Chapter 20: Blood Vessels - Learning Objectives

Flashcards for Cardiovascular System: Vessels Learning Objectives

What are the three tunics common to most vessels?

Tunica intima, tunica media, and tunica externa

What are the distinguishing features of the tunics found in arteries, capillaries, and veins?

Arteries have thicker walls, especially the tunica media, compared to veins. Capillaries are composed of only the tunica intima to facilitate exchange.

How do elastic arteries, muscular arteries, and arterioles differ in composition?

Elastic arteries have a large amount of elastin in their tunica media, muscular arteries have a thick tunica media with smooth muscle, and arterioles are the smallest arteries with only a few layers of smooth muscle.

What is the general anatomic structure and function of capillaries?

Capillaries are small vessels consisting of only the tunica intima, facilitating the exchange of substances between blood and tissues.

How do continuous capillaries, fenestrated capillaries, and sinusoids differ in structure, function, and location?

Continuous capillaries have complete endothelial lining and basement membrane, fenestrated capillaries have pores for increased permeability, and sinusoids have large gaps and incomplete basement membrane.

Trace the movement of blood through a capillary bed, explaining true capillaries and precapillary sphincters.

Blood flows from arterioles into true capillaries, and precapillary sphincters regulate blood flow into these capillaries. Blood then exits through venules.

Describe the structure and general function of veins.

Veins have thinner walls than arteries, larger lumens, and valves to prevent backflow of blood.

What are the simple and alternative pathways of blood vessels?

Simple pathways involve one artery, capillary bed, and vein serving an organ. Alternative pathways include anastomoses or portal systems.

What is the significance of slow blood flow in the capillaries?

It allows for sufficient time for exchange of gases, nutrients, and waste products between the blood and tissues.

What are the processes of diffusion and vesicular transport between capillaries and tissues?

Diffusion allows small molecules to move across the capillary wall, while vesicular transport allows larger molecules to move via endocytosis and exocytosis.

Explain the processes of bulk flow, filtration, and reabsorption.

Bulk flow is the movement of fluid and solutes together due to pressure gradients. Filtration is the movement of fluid out of the capillaries, while reabsorption is the movement of fluid back into the capillaries.

What is the difference between hydrostatic pressure and colloid osmotic pressure in the capillaries?

Hydrostatic pressure pushes fluid out of capillaries, while colloid osmotic pressure pulls fluid into capillaries.

Define net filtration pressure (NFP) and explain why NFP matters in the capillary beds.

NFP is the net pressure driving fluid movement at the capillary bed, determined by the balance between hydrostatic and osmotic pressures. It determines whether filtration or reabsorption occurs.

What is the lymphatic system’s role at the capillary bed?

The lymphatic system collects excess fluid filtered out of the capillaries and returns it to the bloodstream.

What is the relationship between local blood flow and total blood flow?

Local blood flow is the blood supply to a specific tissue or organ, while total blood flow is the overall blood supply to the entire body. Local flow contributes to total flow and is regulated to meet tissue needs.

Define blood pressure, systolic pressure and diastolic pressure.

Blood pressure is the force exerted by blood against the vessel walls. Systolic pressure is the peak pressure during ventricular contraction, and diastolic pressure is the minimum pressure during ventricular relaxation.

Compare and contrast blood pressure in the arteries, capillaries, and veins.

Blood pressure is highest in arteries, decreases significantly in capillaries, and is lowest in veins.

Explain the mechanisms that help overcome the small pressure gradient in veins to return blood to the heart.

Valves, skeletal muscle pump, respiratory pump, and vasoconstriction.

Explain how blood volume can affect blood pressure.

Increased blood volume increases blood pressure, while decreased blood volume decreases blood pressure.

Explain how cardiac output can affect blood pressure.

Increased cardiac output increases blood pressure, while decreased cardiac output decreases blood pressure.

Define resistance, and explain how resistance is influenced by blood viscosity, vessel length, and vessel radius (lumen).

Resistance is opposition to blood flow. It is influenced by blood viscosity (directly proportional), vessel length (directly proportional), and vessel radius (inversely proportional to the fourth power).

Describe the relationship of both the blood pressure gradient and resistance to total blood flow.

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

Explain the neural factors that alter blood pressure.

Neural factors include the sympathetic nervous system, which increases blood pressure via vasoconstriction and increased heart rate.

Describe the hormones that regulate blood pressure.

Hormones such as epinephrine, norepinephrine, ADH, angiotensin II, and aldosterone increase blood pressure, while ANP decreases it.

Explain the renin-angiotensin system and its influence on blood pressure.

The renin-angiotensin system involves the release of renin, leading to the formation of angiotensin II, which increases blood pressure by causing vasoconstriction and stimulating aldosterone release.

Contrast the effects of angiotensin II, aldosterone, and antidiuretic hormone on blood pressure with those of atrial natriuretic peptide.

Angiotensin II, aldosterone, and ADH increase blood pressure. Atrial natriuretic peptide (ANP) decreases blood pressure.

Compare total blood flow and distribution at rest and during exercise.

At rest, blood flow is directed to essential organs. During exercise, blood flow increases to skeletal muscles and decreases to non-essential organs.

Describe the composition and function of the hepatic portal system.

The hepatic portal system transports blood from the digestive organs to the liver for processing.

Describe the vascular changes that occur after the baby is born and must utilize the pulmonary circulation.

After birth, the foramen ovale closes, the ductus arteriosus constricts and becomes the ligamentum arteriosum, and the umbilical vessels constrict and become ligaments. The pulmonary circulation becomes fully functional.