Chapter 21 flashcard

21.1A Pulmonary vs. Systemic Vessels

• Pulmonary vessels: Carry blood between the heart and lungs. Pulmonary arteries transport deoxygenated blood to the lungs, and pulmonary veins return oxygenated blood to the heart.

• Systemic vessels: Deliver oxygenated blood from the heart to the body and return deoxygenated blood back to the heart.

21.1B Functions of the Circulatory System

• Transport gases (oxygen, carbon dioxide), nutrients, and waste.

• Regulate body temperature and pH.

• Protect via immune cells and clotting.

21.2A Types of Arteries, Capillaries, and Veins

• Arteries: Elastic, muscular, arterioles.

• Capillaries: Continuous, fenestrated, sinusoidal.

• Veins: Venules, small veins, large veins.

21.2B Structure & Function of Blood Vessels

• Arteries: Thick walls with smooth muscle for high-pressure transport.

• Capillaries: Thin walls for gas and nutrient exchange.

• Veins: Thinner walls, valves prevent backflow, store blood.

21.2C Innervation of Blood Vessel Walls

• Sympathetic nervous system controls vessel constriction and dilation.

• Vasoconstriction increases blood pressure, vasodilation lowers it.

21.3A Pulmonary Circulation Pathway

Right ventricle → Pulmonary trunk → Pulmonary arteries → Lungs (gas exchange) → Pulmonary veins → Left atrium.

21.4A Major Arteries by Body Area

• Head: Carotid arteries.

• Arms: Subclavian and brachial arteries.

• Abdomen: Celiac, superior/inferior mesenteric arteries.

• Legs: Iliac and femoral arteries.

21.5A Major Veins Returning Blood

• Head: Jugular veins.

• Arms: Subclavian and brachial veins.

• Abdomen: Hepatic portal vein.

• Legs: Iliac and femoral veins.

21.6A Laminar vs. Turbulent Blood Flow

• Laminar: Smooth, layers don’t mix, less resistance.

• Turbulent: Chaotic, increases resistance and noise (bruits).

21.6B Blood Pressure Definition

The force of blood against vessel walls, measured in mmHg.

21.6C How Blood Pressure is Measured

• Sphygmomanometer (BP cuff) and stethoscope.

• Systolic pressure: Peak during heart contraction.

• Diastolic pressure: Pressure during relaxation.

21.6D Poiseuille’s Law Summary

Blood flow is directly related to vessel radius and pressure but inversely related to viscosity and length.

21.6E Viscosity & Blood Flow

Higher viscosity (thicker blood) slows flow and increases resistance.

21.6F Laplace’s Law & Critical Closing Pressure

• Laplace’s Law: Wall tension = pressure × radius.

• Critical closing pressure: When pressure drops too low, vessels collapse.

21.6G Vessel Diameter & Compliance Effects on BP

• Smaller diameter → higher resistance → higher BP.

• High compliance (elasticity) → lower BP.

21.6H Blood Distribution in Systemic Vessels

• Veins: ~60% (blood reservoir).

• Arteries: ~15%.

• Capillaries: ~5%.

21.7A Cross-Sectional Area & Blood Flow Rate

Larger total cross-sectional area (capillaries) → slower flow.

21.7B Blood Pressure & Resistance Changes

Pressure drops as blood moves through arteries → capillaries → veins due to resistance.

21.7C Pulse Pressure Definition

Difference between systolic and diastolic pressure.

21.7D Pulse Locations

Radial (wrist), carotid (neck), brachial (arm), femoral (groin), dorsalis pedis (foot).

21.7E Capillary Exchange

• Diffusion: Gases, nutrients.

• Filtration: Plasma out due to hydrostatic pressure.

• Reabsorption: Water back due to osmotic pressure.

21.7F Factors Affecting Cardiac Output

• Preload: More blood return = stronger contraction.

• Venous tone: Vessel constriction affects return.

• Gravity: Standing reduces venous return.

21.8A Local Control of Blood Flow

• Tissues regulate own blood supply (oxygen demand, waste removal).

21.8B Nervous Control of Blood Flow

• Sympathetic nerves control vasoconstriction/dilation.

21.8C Hormonal Control of Blood Flow

• Epinephrine, angiotensin II, and Antidiuretic Hormone (ADH) increase BP.

• Atrial Natriuretic Peptide(ANP) lowers BP.

21.9A Definitions

• Mean arterial pressure (MAP): Average BP in arteries.

• Cardiac output (CO): Blood pumped per minute.

• Peripheral resistance: Resistance to blood flow.

21.9B Determinants of MAP

MAP = CO × Peripheral Resistance.

21.9C Short-Term BP Regulation

• Baroreceptors detect pressure changes.

• Adjust heart rate and vessel diameter.

21.9D Long-Term BP Regulation

Kidneys regulate blood volume via renin-angiotensin system.