bio 260 chapter 11 the cardiovascular system

Arrange these elements of the intrinsic conduction system in the order that a depolarizing impulse travels during a normal heartbeat.

1) SA node 2) Internodal pathways 3) AV node 4) AV bundle 5) Bundle branches 6) Purkinje fibers

Match the cardiac components in the left column to the blanks near their functions on the right.

1. AV node: Delay(s) occurs here while atria contract 2. SA node: Set(s) the pace for the entire heart 3. AV bundle : Electrical link(s) between atria and ventricles 4. Purkinje fibers: Convey(s) the impulse throughout the ventricular walls 5. Bundle branches: Convey(s) the impulse down the interventricular septum 6. Internodal pathways: Link(s) between the SA node and AV node

Both atria and ventricles are made of the same cardiac muscle tissue. Because most of the pumping work is done by the ventricles, systole and diastole always refer to the activity of the ventricles unless otherwise stated.

1. During atrial diastole, the ventricles fill passively with blood. 2. During systole, the ventricles contract. 3. During isovolumetric relaxation, the ventricles relax and all valves are closed.

Match the term in the left column to the blanks near their definition on the right.

1. Stroke volume (SV): the volume of blood per heart beat pumped out by one ventricle 2. Cardiac output (CO): the volume of blood per minute pumped out by one ventricle 3. End diastolic volume (EDV): the volume of blood in one ventricle before contraction 4. Heart rate (HR): the number of heart beats per minute 5. Venous return (VR): the volume of blood per minute flowing into one atrium 6. End systolic volume (ESV): the volume of blood in one ventricle after contraction

Which of these structures conduct(s) action potentials the slowest?

AV node

Which part of the intrinsic conduction system delays the impulse briefly before it moves on to the ventricles?

AV node

Increased pressure in the ventricles would close what valve(s)?

AV valves only

Which of the following can be heard with a stethoscope most easily?

Closing of atrioventricular valves

Which of the following changes would produce the greatest change in total peripheral resistance?

10% change in vessel diameter

Which of the following would reflect the typical net hydrostatic pressure (HP) at the arterial end of the capillary?

34 mm Hg

Calculate the cardiac output if heart rate (HR) is 90 beats per minute, stroke volume (SV) is 110 ml/beatml/beat, end diastolic volume (EDV) is 140 mlml, and end systolic volume (ESV) is 30 mlml.

9.9 L/min

Which net pressure draws fluid into the capillary?

net osmotic pressure

These activities change heart rate by changing the balance of parasympathetic and sympathetic stimulation of the heart. Sort each of the activities according to whether it decreases or increases heart rate.

Decreases Heart Rate: Lying down, Digesting a meal Increases Heart Rate: Standing up, Fright or Anger, Exercise

Predict the changes in heart rate, stroke volume, and cardiac output for each of the following conditions by filling out the table below.

Increased sympathetic activity: Increase HR, SV, CO Increase Preload: No change in HR, increase SV and CO Increased exercise: Increase HR, SV, CO Increase contractility: No change in HR, increase SV and CO

Match these prefixes, suffixes and roots to their meanings.

The root word -tension means "pressure." The root word cardi- means "heart." The root word scler- means "hard." The root word vas- means "vessel." The root word hepat- means "liver."

What information can a clinician obtain from an electrocardiogram (ECG)?

abnormality in electrical activity of heart

Which of the following would cause vasodilation of arterioles?

decreased activity of the sympathetic nervous system

How would a decrease in blood volume affect both stroke volume and cardiac output?

decreased stroke volume and no change in cardiac output

The following physiological changes either increase or decrease blood pressure.

decreases blood pressure- increase blood vessel diameter increased blood pressure- Increase blood viscosity, Increase total peripheral resistance, Increase blood vessel length, Increase cardiac output, Increase blood volume

Which of the following will reduce blood pressure?

decreasing peripheral resistance

By what pathway does oxygen leave capillaries to supply body tissues?

diffusion through capillary cell membranes

What does the ECG wave tracing represent?

electrical activity of the heart

What is a common cause of valvular stenosis?

endocarditis

Which of the following would increase heart rate?

epinephrine and norepinephrine

A decrease in blood pressure at the arterial baroreceptors would result in which of the following?

an increase in heart contractility

Stimulation of the adrenal medulla would result in which of the following?

an increase in heart rate and contractility

Which of the following is a warning sign of an impending myocardial infarction?

angina pectoris

Which type of vessel has a thick tunica media?

artery

What part of the heart's intrinsic conduction system carries impulses into the interventricular septum?

atrioventricular (AV) bundle

Where does the sinoatrial node send an impulse after it initiates the electrical signal?

atrioventricular (AV) node

When threshold is reached at the SA node (an autorhythmic cell), what channels open causing further depolarization of the membrane?

fast calcium

In the capillaries, hydrostatic pressure (HP) is exerted by __________.

blood pressure

What blood vessel do you palpate when checking the pulse in your neck?

common carotid artery

An increase in sympathetic stimulation of the heart would increase stroke volume by increasing __________.

contractility

Which of the following supply the myocardium with oxygen-rich blood?

coronary arteries

Which of the following is the correct order of events as disease gets progressively worse over time?

coronary atherosclerosis, congestive heart failure, pulmonary edema

Action potentials generated by the autorhythmic cells spread to the contractile cells through what structures in the membrane?

gap junctions

What causes the aortic semilunar valve to close?

greater pressure in the aorta than in the left ventricle

What is a possible complication to arteriosclerosis?

heart attack

Pericarditis is most closely related to which of the following cardiac conditions?

inadequate amounts of serous fluid

If blood pressure is increased at the arterial baroreceptors, what would happen with the activity level of the parasympathetic nervous system (PNS) and sympathetic nervous system (SNS)?

increased PNS activity and decreased SNS activity

How would an increase in the sympathetic nervous system increase stroke volume?

increased contractility

By what mechanism would an increase in venous return increase stroke volume?

increased end diastolic volume

Which of the following would increase cardiac output to the greatest extent?

increased heart rate and increased stroke volume

Which arteries carry oxygen-rich blood into the cranial cavity?

internal carotid arteries and vertebral arteries

Which vessels drain blood from organs of the pelvic cavity?

internal iliac veins

Put the phases of the cardiac cycle in the correct order, starting after ventricular filling.

isovolumetric contraction, ventricular ejection, isovolumetric relaxation

Which chamber receives blood from the superior and inferior vena cavae?

right atrium

Which heart chamber pumps unoxygenated blood out the pulmonary trunk?

right ventricle

Jordan is told that while his atria are beating normally, his ventricles are beating slower than normal. His doctor suspects a heart block. Damage to what part of Jordan's heart is causing this problem?

the atrioventricular (AV) node

In order to cause cardiac muscle contraction, the contractile cells must also depolarize. What causes the depolarization of the contractile cells?

the flow of positive ions from adjacent cells

A pulmonary embolism can be a direct result from which of the following conditions?

thrombophlebitis

Through which valve will blood flow when leaving the right atrium?

tricuspid valve

Which of these is found in capillary walls?

tunica intima

The heart is actually (one, two, or three) pumps?

two pumps

Which of the following will slow the heart rate?

vagus nerve stimulation

Which of these will increase arterial blood pressure (BP)?

vasoconstriction of arteries

Reabsorption of fluid into the capillary takes place at the arterial end or venous end of the capillary?

venous

What does the QRS complex represent in the ECG wave tracing?

ventricular depolarization

Isovolumetric relaxation and ventricular filling (two phases of the cardiac cycle) take place during __________.

ventricular diastole

Repolarization of an autorhythmic cell is due to the opening of which channels?

voltage-gated potassium channels

Describe the pressures in the atria and ventricles that would cause the opening of the AV valves.

Pressure in the atria would be greater than the pressure in the ventricles.

Which of the following is a risk factor for developing essential hypertension?

All of the listed responses are risk factors for developing essential hypertension. (genetics, obesity, race)

Match these vocabulary terms to their meanings.

An infection of the liver is called hepatitis. Hypotension is lower than normal blood pressure. Arteriosclerosis is a condition in which arteries harden. The membrane surrounding the heart is the pericardium. A surgeon who repairs damaged blood vessels is called a vascular surgeon.

During atrial diastole, blood flows passively from the atria to fill their respective ventricles to prepare for systole. During atrial systole, atria contract completing ventricular filling. What is happening during these phases?

Atrioventricular (AV) valves are open. Blood flows passively from veins through atria into ventricles. Atria contract to force the remaining blood into the ventricles.

Which of the following occurs when the pressure in the ventricles rises higher than the pressure in the atria?

Atrioventricular valves close

During isovolumetric contraction, atria relax and ventricles begin to contract. During ventricular systole, high pressure in the ventricles pushes blood through the respective arteries. Atria and ventricles cannot contract at the same time, so the atria are in diastole during ventricular systole.

Intraventricular pressure begins to increase. Atrioventricular (AV)valves close. Intraventricular pressure rises above arterial pressure. Semilunar valves open. Ventricular ejection occurs.

After ventricular contraction, the whole heart is briefly at rest and all the valves are closed. Which of the following statements best summarizes this phase of the cardiac cycle?

Isovolumetric relaxation phase happens during ventricular diastole and the intraventricular pressure decreases.

Which of the following is correct about the filling of the ventricles?

Most blood flows passively into the ventricles through open AV valves.

Contraction of the atria results from which wave of depolarization on the ECG tracing?

P wave

Which part of the intrinsic conduction system normally initiates the depolarizing impulse that causes a heartbeat?

SA Node

Which part of the conduction system initiates the depolarizing impulse, which spreads throughout the heart?

SA node

Match the terms in the left column to the blanks near their definition on the right.

Total peripheral resistance: the amount of friction blood encounters during flow through blood vessels. Blood viscosity: the friction red blood cells encounter when moving past each other. Cardiac output: the volume of blood pumped out by one ventricle each minute. Blood pressure: the force of the blood against the vessel wall. Blood pressure returned

During exercise, cardiac output may increase by more than 170% to meet the body's increased O2 demands. This increase in cardiac output increases blood pressure. But the accompanying increase in arterial pressure is relatively small—only about 40%. What limits this increase in blood pressure so that it doesn't reach dangerously high levels during exercise?

Vasodilation causes arterial diameter to increase in the exercising skeletal muscle.

After listening to Janetta's heart for several seconds, her doctor told Janetta that she has an incompetent right atrioventricular (AV) valve. What did Janetta's doctor hear that led to that conclusion?

a swishing sound heard after the right AV valve has closed

Blood pressure would INCREASE as a result of a DECREASE in __________.

blood vessel diameter

The following activities and body conditions affect blood pressure by changing one of the two listed factors.

blood volume- blood donation; excessive sweating total peripheral resistance- high-altitude living, growth, smoking, increased sympathetic activity

The net hydrostatic pressure (HP) is the hydrostatic pressure in the __________ minus hydrostatic pressure in the __________.

capillary; interstitial fluid

Where are the sensors for the arterial baroreceptor reflex located?

carotid sinus and aortic arch

The beginning of the QRS complex of the electrocardiogram (ECG) immediately precedes which of the following events?

closing of the atrioventricular valves

Where is the radial artery located?

lateral forearm

Which heart chamber receives blood from the pulmonary veins?

left atrium

What chamber of the heart will blood enter after passing through the bicuspid valve?

left ventricle

Which chamber pumps oxygenated blood out the aorta to the systemic circuit?

left ventricle

Carla was born with a ductus arteriosus that did NOT close properly. What organ(s) would be directly affected by this congenital heart defect?

lungs

As part of a blood drive on campus for the American Red Cross, you and your friends have just donated 500 ml of blood. You are now relaxing at the student lounge, waiting for A&P lab to begin. Unfortunately, even though you are thirsty, you haven't bothered to buy yourself a drink. Other than a little soreness of the skin and tissue around your median cubital vein, you feel fine. How has your 500 mlml decrease in blood volume most likely affected your cardiac output, heart rate, and stroke volume?

no change in cardiac output, increased heart rate, decreased stroke volume

One of the changes that occurs in the pacemaker potential (unstable resting membrane potential) in the SA node (an autorhythmic cell) is a decreased efflux of what ion?

potassium

What is the function of the heart valves?

prevents backflow of blood

The colloid osmotic pressure in the capillary is caused by __________.

proteins in the blood

The anatomy of the intrinsic conduction system causes contraction of the ventricles to begin at the apex and move superiorly. Why is this important?

so blood is forced upward, toward the semilunar valves

Which of these describes a fenestrated capillary?

special capillary type with small pores found in tissue where absorption is important

Which of these will decrease heart rate?

stimulation by vagus nerves

From what organs does the hepatic portal vein receive blood?

stomach, intestine, spleen, and pancreas

What term refers to the contraction of the heart?

systole