Chapter 21: Blood Vessels and Circulation

These flashcards cover key concepts related to blood vessels and circulation as outlined in Chapter 21 of the lecture notes.

What is the primary function of blood vessels?

To facilitate blood flow throughout the body.

What are the main types of blood vessels?

Arteries, veins, and capillaries.

What is the significance of the pulmonary trunk?

It carries blood from the right ventricle to pulmonary circulation.

What is the function of the aorta?

It carries blood from the left ventricle to systemic circulation.

What regulates blood flow and pressure in tissues?

The cardiac, vasomotor, and respiratory centers.

What does the cardiovascular system do during exercise?

It adjusts to meet increased oxygen demands and maintains homeostasis.

What are the major circuits of the cardiovascular system?

The pulmonary and systemic circuits.

What is the difference between elastic and muscular arteries?

Elastic arteries are large and can stretch, while muscular arteries have more muscle cells and are responsible for distributing blood.

What is the role of arterioles?

They are resistance vessels that control blood flow to capillaries.

What is an aneurysm?

A bulge in an arterial wall caused by weakness in the vessel.

What characterizes capillaries?

They are the smallest blood vessels and have thin walls for efficient material exchange.

What is the structure of continuous capillaries?

They have a complete endothelial lining allowing diffusion of small substances.

Where are fenestrated capillaries found?

In the kidneys, endocrine organs, and intestinal tract.

What allows sinusoids to permit exchange of larger plasma proteins?

Gaps between adjacent endothelial cells.

What regulates the flow within capillary beds?

Precapillary sphincters.

What is angiogenesis?

The formation of new blood vessels.

How do veins differ from arteries?

Veins have larger diameters, thinner walls, and lower blood pressure.

What is the function of venous valves?

To prevent backflow of blood in veins.

What is capacitance in relation to blood vessels?

The ability of a vessel to stretch and accommodate varying blood volume.

How is total peripheral resistance defined?

The total resistance in the cardiovascular system that must be overcome by blood pressure.

What factors affect vascular resistance?

Vessel length, vessel diameter, and blood viscosity.

What is considered normal blood pressure?

120/80 mm Hg.

What is hypertension?

Abnormally high blood pressure, greater than 140/90 mm Hg.

What assists venous return to the heart?

Skeletal muscular compression and the respiratory pump.

What occurs during capillary exchange?

Materials move between blood and interstitial fluid via filtration and reabsorption.

What is net filtration pressure (NFP)?

The difference between net hydrostatic pressure and net osmotic pressure.

What happens at the arterial end of a capillary?

Fluid is filtered from the capillary into the interstitial fluid.

What is the role of the Bainbridge reflex?

It responds to stretching of the right atrium to regulate heart rate.

What are baroreceptors?

Stretch receptors that monitor blood pressure changes.

What does the cardiovascular center respond to?

Changes in blood pressure and blood composition.

How does the sympathetic nervous system affect blood flow during exercise?

It increases cardiac output and redirects blood flow to essential organs.

What hormonal mechanism increases blood pressure during stress?

The release of epinephrine and norepinephrine.

What effect does aldosterone have on blood volume?

It promotes fluid retention and reabsorption in the kidneys.

How does erythropoietin (EPO) affect blood flow?

It stimulates red blood cell production and vasoconstriction.

What cardiovascular changes occur with aging?

Reduced maximum cardiac output, decreased elasticity of blood vessels.

What is a cerebrovascular accident?

A stroke caused by a blockage or rupture in a cerebral artery.

What effect does regular exercise have on the cardiovascular system?

Improves lipid profile and reduces the risk of heart diseases.

What is the impact of dehydration on capillary dynamics?

Accelerates reabsorption due to increased blood colloid osmotic pressure.

What condition can arise from interfered lymphatic fluid return?

Edema.

What happens to vascular resistance as vessel diameter decreases?

Resistance increases exponentially.

What is the function of the thoracic cavity during inhalation?

It reduces venous pressure and assists in venous return.

How does chronic low oxygen affect blood flow to the heart?

It can lead to coronary vessel dilation to increase blood flow.

What is the role of natriuretic peptides in cardiovascular health?

They reduce blood volume and pressure in response to excessive stretching.

How are blood flow and tissue perfusion related?

Tissue perfusion is the flow of blood through tissues, carrying oxygen and nutrients.

What role do local vasodilators play in blood flow regulation?

They increase blood flow by relaxing precapillary sphincters.

How does the body respond to hemorrhaging in terms of blood pressure?

By increasing cardiac output and vasoconstriction to maintain pressure.

What happens when blood pressure rises?

Cardiovascular centers decrease cardiac output and cause peripheral vasodilation.

What path does blood take in the systemic circuit?

From the heart to the body and back to the heart.

How does the body prioritize blood flow during exercise?

It redirects blood away from non-essential organs to muscles, heart, and lungs.

What happens to blood pressure during heavy exercise?

Cardiac output increases to its maximum, about four times the resting level.

What is the relationship between exercise and plaque formation in arteries?

Regular exercise slows the formation of plaques in arteries.

How do capillary diameters relate to blood cell size?

Capillary diameters are similar to that of red blood cells.

What occurs if there's chronic constriction of blood vessels?

New blood vessel formation (angiogenesis) may occur.

What is the relationship between systolic and diastolic pressure?

Systolic pressure is the peak pressure during heart contraction, while diastolic is the minimum pressure at rest.

How does blood viscosity compare to water?

Whole blood viscosity is approximately four times that of water.

What structure prevents backflow of blood in veins?

Venous valves.

What is the primary role of capillary beds?

They connect arterioles and venules, regulating blood flow.

What changes are seen in aging blood vessels?

Becoming less elastic and developing atherosclerotic plaques.