Biology · General Awareness

Human Circulatory System

818 Questions

The human circulatory system explores the network of blood vessels, heart valves, and structural pathways. Test items often target blood flow sequences and specific vascular functions. Mastering these details is vital for biology preparation.

Heart valves and chambersBlood vessels and venulesArteries of the bodyBlood supply to organsCentral nervous system supply

Human Circulatory System Questions

Multiple choice

Endothelium of blood vessels is made up of

  1. simple cuboidal epithelium

  2. simple squamous epithelium

  3. simple columnar epithelium

  4. simple non-ciliated columnar
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The endothelium lining blood vessels consists of simple squamous epithelium. This thin, single-layered tissue facilitates efficient diffusion of gases, nutrients, and waste products between the blood and surrounding tissues. Simple cuboidal epithelium is found in kidney tubules, simple columnar epithelium lines the digestive tract, and ciliated columnar epithelium is found in the respiratory tract.

Multiple choice

The constituents of plasma are

  1. proteins, salts and hormones

  2. calcium and phosphorus compounds

  3. red blood cells (RBCs), white blood cells (WBCs) and platelets

  4. proteins and sugars

  5. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Plasma constitutes them.

Multiple choice

Which of the following statements about veins are false? P. Veins are blood vessels that carry blood away from the heart. Q. The venous valves are folds of the tunica intima. R. Most veins carry oxygenated blood. S. Thrombophlebitis is an inflammatory condition of the veins related to blood clots.

  1. P and Q

  2. P and R

  3. P and S

  4. Q and R

  5. R and S
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Veins are elastic blood vessels that transport blood from various regions of the body to the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart.

Multiple choice

Which of the following statements is INCORRECT?

  1. Arterioles are small arteries that connect larger arteries with capillaries.

  2. Arteries carry blood from capillaries to the heart.

  3. Capillaries are the points of exchange of fluids, gasses, nutrients, and wastes between the blood and surrounding tissues.

  4. Smaller veins that gather blood from capillary beds into veins are called venules.

  5. Small arterioles branch into collections of capillaries known as capillary beds.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Arteries are blood vessels that carry blood away from heart. Arteries carry blood from capillaries to the heart.

Multiple choice

Left renal vein crosses the aorta

  1. anteriorly, above the superior mesenteric artery

  2. anteriorly, below the superior mesenteric artery

  3. posteriorly, at the level of superior mesenteric artery

  4. anteriorly, below the inferior mesenteric artery
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The left renal vein courses anteriorly across the aorta, passing below the superior mesenteric artery before joining the inferior vena cava. This anatomical relationship is clinically relevant during surgical procedures and imaging.

Multiple choice

Which is the most superior structure at hilum of left lung?

  1. Pulmonary vein

  2. Pulmonary artery

  3. Bronchius

  4. Bronchial artery
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

At the left lung hilum, structures are arranged from superior to inferior: pulmonary artery (most superior), bronchus, and pulmonary vein (inferior). This anatomical relationship is consistent on the left side, though slightly different on the right where the eparterial bronchus is superior to the pulmonary artery.

Multiple choice

All of the following occur, when the blood flows through systemic capillaries, except

  1. increase in hematocrit

  2. Hb curve shifts to the left

  3. increased protein content

  4. decrease in Ph
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

As blood flows through systemic capillaries, CO2 is released from tissues, which causes the oxyhemoglobin dissociation curve to shift RIGHT (Bohr effect) - facilitating oxygen unloading. This is the exception among the listed changes. The other changes DO occur: water leaves capillaries increasing hematocrit, plasma protein concentration increases slightly, and pH decreases due to acidic metabolites.