCS - General Science
Vitamins
Which vitamin deficiency may cause hemolytic anemia in premature infants because of oxidative membrane damage?
A. Vitamin E
B. Vitamin A
C. Vitamin B1
D. Vitamin D
Correct Answer: A
A is correct because vitamin E protects erythrocyte membranes from oxidative injury; deficiency can contribute to hemolysis.