Heart Lectures Academic Notes

What is the medical term for a heart attack? Myocardial infarction What is ventricular fibrillation? Uncoordinated contraction of ventricular muscle fibers What causes a myocardial infarction? Obstruction of blood flow to the heart muscle (coronary attery) What is the main function of cardiovascular system? -Delivery of O2 and removal of CO2/waste -Temperature regulation -Communication between hormones What are the three areas of the cardiovascular system that influence blood pressure? -Heart (pump) -Vessels (pipework) -Blood itself (blood volume) What is the buffy coat? White blood cells (leucocytes) and platelets Where is most blood found? Veins and venules Which part of the body is most of the blood found at rest? Organs and kidneys What is the inner most layer of blood vessels called? Tunica interna What is the smooth layer of muscle called in blood vessels? Tunica media What is the outside layer of connective tissue called in blood vessels? Tuniac adventitia Which layer of blood vessels is most prominent in the heart? Tunica media Why is the layer of elastic smooth muscle Allows for a constant flow of blood even in blood vessels considered a pressure after contraction due to passive recoil reservoir? For health reasons why is it important To absorb pressure to stop capillaries that arteries have a large amount of elasfrom bursting tic tissue? 1/5 Why is it important for capillaries to have Ease of exchange due to short diffusion a single layer of endothelial cells? distance? Do arteries or veins have larger lumens? Veins Do arteries or veins have a thicker tunica media? Arteries What is the key physiological feature of veins which is different from arteries? Valves What is the purpose of valves in veins? Prevent backflow of blood due to gravity Broken valves cause blood to pool in the legs What is varicose veins? What percentage of the blood found in the veins is oxygenated? H70% What is the interatrial septum? Tissue separating atrium What is the interventricular septum? Tissue separating ventricles Why is the interventricular septum thicker? Deals with more pressure Is the right or left AV valve tricuspid? Right (deals with less pressure) What holds valves in place? Tendons What is the name of the tendons holding the AV valves in place? Chordae tendineae What is the name of the valves that stop backflow from blood leaving the heart? Semilunar (pulmonary and aortic) Are semilunar valves bicuspid or tricuspid? Tricuspid Deoxygenated blood re-enters the heart from which vein? Coronary sinus What is coronary artery disease? Atherosclerosis of the coronary arteries What is angina and what is its relevance to heat disease? -Chest pain -First symptom of coronary heart disease What is balloon angioplasty? Using a balloon to insert a stent to increase blood flow 2/5 What sort of molecules can pass the blood brain barrier? Lipophilic ones What is a stroke? Lack of blood supply causing the death of neurons What are the two types of forces acting between capillaries and interstitial spaces? -Colloidal osmotic pressure -Hydrostatic pressure What is the primary force acting between intracellular fluid and interstitial fluid? Osmosis What is osmosis? Net movement of water across a selectivley permeable membrane True or false - osmolarity is dependant on molecular weight? False What determines the osmolarity of a solution? Number of particles dissolves What is the osmotic pressure? Pressure required to prevent osmosis What is the desired intracellular osmolarity? 300 mOsm/L What is colloidal osmotic pressure? Pressure exerted by the high levels of proteins in the plasma compared with the interstitial fluid (pushes back into the blood) What is NFP? Net filtration pressure (balance of hydrostatic and colloidal osmotic pressure) What is the role of the lymphatic system? -Drainage of fluid in the body -Immune system How do the kidneys respond to low blood Secrete renin to increase water retention pressure? and therefore increase blood pressure What is the main reason for decreased colloidal osmotic pressure? Reduction in plasma proteins -Malnutrition Whare are the three main reasons for de-Kidney failure (proteinuria) creased colloidal osmotic pressure (lack -Loss of protein in denuded skin areas of plasma proteins)? (burns) 3/5 What are some of the reasons for blockage of lymph nodes? -Parasites -Cancer -Infections What is an example of intracellular oedema? Friction blister What is the equation for cardiac output? Heart rate (HR) x Stroke volume (SV) What are the two nodes in the heart which contain pacemaker cells? SA node and AV node What are the electrical fibres in the heart called which spread depolarisation to the ventricles form bottom to top? Purkinje fibres What is the name for the 'leaky' sodium channels responsible for the polarisation of pacemaker cells? Funny channels What is the name for the calcium ion channels that are responsible for the polarisation of pacemaker cells? T-type channels (transient) What is the name for the calcium ion channels that are responsible for the rapid influx in pacemaker cell depolarization? L-type channels Which node primarily drives the heart rate? SA node Which type of channel causes the rapid depolarisation of cardiac muscle? Voltage-gated sodium channels Which type of channel is responsible for the temporary plateau of depolarisation Prolonged opening of the voltage-gated in order to allow for sufficient filling of the calcium channels (L-type) blood in the heart? What allows for repolarisation of heart muscle? Potassium channels What is the role of ryanodine receptors in cardiac muscles? Release of calcium from the sarcoplasmic reticulum 4/5 Do skeletal or cardiac muscles have longer refractory periods? Cardiac What is the role of the long refractory periods in cardiac muscle? Allows for ventricles. to fill with blood prior to pumping What is the name of the nerve that connects the brain and the heart as part of the parasympathetic system? Vagus What is the name of the nerve that connects the brain and the heart as part of the sympathetic system? Sympathetic ganglia -Release of ACh -M2 muscarnic receptors on SA node How does the parasympathetic system -Hyperpolarisation occurs due to lack of ions affect heart rate? -Decrease rate of depolarisation -Decrease HR -Release noradrenaline -B1 adrenergic receptors of SA node How does the sympathetic system affect -Increase of sodium and calcium influx heart rate? -Increased rate of depolarisation -Increased heart rate What is the medical term for decreased heart rate? Bradycardia What is the medical term for increased heart rate? Tachycardia What is the P wave? Atrial depolarization (contraction/systole) What is the QRS complex? Ventricular depolarization (contraction/systole) What is the T wave? Ventricular repolarisation What is a ventricular ectopic beat? Heart missing a beat What is the treatment for ventricular fibrillation? Defibrilator 5/5