Skip to main content
Back

Cardiovascular System: Blood Vessels - Capillary Dynamics

Control buttons has been changed to "navigation" mode.
1/26

Terms in this set (26)

  • What are the three tunics common to most blood vessels?

    Tunica intima, tunica media, and tunica externa.

  • What distinguishes arteries from veins anatomically?

    Arteries have thicker tunica media, smaller lumen, and more elastic tissue compared to veins.

  • What are the three types of arteries?

    Elastic arteries, muscular arteries, and arterioles.

  • What is the general structure and function of capillaries?

    Capillaries have thin walls (endothelium) to allow exchange of gases, nutrients, and wastes between blood and tissues.

  • Compare continuous, fenestrated, and sinusoid capillaries.

    Continuous capillaries have tight junctions; fenestrated have pores for increased permeability; sinusoids are most permeable with large gaps.

  • Which capillary type is most permeable and where is it found?

    Sinusoid capillaries are most permeable, found in liver, bone marrow, and spleen.

  • What is the role of precapillary sphincters?

    They regulate blood flow into capillary beds by opening or closing.

  • How do veins serve as a blood reservoir?

    Veins have large lumens and can hold a large volume of blood, releasing it when needed.

  • What is the relationship between total cross-sectional area and velocity of blood flow?

    Velocity decreases as total cross-sectional area increases, slowest in capillaries.

  • Why is slow blood flow important in capillaries?

    It allows time for efficient exchange of gases, nutrients, and wastes.

  • Define hydrostatic pressure in capillaries.

    Pressure exerted by blood against capillary walls, pushing fluid out into interstitial space.

  • Define colloid osmotic pressure in capillaries.

    Pressure exerted by plasma proteins that draws fluid into capillaries from interstitial space.

  • What is net filtration pressure (NFP)?

    The balance of hydrostatic and osmotic pressures determining fluid movement across capillary walls.

  • How to calculate net filtration pressure (NFP)?

    \(\text{NFP} = (HP_b - HP_{if}) - (OP_b - OP_{if})\)

  • What happens at the arterial end of a capillary regarding fluid movement?

    Net pressure favors filtration; fluid moves out of capillary into interstitial fluid.

  • What happens at the venous end of a capillary regarding fluid movement?

    Net pressure favors reabsorption; fluid moves from interstitial fluid back into capillary.

  • What is the role of the lymphatic system at the capillary bed?

    It returns excess interstitial fluid to the bloodstream, preventing edema.

  • What is edema?

    Excess accumulation of interstitial fluid causing swelling.

  • How do skeletal muscle and respiratory pumps aid venous return?

    Muscle contractions and breathing movements squeeze veins, propelling blood toward the heart.

  • What is vasoconstriction and vasodilation?

    Vasoconstriction narrows blood vessels; vasodilation widens them, regulating blood flow and pressure.

  • What is the myogenic response in blood flow regulation?

    Vascular smooth muscle contracts or relaxes in response to stretch to maintain constant blood flow.

  • What is the function of baroreceptors in blood pressure regulation?

    They detect changes in blood pressure and trigger autonomic reflexes to adjust it.

  • How does the renin-angiotensin system influence blood pressure?

    It increases blood pressure by vasoconstriction and stimulating aldosterone release to retain sodium and water.

  • Contrast effects of angiotensin II and atrial natriuretic peptide (ANP) on blood pressure.

    Angiotensin II raises blood pressure; ANP lowers it by promoting vasodilation and sodium excretion.

  • What is pulse pressure and how is it calculated?

    Difference between systolic and diastolic pressure: \(\text{Pulse Pressure} = P_{systolic} - P_{diastolic}\)

  • What is mean arterial pressure (MAP) and its formula?

    Average arterial pressure during one cardiac cycle: \(\text{MAP} = P_{diastolic} + \frac{1}{3}(P_{systolic} - P_{diastolic})\)