(4.2) VASCULAR PHYSIOLOGY I

The system of veins that return blood to the heart. It's a low-pressure system, acting as a reservoir for a significant portion of the blood volume.

Small flaps within veins that prevent blood from flowing backward.

Approximately 65-70% of total blood volume is in the venous system at any given time.

The pressure of the blood within veins, generally lower than arterial pressure.

Mechanism aiding blood movement in veins, specifically utilizing skeletal muscle contractions.

Narrowing of the veins, reducing their diameter and the volume of blood they hold.

Arteries use valves to control blood flow, veins primarily rely on the nervous system (sympathetic nervous system).

Increased venous pressure triggers a sympathetic nervous system response, leading to venoconstriction to manage blood volume.

Part of the autonomic nervous system that regulates involuntary functions like blood pressure and heart rate, including venoconstriction.

Blood vessels carrying blood away from the heart.

Smaller branches of arteries, with thinner walls.

Tiny, single-cell-thick blood vessels for exchange.

Blood vessels carrying blood back to the heart.

Smaller branches of veins.

Force exerted by blood against vessel walls.

Thick layer in arteries providing strength for high blood flow from the heart.

Area of a vessel's inner space; important in exchange process.

Part of the nervous system that controls involuntary actions like blood vessel constriction.

Arteries have low compliance, maintaining shape and pressure. Veins have high compliance, distending easily to act as a reservoir.

Increased venule pressure causes the vessels to expand (distend) to accommodate the extra volume.

Blood pressure decreases as blood travels through vessels, crucial for capillary perfusion.

Venules collect blood from capillaries and return it to the heart, aiding circulation.

In blood loss, the system draws fluid from the interstitial space to maintain blood volume.

Small arteries and arterioles act as valves, controlling blood flow to tissues based on local factors.

Factors like lactic acid levels affect blood flow to certain areas.

A measure of how difficult it is for blood to flow through blood vessels.

Describes the factors that determine blood flow resistance.

The inner diameter of a blood vessel; the most important factor in determining resistance.

The length of a blood vessel; longer vessels have higher resistance, hindering flow.

Thickness of blood; higher viscosity results in greater resistance.

Maintaining consistent blood flow is crucial for proper tissue perfusion and preventing blood clots.

Thrombi forming in the vasculature, potentially leading to serious health issues like Pulmonary Embolism.

Chemicals that affect blood flow to specific tissues.

Thick, muscular walls with elastic layers to withstand high pressure and limit expansion.

Thin muscle layer, wide lumen to accommodate a large volume of blood, acting as a reservoir.

Site of exchange between blood and tissues, characterized by high cross-sectional area and low blood velocity.

Slowest velocity in the vasculature to maximize exchange time between blood and tissues.

Cross-sectional area is highest in capillaries to facilitate the exchange process, while velocity is lowest.

Cells in the Tunica Media regulating blood vessel diameter which influences blood flow.

Single layer of cells lining the blood vessels, playing role in regulating blood flow.

Innermost layer of blood vessel wall, consisting of endothelial cells.

Middle layer of blood vessel wall, containing smooth muscle cells.

Cellular uptake of fluids and dissolved materials via small vesicles.

Movement of large volumes of fluid driven by pressure.

Movement of larger molecules across capillary walls through special openings, following a concentration gradient.

Simple diffusion of small molecules like O2 and CO2 directly across capillary walls.

Pressure pushing fluid out of capillaries.

Pressure pulling fluid back into the capillaries.

Balance between hydrostatic and osmotic pressures in capillaries, determining fluid movement.

Buildup of fluid in tissues due to disrupted hydrostatic/osmotic pressure balance.

Small vessels that collect blood from capillaries.

Blood vessels carrying blood back to the heart, low-pressure system.

Mechanism aided by skeletal muscle contractions that helps move blood back to the heart.

Narrowing of veins, reducing their capacity to accommodate blood volume.