BIOS 252 COMPREHENSIVE TEST PAPER
2026 QUESTIONS WITH FULL SOLUTION
GRADED A+
1. Which blood vessel carries freshly oxygenated blood from the lungs
to the heart?
Answer: Pulmonary veins
Big Rationale:
Most arteries carry oxygenated blood and most veins carry deoxygenated
blood—but the pulmonary vessels are the major exception. After gas
exchange occurs in the alveoli, oxygen-rich blood returns directly to the
left atrium through the pulmonary veins, making them the only veins in
the body that carry oxygenated blood. This is a common high-yield exam
trick.
2. Which layer of the heart is responsible for generating the force of
contraction?
Answer: Myocardium
Big Rationale:
The myocardium is composed of specialized cardiac muscle tissue. It
forms the thick, middle layer of the heart wall. The thickness of this layer
varies by chamber—especially the left ventricle, which pumps blood to
the entire body and therefore has the thickest myocardium of all.
,3. Where does the filtration of blood occur within the nephron?
Answer: Glomerulus
Big Rationale:
The glomerulus is a tuft of fenestrated capillaries that allow water and
small solutes to pass into Bowman’s capsule. This is the first step of urine
formation. Large proteins and cells are normally kept out—so finding
them in urine often signals kidney damage.
4. Which hormone directly increases water reabsorption in the
collecting ducts of the kidneys?
Answer: Antidiuretic hormone (ADH)
Big Rationale:
ADH inserts aquaporin channels into the collecting ducts, allowing water
to be reabsorbed back into circulation. High ADH = concentrated urine.
Low ADH = dilute urine. Disorders like diabetes insipidus disrupt this
pathway.
5. What structure increases the surface area of the small intestine for
nutrient absorption?
Answer: Villi
Big Rationale:
The small intestine relies on villi and microvilli to massively expand its
surface area. Without them, nutrient absorption would drop dramatically,
leading to malabsorption issues. The more folds → the more absorption →
the more efficiency.
, 6. Which formed element initiates the clotting process after a blood
vessel injury?
Answer: Platelets
Big Rationale:
Platelets are not full cells but cell fragments. They detect damaged
tissue, stick together, and release clotting factors. Without platelets, even
small injuries could result in dangerous bleeding.
7. What part of the brain regulates basic life functions such as
breathing and heart rate?
Answer: Medulla oblongata
Big Rationale:
Located in the brainstem, the medulla controls autonomic involuntary
processes—respiration, blood pressure, swallowing, vomiting. Injury to
this region is often fatal due to its central role in survival.
8. Which lobe of the cerebrum processes visual information?
Answer: Occipital lobe
Big Rationale:
The occipital lobe contains the primary visual cortex, which receives and
interprets visual data from the retina. Damage can lead to blindness even
if the eyes are functional.
9. Which type of muscle tissue is found in the walls of hollow organs
like the intestines?
2026 QUESTIONS WITH FULL SOLUTION
GRADED A+
1. Which blood vessel carries freshly oxygenated blood from the lungs
to the heart?
Answer: Pulmonary veins
Big Rationale:
Most arteries carry oxygenated blood and most veins carry deoxygenated
blood—but the pulmonary vessels are the major exception. After gas
exchange occurs in the alveoli, oxygen-rich blood returns directly to the
left atrium through the pulmonary veins, making them the only veins in
the body that carry oxygenated blood. This is a common high-yield exam
trick.
2. Which layer of the heart is responsible for generating the force of
contraction?
Answer: Myocardium
Big Rationale:
The myocardium is composed of specialized cardiac muscle tissue. It
forms the thick, middle layer of the heart wall. The thickness of this layer
varies by chamber—especially the left ventricle, which pumps blood to
the entire body and therefore has the thickest myocardium of all.
,3. Where does the filtration of blood occur within the nephron?
Answer: Glomerulus
Big Rationale:
The glomerulus is a tuft of fenestrated capillaries that allow water and
small solutes to pass into Bowman’s capsule. This is the first step of urine
formation. Large proteins and cells are normally kept out—so finding
them in urine often signals kidney damage.
4. Which hormone directly increases water reabsorption in the
collecting ducts of the kidneys?
Answer: Antidiuretic hormone (ADH)
Big Rationale:
ADH inserts aquaporin channels into the collecting ducts, allowing water
to be reabsorbed back into circulation. High ADH = concentrated urine.
Low ADH = dilute urine. Disorders like diabetes insipidus disrupt this
pathway.
5. What structure increases the surface area of the small intestine for
nutrient absorption?
Answer: Villi
Big Rationale:
The small intestine relies on villi and microvilli to massively expand its
surface area. Without them, nutrient absorption would drop dramatically,
leading to malabsorption issues. The more folds → the more absorption →
the more efficiency.
, 6. Which formed element initiates the clotting process after a blood
vessel injury?
Answer: Platelets
Big Rationale:
Platelets are not full cells but cell fragments. They detect damaged
tissue, stick together, and release clotting factors. Without platelets, even
small injuries could result in dangerous bleeding.
7. What part of the brain regulates basic life functions such as
breathing and heart rate?
Answer: Medulla oblongata
Big Rationale:
Located in the brainstem, the medulla controls autonomic involuntary
processes—respiration, blood pressure, swallowing, vomiting. Injury to
this region is often fatal due to its central role in survival.
8. Which lobe of the cerebrum processes visual information?
Answer: Occipital lobe
Big Rationale:
The occipital lobe contains the primary visual cortex, which receives and
interprets visual data from the retina. Damage can lead to blindness even
if the eyes are functional.
9. Which type of muscle tissue is found in the walls of hollow organs
like the intestines?
