UNIT 2THE CIRCULATORY SYSTEMCHAPTER 12

WELCOME!JULIE J. MCDONALD, BS, MPT

TODAY’S AGENDA

WelcomeCourse Questions, Problems & Issues

Seminar discussion

COURSE QUESTIONS, PROBLEMS & ISSUES

UNIT 1 ISSUES TO REVIEWUniversal Donor: Type O—no A or B antigens present on cells

Universal Recipient: Type AB—no A, B or O antibodies present in plasma

Erythroblastosis fetalis: Rh- mom has second Rh+ baby; mom’s Rh antibodies attack baby’s Rh+ cells; prevented by giving Mom RhoGam after first delivery

UNIT 1 ISSUES TO REVIEWHemoglobin: A chemical pigment in the RBCs that traps O2; made up of protein chains and Fe+ atoms

WBCs: Differential count measures proportions of each type of WBC in blood sample

Phagocytes: Neutrophils most numerous; Eosinophils weak; Monocytes most agressive

UNIT 1 ISSUES TO REVIEWAnticoagulants: Coumadin, Heparin (NOT Vitamin K)

Embolus: Circulating blood clot (a thrombus that has broken free)

CHAPTER 12 THE CIRCULATORY SYSTEM

HeartBlood Vessels

CirculationBlood Pressure

LOCATION, SIZE, AND POSITION OF THE HEART

In mediastinum 2/3 to the left of the body midline Apex = point

Most inferior portion

Shape and size of a closed fist Septum divides right and left sides(internally)

ANATOMY OF THE HEART Heart chambers

Upper Right and left atria (atrium) Small chambers Receiving Chambers

Lower Right and left ventricles Larger chambers Discharging Chambers

SUMMARY OF LAYERS OF THE HEART

Outside (external) to Inside (internal) Parietal Pericardium Pericardial cavity (filled with fluid) Visceral Pericardium/Epicardium Myocardium Endocardium

THREE LAYERS OF THE HEART WALL

Epicardium Outer layer Connective tissue

Myocardium Middle layer Thick Muscle (My/o)

Endocardium Inner layer (lining) Very thin, smooth

CORONARY CIRCULATION

Blood for the myocardium of the heart, flows through the right and left coronary arteries

Blockage of blood flow through the coronary arteries can cause myocardial infarction (heart attack)

Coronary Circulation

VESSELS

Pulmonary Arteries Carry de-oxygenated blood from R ventricle

to lungs R pulmonary artery to R lung L pulmonary artery to L lung

Pulmonary Veins Carry oxygenated blood from lungs to L atria

R pulmonary veins from R lung L pulmonary veins from L lung

VESSELS (CONT.) Vena Cava

Largest VeinsInferior (IVC) and Superior (SVC)Empties blood into R atrium from systemic circulation

VALVES Cuspid valves

Tricuspid: between right atrium and ventricle Bicuspid (mitral): between left atrium and ventricle Open and close from chordae tendineae

Semilunar valves Pulmonary Semilunar: base of pulmonary arteries Aortic Semilunar: base of aorta Open and close from pressure within heart

Heart Valves

THE HEART ACTS AS TWO PUMPS

Right atrium and ventricle

pump deoxygenated blood to the lungs“Pulmonary Circulation”

Left atrium and ventricle pump oxygenated blood to the body

“Systemic Circulation

BLOOD FLOW PATHWAY

➥Right atrium➥Tricuspid valve➥Right ventricle➥Pulmonary Semilunar

Valve➥Pulmonary Arteries➥LungsLungs ➡

➥Pulmonary Veins➥Left atrium➥Bicuspid valve➥Left Ventricle➥Aortic Semilunar Valve➥Aorta➥Arterioles➥Capillaries➡O₂/CO₂

exchange

The Heart—Actions Relaxation: Diastole Contraction: Systole

CONDUCTION SYSTEM OF THE HEART

SA (sinoatrial) node The pacemaker In wall of right atrium near superior vena cava

AV (atrioventricular) node In the floor of right atrium near septum

AV bundle (bundle of His) Located in the septum of the ventricle

Purkinje fibers— Located in the walls of the ventricles Cause contraction of myocardium

Coordination of impulses cause atrial contraction f/b ventricular contraction…

CONDUCTION SYSTEM OF THE HEART

The normal ECG has three deflections or waves called the P wave, the QRS complex, and the T waveP wave—associated with depolarization of the atria

QRS complex—associated with depolarization of the ventricles

T wave—associated with repolarization of the ventricles

HEART SOUNDS Two distinct heart sounds in every

heartbeat or cycle—“lubb-dupp”

First (lubb) sound is caused by the vibration and closure of AV valves during contraction of the ventricles

Second (dupp) sound is caused by the closure of the semilunar valves during relaxation of the ventricles

CARDIAC CYCLE Heart beat is regular and rhythmic—each

complete beat called a cardiac cycle—average is about 72 beats per minute

Each cycle, about 0.8 seconds long, subdivided into systole (contraction phase) and diastole (relaxation phase)

CARDIAC CYCLE Stroke volume is the volume of blood ejected from

one ventricle with each beat Cardiac output is amount of blood that one

ventricle can pump each minute—average is about 5 L per minute at rest

Blood Pressure= measures the gradient between pressure at the aorta and vena cava

MABP= CO x SV

SOME OTHER ODDS AND ENDS…Assignment– Unit 4

Unit 3- Lymphatic System and Immunity