Human Anatomy and Physiology - Circulatory and Excretory Systems MCQs 2026

Which of the following organs is NOT considered part of the excretory system

1. AKidney✓
2. BPancreas✓
3. CSkin✓
4. DLungs✓

The hormone erythropoietin, which stimulates red blood cell production, is secreted mainly by the

1. AKidneys✓
2. BLiver✓
3. CPancreas✓
4. DSpleen✓

The renal artery that supplies blood directly to the kidney branches from the

1. APulmonary artery✓
2. BAorta✓
3. CVena cava✓
4. DHepatic artery✓

An artificial kidney (dialysis) machine works mainly on the principle of

1. AOsmosis✓
2. BFiltration only✓
3. CDiffusion across a semi-permeable membrane✓
4. DActive transport✓

The liver converts toxic ammonia into less toxic urea through the

1. AKrebs cycle✓
2. BOrnithine (urea) cycle✓
3. CCalvin cycle✓
4. DGlycolysis✓

Sweat glands assist excretion mainly by removing

1. AWater, salts and small amounts of urea✓
2. BBile pigments✓
3. CUric acid only✓
4. DCarbon dioxide✓

The tube that carries urine out of the body during urination is the

1. AUreter✓
2. BUrethra✓
3. CRenal vein✓
4. DBowman's capsule✓

The inner region of the kidney containing the renal pyramids is the

1. ACortex✓
2. BCapsule✓
3. CMedulla✓
4. DHilum✓

The outer region of the kidney is called the

1. AMedulla✓
2. BPelvis✓
3. CCortex✓
4. DCapsule✓

Birds and reptiles excrete nitrogenous waste mainly as

1. AUric acid✓
2. BUrea✓
3. CAmmonia✓
4. DCreatinine✓

Fish primarily excrete nitrogenous waste in the form of

1. AAmmonia✓
2. BUrea✓
3. CUric acid✓
4. DCreatinine✓

Kidney stones are most commonly composed of

1. AUric acid crystals✓
2. BCholesterol✓
3. CSodium chloride✓
4. DCalcium oxalate✓

Hemodialysis is a treatment used for patients suffering from

1. ADiabetes✓
2. BAnemia✓
3. CKidney failure✓
4. DHypertension✓

The hormone that regulates water reabsorption in the kidney tubules is

1. AInsulin✓
2. BAldosterone✓
3. CRenin✓
4. DAntidiuretic hormone (ADH)✓

Reabsorption of most filtered water and glucose mainly occurs in the

1. AProximal convoluted tubule✓
2. BDistal convoluted tubule✓
3. CLoop of Henle✓
4. DBowman's capsule✓

The main nitrogenous waste product excreted by humans is

1. AUrea✓
2. BAmmonia✓
3. CUric acid✓
4. DCreatine✓

The tube that carries urine from each kidney to the bladder is the

1. AUreter✓
2. BUrethra✓
3. CRenal vein✓
4. DRenal artery✓

Urine is temporarily stored in the

1. AUreter✓
2. BUrinary bladder✓
3. CUrethra✓
4. DKidney✓

The cup-shaped structure that surrounds the glomerulus is called the

1. ALoop of Henle✓
2. BRenal pelvis✓
3. CCollecting duct✓
4. DBowman's capsule✓

The part of the nephron where blood filtration first occurs is the

1. ALoop of Henle✓
2. BCollecting duct✓
3. CDistal convoluted tubule✓
4. DGlomerulus✓

The scientist credited with discovering the circulation of blood is

1. ALouis Pasteur✓
2. BRobert Koch✓
3. CWilliam Harvey✓
4. DEdward Jenner✓

The opening in the fetal heart that allows blood to bypass the non-functional lungs is the

1. AForamen ovale✓
2. BDuctus deferens✓
3. CSemilunar valve✓
4. DInterventricular septum✓

Which of the following is NOT a normal component of blood

1. APlasma✓
2. BPlatelets✓
3. CLeukocytes✓
4. DSynovial fluid✓

The lymphatic system helps return excess tissue fluid to

1. AThe kidneys✓
2. BThe liver✓
3. CThe bloodstream✓
4. DThe lungs✓

Blood is classified as which type of tissue

1. AEpithelial tissue✓
2. BConnective tissue✓
3. CMuscular tissue✓
4. DNervous tissue✓

The average lifespan of a human red blood cell is about

1. A10 days✓
2. B120 days✓
3. C1 year✓
4. D7 days✓

Hardening and narrowing of arteries due to fatty deposits is called

1. AThrombosis✓
2. BVaricose veins✓
3. CAneurysm✓
4. DAtherosclerosis✓

The medical condition of persistently high blood pressure is called

1. AHypotension✓
2. BAnemia✓
3. CArrhythmia✓
4. DHypertension✓

Blood pressure is measured using an instrument called a

1. AStethoscope✓
2. BThermometer✓
3. CSphygmomanometer✓
4. DBarometer✓

Which blood vessel carries oxygenated blood from the lungs to the heart

1. APulmonary artery✓
2. BVena cava✓
3. CAorta✓
4. DPulmonary vein✓

The heart is enclosed by a protective double-layered membrane called the

1. APeritoneum✓
2. BPleura✓
3. CMeninges✓
4. DPericardium✓

White blood cells primarily function in

1. AOxygen transport✓
2. BBody defense and immunity✓
3. CBlood clotting✓
4. DNutrient transport✓

The Rh blood factor was first discovered in which animal

1. AChimpanzee✓
2. BRhesus monkey✓
3. CGuinea pig✓
4. DRabbit✓

Which blood vessels have walls only one cell thick, allowing exchange of substances with tissues

1. AArteries✓
2. BVeins✓
3. CCapillaries✓
4. DVenules✓

The straw-colored fluid part of blood, obtained after removing the blood cells, is called

1. APlasma✓
2. BSerum✓
3. CLymph✓
4. DChyme✓

Blood circulation between the heart and the lungs is known as

1. ASystemic circulation✓
2. BPortal circulation✓
3. CPulmonary circulation✓
4. DCoronary circulation✓

The instrument used to record the electrical activity of the heart is the

1. ASphygmomanometer✓
2. BStethoscope✓
3. CElectrocardiograph (ECG)✓
4. DSpirometer✓

Normal human blood pressure is approximately

1. A140/90 mmHg✓
2. B120/80 mmHg✓
3. C100/60 mmHg✓
4. D160/100 mmHg✓

The natural pacemaker of the heart is the

1. ASinoatrial (SA) node✓
2. BAtrioventricular (AV) node✓
3. CBundle of His✓
4. DPurkinje fibers✓

Deoxygenated blood is carried from the heart to the lungs by the

1. AAorta✓
2. BPulmonary vein✓
3. CVena cava✓
4. DPulmonary artery✓

The largest artery in the human body is the

1. AAorta✓
2. BPulmonary artery✓
3. CCarotid artery✓
4. DRenal artery✓

The valve located between the left atrium and left ventricle is the

1. ATricuspid valve✓
2. BPulmonary valve✓
3. CAortic valve✓
4. DBicuspid (mitral) valve✓

The iron-containing protein in red blood cells that carries oxygen is

1. AMyosin✓
2. BHemoglobin✓
3. CCollagen✓
4. DAlbumin✓

The universal blood recipient group is

1. AAB positive✓
2. BO negative✓
3. CA negative✓
4. DB positive✓

The universal blood donor group is

1. AO negative✓
2. BAB positive✓
3. CA positive✓
4. DB negative✓

The functional and structural unit of the kidney is called

1. AAlveolus✓
2. BNeuron✓
3. CNephron✓
4. DVillus✓

The heart chamber that pumps oxygenated blood to the rest of the body is the

1. ARight atrium✓
2. BLeft ventricle✓
3. CRight ventricle✓
4. DLeft atrium✓

Blood vessels that carry blood away from the heart are called

1. AVeins✓
2. BCapillaries✓
3. CArteries✓
4. DVenules✓

Which blood cells are mainly responsible for clotting

1. AErythrocytes✓
2. BPlatelets (thrombocytes)✓
3. CLeukocytes✓
4. DLymphocytes✓

The number of chambers in the human heart is

1. A2✓
2. B3✓
3. C5✓
4. D4✓