Chapter 21: Blood Vessels & Circulation Study Guide

which blood vessels carry blood away from the heart? which blood vessels carry blood to the heart?

arteries carry blood away from the heart and veins carry blood to the heart, whether the blood is oxygenated or deoxygenated

list the layers of blood vessel walls from deep to superficial

tunica intima, tunica media, & tunica externa

what happens to a blood vessel's diameter when the smooth muscle in the wall contracts?

vessel decreases in diameter

what happens to a blood vessel's diameter when the smooth muscle in the wall relaxes?

vessel increases in diameter

why are artery walls typically thicker than in veins?

to help resist the arterial pressure generated by the heart as it pumps blood into the pulmonary trunk & aorta

what is the name of the force that opposes blood flow?

resistance

what is an aneurysm?

a weakening in the arterial wall causing an outpouching or enlargement of the artery

what is arteriosclerosis?

the formation of lipid deposits (plaque) in the tunica media associated with damage to the endothelial lining

what is the scientific name for a stroke?

cerebrovascular accident (CVA)

what are plaques?

a typical lesion

what is the difference between continuous and fenestrated capillaries?

continuous capillaries have a complete endothelial lining without gaps, while fenestrated capillaries have pores, or "windows" in their endothelial lining

define angiogenesis

the formation of new blood vessels from preexisting vessels & occurs under the direction of vascular endothelial growth factor

what is the function of vein valves?

allow blood flow only to the heart, prevent blood from flowing backward toward the capillaries

what is deep vein thrombosis?

a serious condition where a blood clot forms in the deep veins of the leg; occurs when venous blood flow slows significantly, triggering coagulation

what is a pulmonary embolism?

a condition where a blockage occurs in the pulmonary arteries, which supply blood to the lungs

which two forces determine capillary blood flow?

pressure & resistance

which force is directly proportional to blood flow?

pressure

which force is inversely proportional to blood flow?

resistance

what occurs during capillary exchange?

the transfer of liquid & solutes between the blood and interstitial fluid

define blood pressure

a force exerted against vessel walls by the blood in the vessels due to the push exerted by cardiac contraction & the elasticity of the vessel walls

what is capillary hydrostatic pressure

the pressure of blood within capillary walls

what is venous pressue?

the pressure of blood within the venous system

list the three factors that determine the total peripheral resistance of the cardiovascular system

vascular resistance, blood viscosity, & turbulence

the forces that oppose blood flow through a vessel is called vascular resistance. the most important factor is friction between the blood and the vessel wall. name two factors that determine the amount of friction.

vessel length & internal vessel diameter

what effect on friction, and therefore vascular resistance, does increasing the length of a blood vessel have?

vascular resistance would be increased

what effect on friction, and therefore vascular resistance, does increasing the luminal diameter of a blood vessel have?

decreases vascular resistance

what effect on resistance does viscous blood and turbulent blood have?

blood with higher viscosity requires more pressure to flow, increasing peripheral resistance turbulence increases resistance & slows down blood flow

when taking someone's blood pressure, you obtain a reading of 115/75. what does the top number and bottom number represent?

systolic pressure and diastolic pressure

define hypertension

abnormally high blood pressure

hypotension

abnormally low blood pressure

the mean arterial pressure declines as the arterial branches become smaller and more numerous. what effect does this have on blood pressure?

blood pressure decreases as it overcomes friction & produces blood flow

define venous return

the amount of blood arriving at the right atrium each minute

what two factors assist the low venous pressures in propelling blood toward your heart?

muscular compression of peripheral veins & the respiratory pump during inhalation

where do all gaseous and chemical exchanges between blood and interstitial fluid take place?

across capillary walls

list three important processes that move materials across typical capillary walls

diffusion, filtration, & reabsorption

define filtration

the removal of solutes as a solution passes through a porous membrane

what process is used for reabsorption?

osmosis

you are measuring pressures in a capillary and find that the CHP is 37mmHg and BCOP is 23mmHg. what type of movement, if any, would occur at this part of the capillary?

filtration (fluid pushed out of the capillary)

what type of movement, if any, would occur at a capillary if the NFP equaled 0?

no movement

why doesn't BCOP change along the length of a capillary?

plasma proteins do not leave the bloodstream, maintaining steady osmotic pressure

since we don't have enough blood to maintain adequate blood flow to all the capillaries in the body homeostatic mechanisms operating at the local, regional, and systemic levels adjust blood flow through the capillaries to meet the demands of peripheral tissues. list three homeostatic mechanisms that accomplish this.

autoregulation, neural mechanisms, & endocrine mechanisms

which mechanism causes immediate, localized homeostatic adjustments to blood flow: autoregulation, neural mechanism, or endocrine mechanism?

autoregulation

where is the cardiovascular center located in the brain?

the medulla oblongata

which activities does the vasomotor center control?

activity of the sympathetic motor neurons

where are baroreceptors associated with central regulation of blood flow located in the body? what do they monitor?

the carotid sinuses, the aortic arch, & the wall of the right atrium; they monitor blood pressure & regulate cardiovascular function

when blood pressure rises, the increased output from the baroreceptors alters activity in the cardiovascular center and produces two major effects. what are they?

a decrease in cardiac output & widespread peripheral vasodilation

when blood pressure falls below normal, the decreased output from the baroreceptors alters activity in the cardiovascular center and produces two major effects. what are they?

an increase in cardiac output & widespread peripheral vasoconstriction

where are chemoreceptors associated with central regulation of blood flow located in the body? what do they monitor?

the carotid bodies, situated in the neck near the carotid sinuses, & the aortic bodies, near the aortic arch

list five hormones that function in central regulation of blood flow.

epinephrine (E), norepinephrine (NE), antidiuretic hormone (ADH), angiotensin II, natriuretic peptides (ANP & BNP)

what effect on blood vessels does the release of EPO have? does this increase or decreased blood pressure?

vasoconstriction is caused, thereby increasing blood pressure

what effect on blood volume and blood pressure does the release of ANP and BNP produce?

reduce blood volume and blood pressure

the term special circulation refers to the vascular supply through organs in which blood flow is controlled by separate mechanisms. what are three organs where special circulation occurs?

the brain, the heart, & the lungs

list three changes to the cardiovascular response that occur during light exercise

extensive vasodilation occurs, the venous return increases, & cardiac output rises

during strenuous exercise, what three organs have an increase in blood flow?

the skeletal muscles, the lungs, & the heart

which type of cholesterol is considered "bad" cholesterol? how does exercise lower cholesterol levels?

low-density lipoproteins; by stimulating enzymes that help move LDLs from the blood to the liver

when a person hemorrhaging, there are a few cardiovascular system short-term responses that promote elevation of blood pressure. what effect do these have on cardiac output on vessel diameter?

vasoconstriction

where does the systemic circuit being & end?

at the left ventricle & ends at the right atrium

what blood vessel begins at the aortic valve of the left ventricle?

the ascending aorta

what two parts of the aorta are connected by the aortic arch?

the ascending aorta & the descending aorta

name the three elastic arteries that originate along the aortic arch that deliver blood to the head, neck, shoulders, & upper limbs

the brachiocephalic trunk, the left common carotid artery, & the left subclavian artery

what parts of the body receive blood from the subclavian artery?

the arms, chest wall, shoulders, bacl, & central nervous system

which blood vessel are you feeling when checking for a pulse along either side of the windpipe?

the carotid artery

which blood vessels deliver oxygenated blood to the brain?

the vertebral arteries & the internal carotid arteries

define cerebrovascular accident (stroke)

interruptions of the vascular supply to a portion of the brain

the neck and the limbs generally have two sets of peripheral veins, one superficial and the other deep. what is the important function does this serve?

dual venous drainage is important for controlling body temperature

which great vessel receives blood from all the body's systemic veins (except the cardiac veins)?

either the superior vena cava or the inferior vena cava

which part of the vena cava receives blood from the tissues and organs of the head, neck, chest, shoulders, and upper limbs?

the superior vena cava (SVC)

which part of the vena cava collects most of the venous blood from organs inferior to the diaphragm?

inferior vena cava (IVC)

what is the largest vessel of the hepatic portal system?

the hepatic portal vein

which blood vessels bring blood to the placenta?

a pair of umbilical arteries

which blood vessel transfers blood from the placenta?

the single umbilical vein

what occurs at the foramen ovale?

blood is allowed to flow directly from the right atrium to the left atrium

a short-circuit exists between the pulmonary and aortic trunks. what are they connected by?

the ductus arteriosus