Blood Vessels & Hemodynamics: Structure, Function, and Regulation

What are the five main types of blood vessels?

Arteries, arterioles, capillaries, venules, and veins.

What are the three layers of blood vessels?

Tunica interna (intima), tunica media, and tunica externa.

What is the primary function of arteries?

To carry blood away from the heart.

What properties do arteries possess?

High elasticity and contractility.

What are elastic arteries responsible for?

Conducting blood from the heart.

What is the role of arterioles?

To regulate blood flow into capillaries.

What are capillaries primarily known for?

Sites of exchange between blood and tissues.

What is the structure of capillaries?

Made of a single layer of endothelial cells.

What are the three types of capillaries?

Continuous capillaries, fenestrated capillaries, and sinusoids.

What are venules?

Small veins that receive blood from capillaries.

What is the primary function of veins?

To carry blood toward the heart.

What percentage of blood is typically found in veins and venules at rest?

~64%.

What is capillary exchange?

Movement of substances between blood and interstitial fluid.

What are the three mechanisms of capillary exchange?

Diffusion, transcytosis, and bulk flow.

What is the primary method of exchange in capillaries?

Diffusion.

What is bulk flow in the context of blood vessels?

Movement of fluids and solutes together.

What is blood pressure?

The force exerted by blood on vessel walls.

What factors influence blood pressure?

Cardiac output, blood volume, vascular resistance, blood viscosity, and artery elasticity.

What is venous return?

Blood returning to the heart via veins.

What mechanisms assist venous return?

Skeletal muscle contractions, venous valves, breathing, gravity, and vasoconstriction.

What is the cardiovascular center responsible for?

Regulating heart rate, strength of contraction, and blood vessel diameter.

What are baroreceptor reflexes?

Reflexes that detect changes in blood pressure.

What is shock in the context of the cardiovascular system?

Failure of the cardiovascular system to deliver adequate oxygen and nutrients.

What are the signs and symptoms of shock?

Cold, pale, clammy skin; rapid heart rate; low blood pressure; confusion; reduced urine output.

What are the types of shock?

Hypovolemic, cardiogenic, vascular (anaphylactic, neurogenic, septic), and obstructive.

What is hypertension?

Persistent high blood pressure.

What are the two types of hypertension?

Primary (no known cause) and Secondary (known cause).

What are varicose veins?

Enlarged, twisted veins due to valve failure.

What is edema?

Excess fluid in tissues.

What does syncope refer to?

Temporary loss of consciousness (fainting).

What is the function of arteries?

Carry blood away from the heart.

What are arterioles?

Small arteries that control blood flow into capillaries.

What is the role of capillaries?

Exchange nutrients, gases, and wastes.

What do venules do?

Collect blood from capillaries.

What is the function of veins?

Carry blood toward the heart.

What are elastic arteries?

Closest to the heart, they stretch and recoil (e.g., Aorta).

What are muscular arteries?

Deliver blood to organs and tissues.

What are continuous capillaries?

Most common type, found in most tissues.

What are fenestrated capillaries?

Have pores, found in kidneys and small intestine for rapid exchange.

What are sinusoids?

Capillaries with the largest openings, found in liver, spleen, and bone marrow.

What is the main method of capillary exchange?

Diffusion.

What is net filtration pressure (NFP)?

Determines whether fluid leaves or enters capillaries.

What does a positive NFP indicate?

Filtration.

What does a negative NFP indicate?

Reabsorption.

What factors affect blood pressure?

Cardiac output, blood volume, resistance, blood viscosity, artery elasticity.

What is the role of baroreceptors?

Detect changes in blood pressure.

What hormones increase blood pressure?

Epinephrine, Norepinephrine, Renin-Angiotensin-Aldosterone (RAA) System, Antidiuretic Hormone (ADH).

What hormone decreases blood pressure?

Atrial Natriuretic Peptide (ANP).

What is shock in a medical context?

Failure of the cardiovascular system to deliver enough oxygen and nutrients to tissues.