Chapter 21- Blood Vessels and Circulation

Anatomy and Physiology

Which blood vessels carry blood away from the heart?

arteries

Which blood vessels carry blood to the heart? 

veins

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?

decreases

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

increases

Why are artery walls typically thicker than in veins?

The tunica media of an artery contains more smooth muscle and elastic fibers than a vein does

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? 

Formation of lipid deposits in the tunica media associated with damage to the endothelial lining  

What is a scientific term for a stroke? 

Cerebrovascular accidents (CVAs) 

What are plaques? 

Fatty deposits in arterial walls  

Continuous capillary

the endothelium is a complete lining

Fenestrated capillaries

contain numerous “windows” or pores that penetrate the lining 

Define angiogenesis. 

The formation of new blood vessels from preexisting vessels  

What is the function of vein valves? 

Prevent backflow of blood 

What is deep vein thrombosis? 

clot formation in a deep vein

What is a pulmonary embolism?

clot traveling to and blocking a lung artery

Which two forces determine capillary blood flow?  

pressure and 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 and solutes between the blood and interstitial fluid

Define blood pressure. 

arterial pressure

What is capillary hydrostatic pressure? 

pressure of blood within the capillaries

What is venous pressure? 

pressure of blood in the venous system

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

Vascular resistance, blood viscosity, and 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 and internal vessel diameter  

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

increases friction and resistance

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

Decreases friction and resistance  

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

increase resistance

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

top- systolic pressure (pressure during ventricle systole)

bottom- diastolic pressure (pressure at the end of ventricle diastole)

hypertension 

abnormally high blood pressure

hypotension

abnormally low pressure pressure

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

Decreases as it overcomes friction and produces blood flow 

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 and the respiratory pump during inhalation 

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

capillary walls

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

diffusion, filtration, amd reabsorption

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 moves out of the capillary (filtration)

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

no net movement of fluid

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

Plasma proteins that create BCOP remain in the blood and cannot cross the capillary wall 

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, and endocrine mechanisms 

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 oblongata 

Which activities does the vasomotor center control?  

Vasocontraction and vasodilation 

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

Carotid sinuses, the aortic arch, and the wall of the right atrium, and they monitor the degree of stretch in the walls of expandable organs 

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 and 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 and widespread peripheral vasoconstriction 

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

Carotid and aortic bodies; monitor CO2, O2 and Phantidiuretic hormone, angiotensin II, erythropoietin, and natriuretic peptides (ANP and BNP) 

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

antidiuretic hormone, angiotensin II, erythropoietin, and natriuretic peptides (ANP and BNP) 

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

vasoconstriction, increases blood pressure 

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

decreases blood volume and 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? 

brain, heart, and lungs

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

extensive vasodilation, venous return increases, and cardiac output rises 

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

skeletal muscles, heart, and skin

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

increased oxygen/nutrient demand and heat dissipation 

Regular, moderate exercise can lower the risk of cardiovascular disease by lowering total blood cholesterol levels. Which type of cholesterol is considered “bad” cholesterol? How does exercise lower cholesterol levels? 

low-density lipoproteins (LDLs) 

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? 

increase cardiac output and vasoconstriction elevates BP 

Pathway of blood through pulmonary circuit

Right atrium → right ventricle → pulmonary trunk → left/right pulmonary arteries → lungs → pulmonary veins → left atrium

Trace blood through lungs

Right ventricle → pulmonary trunk → left/right pulmonary arteries → pulmonary arterioles → capillaries around alveoli → pulmonary venules → pulmonary veins → left atrium

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

Starts at the left ventricle and 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 aorta and the 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, the left common carotid artery, and the left subclavian artery 

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? 

vertebral arteries and the internal carotid arteries

cerebrovascular accident (stroke)

interruptions of the vascular supply to a portion of the brain causing damage of death to brain tissue erve? 

• C

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? 

controlling body temperature

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

superior and 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 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? 

hepatic portal vein  

Which blood vessels bring blood to the placenta? 

umbilical arteries 

which blood vessel transfers blood from the placenta? 

umbilical veins

What occurs at the foramen ovale?  

blood flows freely from the right atrium to the left atrium 

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

ductus arteriosus