The innermost layer of every blood vessel is lined by a simple squamous epithelium called the endothelium.
Missing Word
endothelium
The endothelium is the single layer of flat cells lining the lumen of all blood vessels and the heart. It provides a smooth surface for flow and releases chemicals that regulate vessel diameter.
Category: Vessel Structure
Question 2
A short vessel that branches from a terminal arteriole and feeds a capillary bed, with precapillary sphincters guarding its capillary entrances, is called a metarteriole.
Missing Word
metarteriole
A metarteriole is a small vessel with scattered smooth muscle that links a terminal arteriole to a capillary bed. Precapillary sphincters at the capillary entrances open or close to control how much blood flows through the bed.
Category: Vessel Structure
Question 3
Fenestrated capillaries, whose lining cells have small pores, are found in the kidneys, the small intestine and many endocrine glands.
Missing Word
Fenestrated
Fenestrated capillaries have pores in their endothelial cells that allow rapid exchange of fluid and small molecules. That suits organs that filter, absorb or secrete.
Category: Vessel Structure
Question 4
Hypertension is a chronically elevated blood pressure that raises the risk of stroke, heart attack and kidney disease.
Missing Word
Hypertension
Hypertension is persistently high arterial pressure. It often causes no symptoms while it damages vessels and organs over time.
Category: Blood Pressure and Flow
Question 5
A sphygmomanometer is used together with a stethoscope to measure blood pressure in the upper arm.
Missing Word
sphygmomanometer
A sphygmomanometer is the inflatable cuff and gauge used to measure blood pressure. Listening for Korotkoff sounds with a stethoscope during deflation gives systolic and diastolic values.
Category: Blood Pressure and Flow
Question 6
Edema is swelling caused by excess fluid accumulating in the interstitial spaces of tissues.
Missing Word
Edema
Edema develops when more fluid leaves the capillaries than the capillaries and lymphatic vessels can return. Causes include high capillary pressure, low plasma protein and blocked lymphatic drainage.
Category: Capillary Exchange
Question 7
Renin is an enzyme released by the kidneys when blood pressure falls, starting the cascade that produces angiotensin II.
Missing Word
Renin
Renin converts angiotensinogen to angiotensin I, which is then converted to angiotensin II. This system raises blood pressure through vasoconstriction and fluid retention.
Category: Vascular Regulation
Question 8
Aldosterone, a hormone from the adrenal cortex, increases sodium and water retention by the kidneys.
Missing Word
Aldosterone
Aldosterone acts on the kidney tubules to reabsorb sodium, and water follows the sodium. The added fluid raises blood volume and pressure.
Category: Vascular Regulation
Question 9
The myogenic response is the tendency of arteriole smooth muscle to contract when stretched, which keeps capillary blood flow steady.
Missing Word
myogenic
The myogenic response is a form of local autoregulation. Smooth muscle constricts when stretched by high flow and relaxes when flow drops, stabilizing flow into the capillary beds.
Category: Vascular Regulation
Question 10
The femoral artery becomes the popliteal artery as it passes behind the knee.
Missing Word
popliteal
The popliteal artery is the continuation of the femoral artery in the space behind the knee. It then divides into the anterior and posterior tibial arteries to supply the leg.
Category: Circulatory Pathways
Question 11
Near the elbow, the brachial artery divides into the radial and ulnar arteries.
Missing Word
brachial
The brachial artery is the continuation of the axillary artery in the arm. It is the vessel used for blood pressure measurement before it splits into the radial and ulnar arteries of the forearm.
Category: Circulatory Pathways
Question 12
The azygos vein drains the posterior thoracic wall and empties into the superior vena cava.
Missing Word
azygos
The azygos vein runs along the right side of the vertebral column and collects blood from the intercostal veins. It joins the superior vena cava just before that vessel enters the right atrium.
Category: Circulatory Pathways
Question 13
The largest artery in the body, which receives blood directly from the left ventricle, is the aorta.
Missing Word
aorta
The aorta carries oxygenated blood from the left ventricle to all systemic arteries. It forms the ascending aorta, the aortic arch and the descending aorta.
Category: Circulatory Pathways
Question 14
Fetal blood exchanges gases, nutrients and wastes with maternal blood across the placenta.
Missing Word
placenta
The placenta is the organ where fetal and maternal blood come close without mixing. The fetus receives oxygen and nutrients there and gives up carbon dioxide and wastes.
Category: Vessel Development and Fetal Circulation
Question 15
Angiogenesis is the formation of new blood vessels from existing vessels, a process that continues throughout life.
Missing Word
Angiogenesis
Angiogenesis is the sprouting of new vessels from vessels that already exist. It supports growth, wound healing and tissue repair, while the first embryonic vessels form from mesoderm by a different process.
Category: Vessel Development and Fetal Circulation