The Heart 4-chambered muscular double pump Right-side collects and delivers deO 2 blood to lungs Left-side collects and delivers O 2 blood to the heart

The Electrical Heart The heart can contract and relax (i.e. beat) on its own It is wired for action (SA node, AV node and Purkinje fibres) The medulla oblongata of the brainstem controls that rate at which the heart beats The amount of CO 2 in the blood determines the heart rate

Electrical Activity of the Heart

Structures of the Heart

Structure & Function of Heart Superior vena cavaReturns deO 2 blood to RA from upper body Inferior vena cavaReturns deO 2 blood to RA from lower body Right atrium (RA)Collects and pumps blood to RV Right atrioventricular valve (tricuspid valve) Closes to prevent backflow of blood into RA; responsible for LUB sound Right ventricle (RV)Contracts and pumps blood to lungs

Pulmonary trunkA large artery exiting the RV responsible for conducting deO 2 blood to lungs. Right semi-lunar valve (pulmonary valves) Closes to prevent blood from returning to the RV when ventricle relaxes. Responsible for the DUB heart sound heard with a stethoscope. R and L Pulmonary arteries Divisions of pulmonary trunk that conduct deO 2 blood to the R and L lungs for gas exchange. Pulmonary capillariesSite of gas exchange in lungs. Pulmonary veinsCarry O 2 blood from R and L lungs to the LA Left atrium (LA)Collects and pumps blood to LV Left atrioventricular valve (mitral valve) Closes to prevent blood from returning to LA when the LV contracts (systole). Responsible for LUB heart sound heard with a stethoscope. Left ventricle (LV)Contracts and pumps (systole) blood to the body by way of the aorta

AortaLargest artery in body. Artery that exits from the LV and conducts O 2 blood to the body. Left semi-lunar valve (aortic valve) Closes to prevent blood from returning to the LV when ventricle relaxes (diastole). Responsible for the DUB heart sound heard with a stethoscope. Carotid arteriesDivisions of aorta that conduct O 2 blood to the head Descending aortaContinuation of aorta that sub-divides into smaller arteries that conduct O 2 blood to all organs of the lower body (systemic circulation). PericardiumA thick double membrane that protects the heart from physical injury as it bumps against the ribcage. Keeps the heart moist. SeptumThick muscular wall that subdivides the L and R sides of the heart

Coronary arteriesArteries that branch off the aorta and conduct O 2 and nutrients to the heart muscle itself. Site of blockages that lead to angina and heart attacks. Coronary veinsVeins that collect wastes including CO 2 from the heart muscle and conduct them to the vena cavae

Monitoring Circulatory Health Drawing a blood sample for a CBC (complete blood count) test or heart enzymes test (to indicate heart damage due to a heart attack) Feeling for a pulse (number of heart beats per minute) Listening to heart sounds (normal or a heart murmur) using a stethoscope

Monitoring Circulatory Health Using a sphygmomanometer to measure blood pressure (looking for evidence of hypotension or hypertension) Perform an electrocardiogram (ECG – to check out electrical activity of heart for unusual patterns)

Monitoring Circulatory Health Perform an echocardiogram (using ultrasound to check on heart valve function) Performing an angiogram (use dyes/contrasts to look for blockages of coronary arteries that may cause angina or a heart attack)

Coronary Heart Disease Treatment

The Excretory System Excretion – ridding of water-soluble wastes from body Excretory organs – kidneys, lungs and skin Kidneys – remove excess H 2 O and wastes (urea, salts & vitamins from blood); balance water levels in body 1-2 L urine per day

The End