KINE 1020: Cardiovascular Physiology (Normal) PDF

KINE 1020: Cardiovascular Physiology (Normal) Friday Nov 1 Loading… Cardiorespiratory Systems 3  The Cardiovascular System is complex network that includes the heart and vasculature Fun facts about our cv system: There are ~100,000 km of blood vessels in you...

KINE 1020: Cardiovascular Physiology (Normal) Friday Nov 1 Loading… Cardiorespiratory Systems 3  The Cardiovascular System is complex network that includes the heart and vasculature Fun facts about our cv system: There are ~100,000 km of blood vessels in your body. That's enough to go around the world twice. Your heart will beat over 100,000 times each day. Your heart pumps about 7,500 litres of blood every day. Note: Don’t need to memorize all this anatomy for 1020! The Heart What is it? Hollow muscular organ about the size of your fist (about 280-300g on average as a young adult) Where is it? Between sternum and vertebrae What does it do? Loading… Dual - Pump Delivery mechanism Suction device Performance Engine What is unique / interesting about it? Fully automatic Highly adaptive Incredible endurance! During an average lifetime, the human heart will beat more than 2.5 billion time Heart Structure and Anatomy Divided into right and left halves, the heart has 4 chambers (2 hold deoxidated blood and 2 hold oxygenated blood) 2 Atria Upper chambers Receive blood returning to heart and transfer it to lower chambers 2 Ventricles Lower chambers that pump blood from heart Pericardium either to the lungs (right side) or the rest of the  body (left side) Heart pumps 4-5L a minute at rest… Where does all that blood go?… Technically two pumps, so it sends blood 1) to two main/different places! 2)  Cardiac Output (how much the heart pumps per minute) Cardiac output in humans is generally 5-6 L/min in an at-rest During peak exercise in elite cross-country skiers, the heart (But the amount of blood pumped changes constantly can pump over 40 litres a minute even at rest based on an everchanging heart rate…) https://doi.org/10.1111/sms.12601 Heart rate Variability (HRV) is how variable your heart rate beats… from beat to beat.. Hear rate changes constantly HRV is how much your heart rate is changing over a given period of time HRV changes naturally from day to day, depending on the level of activity and amount of, for example, work-related stress. If a person is chronically stressed or overloaded – physically or mentally – the natural interplay between the two nervous systems (SNS, PNS) is disrupted, and the body can get stuck in a sympathetically dominant fight state, with low HRV and high stress hormone levels even during rest. This is very consuming on the body and can result in mental and physical health problems.  The Role of Atria 2 atria (RA, LA) with thinner walls (when compared to ventricles) Deliver blood to the 2 ventricles (left and right) Septum Dividing wall Foramen Ovale* The sinoatrial (SA) node is located in the upper wall of the RA. It sets the HR and the HRV! the foramen ovale is a hole between the left and right atria (upper chambers) of the heart. This hole exists in everyone before birth, but most often closes shortly after being born. If it is open after birth, it is called a patent foramen ovale  The Role of Ventricles Primary pumps of the heart… Right ventricle sends blood to the lungs for oxygenation Left ventricle is the delivery driver for all essential organ systems Loading… Thicker walls are more muscular and generate greater force of contraction Force of contraction is known as “contractility” The LV is most powerful chamber Larger volumes compared to atria They can handle and deliver huge volumes of blood during exercise (up to 40 L/min)...  Layers of the Heart Heart is a muscle too! 3 layers Endocardium Myocardium Epicardium Unique aspects of cardiac muscle Involuntary Endurance specialist! Isn’t found anywhere else in the body! What do muscles need? An electrical signal to contract, typically via the SA node WHY SHOULD WE FIND THIS LAST POINT Its own blood supply (oxygen, nutrients) called the coronary circulation INTERESTING? Note: Coronary blood flow occurs more when the ventricles are filling (cardiac  Coronary Circulation Coronary vasculature Supplies oxygen and nutrients Removes metabolic by-products ESSENTIAL for heart function Site of ischemia / plaque formation / heart attacks Aka “Descending”  Blood Flow Through The Heart sends it to - right pump the lungs Deoxygenated blood from the systemic circulation left and right one ven carries -h chambers : atria and - blood oxygenated left and right ventricle artery carries one bood - deoxygenated - as we grow the , heart gets bigger but will also get weater sends it to - left pump the body - heart is protected by sternum (separates the chambers heart is used to deliver nutrients the heart) of - blood and oxygen and remove waste and carbon dioxide Blood Flow Through The Heart Blood Flow Through The Heart Blood Flow Through The Heart Deoxygenated blood leaves right atrium via pulmonary arteries Blood Flow Through The Heart Oxygenated blood from the lungs via pulmonary veins Blood Flow Through The Heart Blood Flow Through The Heart Blood Flow Through The Heart Oxygenated blood leaves left ventricle via aorta and sent to systemic circulation Blood Flow Through The Heart (Full overview)  The Cardiac Cycle Alternating contraction and relaxation Systole (Ventricular Contraction – ‘ejection’) Diastole (Ventricular Relaxation - ‘filling’) Valves play a major role Ensure 1-way flow of blood through the heart Atrio-ventricular valves Right = Tricuspid Left = Bicuspid (mitral) Chordae Tendinae Prevent eversion Papillary muscles  The Cardiac Cycle Alternating contraction and relaxation Systole (Ventricular Contraction – ‘ejection’) Diastole (Ventricular Relaxation - ‘filling’) Valves play a major role Ensure 1-way flow of blood through the heart Semilunar valves Aortic (LV→ AORTA) Pulmonary (RV → PULMONARY ARTERIES) Both have 3 flaps  The Cardiac Cycle 4 Main Phases 1. Ventricular Filling Period (diastole) AV Valves open, blood flows into ventricles Enhanced by “Suction” End of this phase includes Atrial contraction to “top up” ventricles About 80% of filling is passive  The Cardiac Cycle 4 Main Phases 2. Isovolumetric Contraction Period Occurs from electrical conduction system stimulation Immediate increase in pressure Temporary moment when pressure doesn’t exceed that needed to open semilunar valves Atria are empty All Valves Closed Ventricles Full  The Cardiac Cycle 4 Main Phases 3. Ventricular Ejection Period (systole) Systole Semilunar valves are open and blood flows freely into Aorta and Pulmonary artery Atria fill during this time  The Cardiac Cycle 4 Main Phases 4. Isovolumetric Relaxation Period Brief moment when ventricles are relaxed and atrioventricular valves are closed As soon as the pressure in the atria exceeds that of the ventricles, the cycle repeats  What ECG shows a heart beating fastest? Loading… Control of Heart Rate Control of Heart Rate Autonomic nervous system Sympathetic vs Parasympathetic Fight or Flight! Gas and Brakes Go and Slow Other factors Exercise! Drugs Environmental Factors Toxins Altitude Heat / Cold