Chapter 21: Blood Vessels and Circulation

Compare and contrast the structure of veins, arteries, and capillaries

Arteries: elastic or muscular ; veins, which contain valves both have 3 layered walls while capillaries have 1 layer

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

arteries carry blood away, veins return it

List the layers of blood vessel walls from deep to superficial.

tunica intima, tunica, media, and tunica externa

What happens to a blood vessel’s diameter when the smooth muscle in the wall contracts/relaxes?

decreases during contraction and increases during relaxation

Why are artery walls typically thicker than in veins?

more smooth muscle and fiber in the tunica media to help resist arterial pressure from heart as it pumps blood out

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

resistance

What is an aneurysm?

a bulge in a weakend arterial wall

What is arteriosclerosis?
(clinical note)

thickening/toughening of artery walls

What is a scientific term for a stroke?

cerebrovascular accidents

What are plaques?

lipid deposits in the arteries

What is the difference between continuous and fenestrated capillaries?

continuous has complete endothelial lining while fenestrated has a pourous endothelium

Define angiogenesis.

formation of new blood vessels from preexisting ones

What is the function of vein valves?

to prevent backflow of blood

What is deep vein thrombosis? (clinical note)

formation of a blood clot in a deep vein due to slowed blood flow

What is a pulmonary embolism?

when a blood clot reaches the lungs

What factors determine blood flow and affect rates of capillary exchange/flow?

Pressure and resistance

Which force is directly proportional to blood flow? Which force is inversely proportional to blood flow?

pressure directly, resistance indirectly

What occurs during capillary exchange?

transfer of liquid and solutes between the blood and interstitial fluid

Define blood pressure.

arterial pressure, force exerted on vessel walls

What is capillary hydrostatic pressure?

pressure of blood within the capillary walls

What is venous pressure?

pressure of blood in the veinous system

List the three combined factors that determine the total peripheral resistance of the cardiovascular

vascular resistance, blood viscocity and turbulence

Name two factors that determine the amount of friction between the blood and vessel wall.

length and diameter

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

increased length increases friction

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

increasing diameter decreases fricition

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

both increase resistance

When taking someone’s blood pressure, you obtain a reading of 115/75. What does the top number and bottom number represent?

top number is systolic bp(peak bp), bottom number is diastolic(lowest bp)

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

bp decreases

Define venous return.

amount of blood arriving at the atrium each minute

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

increased diameter and valves

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

capillaries

List three important processes that move materials across typical capillary walls.

diffusion, filltration, and reabsorption

Define filtration.

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?

fluid forced out of the capillary

Why doesn’t BCOP change along the length of a capillary?

primarily determined by plasma protein concentration which typically do not leave the capillary

What 2 processes control blood flow and pressure in tissues 

autoregulation and central regulation

List three homeostatic mechanisms that adjust blood flow through the capillaries to meet the demands of peripheral tissues.

autoregulation, neural, and endocrine

Which of the mechanisms from question #1 cause immediate, localized homeostatic adjustments to blood flow?

autoregulation

Where is the cardiovascular center located in the brain?

medulla oblangata

Which activities does the vasomotor center control?

vasoconstriction and vasodilation via sympathetic motor neurons

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

in the walls of the carotid sinuses, aortic arch, and right atrium. They maintain normal arterial pressures by adjusting resistance and output

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

decreased output and 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?

increased cardiac output and vasoconstriction

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

carotid bodies and aortic bodies. Monitor composition of arterial blood

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

E/NE, ADH, Angeotensin II, erythopoietin, natriuetic peptides (ANP n BNP)

What effect on blood vessels does the release of EPO have? Does this increase or decrease blood pressure?

vasoconstriction of blood vessels, increases BP

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

reduce blood volume and BP

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?

brain, heart, lungs

List three changes to the cardiovascular response that occur during light exercise.

vasodilation, venous return and cardiac output rise

During strenuous exercise, what three organs have an increase in blood flow.

skin, heart, skeletal muscle

Why do you think each of these organs receive additional blood?

blood to skin cools the body

Which type of cholesterol is considered “bad” cholesterol? How does exercise lower cholesterol levels?

low-density lipoproteins, they are converted to bile in the liver and excreted

When a person is 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?

decreases vessel diameter

The vessels of the cardiovascular system make up what two circuits?

pulmonary and systemic

Pathway of blood flow through pulmonary circuit

from lungs to left ventricle and right ventricle to lungs

pathway of blood flow through systemic circuit

left ventricle to upper limbs, then brain, and lower body (kidneys, spleen, digestive organs) then lower limbs

Trace the path of a drop of blood through the lungs, beginning at the right ventricle and ending at the left atrium. Be sure to know the names of the major vessels.

right ventricle, pulmonary trunk, left/right pulmonary arteries, pulmonary arterioles, alveolar capillary network, pulmonary venules, pulmonary veins, left artirum

Where does the systemic circuit begin? Where does it end?

begins at the left ventricle, ends at the right atrium

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

ascending aorta

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

ascending and descending aorta

Name the three elastic arteries that originate along the aortic arch that deliver blood to the head, neck, shoulders, and upper limbs.

brachiocephalic trunk, left common carotid artery, and left subclavian

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

arms, chest wall, shoulders, back, and CNS

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

Carotid artery

Which blood vessels deliver oxygenated blood to the brain?

internal carotid arteries

Define cerebrovascular accident (stroke).

inturruptions 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?

regulation of body temp

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

superior or 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?

superior

What is the largest vessel of the hepatic portal system?

heptic portal vein

Which blood vessels bring blood to the placenta?

umbilical arteries

Which blood vessel transfers blood from the placenta?

umbilical vein

What occurs at the foramen ovale?

allows blood to flw freely between atriums

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

ductus arteriosus