1

Essentials of Human Anatomy & Physiology

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Slides 11.1 – 11.19

Seventh Edition

Elaine N. Marieb

Chapter 11

The Cardiovascular System

Lecture Slides in PowerPoint by Jerry L. Cook

Functions of the Cardiovascular

system

Slide 11.2aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Function of the heart: to pump blood

• Function of the blood vessels: to provide the conduits within which blood circulates to all body tissues

• Function of the lymphatic system: to return leaked plasma to the blood vessels after cleansing it of bacteria and other foreign matter

Circulatory System vs.

Cardiovascular system

Slide 11.2aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Circulatory system = cardiovascular system and the lymphatic system

• Cardiovascular system: muscular pump with one way valves (heart) and contains large and small plumbing tubes that the blood travels through (vessels).

The Heart

Slide 11.2bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Location and size:

Heart – size of a person’s fist

Weighs less than a pound

Flanked by the lungs

Apex (point) is pointed towards the left hip

Rests on the diaphragm

Base – points toward the right shoulder

The Heart

Slide 11.2bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 11.1

The Heart: Coverings

Slide 11.3Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Pericardium – double sac of serous membrane providing a nearly frictionless for the heart to beat in.

• A slippery lubricating fluid is produced by the pericardial membrane and allows the heart to beat easily.

2

The Heart: Heart Wall

Slide 11.4Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• 3 layers

•Epicardium

•Outer layer of the heart part of the pericardium

•Myocardium

• Thick bundles of cardiac muscle

•Reinforced by thick connective tissue

•Endocardium

• Thin sheet of endothelium

• Lines chamber of heart

•Continues with the lining of blood vessels leaving and entering the heart.

External Heart Anatomy

Slide 11.5Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.2a

The Heart: Chambers

Slide 11.6Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Two atria and two ventricles

• Lined with endocardium

•Atria

•Receiving chambers

•Not important in the pumping activity of the heart

•Blood flows from the veins through the atria and usually straight to the ventricles

•Ventricles

•Discharge Chambers

•Pumps of the heart

The Heart: Septum

Slide 11.6Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Septum divides the left and the right side of the heart

•Interventricular divides ventricles

•Interatrial divides atrium

The Heart works as a double pump

Slide 11.6Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Heart is twisted

• Right side is for the pulmonary circuit (lungs)

• Pulmonary circuit

•Receives blood from inferior and superior vena cava

•Pumps blood out through the pulmonary trunk

•Splits into right and left pulmonary arteries

•To right and left lung

•Oxygen is picked up and Carbon dioxides

•Pulmonary vein returns blood to the left atria

Blood Circulation

Slide 11.7Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

•Systemic circulation

•Left atria

•Left ventricle

•Aorta

•Systemic arteries branch to

supply all body tissue

3

Blood Circulation

Slide 11.7Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 11.3

The Heart: Valves

Slide 11.8Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Four valves

• Allows blood to flow in one direction

• Atrioventricular valves (AV Valves)

•Between atria and ventricles

•Left AV Valve

•Bicuspid

•Two cusps

The Heart: Valves

Slide 11.9Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Right AV Valve

•Tricuspid

•Three cusps

• Chordate tendineae

•Tiny chords that anchor the cusps to the heart wall.

• Heart is relaxed blood passively fills atria

The Heart: Valves

Slide 11.9Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• AV valve hangs into ventricle

• Ventricle contracts

•AV valve forced up and closes

•Blood does not go into atria

Semilunar valve

Slide 11.9Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Valves that leave the ventricles

• Pulmonary Valve

• Aortic semilunar valve

• When ventricles contract cusps are forced open and blood moves through

• As blood pressure decreases blood flows back and gathers in cusps causing them to close

Operation of Heart Valves

Slide 11.10Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 11.4

AV valves

open when

heart relaxes

and closed

when

ventricles

contract

4

Operation of Heart Valves

Slide 11.10Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 11.4

Semilunar

valves are

closed

during

relaxation

and open

during

contraction

Problems with valves

Slide 11.9Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Problems with valves

• Leaky valves

• OK as long as small

• Incompetent valve forces the heart to pump and repump the same blood

• Valvular stenosis

•Valve flaps are stiff

•Caused by repeated bacterial infections of the endocardium

Coronary Circulation

Slide 11.12Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Blood in heart does not nourish the myocardium

• Right and left coronary arteries (off of the aorta) nourish the heart

• Compress when the ventricles are contracting and fill when the heart is relaxed

• Myocardium is drained by cardiac vein

• Cardiac vein empties into the coronary sinus

• Coronary sinus empties into the right atrium

Problems with Coronary circulation

Slide 11.12Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Heart beats rapidly

•Myocardium receives inadequate blood

•Not enough relaxation to get blood to the heart

•Myocardium is deprived of oxygen

•Angina pectoris results

•Crushing chest pains

Angina

Slide 11.12Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Angina is prolongs cells may die and a infarct can occur = myocardial infarct

•Heart attack or coronary

•Heart not receiving adequate blood

Physiology

Slide 11.12Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• One day – 6 quarts of blood through your body over 1,000.

5

The Heart: Conduction System

Slide 11.13aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Regular, spontaneous, independent contractions of the heart

•Atrial cells beats about 60 times/minute

•Ventricular cells beat about 20-440 times/minute

•Therefore they need a mechanism, that will synchronize the cells

Regulation of Heart Rate

Slide 11.20Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Autonomic nervous system

•Increases and decreases the heart rate

Regulation of Heart Rate - Intrinsic

conduction system (nodal system)

Slide 11.20Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Built into the heart tissue

• Cross between muscle and heart tissue

• Heart depolarizes in one direction

•Atria to ventricles

• Heart rate is set at about 75 beats/minute

Regulation of Heart Rate - Intrinsic

conduction system (nodal system)

Slide 11.20Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Heart beats as a coordinated unit measured with Electrocardiography

• Sinoatrial nodes (SA nodes)

•Right atrium

•Highest rate of depolarization

•Starts each heart beat

•Sets the pace for the whole heart

•Often called the pacemaker

Regulation of Heart Rate - Intrinsic

conduction system (nodal system)

Slide 11.20Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Atrioventricular node (AV node)

• Junction of the atria and ventricle

•Atrioventricular bundle (AV bundle) or Bundle of His

•Right and left bundle branches into the interventricular septum

•Purkinje fibers spread between the muscle of the ventricle wall

Regulation of Heart Rate - Intrinsic

conduction system (nodal system)

Slide 11.20Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• SA node through the atria to the AV node = atria contracts

• AV node delays impulse briefly to allow atria to finish contraction

• Through the AV bundle, the bundle branches, and the Purkinje fibers = wringing contraction

•Begins at the heart apex and moves toward the atria

• Page 334

6

Heart Contractions

Slide 11.14bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 11.5

The Heart: Cardiac Cycle and Heart

Sounds

Slide 11.16Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Atria contract simultaneously, and as they relax, contraction of the ventricles begin

• Systole

•Contraction of the ventricles

• Diastole

•Relaxation of the ventricles

The Heart: Cardiac Cycle

Slide 11.17Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Cardiac cycle = one complete heart beat

• Average heart beat is about 75 times/minute

The Heart: Cardiac Cycle

Slide 11.17Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Length of the cardiac cycle is about .8 seconds

•Mid to late diastole

•Heart in complete relaxation

•Heart pressure is low

•Blow flows passively through the atria to the ventricles

•Semilunar valves are closed

•AV valves are open

•Atria contracts and remaining blood moves into the ventricles

The Heart: Cardiac Cycle

Slide 11.17Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Ventricular systole

•Shortly after ventricular contraction (systole)

•Ventricular pressure increases and AV valves close

•Semilunar valves are forced open and blood rushes through them and out the ventricles

•Atria are relaxed and begin to fill with blood

The Heart: Cardiac Cycle

Slide 11.17Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Early diastole

•Ventricles relax

•Semilunar valves shut

•Interventricular pressure drops

•AV Valves are forced open and the ventricles again begin to refill rapidly with blood

7

Filling of Heart Chambers –the Cardiac Cycle

Slide 11.15Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 11.6

The Heart: Cardiac Cycle

Slide 11.17

• Heart sounds + lub dup

• Lub

•Closing of AV valve

•Dup

•Semilunar valves shut

•Abnormal heart sounds

•Murmurs

•Usually indicate valve problems

•Not fully shut swishing sound after the valve should have shut

The Heart: Cardiac Output

Slide 11.18

• Amount of blood pumped out by each side of the heart in 1 minute

• Product of the heart rate and stroke volume

• Average

•75 beats/minutes X 70 ml/beat = 5250 ml/min

•All of the blood in the body circulates in about 1 minute

The Heart: Cardiac Output

Slide 11.18Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Regulation of Stroke volume

•Healthy heart pumps about 60% of blood in it

•70 ml (2 ounces) with each heartbeat

The Heart: Cardiac Output

Slide 11.18Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• More the heart walls stretch stronger the contraction

•More venous return

•Amount of blood entering the heart and distending the ventricles

•Anything that increases volume or speeds venous return increases stroke volume and force of contraction

Cardiac Output Regulation

Slide 11.19Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 11.7