2. Aerobic health

= circulates blood and lymph through body consisting of heart blood vessels, blood lymph and lymphatic vessels/glands = humans have a closed circulatory system. • physically separated from the rest of the body • Consists of vessels and a pump • Humans have a double circulatory system as our heart is divided completely into right and left sides

artery = Carries AWAY from the heart Venous = Returns blood to the heart

= generates a pressure to forces blood continuously around the body • composed predominantly of cardiac muscle • One way flow • Left side is more muscular as it pumps blood all around the body • right side only pumps to the lungs

Right Atrium = receives blood from the superior and inferior vena cava and the coronary sinus Right Ventricle = receives blood from the right atrium and sends blood to the lungs Left atrium = Receives blood from the pulmonary veins Left ventricle = Receives blood from the left atrium and sends blood all over the body. - wall of left ventricle is much thicker than the right as it pumps oxygenated blood all over the body rather than just to the lungs. • ventricles produce high pressures and are discharging chambers that push the blood back out of the heart

= Sac like structure with two layers. • keeps the heart contained in the chest cavity • prevents the heart from over-expanding when blood volume increases • limits heart motion • pericardial fluid reduces friction between the two membranes of the serous pericardium. • Fibrous pericardium = tough, fibrous sac • Serous pericardium = parietal lay and visceral layer (epicardium) • Pericardial cavity = in-between the 2 layers of the serous pericardium and contains pericardial fluid

• Epicardium = outer • Myocardium = muscle • Endocardium = inner

Artery • can withstand pressure • elastic wall enable to absorb pressure • can alter in diameter due to blood pressure and environmental changes • carry blood away from the heart Capillaries - microscopic vessels that connect to arterioles and venule’s - single layer walls allow for nutrients and waste to exchange between blood and cells Veins • several venules • carry deoxygenated blood

= cardiac muscle contraction • myocardium muscles that contracts through process of sliding filaments Intercalated discs unique structural formations found between the myocardial cells of the heart.

= unique structural formations found between the myocardial cells of the heart that contain 2 cell junctions: • Desmosomes = hold fibre structures together so heart doesn’t pull apart. • Gap Junctions = allows electric pulse to move cell to cell so the heart beats are synchronised. - they enable the myocardium to behave as a single coordinated unit

• cardiac muscles auto rhythmic • cardiac muscles repeatedly generate spontaneous action potentials that then trigger heart contractions = the conduction system • Resting state - intracellular fluid is more negatively charged then extracellular • Cells are polarised when electrically stimulated by another cell

REpolarisation = Relaxing (setting back to start) Depolarisation = electrical activation of myocardium - contracting - going off or doing something ECG = sum total of electrical charges of individual cells

• one cycle consists of contraction and relaxation of both atrias followed by systole and diastole of both ventricles. Electrical event = depolarising or repolarising Mechanical event = what is physically happening to the heart.

SA node = natural pacemaker - autorhythmic fibres initiate action potentials most often Neurotransmitters and hormones from sympathetic nervous system can modify the heart rate and force contractions. Cardiac muscles generate ATP mainly by aerobic metabolism.

ECG Electrical Mechanical P Atrial Depolarisation Atrial contraction QRS Ventricular depolarisation Ventricular contraction T. Ventricular repolarisation Ventricular relaxation

• SA node • through atria - causing atrial contraction • AV node • AV bundle • R and L bundle branches • Purkinje fibres - causes ventricular contraction

= blood flow to the heart • delivers oxygen to heart muscles • left and right coronary artery • coronary artery = delivers oxygenated blood and nutrients to the heart. • coronary veins remove CO2 and wasted from myocardium LEARN PICTURE

Stroke volume is thee amount of blood pumped out of a ventricle in ONE PUMP.

= is the volume of blood ejected from left or right ventricle into aorta EACH MINUET. CO = stroke volume ml/b X Heart rate (bpm)

• Preload = amount ventricles are stretched by contained blood prior to contraction • Afterload = force at which heart has to contract to eject blood • Contractibility = ability to self contract

= control flow of blood through heart preventing back flow - controlled by pressure differences Tricuspid, Pulmonary, Mitral, Aortic valve Murmor = faulty blood flow in heart

= the pressure exerted by the blood against the walls of the arteries affected by: • cardiac output • peripheral resistance • Viscosity and blood volume Blood Pressure is determined by Cardiac output and Vascular resistance

= the opposition to blood flow due to friction between blood and walls of vessels.

= the volume of blood flowing back to heart through systemic veins occurs due to the pressure generated by contractions fo the hearts left ventricle.

= how much O2 is getting into tissues. • valve is important because it is the difference between MAP and venous pressure that drives blood through capillaries of organs.