Essentials of Human Anatomy & Physiology Slides 11.1 – Seventh Edition Chapter 11 The Cardiovascular System

The Cardiovascular System Slide 11.1  A closed system of the heart and blood vessels  The heart pumps blood  Blood vessels allow blood to circulate to all parts of the body  Function:  deliver oxygen and nutrients  remove carbon dioxide and other waste products

The Heart Slide 11.2b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.1  Location  Thorax between the lungs  Pointed apex directed toward left hip  Base (great vessels emerge here) pointed towards right shoulder  About the size of your fist

The Heart: Coverings Slide 11.3 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Pericardium – a double serous membrane  Visceral pericardium  Next to heart  Parietal pericardium  Outside layer  Serous fluid fills the space between the layers of pericardium

The Heart: Heart Wall Slide 11.4 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Three layers 1.Epicardium  Outside layer  This layer is the parietal pericardium  Connective tissue layer 2.Myocardium  Middle layer  Mostly cardiac muscle 3.Endocardium  Inner layer  Endothelium

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

The Heart: Chambers Slide 11.6 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Right and left side act as separate pumps  Four chambers  2 Atria  Receiving chambers  Right atrium (from body)  Left atrium (from lungs)  2 Ventricles  Discharging chambers  Right ventricle (to lungs)  Left ventricle (to body)

The Heart: Associated Great Vessels Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Aorta  Leaves left ventricle  Pulmonary arteries  Leave right ventricle  Vena cava  Enters right atrium  Pulmonary veins (four)  Enter left atrium

Types of BodyCirculations 1.Pulmonary circulation right ventricle, left atrium, pulmonary arteries & veins Blood circulation to and from lungs 2.Systemic circulation Left ventricle, right atrium, aorta, vena cava Blood circulation to and from body 3.Coronary circulation Coronary arteries & veins that nourish the heart Blockages in these arteries cause heart attacks

Blood Circulation Slide 11.7 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.3

Blood circulation Blue: oxygen-poor blood Red: oxygen-rich blood Body  Superior & inferior vena cava  right atrium  tricuspid valve  right ventricle  pulmonary semilunar valve  pulmonary artery  lungs  pulmonary vein  left atrium  bicuspid valve  left ventricle  aortic semilunar valve  aorta  body

The Heart: Valves Slide 11.8 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Allow blood to flow in only one direction  Four valves  Atrioventricular valves – between atria and ventricles  Bicuspid/mitral valve (left)  Tricuspid valve (right)  Semilunar valves between ventricle and artery  Pulmonary semilunar valve  Aortic semilunar valve

The Heart: Valves Slide 11.9 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Valves open as blood is pumped through  Held in place by chordae tendineae (“heart strings”)  Close to prevent backflow Chordae tendineae

Cardiac Cycle Animation topics/topics/hhw/contraction.htmlhttp:// topics/topics/hhw/contraction.html

Operation of Heart Valves Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.4

Let’s Review

Filling of Heart Chambers – the Cardiac Cycle Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.6

The Heart: Cardiac Cycle Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Atria contract simultaneously  Atria relax, then ventricles contract  Systole = contraction of ventricles  Diastole = relaxation of ventricles

The Heart: Cardiac Cycle Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Cardiac cycle – events of one complete heart beat  Mid-to-late diastole – blood flows into ventricles  Ventricular systole – blood pressure builds before ventricle contracts, pushing out blood  Early diastole – atria finish re-filling, ventricular pressure is low

The Heart: Conduction System Slide 11.13a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  2 systems regulate heart activity 1.Nerves of ANS that increase or decrease heart rate 2.Intrinsic conduction system (nodal system) that is built into the heart tissue  Heart muscle cells contract, without nerve impulses, in a regular, continuous way

The Heart: Conduction System Slide 11.13b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Special tissue sets the pace  Sinoatrial (SA) node (right atrium)  Aka: Pacemaker  Atrioventricular (AV) node  Atrioventricular (AV) bundle  Bundle branches  Purkinje fibers

Heart Contractions Slide 11.14a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Contraction is initiated by the sinoatrial node (pacemaker)  Starts depolarization & sets pace of heart beat  Sequence of events: SA node  AV node  AV bundle  bundle branches  Purkinje fibers  AV stimulates atria; bundle branches & Purkinje stimulate ventricles

Heart Contractions Slide 11.14b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.5

Heart Contractions Electricity Video ideoId=10006&cId=7&type=relhttp:// ideoId=10006&cId=7&type=rel

Measuring the Cardiac Cycle: The Electrocardiogram (ECG or EKG)

EKG: Important Curves P: atrial depolarization (atria squeeze) QRS: ventricular depolarization (ventricles squeeze) T: ventricular repolarization (ventricles relax)

EKG: Actions in the Heart Atrial depolarization Ventricular depolarization Ventricular repolarization P curveQRS curveT curve

How to Read an EKG how-to-read-an-electrocardiogram-ecgekg/ how-to-read-an-electrocardiogram-ecgekg/

Blood Vessels: The Vascular System Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Taking blood to the tissues and back  Arteries  Arterioles  Capillaries  Venules  Veins

The Vascular System Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.8b

Blood Vessels: Anatomy Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Three layers (tunics)  Tunic intima  Endothelium  Tunic media  Smooth muscle  Controlled by sympathetic nervous system  Tunic externa  Mostly fibrous connective tissue

Differences Between Blood Vessel Types Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Walls of arteries are the thickest  Lumens of veins are larger  Skeletal muscle “milks” blood in veins toward the heart  Walls of capillaries are only one cell layer thick to allow for exchanges between blood and tissue

Movement of Blood Through Vessels Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Most arterial blood is pumped by the heart  Veins use the milking action of muscles to help move blood  Veins has valves that prevent backflow of blood due to gravity Figure 11.9

Capillary Beds Slide 11.28a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Capillary beds consist of two types of vessels  Vascular shunt – directly connects an arteriole to a venule Figure 11.10

Capillary Beds Slide 11.28b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  True capillaries – exchange vessels  Oxygen and nutrients cross to cells  Carbon dioxide and metabolic waste products cross into blood Figure 11.10

Diffusion at Capillary Beds Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.20

Capillary Exchange Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Substances exchanged due to concentration gradients  Oxygen and nutrients leave the blood  Carbon dioxide and other wastes leave the cells

Capillary Exchange: Mechanisms Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Direct diffusion across plasma membranes  Endocytosis or exocytosis  Some capillaries have gaps (intercellular clefts)  Plasma membrane not joined by tight junctions  Fenestrations of some capillaries  Fenestrations = pores

Major Arteries of Systemic Circulation Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.11

Summary of Major Arteries Ascending aorta Carotid arteries: to head Descending aorta Subclavian artery: to arms Femoral arteries: to legs

Major Veins of Systemic Circulation Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.12

Summary of Major Veins Superior Vena Cava: drains structures above heart Jugular Veins: drains head Inferior Vena Cava: drains structures below heart Subclavian Vein: drains arm Femoral Vein: drains leg Hepatic Portal System: drains the abdominal organs

Hepatic Portal Circulation Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.14

Circulation to the Fetus Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure Fetal circulation skips the lungs since fetus is receiving oxygen from placenta that is supplied by mother’s blood Does this via the: 1.Ductus arteriosus: between aorta & pulmonary truck 2.Foramen ovale: between right & left atria

The Heart: Regulation of Heart Rate Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Stroke volume usually remains relatively constant  Starling’s law of the heart – the more that the cardiac muscle is stretched, the stronger the contraction  Changing heart rate is the most common way to change cardiac output

Cardiac Output Regulation Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.7

The Heart: Regulation of Heart Rate Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Increased heart rate  Sympathetic nervous system  Crisis  Low blood pressure  Hormones  Epinephrine  Thyroxine  Exercise  Decreased blood volume

The Heart: Regulation of Heart Rate Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Decreased heart rate  Parasympathetic nervous system  High blood pressure or blood volume  Decreased venous return of blood

The Heart: Cardiac Output Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Cardiac output (CO)  Amount of blood pumped by each side of the heart in one minute  CO = (heart rate [HR]) x (stroke volume [SV])  Stroke volume  Volume of blood pumped by each ventricle in one contraction

Pulse Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Pulse – pressure wave of blood  Monitored at “pressure points” where pulse is easily palpated Figure 11.16

Blood Pressure Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Measurements by health professionals are made on the pressure in large arteries  Systolic – pressure at the peak of ventricular contraction  Diastolic – pressure when ventricles relax  Pressure in blood vessels decreases as the distance away from the heart increases

Measuring Arterial Blood Pressure Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.18

Comparison of Blood Pressures in Different Vessels Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.17

Blood Pressure: Effects of Factors Slide 11.39a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Neural factors  Autonomic nervous system adjustments (sympathetic division)  Causes vasoconstriction, which narrows the blood vessels & increases BP  Renal factors (in kidneys)  Regulation by altering blood volume  BP too high, kidneys excrete more urine  Renin – hormonal control (vasoconstriction)

Blood Pressure: Effects of Factors Slide 11.39b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Temperature  Heat has a vasodilation effect (increases diameter of blood vessels)  Cold has a vasoconstricting effect  Chemicals  Various substances can cause increases or decreases  Diet can prevent hypertension

Factors Determining Blood Pressure Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.19

Variations in Blood Pressure Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Human normal range is variable  Normal  140–110 mm Hg systolic  80–75 mm Hg diastolic  Hypotension  Low systolic (below 110 mm HG)  Often associated with illness  Hypertension  High systolic (above 140 mm HG)  Can be dangerous if it is chronic

Developmental Aspects of the Cardiovascular System Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  A simple “tube heart” develops in the embryo and pumps by the fourth week  The heart becomes a four-chambered organ by the end of seven weeks  Few structural changes occur after the seventh week