Chapter 21 Blood Vessels

The walls of all blood vessels except the smallest consist of three layers

The ____________ reduces friction between the vessel walls and blood

The __________ controls vasoconstriction and vvasodilation of the vessel

THe __________ protects, reinforces, and anchors the vessel to surrounding structures

Elastic, or ________, arteries contain large amounts of elastin which enables these vessels to withstand and smooth out pressure fluctuations due to heart action

Muscular, or __________, arteries deliver blood to specific body organs, and have the greatest proportion of tunica media of all vessels, making them more active in vasoconstriction

____________ are the smallest arteries and regulate blood flow into capillary beds through vasoconstriction and vasodilation

___________ are the smallest vessels and allow for exchange between the blood and interstitial fluid

_____________ capillaries are most common and allow passage of fluids and small solutes

___________ capillaries are leaky capillaries that allow large molecules to pass between the blood and surrounding tissues

________________ capillaries are more permeable to fluids and solutes than continuous capillaries

___________ are microcirculatory networks consisting of a vascular shunt and true capillaries, which function as the exchange vessels

A cuff of smooth muscles, called a _________________, surrounds each capillary at the ____________ and acts as a valve to regulate blood flow into the capillary

__________ are formed where capillaries converge and allow fluid and white blood cells to move easily between the blood and tissues

Venules join to form

_____________ are relatively thin-walled vessels with large lumens containing about 65% of the total blood volume

______________ form where vascular channels unite, allowing blood to be supplied to and drained from an area even in one channel is blocked

___________ is the volume of blood flowing through a vessel, organ, or the entire circulation in a given period, and may be expressed as ml/min

___________ is the force per unit area exerted by the blood against a vessel wall, and is expressed in millimeters of mercury (mm Hg).

____________ is a measure of the friction between blood and the vessel wall, and arises from three sources:

If blood pressure increases, blood flow _________; if peripheral resistance increases, blood flow ________

Peripheral resistance is the most important factor influencing local blood flow, because...

pressure results when blood flow is

Systemic blood pressure is highest in the ______, and declines throughout the pathway until it reaches 0 mmHg in the _______

___________ reflects how much the arteries close to the heart can be stretched (compliance, or distensibility), and the volume forced into them at a given time

When the __________ contracts, blood if forced into the aorta, producing a peak in pressure called _____________ (120 mm Hg)

___________ occurs when blood is prevented from flowing back into the ventricles by the closed semilunar valve, and the aorta recoils (70-80 mm Hg)

THe difference between diastolic and systolic pressure is called the

The mean atrial pressure (MAP) represents the

Capillary blood pressure is low, ranging from _______ mm Hg, which protest the capillaries from rupture, but is still adequate to ensure exchange between blood and tissues

Venous blood pressure changes very little during the _________, and is low, reflection cumulative effects of peripheral resistance

Blood pressure varies directly with changes in blood volume and cardiac output, which are dertmined primarily by

__________________________ alter blood distribution to meet specific tissue demands, and maintain adequate MAP by altering blood vessels diameter

___________________ is a cluster of sympathetic neurons in the medulla that controls changes in the diameter of blood vessels

____________ detect stretch and send impulse to the vasomotor center, inhibiting its activity and promoting vasodilation of arterioles and veins

______________ detect a rise in carbon dioxide levels of the body, and stimulate the cardioacceletory and vasomotor centers, which increase cardiac output and vasoconstriction

The _______ and __________ can modify arterial pressure by signaling the medullary centers

Chemical controls influence blood pressure by

___________ and ___________ promote an increase in cardiac output and generalized vasoconstriction

________________ acts as a vasodilator and an antagonist to aldosterone, resulting in a drop in blood volume

______________ promotes vasoconstriction and water conservation by the kidneys, resulting in an increase in blood volume

_____________ acts as a vasoconstrictor, as well as promoting the release of aldosterone and antidiuretic hormone

_______________ promote vasoconstrictions, and are released in response to low blood flow

_____________________ counteracts an increase in blood pressure by altering blood volume, which increase the rate of kidney filtration

The __________________ is the renin-angiotensin mechanism, which counteracts a decline in arterial blood pressure by causing systemic vasoconstriction

Monitoring circulatory efficiency is accomplished by measuring _______________; these values together with respiratory rate and body temperature are called

A ________ is generated by the alternating stretch and recoil of elastic arteries during each cardiac cycle

Systemic blood pressure is measured indirectly using the ____________ method, which relies on the uses of a blood pressure cuff to alternately stop and reopen blood flow into the brachial artery of the arm

________ = low bp

_________ = high bp

___________ is the slow intermittent flow of blood throughout he capillaries. It reflects the action of the ______________ in response to local _______________

Capillary exchange of nutrients, gases, and metabolic wastes occurs between the blood and interstitial space through ________

________________ is the force of a fluid against a membrane

________________, the force opposing hydrostatic pressure, is created by the presence of large, nondiffusible molecules that are prevented from moving through the capillary membrane

Fluids will ________ the capillaries if net HP exceeds net OP, but fluids will ____________ the capillaries if net OP exceeds net HP