Advanced Biology Heart

Size, Shape, Location Fist Fist Hollow, cone shaped Hollow, cone shaped Mediastinum, Rests on diaphragm, posterior to sternum, Lungs on each side Mediastinum, Rests on diaphragm, posterior to sternum, Lungs on each side

Size, Shape, Location 2/3 lie to left of midsternal line 2/3 lie to left of midsternal line Points toward right shoulder and left hip (apex, PMI) Points toward right shoulder and left hip (apex, PMI)

Structure/Function 4 Chambers 2 Superior Atria 2 Superior Atria 2 Inferior Ventricles 2 Inferior Ventricles Divided by interatrial/interventricular septum Divided by interatrial/interventricular septum

Structure/Function 4 Chambers Most Mass in Right and Left Ventricles; pumping chambers Most Mass in Right and Left Ventricles; pumping chambers Right= Forms most of the anterior surface Right= Forms most of the anterior surface Left= Forms inferoposterior aspect. Much more muscular! Left= Forms inferoposterior aspect. Much more muscular!

Structure/Function 4 Chambers Posterior Atrial walls are smooth Posterior Atrial walls are smooth Anterior Atrial walls are rigid with bundles of muscle tissue Anterior Atrial walls are rigid with bundles of muscle tissue Atria are the Receiving chambers; thin walled Atria are the Receiving chambers; thin walled

Pathway of Blood Blood Flow through chambers Blood Flow through chambers Right Atrium – Superior Vena Cava, Inferior Vena Cava, Coronary Sinus Right Atrium – Superior Vena Cava, Inferior Vena Cava, Coronary Sinus Left Atrium – 4 Pulmonary veins pump blood back Left Atrium – 4 Pulmonary veins pump blood back

Pathway of Blood Right Ventricle – pumps blood to pulmonary trunk (goes to lungs) Right Ventricle – pumps blood to pulmonary trunk (goes to lungs) Left Ventricle – pumps blood to Aorta, then out to body Left Ventricle – pumps blood to Aorta, then out to body

Pathway of Blood Valves – Atrioventricular (AV) Valves – Atrioventricular (AV) Right – Tricuspid Right – Tricuspid Left – Bicuspid Left – Bicuspid Semilunar valves in pulmonary trunk/aorta Semilunar valves in pulmonary trunk/aorta

Pathway of Blood Pulmonary Circuit – Pulmonary veins have blood with oxygen Pulmonary Circuit – Pulmonary veins have blood with oxygen Pulmonary arteries have blood without oxygen Pulmonary arteries have blood without oxygen

Pathway of Blood Systemic Circuit – Arteries have blood with oxygen Systemic Circuit – Arteries have blood with oxygen Veins have blood without oxygen Veins have blood without oxygen See page 662 See page 662

Major Branches Coronary Circulation – supply blood to the heart Coronary Circulation – supply blood to the heart Left Coronary – runs to left side and divides into two parts Left Coronary – runs to left side and divides into two parts

Major Branches Anterior Interventricular artery Anterior Interventricular artery Supplies blood to interventricular septum and anterior walls of ventricles Supplies blood to interventricular septum and anterior walls of ventricles

Major Branches Circumflex artery Circumflex artery Supplies blood to the left atrium and posterior wall of left ventricle Supplies blood to the left atrium and posterior wall of left ventricle

Major Branches Right Coronary – Runs to the right and also divides into two parts Right Coronary – Runs to the right and also divides into two parts

Major Branches Marginal Artery – lateral part of right side of heart (atrium) Marginal Artery – lateral part of right side of heart (atrium) Posterior interventricular artery – Runs to the apex, supplies posterior ventricle walls Posterior interventricular artery – Runs to the apex, supplies posterior ventricle walls

Major Branches Cardiac Veins – 1 major, 3 minor that dump into Cardiac Veins – 1 major, 3 minor that dump into Coronary Sinus – empties blood into the right atrium. Coronary Sinus – empties blood into the right atrium. Located on Posterior side Located on Posterior side

Major Branches Great Cardiac Vein – Found in the anterior interventricular sulcus (groove) Great Cardiac Vein – Found in the anterior interventricular sulcus (groove) Middle Cardiac Vein – In posterior interventricular sulcus Middle Cardiac Vein – In posterior interventricular sulcus

Major Branches Small Cardiac Vein – runs along heart’s right inferior margin Small Cardiac Vein – runs along heart’s right inferior margin Several other anterior cardiac veins empty directly into Right Atrium Several other anterior cardiac veins empty directly into Right Atrium

Problems? Myocardial Infarction (MI) – Heart Attack. Myocardial Infarction (MI) – Heart Attack. Blockage to coronary arteries reduces blood flow Blockage to coronary arteries reduces blood flow Damage to the Left Ventricle is the most serious Damage to the Left Ventricle is the most serious

Conduction System Intrinsic Cardiac Conduction System – Non-contractile cells that initiate and distribute impulses Intrinsic Cardiac Conduction System – Non-contractile cells that initiate and distribute impulses

Conduction System Sinoatrial Node (SA) – In right atria Sinoatrial Node (SA) – In right atria Heart’s Natural Pacemaker Heart’s Natural Pacemaker Atrioventricular Node (AV) – In interatrial septum above tricuspid valve Atrioventricular Node (AV) – In interatrial septum above tricuspid valve

Conduction System Atrioventricular Bundle (bundle of His) – electrical connection between atria and ventricle Atrioventricular Bundle (bundle of His) – electrical connection between atria and ventricle Bundle Branches – Run down interventricular septum to apex Bundle Branches – Run down interventricular septum to apex

Conduction System Purkinje Fibers – penetrate apex, run superiorly up ventricle walls Purkinje Fibers – penetrate apex, run superiorly up ventricle walls Like milking a cow Like milking a cow

ECG Electrocardiograph Electrocardiograph Waves include Waves include P – SA node sends first impulse P – SA node sends first impulse

ECG QRS – Ventricular depolarization QRS – Ventricular depolarization Precedes ventricular contraction Precedes ventricular contraction T – Ventricular Repolarization T – Ventricular Repolarization

ECG Intervals Intervals P-R (P-Q) – Beginning of atrial excitation and ventricular contraction P-R (P-Q) – Beginning of atrial excitation and ventricular contraction Q-T – Action potential through Heart Q-T – Action potential through Heart

Cardiac Cycle Systole – Contraction of ventricles or atria Systole – Contraction of ventricles or atria Diastole – Relaxation of ventricles or atria Diastole – Relaxation of ventricles or atria

Cardiac Cycle Systolic Pressure – Ventricular contraction 120mmHg Systolic Pressure – Ventricular contraction 120mmHg Diastolic Pressure – Ventricular refilling 80mmHg Diastolic Pressure – Ventricular refilling 80mmHg Hypertension – High BP Hypertension – High BP Hypotension – Low BP Hypotension – Low BP

Heart Sounds Lub-dup Lub-dup Lub – AV valves close (systole) Lub – AV valves close (systole) Dup – SL valves close (diastole) Dup – SL valves close (diastole)

Heart Sounds Murmurs – obstructions in BV Murmurs – obstructions in BV Thin walled vibrations Thin walled vibrations

Cardiac Output CO = amount of blood pumped by each ventricle in 1 minute CO = amount of blood pumped by each ventricle in 1 minute CO = HR x SV (stroke volume) CO = HR x SV (stroke volume) SV = Volume of blood pumped out by ventricle (Force of contraction) SV = Volume of blood pumped out by ventricle (Force of contraction)

Cardiac Output CO = 75 bpm x 70mLpb CO = 75 bpm x 70mLpb CO = 5250 mL/min CO = 5250 mL/min

Developmental Aspects Heart pumps by 23 rd day Heart pumps by 23 rd day 1-2 days later, chambers start to form 1-2 days later, chambers start to form Chambers are: Chambers are:

Developmental Aspects Sinus venosus – receives all venous blood, becomes Rt. Atrium & Coronary Sinus, SA node Sinus venosus – receives all venous blood, becomes Rt. Atrium & Coronary Sinus, SA node Atrium – becomes muscle ridged parts of atrium Atrium – becomes muscle ridged parts of atrium

Developmental Aspects Ventricle – Becomes left ventricle Ventricle – Becomes left ventricle Bulbus cordis – Gives rise to the pulmonary trunk, first part of the aorta, most of the right ventricle Bulbus cordis – Gives rise to the pulmonary trunk, first part of the aorta, most of the right ventricle

Age Related Changes Sclerosis – Thickening of valve flaps Sclerosis – Thickening of valve flaps Decline in Cardiac Reserve – Heart is less able to adjust to changes Decline in Cardiac Reserve – Heart is less able to adjust to changes

Age Related Changes Fibrosis of cardiac muscle – Scarred nodes, increase in arrhythmias Fibrosis of cardiac muscle – Scarred nodes, increase in arrhythmias Atherosclerosis – acclerated by inactivity, smoking, stress. CV disease Atherosclerosis – acclerated by inactivity, smoking, stress. CV disease