Human A&P Ch.19,20,21

Abnormally slow conduction through the ventricles would change the shape of the _________ in an ECG tracing

QRS complex

In a normal electrocardiogram, the

QRS complex results from ventricular depolarization.

Edema can occur when there is

an decrease in blood colloid osmotic pressure.

Within normal limits, an increase in preload leads to

an increase in cardiac output and force of left ventricular contraction.

On this diagram label pulse point "B". A. femoral artery B. radial artery C. common carotid artery D. popliteal artery E. brachial artery

brachial artery

Which of the following functions is associated with the blood?

delivery of oxygen to tissue cells

The cascade of events in the intrinsic pathway can be set into motion when _____ comes into contact with collagen.

factor XII

On this diagram label pulse point "D". A. femoral artery B. radial artery C. common carotid artery D. popliteal artery E. brachial artery

femoral artery

Continuous capillaries

have a wall where the endothelial cells fit very tightly together.

Blood does not enter or leave the ventricles during the period called

isovolumic contraction.

Below is a diagram of RBC production? What does "B" represent?

kidney

Which of the following organs would be most likely to contain fenestrated capillaries?

kidney

An incompetent mitral valve may cause blood to back up into the

left atrium

The anterior interventricular artery is a branch of the

left coronary artery.

The chamber of the heart that endures the highest pressure is the

left ventricle.

Pressure in the right ventricle must exceed pressure in the ____ before the right ventricle can eject blood.

pulmonary trunk

These vessels open directly into the left atrium.

pulmonary veins

The difference between systolic and diastolic pressures is the _____________, felt as a throbbing over arteries.

pulse pressure

On this diagram label pulse point "C". A. femoral artery B. radial artery C. common carotid artery D. popliteal artery E. brachial artery

radial artery

Hemolysis is rupture of

red blood cells

Below is a diagram of RBC production? What does "D" represent?

red bone marrow

The pericardial fluid

reduces friction as the heart beats.

A force that causes the movement of fluid out of the capillary is

blood pressure

Angina pectoris is chest pain caused by reduced

blood supply to cardiac muscle.

Which of the following statements regarding leukocytes is true?

Leukocytes are the largest of the formed elements.

__________ are the smallest leukocytes; some produce antibodies.

Lymphocytes

In capillary exchange, which of the following statements is true?

Most fluid that leaves the arterial end of a capillary reenters the venous end of a capillary.

In capillary exchange, which of the following statements is true? 1. Most fluid that leaves the arterial end of a capillary reenters the venous end of a capillary. 2. Interstitial fluid normally has a higher osmotic pressure than plasma. 3. Constriction of the precapillary sphincter will increase blood pressure in the capillary. 4. Interstitial protein concentration is normally higher than plasma protein concentration. 5. Most fluid that leaves the arterial end of a capillary enters the lymphatic system.

Most fluid that leaves the arterial end of a capillary reenters the venous end of a capillary.

Which of the following is true? A. The semilunar valves remain closed throughout ventricular systole. B. Blood enters the right and left atria only during diastole. C. During ventricular systole, the AV valves open. D. Most ventricular filling occurs before the atria contract. E.Most of end-diastolic volume comes from active filling.

Most ventricular filling occurs before the atria contract.

__________ are phagocytic, have a multilobed nucleus, and make up the largest percentage of leukocytes.

Neutrophils

The major component of plasma is

Water.

A person with an increased eosinophil count might be suffering from

a allergic reaction.

Which of the following would increase resistance to blood flow?

a decrease in the radius of the vessel

If your son is diagnosed with hemophilia, he would have

a disorder of the clotting process.

When blood pressure is greater than the blood colloid osmotic pressure, there is

a net movement of fluid out of the capillary

The period of time in which the myocardium is insensitive to further stimulation is called the

absolute refractory period.

Anemia may result from a

decrease in the number of RBCs

When a prepotential in the SA node reaches threshold,

an action potential is generated.

If fluid is collecting in the interstitial space, then blood volume......venous return.....which means preload is ______________.

decreased

Below is a diagram of RBC production? What does "A" represent?

decreased blood oxygen

Increased number of reticulocytes in circulating blood indicates

erythropoiesis

Increased pressure in the aortic arch will activate the aortic arch reflex and cause

increased parasympathetic stimulation of the heart.

Each erythrocyte carries how many oxygen atoms?

1 billion

If the heart rate for a patient is 80 bpm, and her stroke volume is 70 mL/beat, then her cardiac output is

5600 mL/min

The PMI is located

5th intercoastal space, 7.5 cms to the left of the midline.

temperature of blood?

100.4

The average end-diastolic volume of the ventricles is about __________ , whereas the end-systolic volume is about __________ .

130 mL, 50 mL

Which of the following factors assists in the return of venous blood to the heart? 1. arterial dilation 2. valves in the veins 3. changing respiratory pressures 4. compression of veins by muscular movements

2, 3, 4

Arrange the following events of coagulation in proper sequence. 1. prothrombin ® thrombin 2. fibrinogen ® fibrin 3. activation of factor XII 4. formation of prothrombinase

3, 4, 1, 2

When stimulated by erythropoietin to produce red blood cells, the hemocytoblast deliver these new cells in

4 days

Choose the arrangement that lists the chemicals in the order in which they would be used for coagulation. 1. thrombin 2. fibrinogen 3. prothrombinase 4. activated Factor XII

4, 3, 1, 2

Given these valves: 1. aortic semilunar valve 2. bicuspid (mitral) valve 3. pulmonary semilunar valve 4. tricuspid valve. Arrange them in the order in which an erythrocyte would pass through them after returning to the heart from the left arm.

4,3,2,1

Each hemoglobin molecule has __________ heme group(s) and __________ globin molecule(s).

4,4

Total blood volume (in liters) in the body?

4-6 liters

% of blood that represents formed elements

45%

Arrange the following five events in the order they occur as erythrocytes are broken down:

5. hemoglobin is broken down to heme groups and globin molecules 3. biliverdin is produced 4. free bilirubin is produced 1. bilirubin is conjugated to glucuronic acid 2. bilirubin is excreted in bile

% of blood that is plasma?

55%

pH range of blood?

7.35-7.45

% of total body weight represented by blood?

8%

% of Water in plasma?

91%

Use the following key to mark the most correct answer. A) Choose A if the first item is greater than the second item. B) Choose B if the first item is less than the second item. C) Choose C if the first item is equal or nearly equal to the second item. 1) heart rate after stimulation of the cardiac nerves; 2) heart rate after stimulation of the vagus nerve

A) Choose A if the first item is greater than the second item.

Which of the formed elements are correctly matched with its alternate name

A. Red blood cells------Erythrocytes B. White blood cells------Leukocytes C. Platelets-----Thrombocytes

Which of these statements is true? A. The great cardiac vein collects blood from the anterior surface of the heart. B. The pulmonary arteries carry blood to the left atrium. C. The left coronary artery is a branch of the left pulmonary vein. D. The coronary arteries arise from the pulmonary trunk. E. The coronary sinus returns blood to the left atrium.

A. The great cardiac vein collects blood from the anterior surface of the heart.

Platelets

A. are also known as thrombocytes. B. are actually fragments of cells. C. play a role in preventing blood loss. D. can become sticky when exposed to connective tissue

Which of the following cell types is incorrectly matched with its description?

A. basophils - release histamine C. neutrophils - most numerous WBC D. eosinophils - parasites; decrease inflammation E. monocytes - largest of the WBC

Which of the following characterize the connective tissue components of blood?

A. formed elements B. plasma C. clotting factors

The biconcave shape of a red blood cell allows this cell to

A. pass through narrow capillaries B. maximizes its surface area for exchange of oxygen and carbon dioxide

In the adult, hematopoiesis takes place in red bone marrow found in the

A. ribs and and sternum B. vertebrae and pelvis C. proximal femur and proximal humerus

Which of the following is/are true of the heart?

A. size of a closed fist B. hollow C. weighs less than a pound. D. has a superior base and an inferior apex

The alteration of blood flow, due to the action of the precapillary sphincters, depends on pillary.

A. the immediate needs of the tissue bed it supplies. B. the abscence of a more urgent need somewhere else in the body. C. the autoregulation of the precapillary sphincters.

Functions of blood include

A. transport B. regulation C. protection

During the isovolumic contraction period of the cardiac cycle,

AV and semilunar valves are closed

The group of modified cardiac muscle cells that delays action potentials between the atria and the atrioventricular bundle is called the

AV node

When ventricular pressure exceeds atrial pressure, the

AV valves close.

If the SA node becomes damaged and nonfunctional, which of these is the most likely to occur?

Another part of the heart, possibly the AV node, will become the pacemaker.

If the SA node is nonfunctional, which of the following is most likely to occur?

Another portion of the heart will become the pacemaker.

Use the following key to choose the most correct answer. A) Choose this if the first item is greater than the second item. B) Choose this if the first item is less than the second item. C) Choose this if the first item is equal or nearly equal to the second item. 1) systolic pressure; 2) diastolic pressure

B

Which of the following sequences is correct? A. Purkinje fibers, bundle branches, AV node, AV bundle, SA node B. SA node, AV node, AV bundle, bundle branches, Purkinje fibers C. AV node, AV bundle, SA node, Purkinje fibers, bundle branches D. AV node, SA node, bundle branches, AV bundle, Purkinje fibers E. SA node, AV bundle, AV node, bundle branches, Purkinje fibers

B. SA node, AV node, AV bundle, bundle branches, Purkinje fibers

When blood pressure increases, a number of events occur that return blood pressure to normal. Which of the following is one of the events that occurs after an increase in blood pressure? A. Baroreceptors are stimulated. B. Action potential frequency to the cardioregulatory center of brain decreases. C. Sympathetic stimulation of the heart increases. D. Heart rate increases. E. An increase in number of action potentials in the cardiac nerve.

Baroreceptors are stimulated

On this diagram label pulse point "A". A. femoral artery B. radial artery C. common carotid artery D. popliteal artery E. brachial artery

C. common carotid artery

From the heart to body tissues, which of the following sequences of vessels is correct? A. muscular artery, arteriole, elastic artery, capillary B. arteriole, muscular artery, elastic artery, capillary C. elastic artery, muscular artery, arteriole, capillary D. elastic artery, arteriole, muscular artery, capillary E. distributing artery, muscular artery, medium artery, capillary

C. elastic artery, muscular artery, arteriole, capillary

Long term regulation of blood pressure A. has a much slower onset than short term blood pressure regulation. B. utilizes hormones to regulate blood volume, enhancing filtrate formation and fluid loss in urine, decreasing blood volume and therefore decreasing blood pressure. C. may use of the interstitial spaces to hide extra fluid when blood pressure is high. and to tap into this reservoir when blood pressure is low. D. all may be true.

D. all may be true

Which of the following statements regarding intrinsic regulation of the heart is true?

If cardiac muscle fibers are slightly stretched, they have a stronger contraction force.

The "pacemaker" of the heart is the

SA node.

Concerning heart sounds, which of the following is correct?

The first heart sound occurs at the beginning of ventricular systole.

Which of these descriptions of the heart's location is correct?

The heart lies obliquely in the mediastinum.

Which of the following statements about laminar blood flow is true? A. The innermost layer of blood moves at the lowest velocity. B. Laminar blood flow occurs when blood flows past an area of constriction. C. The outermost layer of blood experiences the greatest resistance to flow. D. In laminar blood flow, the rapid rate of blood flow exceeds critical velocity. E. It makes lots of different noises.

The outermost layer of blood experiences the greatest resistance to flow.

Which of the following statements concerning blood vessel walls is true? A. The tunica intima is the innermost layer of a blood vessel wall. B. The tunica media is found in all blood vessels except veins. C. The tunica adventitia is composed of smooth muscle and endothelium. D. Capillaries have both a tunica intima and a tunica media. E. Vessel diameter is control primarily by the tunica intima.

The tunica intima is the innermost layer of a blood vessel wall.

When comparing cardiac muscle cells and skeletal muscle cells,

action potentials are conducted from cell to cell only in cardiac muscle.

The major plasma protein that does NOT leave the capillary, facilitating fluid re-entry is

albumin

Which of the following plasma proteins is most abundant?

albumin

Which of the following happen when a person stands in one place for a long period of time? A. Gravity causes an increased accumulation of blood in the veins in the feet and legs. B. Blood pressure rises in the venules of the feet. C. Without muscular movement the pressure at the venous end of the capillaries increases. D. Edema may occur in the lower extremities. E. All of the above

all of the above

When a person rises quickly from a lying position, there is

an increase in vasomotor sympathetic stimulation to the blood vessels causing vasoconstriction..

During the ejection phase of the cardiac cycle, blood exits the left ventricle through the

aorta

As soon as left ventricular pressure exceeds the pressure in the aorta, the

aortic semilunar valve opens.

Ventricular contraction begins at the

apex of the heart

Chemoreceptors

are located in the aortic and carotid bodies

Cardiac muscle cells

are maintained by an extensive capillary network.

__________carry oxygen rich blood from the heart through the first part of the systemic circulation.

arteries

__________ are the smallest branches of the artery delivery system.

arterioles

The action potentials are slowed at the AV node to allow the

atria to complete their contraction.

The P wave of an ECG indicates

atrial depolarization.

When there is a drop in blood pressure, the body reacts immediately by way of the

baroreceptor mechanism.

Baron von Quacko, famous tag-team wrestler, has a famous "sleeper hold" that he uses on his opponents. Using only a single digit on each hand, he presses on his opponent's neck until his opponent passes out. What are the structures on which he is pressing and what is the effect?

baroreceptors in carotid sinus; peripheral vasodilation and decreased heart rate

Blood vessels enter and exit from the _____ of the heart.

base

These leukocytes produce heparin and histamine; they play a role in inflammatory and allergic reactions.

basophils

Blood is more viscous than water. This is because it

becomes more dense when cells are added

The AV valve (AV means atrio-ventricular) that is located on the same side of the heart as the origin of the aorta is the

bicuspid valve

Jaundice is a buildup of __________ in the circulation and interstitial spaces.

bilirubin

Jaundice is associated with plasma and interstitial space buildup of

bilirubin

Hematopoiesis is the process of

blood cell production.

A force that attracts fluid into the capillary from the tissue spaces is

blood colloid osmotic pressure.

In which of the following clinical situations would you expect edema? A. shock (which is accompanied by low blood pressure) B. burns (which result in increased capillary permeability to plasma proteins) C. dehydration (which results in low blood pressure) D. vomiting (which leads to a decreased plasma volume) E. diarrhea (which leads to a decreased blood volume)

burns (which result in increased capillary permeability to plasma proteins)

Efficient exchange of oxygen and nutrients from the blood to the tissues is the job of the ______________.

capillaries

The exchange of nutrients and gases between the blood and tissue cells is the primary function of

capillaries.

The product of the stroke volume times the heart rate is known as the

cardiac output.

The difference between resting and maximal cardiac output is

cardiac reserve.

arota

carries blood from the left ventricle into systemic circulation

pulmonary veins

carries blood from the lungs to the left atrium

pulmonary arteries

carries blood from the pulmonary trunk to the lungs

pulmonary trunk

carries blood from the right ventricle to the pulmonary arteries

When a person develops a sore throat, white blood cells are drawn to the area of infection by a process called

chemotaxis.

Occlusion of which of the following would primarily damage the left ventricle?

circumflex artery

Once blood is moved past a valve, it holds that blood until the next surge pushes it

closer to the heart.

Which of the following is mismatched? A. opening of sodium fast channels - depolarization B. closing of calcium slow channels - plateau phase C. opening of potassium channels - rapid repolarization D. closure of sodium channels - early repolarization E. opening of calcium slow channels - plateau phase

closing of calcium slow channels - plateau phase

Fibrinolysis is responsible for

clot dissolution

Which of the following is a stage of hemostasis?

coagulation

Distributing arteries

contain a thick tunica media.

The blood-brain barrier is a special ________________, containing abundant tight junctions and no intercellular clefts.

continuous capillary.

Precapillary sphincters

control the blood flow into capillary beds.

Which of the following events is one of the three main stages of coagulation?

conversion of fibrinogen to fibrin

The great cardiac vein and middle cardiac vein empty into a venous cavity called the

coronary sinus.

The epicardium

covers the surface of the heart.

The spontaneous opening of sodium fast channels marks the beginning of ____ of a myocardial cell.

depolarization

The ability of white blood cells to leave the circulation and enter tissues is called

diapedesis

Which of these areas does NOT contain red marrow in the adult?

distal femur

Plasma is considered a colloid because it contains suspended substances that

don't settle out in solution

The tricuspid valve is closed

during ejection.

The blood vessels that are under the greatest pressure are the

elastic arteries.

The lining of a capillary is called the

endothelium.

These leukocytes produce enzymes that reduce the inflammatory response and are associated with allergies or parasitic infections.

eosinophils

Another name for the visceral pericardium is the

epicardium.

The most numerous formed element is the

erythrocyte

The plasma component that forms fibrin, the insoluble protein, in a blood clot is

fibrinogen.

The pericardial layer that is tough and protective is the

fibrous pericardium.

1) the number of erythrocytes in a milliliter sample of blood 2) the number of leukocytes in a milliliter sample of blood

first item is greater than the second item.

1) the rate of erythropoiesis when erythropoietin is present 2) the rate of erythropoiesis when erythropoietin is absent

first item is greater than the second item.

Red blood cells, white blood cells and platelets are all

formed elements

The cellular components of blood, representing 45% of blood volume are called

formed elements

Although cardiac muscle cells are short and branched, special cell connections allow them to

function as single unit, both electrically and functionally

Action potentials pass from one myocardial cell to another through areas of low electrical resistance called

gap junctions.

Stem cells

give rise to formed elements in the blood.

Which of these components of hemoglobin is correctly matched with its fate following the destruction of an erythrocyte?

globin -- broken down into amino acids

Stroke volume and heart rate may increase cardiac output to 18-30 l/ min in

healthy adults.

The study of blood is called

hematology

The stem cell capable of dividing to produce any formed element cell line is the

hemocytoblast

The function of plasmin is to

hydrolyze fibrin.

According to Poiseuille's law,

if resistance increases, flow decreases.

If the heart receives more sympathetic stimulation than parasympathetic stimulation, the heart will

increase its rate and force of contraction.

Stimulation of the heart via the sympathetic nerves would

increase the force of ventricular contraction.

Below is a diagram of RBC production? What does "E" represent?

increased blood oxygen

Which of the following factors would cause an increase in heart rate?

increased epinephrine release from the adrenal medulla

Below is a diagram of RBC production? What does "C" represent?

increased erythropoietin

Coronary artery disease can diminish myocardial blood flow resulting in the death of myocardial cells. This condition is known as a myocardial

infarction.

Plasma

is a colloidal solution.

The heart

is a four-chambered muscular pump.

Heparin

is a potent anticoagulant.

The velocity of blood flow inside a blood vessel

is faster in the center of the blood vessel.

Plasma

is the liquid matrix of the blood.

The endocardium

is the smooth inner lining of the heart chambers.

tricuspid valve

located between the right atrium and right ventricle

pulmonary valve

located between the right ventricle and the pulmonary trunk

The blood flows through the _______ of each vessel.

lumen

An incompetent pulmonary semilunar valve could result in less blood reaching the

lungs

Which of the following cell types is incorrectly matched with its description?

lymphocytes - become macrophages

Old, damaged, or defective erythrocytes are removed from the blood by

macrophages.

Veins

may contain valves and are lined with endothelium.

Blood pressure is the

measure of force blood exerts against blood vessel walls.

The heart lies between the lungs in a region called the

mediastinum

The cardioregulatory center of the brain is located in the

medulla oblongata.

Which of the following is an agranulocyte?

monocytes

Macrophages are derived from

monocytes.

The greater the compliance the

more easily the vessel wall stretches.

Lack of cytoplasmic organelles is important to red blood cells because

more space is available to carry hemoglobin

The muscle layer of the heart, whose fuction is to act as the pump for the cardiovascular system is the

myocardium

Which of the following layers forms the bulk of the heart wall?

myocardium

The most numerous of the leukocytes is the

neutrophil

Which leukocyte's main function is phagocytosis; these are the first cells to respond?

neutrophils

Where is oxygen attached on a hemoglobin molecule?

on the iron attached to the heme

The plateau phase seen during the action potential of a cardiac muscle cell is due to the

opening of calcium slow channels.

When large quantities of blood are lost, erythrocytes must be replaced to restore

oxygen-carrying capacity.

The pericardial sac is lined with

parietal pericardium.

Between the parietal pericardium and the visceral pericardium is the

pericardial cavity containing pericardial fluid.

The pale yellow fluid that makes up about 55% of blood volume is

plasma

When a blood vessel is damaged, which of the following events occurs last?

platelets begin to stick to each other and form a plug.

During platelet plug formation,

platelets stick to the exposed collagen fibers of injured vessels.

The central nervous system ischemic response

plays an important role in controlling blood pressure under emergency conditions.

On this diagram label pulse point "E". A. femoral artery B. radial artery C. common carotid artery D. popliteal artery E. brachial artery

popliteal artery

Which of the following phrases would apply to cardiac muscle cells?

possess special cell-to-cell contacts called intercalated discs

Which of the following events occurs first?

prepotential

Contraction of the papillary muscles would

prevent the AV valves from protruding into the atria.

The long refractory period observed in cardiac muscle

prevents tetanic contractions of the cardiac muscle.

A blood clot that forms when a blood vessel is cut is an example of blood functioning in

protection

Capillary walls serve as effective permeability barriers for

proteins.

The major function of arterioles is to

regulate the flow of blood reaching the capillary beds downstream from them.

Functions of plasma proteins include

regulation of osmotic pressure.

The process of erythropoiesis

requires vitamin B12 and folate.& is stimulated when oxygen decreases in the blood.

inferior vena cava

returns blood to the heart from the lower extremities

superior vena cava

returns blood to the heart from the upper extremities

Blood in the superior vena cava will enter the _____.

right atrium

Which of these conditions occur in a normal individual living at a high altitude?

secondary polycythemia

The liquid material remaining after blood-clotting proteins have been removed as a result of clotting is called

serum

An increased amount of heparin in the blood might

slow down the clotting process.

The vasa vasorum are

special capillaries that supply nutrients to the walls of arteries and veins.

Cells in the red bone marrow that give rise to all the formed elements of the blood are called

stem cells.

End-diastolic volume minus end-systolic volume is equal to

stroke volume

The volume of blood pumped during each cardiac cycle is the

stroke volume

Which of the following best describes arteries?

strong, elastic vessels that carry blood under high pressure

List the path of blood as it travels through the heart. Include all vessels, valves, chambers and tissues.

superior and inferior vena cava...right atrium...tricuspid valve...right ventricle..pulmonary valve.....pulmonary trunk...pulmonary arteries....lungs...pulmonary veins....left atrium....bicuspid valve....left ventricle....aortic valve....aorta

The great veins and arteries are connected to the heart at the

superiorly located base.

What occurs during the time between the first heart sound and the second heart sound?

systole

Contraction of the ventricles is referred to as ventricular

systole.

Resistance in the cardiovascular system

tends to increase if blood viscosity increases.

Which of the following will depolarize immediately after the AV node depolarizes?

the AV bundle

You are normally unable to see a waveform indicating repolarization of the atria on an ECG because

the QRS complex is such a large electrical event, it hides the waveform.

Afterload is

the arterial pressure that the ventricles must overcome to eject blood.

When left atrial pressure exceeds left ventricular pressure

the bicuspid (mitral) valve opens.

A stab wound into the heart can result in cardiac tamponade. This means that

the heart is compressed by blood in the pericardial sac.

Increased vagal stimulation would cause

the heart rate to decrease.

What makes blood an unusual connective tissue is

the highly fluid nature of its extracellular matrix and the lack of fibers there.

E.Z. Goen is admitted to the cardiac unit with a diagnosis of endocarditis. When E.Z. asks the nurse where the infection is located, the nurse replies that the infection is in

the inner lining of the heart.

Plasma is ____ while formed elements are ____.

the liquid portion of blood; the cells

Depolarization of a cardiac muscle cell occurs as the result of

the opening of voltage-gated sodium channels.

The period of isovolumic contraction is immediately followed by

the period of ejection.

As viscosity of the blood increases,

the pressure required to force it to flow increases.

In the cardiac cycle,

the two atria relax while the two ventricles contract.

Which of the following acts as a storage area for blood?

the veins

The cardiac electrical impulse normally begins spontaneously in the SA node because

this area depolarizes more rapidly than any other portion of the conduction system.

If oxygen and nutrients are not needed at the time or if these products are required urgently somewhere else in the body, the precapillary sphincters vasoconstrict, allowing blood to flow from the through the

throughfare channel to the postcapillary venule.

In the extrinsic pathway, damaged tissues release

tissue factor (TF)

Stroke volume and heart rate may increase cardiac output to 40 l/ min in

trained athletes.

The outer layer of a blood vessel, composed of connective tissue and scattered elastic fibers is called the

tunica externa

This layer lines the lumen and is composed of endothelium and connective tissue.

tunica intima

Which coat of an artery contains endothelium?

tunica intima

Arteries can constrict or dilate as needed because of the smooth muscle found in the

tunica media.

Sympathetic nerve fibers that innervate blood vessel walls, allowing for vasoconstiction and vasodilation are found primarily in the

tunica media.

When the tissue needs oxygen and nutrients, the precapillary sphincters ________.

vasodilate, filling the capillary bed with nutrients and oxygen.

The middle layer of a blood vessel, contains smooth muscle that allows the vessel to increse in diameter, a property called ___________________.

vasodilation

The vessels carrying oxygen poor blood and waste products away from the tissues and all the way back to the heart are called ___________.

veins

Valves similar to semilunar valves are found in some

veins

The QRS complex of the ECG appears as the

ventricles depolarize

The smallest vessels leading back to the heart are called ______.

venules

The first and second heart sounds are most directly related to

vibrations that occur when the valves close.

The pericardial layer that is in contact with the heart is the

visceral pericardium.

If a person develops high blood pressure, one of the compensatory mechanisms that comes into play is the fluid shift mechanism. This mechanism causes

water to shift from the capillaries into the interstitial spaces.

The chemoreceptor reflexes help maintain homeostasis

when carbon dioxide levels increase.

bicuspid valve

when closed, prevents the back-flow of blood into the left atrium

aortic valve

when closed, prevents the back-flow of blood into the left ventricle