Ch.20 flashcards

Circulatory System

The system that circulates blood and lymph through the body, consisting of the heart, blood vessels, and blood.

Arteries

Blood vessels that carry blood away from the heart.

Veins

Blood vessels that carry blood back to the heart.

Capillaries

Small blood vessels that connect arteries and veins, facilitating the exchange of gases, nutrients, and waste.

Tunica interna

The innermost layer of a blood vessel, exposed to blood.

Tunica media

The middle layer of a blood vessel, comprised of smooth muscle and elastic tissue.

Tunica externa

The outermost layer of a blood vessel, providing support and structure.

Endothelium

A layer of simple squamous epithelium that lines the blood vessels.

Basement Membrane

The thin layer of fibrous material supporting the endothelium in blood vessels.

Vasa Vasorum

Small blood vessels that supply blood to the outer part of larger blood vessels.

Conducting arteries

Large arteries that carry blood under high pressure and have more elastic tissue.

Distributing arteries

Medium-sized arteries that direct blood flow to specific organs.

Resistance arteries

Small arteries that help regulate blood flow and blood pressure.

Arterioles

Small branches of arteries that lead to capillaries.

Precapillary sphincters

Muscle cells that regulate blood flow into capillaries.

Aneurysm

A weak point in an artery wall that can bulge or rupture.

Baroreceptors

Sensory structures that monitor blood pressure and send signals to the brainstem.

Chemoreceptors

Sensory structures that monitor blood chemistry and regulate respiration.

Continuous capillaries

Capillaries with uninterrupted endothelial linings, allowing for the passage of small solutes.

Fenestrated capillaries

Capillaries with pores that allow for increased permeability, found in organs needing rapid absorption.

Sinusoids

Discontinuous capillaries with large openings, allowing cells to pass easily, found in the liver and spleen.

Capillary beds

Networks of capillaries that supply blood to tissues.

Venules

Small veins that collect blood from capillaries.

Muscular venules

Larger venules that contain smooth muscle in their walls.

Medium veins

Veins that are larger and have valves to prevent backflow.

Varicose veins

Enlarged veins that result from valve failure allowing blood to pool.

Portal system

A system where blood flows through two consecutive capillary networks before returning to the heart.

Vasomotor tone

The level of constriction of blood vessels, influenced by smooth muscle contractility.

Blood flow

The amount of blood that passes through a given area in a certain period of time.

Perfusion

The flow of blood per given volume or mass of tissue in a given time.

Hemodynamics

The study of blood flow and its principles in relation to pressure and resistance.

Blood pressure

The force that blood exerts against the wall of a blood vessel.

Systolic pressure

The highest arterial pressure during ventricular contraction.

Diastolic pressure

The lowest arterial pressure during ventricular relaxation.

Pulse pressure

The difference between systolic and diastolic blood pressure.

Mean arterial pressure (MAP)

The average arterial pressure during one cardiac cycle.

Arteriosclerosis

The thickening and hardening of arterial walls.

Atherosclerosis

The buildup of fats, cholesterol, and other substances in and on the artery walls.

Hypotension

Abnormally low blood pressure.

Hypertension

Abnormally high blood pressure, typically over 140/90 mm Hg.

Peripheral resistance

The resistance of the arteries to blood flow.

Vasoconstriction

Narrowing of blood vessels due to contraction of smooth muscle.

Vasodilation

Widening of blood vessels due to relaxation of smooth muscle.

Capillary exchange

The process of transferring gases, nutrients, and waste between the blood and tissue fluid.

Diffusion

The movement of substances from an area of higher concentration to an area of lower concentration.

Transcytosis

The process of transport across the cell via endocytosis and exocytosis.

Hydrostatic pressure

The physical force exerted by liquids within the blood vessels.

Colloid osmotic pressure

The osmotic pressure exerted by proteins in the blood plasma.

Net filtration pressure

The difference between the hydrostatic pressure and colloid osmotic pressure within capillaries.

Mechanisms of venous return

The processes facilitating the return of blood to the heart.

Thoracic pump

The mechanism whereby pressure changes in the thoracic cavity facilitate venous return.

Neurogenic shock

Shock resulting from the loss of vasomotor tone.

Septic shock

Shock caused by sepsis leading to extreme vasodilation and increased capillary permeability.

Anaphylactic shock

A severe allergic reaction causing widespread vasodilation.

Circulatory shock

A condition in which the cardiac output is insufficient to meet the body's metabolic needs.

Cardiogenic shock

Shock resulting from inadequate cardiac output.

Low venous return (LVR) shock

Shock resulting from low blood returning to the heart.

Hypovolemic shock

Shock due to significant blood or fluid loss.