Marieb Human Anatomy & Physiology Chapter 19 - Blood Vessels Flashcards

A complete set of vocabulary flashcards covering blood vessel structure, physiology of circulation, blood pressure regulation, and developmental aspects from Chapter 19.

Arteries

Blood vessels that carry blood away from the heart toward capillaries; systemic ones carry oxygenated blood while pulmonary ones carry oxygen-poor blood.

Capillaries

Exchange vessels directly serving cellular needs where substances move across walls between tissue cells and blood.

Veins

Blood vessels that carry blood away from capillaries toward the heart; systemic ones carry oxygen-poor blood while pulmonary ones carry oxygenated blood.

Lumen

The central blood-containing space of a vessel surrounded by its wall.

Tunica intima

The innermost layer of a vessel in intimate contact with blood, containing the endothelium and subendothelial layer.

Endothelium

The simple squamous epithelium that lines the lumen of all vessels and is continuous with the endocardium.

Tunica media

The middle layer of a blood vessel composed mostly of circularly arranged smooth muscle cells and elastin, responsible for maintaining blood flow and pressure.

Vasoconstriction

The process where the lumen diameter decreases as the smooth muscle of the tunica media contracts.

Vasodilation

The process where the lumen diameter increases as the smooth muscle of the tunica media relaxes.

Tunica externa

The outermost layer (also called tunica adventitia) composed mostly of collagen fibers that protect, reinforce, and anchor the vessel.

Vasa vasorum

A system of blood vessels found in the walls of larger vessels, meaning "vessels of the vessels," that nourish the external tissues of the wall.

Elastic arteries

Thick-walled arteries near the heart (aorta and pulmonary trunk) that act as pressure reservoirs; also called conducting arteries.

Muscular arteries

Also called distributing arteries, they deliver blood to specific body organs and have the thickest tunica media of all vessels.

Arterioles

The smallest arteries that lead into capillary beds and are known as resistance vessels because they control flow through diameter changes.

Continuous capillaries

The most common and least permeable type of capillaries, abundant in the skin, muscles, lungs, and CNS.

Fenestrated capillaries

Capillaries containing Swiss cheese–like pores called fenestrations that provide increased permeability for active filtration, absorption, or secretion.

Sinusoidal capillaries

The most permeable and least common capillaries, found in the liver, bone marrow, spleen, and adrenal medulla, exhibiting large intercellular clefts.

Capillary bed

An interwoven network of capillaries between arterioles and venules where microcirculation happens.

Capacitance vessels

A term for veins because they can accommodate large volumes of blood, containing up to $65\%$ of the blood supply at any time.

Venous valves

Structures most abundant in the limbs that resemble the heart’s semilunar valves and prevent the backflow of blood.

Varicose veins

Tortuous and dilated veins resulting from incompetent (leaky) valves, often caused by heredity, obesity, pregnancy, or prolonged standing.

Hemorrhoids

Varicosities in the anal veins caused by elevated intra-abdominal pressure.

Blood flow

The amount of blood flowing through a vessel, organ, or entire circulation in a given period of time, measured in $\text{ml/min}$.平衡

Blood pressure (BP)

The force per unit area exerted on a vessel wall by blood, expressed in millimeters of mercury ($\text{mm Hg}$).

Total peripheral resistance (TPR)

The opposition to flow and measure of friction blood encounters; its three sources are blood viscosity, vessel length, and diameter.

Blood viscosity

The internal resistance to flow in fluids, referring to the thickness or "stickiness" of the blood.

Systolic pressure

The pressure exerted in the aorta during ventricular contraction, averaging $120\,\text{mm Hg}$ in a healthy adult.

Diastolic pressure

The lowest measure of aortic pressure when the heart is at rest, averaging $70\,\text{mm Hg}$ to $80\,\text{mm Hg}$ in a healthy adult.

Pulse pressure

The difference between systolic and diastolic pressure, felt as a throbbing pulsation in an artery.

Mean arterial pressure (MAP)

The pressure that propels blood to tissues, calculated as diastolic pressure + $1/3$ pulse pressure.

Auscultatory method

The indirect method of measuring systemic arterial blood pressure using a sphygmomanometer and listening for sounds of Korotkoff.

Muscular pump

A functional adaptation where contraction and relaxation of skeletal muscles around deep veins "milks" blood toward the heart.

Respiratory pump

A mechanism where pressure changes during breathing move blood toward the heart by squeezing abdominal veins as thoracic veins expand.

Atrial natriuretic peptide (ANP)

A hormone that decreases MAP by antagonizing aldosterone and causing generalized vasodilation.

ADH (vasopressin)

A hormone that stimulates the kidneys to conserve water and stimulates vasoconstriction to increase blood pressure.

Renin-angiotensin-aldosterone system

The indirect renal mechanism triggered by a drop in MAP where the kidneys release renin to eventually produce Angiotensin II.

Primary hypertension

Chronic high blood pressure ($> 130/80\,\text{mm Hg}$) with no identifiable underlying cause, resulting from genetic and environmental factors.

Secondary hypertension

High blood pressure due to identifiable disorders such as obstructed renal arteries, kidney disease, or endocrine disorders.

Orthostatic hypotension

Temporary low blood pressure and dizziness that occurs when suddenly rising from a sitting or reclining position.

Circulatory shock

Condition where blood vessels are inadequately filled and cannot circulate blood normally to meet tissue needs.

Hypovolemic shock

The most common form of circulatory shock, resulting from large-scale blood loss.

Vascular shock

Shock resulting from extreme vasodilation and decreased peripheral resistance, including anaphylactic, neurogenic, and septic types.

Active hyperemia

A metabolic autoregulation process where blood flow increases in active muscles in direct proportion to metabolic activity.

Angiogenesis

Long-term autoregulation where existing vessels enlarge and new vessels form to meet tissue demands.

Blood islands

Masses of mesodermal cells from which blood vessel endothelium arises during development.

Ductus venosus

A fetal vascular modification that allows blood to bypass the liver.