HISTO (F): CIRCULATORY SYSTEM

staying lizzy mcalpine

B

What is the estimated total length of the blood vessels in an adult human?

a. 50,000 to 75,000 km

b. 100,000 to 150,000 km

c. 200,000 to 250,000 km

d. 10,000 to 20,000 km

A

Which layer of the heart wall consists mainly of contractile cardiac muscle fibers?

a. Myocardium

b. Epicardium

c. Endocardium

d. Pericardium

C

What is the specific name for the simple squamous epithelium that lines the internal surface of all blood and lymphatic vessels?

a. Mesothelium

b. Stratified squamous

c. Endothelium

d. Transitional epithelium

D

Which type of vessel is the site of O2, CO2, nutrient, and waste product exchange between blood and tissues?

a. Arterioles

b. Veins

c. Arteries

d. Capillaries

C

The left ventricle wall is approximately how many times thicker than the right ventricle wall?

a. Two times

b. Five times

c. Three times

d. Four times

D

Which structure acts as the "pacemaker" of the heart?

a. AV node

b. Purkinje fibers

c. Bundle of His

d. SA node

A

What occurs when the parasympathetic division (vagus nerve) stimulates the heart?

a. The heartbeat slows down

b. The heartbeat accelerates

c. Blood pressure increases immediately

d. The pacemaker is deactivated

B

Which condition is characterized by an abnormal heart sound resulting from blood regurgitation through a defective valve?

a. Angina pectoris

b. Heart murmur

c. Myocardial infarct

d. Hypertension

B

What is the primary role of the elastic lamellae in large arteries during diastole?

a. They contract to push blood forward

b. They rebound passively to maintain arterial pressure

c. They prevent backflow into the heart

d. They signal the brain to lower heart rate

C

Which type of capillary is found in the liver, spleen, and bone marrow, allowing for maximal exchange of macromolecules?

a. Continuous capillaries

b. Fenestrated capillaries

c. Discontinuous capillaries (sinusoids)

d. Lymphatic capillaries

A

What are the small vessels called that provide nutrients and oxygen to the walls of very large blood vessels?

a. Vasa vasorum

b. Arterioles

c. Metarterioles

d. Venules

D

Which cells are lipid-filled macrophages that represent an early sign of atherosclerosis?

a. Glomus cells

b. Satellite cells

c. Pericytes

d. Foam cells

B

In the impulse conducting system, which fibers trigger the simultaneous contraction of both ventricles?

a. SA node fibers

b. Purkinje fibers

c. AV node fibers

d. Bundle of His

C

What substance is a serine protease used intravenously to break down fibrin and dissolve blood clots?

a. Heparin

b. Nitric oxide

c. tPA (tissue plasminogen activator)

d. von Willebrand factor

C

Which layer of a blood vessel is primarily composed of type I collagen and elastic fibers?

a. Tunica media

b. Tunica intima

c. Tunica adventitia

d. Internal elastic lamina

C

What structures in the carotid sinuses monitor arterial blood pressure?

a. Chemoreceptors

b. Thermoreceptors

c. Baroreceptors

d. Nociceptors

B

Which vessel type is the major determinant of systemic blood pressure due to its smooth muscle tone?

a. Capillaries

b. Arterioles

c. Large veins

d. Elastic arteries

C

Where is the hepatic portal system located?

a. Between the heart and lungs

b. Between the hypothalamus and pituitary

c. Between the gut and the liver

d. Between the kidneys and the heart

B

What is the function of the "precapillary sphincters" found in metarterioles?

a. To pump blood faster into the veins

b. To control blood flow into the capillaries

c. To prevent backflow into the arteries

d. To filter out large proteins

C

Which cells, found along continuous capillaries, can differentiate to form smooth muscle during vessel repair?

a. Glomus cells

b. Mesothelial cells

c. Pericytes

d. Fibroblasts

B

What characterizes "essential hypertension"?

a. Elevated blood pressure due to renal failure

b. Elevated blood pressure due to increased arteriolar constriction

c. Low blood pressure caused by dehydration

d. Normal blood pressure during exercise

C

Which vascular system collects excess interstitial fluid and returns it to the blood?

a. Cardiovascular system

b. Venous system

c. Lymphatic vascular system

d. Pulmonary circulation

A

Where does the thoracic duct empty lymph back into the blood?

a. Near the junction of the left internal jugular and subclavian veins

b. Directly into the right atrium

c. Into the superior vena cava

d. At the junction of the pulmonary artery

C

What is the thickness of the left ventricular wall compared to the right?

a. 5x thicker

b. 2x thicker

c. 3x thicker

d. 10x thicker

B

Which hormone or factor is a potent vasodilator secreted by endothelial cells?

a. Endothelin-1

b. Nitric oxide (NO)

c. Angiotensin-converting enzyme

d. Norepinephrine

C

Which layer of the heart is equivalent to the visceral layer of the pericardium?

a. Endocardium

b. Myocardium

c. Epicardium

d. Pericardium

B

What are the "Weibel-Palade bodies" in endothelial cells?

a. Mitochondria for energy production

b. Granules that express P-selectin for leukocyte adhesion

c. Clusters of ribosomes for protein synthesis

d. Waste storage vesicles

C

What occurs during "systole"?

a. The ventricles relax

b. The atria fill with blood

c. The ventricles contract forcefully

d. Blood flows back from the lungs

B

Which vessels are also called "distributing arteries"?

a. Elastic arteries

b. Muscular arteries

c. Arterioles

d. Venules

B

What is a "thrombus"?

a. A detached blood clot traveling through the blood

b. A localized bulge in an artery wall

c. An intravascular clot that forms to stop blood loss

d. A type of white blood cell

B

Which nerve transmits signals from the carotid body chemoreceptors to the brain?

a. Vagus nerve (X)

b. Glossopharyngeal nerve (IX)

c. Phrenic nerve

d. Sciatic nerve

B

What is the typical diameter of a capillary?

a. 100 to 200 µm

b. 4 to 10 µm

c. 50 to 80 µm

d. 1 to 2 mm

C

Which type of capillary has pores covered by thin diaphragms and is found in the kidneys?

a. Discontinuous

b. Continuous

c. Fenestrated

d. Lymphatic

B

What is the primary function of valves in veins?

a. To increase blood pressure

b. To prevent the backflow of blood

c. To filter the blood of toxins

d. To speed up blood flow to the lungs

C

What is the name for the fibrous sac that surrounds the heart?

a. Myocardium

b. Endocardium

c. Pericardium

d. Pleura

A

Which layer of the heart contains the impulse-conducting system?

a. Subendocardial layer

b. Epicardium

c. Pericardium

d. Outer tunica media

B

How does the body conserve heat through the circulatory system in cold weather?

a. By increasing blood flow to skin capillaries

b. By opening arteriovenous shunts to bypass skin capillaries

c. By reducing the heart rate

d. By dilating the aorta

B

What is "angina pectoris"?

a. A type of heart valve defect

b. Chest pain caused by local oxygen deprivation in the heart

c. A rapid, irregular heartbeat

d. High blood pressure in the pulmonary artery

D

Which vessel type has the largest lumen diameter relative to the thickness of its wall?

a. Arteries

b. Arterioles

c. Capillaries

d. Venules

B

What is the main component of the "cardiac skeleton"?

a. Elastic cartilage

b. Dense irregular connective tissue

c. Hyaline bone

d. Smooth muscle

B

Which growth factor stimulates the formation of the vascular system in embryos?

a. Angiopoietin

b. VEGF (Vascular endothelial growth factor)

c. Interleukin-1

d. Nitric oxide

C

Which arteries are also known as "conducting arteries"?

a. Muscular arteries

b. Arterioles

c. Elastic arteries

d. Coronary arteries

B

What makes the SA node cells different from typical contractile fibers?

a. They are much larger and have more myofibrils

b. They are smaller, with fewer myofibrils and fewer intercalated disks

c. They contain no nuclei

d. They are strictly controlled by skeletal muscle

B

What is the role of "anchoring filaments" in lymphatic capillaries?

a. To pump lymph toward the heart

b. To prevent the collapse of the thin-walled vessels

c. To filter bacteria out of the lymph

d. To provide a site for red blood cell attachment

B

Which of the following is NOT a predisposing factor for atherosclerosis?

a. Hyperglycemia (diabetes)

b. High HDL levels

c. Hypertension

d. Smoking toxins

B

What do glomus cells in the carotid bodies respond to?

a. Changes in body temperature

b. Low O2 (hypoxia) and high CO2 (hypercapnia)

c. Mechanical stretching of the vessel wall

d. Changes in blood glucose levels

C

Which tunic of a blood vessel is composed mainly of smooth muscle?

a. Tunica intima

b. Tunica adventitia

c. Tunica media

d. Internal elastic lamina

B

hy do large veins have more vasa vasorum than large arteries?

a. Veins are thicker than arteries

b. Veins carry deoxygenated blood

c. Veins have higher blood pressure

d. Veins lack an endothelial lining

B

What is a "heart murmur"?

a. A normal sound of the heart valves closing

b. An abnormal sound produced by blood backflow through a valve

c. The sound of the SA node firing

d. The sound of blood entering the aorta

C

What percentage of total blood volume is typically in the capillaries at any given time?

a. 50%

b. 25%

c. 5%

d. 80%

C

Which structure prevents backflow of blood into the heart after ventricular contraction?

a. SA node

b. AV valve

c. Aortic and pulmonary valves

d. Purkinje fibers

B

What is the function of the "AV bundle" (Bundle of His)?

a. To slow down the heart rate

b. To pass impulses from the AV node through the cardiac skeleton

c. To receive blood from the atria

d. To oxygenate cardiac muscle

B

Where do the largest lymph vessels empty?

a. Into the right and left ventricles

b. Into the large veins near the heart

c. Into the pulmonary artery

d. Directly into the liver

B

What are "atheromas"?

a. Small blood clots in the brain

b. Fibro-fatty plaques in the artery wall

c. Benign tumors of the heart

d. Inflammation of the veins

Which cells are found in the carotid bodies and release neurotransmitters like dopamine?

a. Satellite cells

b. Glomus cells

c. Pericytes

d. Endothelial cells

B

Which vessel lacks a tunica media?

a. Arterioles

b. Capillaries

c. Muscular venules

d. Small arteries

C

What is the term for the movement of white blood cells out of venules into tissue?

a. Transcytosis

b. Vasculogenesis

c. Transendothelial migration

d. Endocytosis

B

Which structure acts as an electrical insulator between the atria and ventricles?

a. Myocardium

b. Cardiac skeleton

c. Pericardium

d. Endocardium

B

What happens to blood velocity as distance from the heart increases?

a. It increases

b. It decreases

c. It remains constant

d. It stops completely

B

What is the primary characteristic of "elastic arteries"?

a. They have very thin walls

b. They have thick media with many elastic lamellae

c. They contain no smooth muscle

d. They are the smallest arteries in the body

B

What defines an "aneurysm"?

a. A blockage in a vein

b. An arterial bulge that can rupture

c. A type of heart infection

d. High blood pressure in the capillaries

C

Which layer of the heart is equivalent to the lining of a blood vessel?

a. Myocardium

b. Epicardium

c. Endocardium

d. Pericardium

B

What is "lymph"?

a. Deoxygenated blood in the veins

b. Fluid collected from tissue spaces by lymphatic capillaries

c. A byproduct of digestion in the liver

d. The fluid inside the heart chambers

C

Which vessels are known as "resistance vessels" that regulate blood pressure?

a. Veins

b. Elastic arteries

c. Arterioles

d. Lymphatic vessels

B

What is the role of "pericytes" in the Central Nervous System (CNS)?

a. To produce red blood cells

b. To maintain the blood-brain barrier

c. To act as the primary pacemaker

d. To pump cerebrospinal fluid

B

Which type of vessel is primarily used for blood sample collection?

a. Arteries

b. Medium or large veins

c. Capillaries

d. Arterioles

B

What is the "microvasculature"?

a. The large vessels like the aorta

b. The system of arterioles, capillaries, and venules

c. The lymphatic system only

d. The internal lining of the heart

B

What occurs when the sympathetic nerve stimulates the pacemaker?

a. The heartbeat slows

b. The heartbeat accelerates

c. Heart activity stops

d. The valves close tightly

B

Which of the following is an example of a "venous portal system"?

a. The pulmonary circulation

b. The hepatic portal system

c. The coronary circulation

d. The carotid sinus system

B

What is the main function of the "pulmonary circulation"?

a. To bring nutrients to the body tissues

b. To oxygenate blood in the lungs

c. To filter the blood through the kidneys

d. To return lymph to the heart

B

Which structure anchors the heart valves?

a. Myocardium

b. Cardiac skeleton

c. Endocardium

d. Epicardium

B

What is "ischemic heart disease"?

a. A disease caused by leaky valves

b. Disease resulting from occluded blood flow to heart muscle

c. A congenital hole in the heart septa

d. High blood pressure in the right atrium

B

What is the "internal elastic lamina"?

a. A layer of muscle in the heart

b. A layer of elastin in the tunica intima of arteries

c. The outer coating of a vein

d. A valve inside the lymphatic system

B

Which cells are "neural crest-derived"?

a. Endothelial cells

b. Glomus cells

c. Smooth muscle cells

d. Cardiac muscle cells

B

What property of endothelium prevents blood clotting?

a. Thrombogenic

b. Antithrombogenic

c. Acidic

d. Permeable

B

What is "lymphedema"?

a. A blood clot in the lymph nodes

b. Swelling caused by disrupted lymphatic drainage

c. A type of cancer in the blood

d. Inflammation of the heart muscle

C

How many layers of smooth muscle are typically in an arteriole's tunica media?

a. 40 layers

b. 10 to 15 layers

c. 1 or 2 layers

d. 0 layers

B

Which vessels have "valves" that are complete intimal folds?

a. Arterioles

b. Lymphatic vessels

c. Capillaries

d. Elastic arteries

B

What is the function of "vasomotor nerves"?

a. To detect pain in the heart

b. To release norepinephrine for vasoconstriction

c. To control the opening of the AV node

d. To signal when the bladder is full

B

What is "angiogenesis"?

a. The destruction of blood vessels

b. Capillary sprouting and growth from existing vessels

c. The hardening of arteries

d. The formation of the heart in an embryo

B

Where are "continuous capillaries" typically found?

a. Liver and spleen

b. Muscle, lungs, and nervous tissue

c. Kidneys and endocrine glands

d. Bone marrow

B

What is the role of the "cardiac muscle fibers" in the atria?

a. To pump blood to the entire body

b. To receive blood and contract to push it into ventricles

c. To filter the blood

d. To produce elastic fibers for the aorta

B

Which structure is located in the right atrial wall near the superior vena cava?

a. AV node

b. SA node

c. Mitral valve

d. Purkinje network

B

What happens when blood platelets contact subendothelial collagen?

a. They dissolve and disappear

b. They aggregate and initiate a clotting cascade

c. They release oxygen into the tissue

d. They transform into endothelial cells

B

What is the "subendocardial layer"?

a. The outermost layer of the heart

b. Connective tissue containing the impulse conducting system

c. The muscle layer of the ventricles

d. The lubricant fluid in the pericardium

B

What is the function of "nitric oxide" in the vascular system?

a. To stimulate muscle contraction

b. To stimulate muscle relaxation (vasodilation)

c. To cause blood to clot

d. To increase heart rate

B

Which vessel connects the two capillary beds in a portal system?

a. Arteriole

b. Portal vein

c. Metarteriole

d. Thoroughfare channel

B

Why is the left ventricle's myocardium thicker than the right?

a. It handles deoxygenated blood

b. It must pump blood through the larger systemic circulation

c. It contains more fat for cushioning

d. It is controlled by the vagus nerve

B

What are "fenestrations"?

a. Small valves in the veins

b. Circular openings in endothelial cells of certain capillaries

c. Nerve endings in the adventitia

d. Connective tissue fibers in the heart

B

Which organ lacks lymphatic capillaries?

a. Skin

b. Bone marrow

c. Lungs

d. Intestines

B

What is the "tunica intima"?

a. The middle layer of a vessel

b. The innermost layer of a vessel

c. The outer covering of a vessel

d. The muscle layer of the heart

B

What are "metarterioles"?

a. Vessels that bypass the lungs

b. Terminal arteriole branches that supply capillary beds

c. Large veins that enter the heart

d. The smallest type of lymphatic vessel

B

What is the "epicardium"?

a. The inner lining of the heart

b. The outer layer of the heart wall

c. The valve between the atria and ventricles

d. The muscle of the heart

B

What is an "embolus"?

a. A stationary blood clot

b. A detached mass (like a clot) carried by the blood

c. A type of protein in the plasma

d. A sensory structure in the aorta

B

What are the "Purkinje fibers" made of?

a. Nervous tissue

b. Modified cardiac muscle cells

c. Pure collagen

d. Smooth muscle cells

B

What is the primary function of the "lymph nodes"?

a. To pump lymph back to the heart

b. To process lymph by cells of the immune system

c. To produce red blood cells

d. To store oxygen for the tissues

B

Which type of artery includes the aorta and pulmonary artery?

a. Muscular arteries

b. Elastic arteries

c. Arterioles

d. Arteriovenous shunts

B

What is "vasodilation"?

a. Narrowing of the blood vessel lumen

b. Widening of the blood vessel lumen

c. The formation of new blood vessels

d. The process of blood clotting

B

Which component of the vascular wall provides resiliency to expand under pressure?

a. Type I collagen

b. Elastic fibers

c. Smooth muscle

d. Ground substance

B

Where is the "atrioventricular (AV) node" located?

a. At the apex of the heart

b. In the floor of the right atrium near the AV valve

c. Inside the left ventricle

d. In the wall of the pulmonary artery