Chapter 20 - Blood Vessels

What are the three main types of blood vessels in the circulatory system?

Arteries, Capillaries, and Veins.

What is the primary function of arteries?

To carry blood away from the heart.

What is unique about the blood in pulmonary arteries?

It is deoxygenated, unlike most arteries which carry oxygenated blood.

What is the role of capillaries in the circulatory system?

To facilitate the exchange of substances between blood and tissues.

What are the three layers of blood vessel walls?

Tunica intima, Tunica media, and Tunica externa.

What is the tunica intima composed of?

Endothelium (simple squamous epithelium) lined with a subendothelial layer of connective tissue.

What is the function of the tunica media?

To control vasoconstriction and vasodilation through smooth muscle and elastin.

What are muscular arteries primarily responsible for?

Delivering blood to specific body organs and regulating blood flow.

What are capillary beds?

Interwoven networks of capillaries between arterioles and venules.

What causes the pressure to leave the capillaries at the arterial end?

Capillary hydrostatic pressure.

Define mean arterial pressure (MAP).

The pressure that propels blood to tissues, calculated as diastolic pressure plus one-third of pulse pressure.

What is the relationship between blood flow, blood pressure, and resistance?

Blood flow is directly proportional to blood pressure gradient and inversely proportional to resistance.

What factors can increase total blood flow?

Increased cardiac output and vasodilation.

How does the body adapt blood flow during exercise?

By redistributing blood through vasodilation in exercising muscles and vasoconstriction in non-essential areas.

What is the role of baroreceptors in blood pressure regulation?

To sense stretch in blood vessels and help regulate blood pressure by influencing heart rate and vessel diameter.

What effect does higher blood viscosity have on resistance?

It increases resistance to blood flow.

What is the purpose of the respiratory pump in venous return?

To help move blood towards the heart through pressure changes during breathing.

What is autoregulation in blood flow?

The intrinsic ability of organs to regulate their blood supply based on local conditions.

Describe the difference between continuous, fenestrated, and sinusoid capillaries.

Continuous capillaries have tight junctions and are least permeable; fenestrated capillaries have pores for increased permeability; sinusoid capillaries have large openings for passage of larger molecules.

What is the significance of the renin-angiotensin-aldosterone system?

It regulates blood pressure and fluid balance through hormone signaling.

What are venous sinuses?

Flattened veins with extremely thin walls that hold a large volume of blood.

How does the cardiovascular center influence blood pressure?

By regulating cardiac output and blood vessel diameter.

What are the main components that influence blood pressure?

Cardiac output, peripheral resistance, and blood volume.