UST General Santos Cardiovascular System PDF

Prayer before study Lord, true source of light and wisdom, give me a keen sense of understanding, a retentive memory and the capacity to grasp things correctly. Grant me the grace to be accurate in my expositions and the skill to express myself with thoroughness and clarity. Be with me at the start...

Prayer before study Lord, true source of light and wisdom, give me a keen sense of understanding, a retentive memory and the capacity to grasp things correctly. Grant me the grace to be accurate in my expositions and the skill to express myself with thoroughness and clarity. Be with me at the start of my work, guide its progress and bring it to completion. Grant this through Christ our Lord. Amen.  UST General Santos School of Health Sciences Unit 8:The Cardiovascular SHS 120201: ANATOMY AND PHYSIOLOGY WITH PATHOPHYSIOLOGY System Unit Intended Learning Outcomes: At the end of the unit, the student must be able to: Explain how the cardiovascular system works in the normal state and how it is affected in the presence of a pathophysiologic state Understand the cardiac cycle and the role of the electrical conduction system in regulating heartbeats. Analyze the process of blood circulation, including system and pulmonary circulation. Discuss the different physiological tests and procedures to determine diseases/disorders associated with the cardiovascular system. Apply the knowledge gained about the cardiovascular system to actual health situations. Cardiovascular System BLOOD  Blood Composition Blood: type of connective tissue consisting of a liquid matrix containing cells and cell fragments BLOOD  Functions of Blood 1. Transport of gases, nutrients, and waste products 2. Transport of processed molecules 3. Transport of regulatory molecules 4. Regulation of pH and osmosis 5. Maintenance of body temperature 6. Protection against foreign substances 7. Clot formation BLOOD  FUNCTION: Transport of gases, nutrients, and waste Oxygen from lungs → carried to the cells Carbon dioxide from cells → carried to the lungs → exhaled Nutrients, ions, water from digestive tract → carried to cells Waste products from cells → carried to kidneys for elimination BLOOD  FUNCTION: Transport of processed molecules BLOOD  FUNCTION: Transport of regulatory molecules Hormones Enzymes BLOOD  FUNCTION: Regulation of pH and osmosis Blood pH: 7.35 - 7.45 BLOOD  FUNCTION: Maintenance of body temperature Recall: Chapter 5 (Integumentary) BLOOD  FUNCTION: Protection against foreign substances Certain cells and chemicals in the blood are part of the immune system that fights against microorganisms and toxins BLOOD  FUNCTION: Clot formation Blood clotting protects against excessive blood loss when blood vessels are damaged BLOOD What do you think will happen if our blood does not clot? BLEEDING 🩸  BLOOD: Pathophysio Specimen: BLOOD Tests for the blood’s ability to clot: Platelet count ○ N: 150,000 - 450,000 platelets per microliter of blood Prothrombin time and Activated partial thromboplastin time measurement ○ Measures how long it takes for the blood to start clotting ○ PT N: 10-13s ○ APTT N: 25-35s Clotting Factors Tests/Assays: ○ Factors VIII and IX - proteins in the blood that help form clots and stop bleeding BLOOD: Tests What other blood tests do you know? COMPLETE BLOOD COUNT RBC count Hemoglobin & hematocrit measurements WBC count (total WBC) Differential WBC count ○ 5 kinds of WBC: neutrophils, lymphocytes, monocytes, basophils, eosinophils BLOOD: Tests Anemia: reduction in the proportion of the red blood cells reduction in hemoglobin (Hb) or hematocrit (Hct) or RBC count BLOOD: Pathophysio https://www.researchgate.net/figure/Complete-blood-cell-count-CBC-result-in-iron-deficiency-anaemia-IDA-and-control_tbl2_51847835 HEART Overview: Heart Anatomy Overview: Heart Anatomy Overview: Heart Anatomy Blood Flow through the Heart Conducting system of the heart Conducting system relays action potentials through the heart Composed of: ○ Two nodes Sinoatrial (SA) node Atrioventricular (AV) node ○ Conducting bundle Atrioventricular (AV) bundle aka Bundle of His Right & Left bundle branch ○ Purkinje fibers  Conducting system of the heart 0.04 second  Conducting system of the heart 0.04 second 0.11 second delay Conducting system of the heart Conducting system of the heart Medical Animation Media. (2023). How The Cardiac Conduction System Works || Electrical System of The Heart | [YouTube Video]. In YouTube. https://www.youtube.com/watch?v=i7wVJ9UFmnY&ab_channel=MedicalAnimationMedia What do you think will happen if there’s a disruption in the conducting system of the heart?  Arrhythmia Abnormal cardiac rhythm Abnormal conduction pathways AV NODE BLOCK interruption or delay of electrical conduction from the atria to the ventricles due to conduction system abnormalities in the AV node or the His-Purkinje system HEART: Pathophysio  Arrhythmia Abnormal cardiac rhythm Abnormal conduction pathways ATRIAL FIBRILLATION Irregular timing, ventricles constantly stimulated by atria VENTRICULAR FIBRILLATION No rhythmic contraction of the myocardium, asynchronously contracting ventricular muscle HEART: Pathophysio Electrocardiogram (ECG) Action potentials conducted through the myocardium during the cardiac cycle produce electrical currents that can be measured at the body surface Record of electrical activity of the heart HEART: Tests Cardiac Cycle Refers to the repetitive pumping process that begins with the onset of cardiac muscle contraction and ends with the beginning of the next contraction  Cardiac Cycle systole diastole to contract to dilate Cardiac Cycle 1. Atrial systole: active ventricular filling 2. Ventricular systole: period of isovolumetric contraction 3. Ventricular systole: period of ejection 4. Ventricular diastole: period of isovolumetric relaxation 5. Ventricular diastole: passive ventricular filling  LUXSONTube. (2012). The cardiac cycle [YouTube Video]. In YouTube. https://www.youtube.com/watch?v=5tUWOF6wEnk&ab_channel=LUXSONTube Cardiac Cycle: Atrial systole Cardiac Cycle: Ventricular systole Cardiac Cycle: Ventricular systole Cardiac Cycle: Ventricular diastole Cardiac Cycle: Ventricular diastole Cardiac Cycle: Ventricular diastole  LUXSONTube. (2012). The cardiac cycle [YouTube Video]. In YouTube. https://www.youtube.com/watch?v=5tUWOF6wEnk&ab_channel=LUXSONTube BLOOD VESSELS Circulatory System Blood vessels are organized into two sets: 1. Pulmonary vessels 2. Systemic vessels Vessel Anatomy Arteries carry blood away from the heart to capillaries Capillaries allow for the exchange of materials between the blood & tissues Veins deliver blood from the capillaries back to the heart Functions of the circulatory system 1. Carries blood 2. Exchanges nutrients, waste products, and gases with tissues 3. Transports substances 4. Helps regulate blood pressure 5. Directs blood flow to tissues Functions of the circulatory system 1. Carries blood 2. Exchanges nutrients, waste products, and gases with tissues 3. Transports substances 4. Helps regulate blood pressure 5. Directs blood flow to tissues Functions of the circulatory system 1. Carries blood 2. Exchanges nutrients, waste products, and gases with tissues 3. Transports substances 4. Helps regulate blood pressure 5. Directs blood flow to tissues Functions of the circulatory system 1. Carries blood 2. Exchanges nutrients, waste products, and gases with tissues 3. Transports substances 4. Helps regulate blood pressure 5. Directs blood flow to tissues Functions of the circulatory system 1. Carries blood 2. Exchanges nutrients, waste products, and gases with tissues 3. Transports substances 4. Helps regulate blood pressure 5. Directs blood flow to tissues Blood pressure Measure of the force blood exerts against the blood vessel walls Unit: millimeters of mercury (mmHg) Auscultatory method Physiology of the Systemic Circulation Primary function of the circulatory system: distribution ○ ensuring that O2, CO2, nutrients, hormones, and other substances are efficiently moved from one area of the body to other areas Factors that affect systemic circulation function: ○ Cross-sectional area of blood vessels ○ Pressure and resistance ○ Pulse and pulse pressure ○ Capillary exchange and regulation of interstitial fluid volume ○ Functional characteristics of veins ○ Blood pressure and effect of gravity Cross-sectional area of blood vessels Velocity of blood flow is inversely proportional to its cross-sectional area Aorta: greatest velocity, but total cross-sectional area is small Capillaries: Total cross-sectional area is large, but low blood flow Pressure and resistance Blood pressure changes as blood moves from one blood vessel type to another The decrease in blood pressure in each part of the systemic circulation is directly proportional to the resistance to blood flow ○ I.e., the greater the resistance in a blood vessel, the more rapidly the pressure decreases as blood flows through it Resistance to flow is associated with the diameter of the vessel Image source: Guyton and Hall Textbook of Medical Physiology ○ ↓ Vessel diameter = ↑ Resistance Pressure and resistance Resistance to flow also affects the speed at which pressure changes in the different vessels of the body ○ Aorta: Low resistance, high pressure ○ Capillaries: High resistance, low pressure Imagine a water hose. Aorta (thick hose): Water flows quickly and with a lot of force. This is because it's a big, open hose with low resistance to the water. Capillaries (tiny, thin hoses): Water flows slowly and with less force. This is because they're very small and have a lot of resistance to the water. Now, think about pressure: Aorta: The pressure is high because the water is flowing quickly and forcefully. Capillaries: The pressure is low because the water is flowing slowly and with less force. Pulse and Pulse Pressure As blood is ejected from the left ventricle into the aorta, it produces a pressure wave, or pulse, that travels rapidly along the arteries The pressure wave that we recognize as a pulse is generated by pulse pressure ○ Definition: The difference between systolic and diastolic pressures ○ E.g., if BP 120/80, PP = 120-80 = 40 mmHg Pulse and Pulse Pressure Pulse 10 major locations on each side of the body where large arteries are close to the surface Pulse and Pulse Pressure Pulse pressure is influenced by two factors: ○ Stroke volume (SV) of the heart ○ Vascular compliance PP is directly proportional to SV ○ E.g., during exercise, the heart works harder so SV increases, thus increasing PP PP is inversely proportional to vascular compliance ○ E.g., as we get older, the arteries stiffen and become less compliant, hence decreasing PP Capillary Exchange and Regulation of Interstitial Fluid Volume Capillary exchange is the process by which cells receive everything they need to survive and to eliminate metabolic waste products The most important means by which capillary exchange occurs is diffusion ○ Oxygen, hormones, glucose, and amino acids diffuse from a higher concentration in capillaries to a lower concentration in the interstitial fluid ○ Waste products, including CO2, diffuse from a higher concentration in the interstitial fluid to a lower concentration in the capillaries. Recall: What is Diffusion? movement of particles from a region of higher concentration to a region of lower concentration Capillary Exchange and Regulation of Interstitial Fluid Volume Driven by ff forces: Net filtration pressure, net hydrostatic pressure, net osmotic pressure, Local Control of Blood Flow in Tissues Blood flow is not equal in all tissues of the body ○ Some organs require a greater blood flow than others! ○ E.g., Blood flow to the brain, kidneys, and liver is high, while blood flow through resting skeletal muscles is not high Local control of blood flow achieved by: periodic relaxation and contraction of precapillary sphincters regulating blood flow through capillary networks of tissues Autoregulation of Blood Flow Maintenance of blood flow by tissues is called autoregulation ○ I.e., Blood flow to an organ remains constant (or within normal range) over a wide range of pressures Organs that exhibit autoregulation are the heart, brain, and kidney ○ E.g., if perfusion pressure to the heart is suddenly decreased, compensatory vasodilation of the arterioles will occur to maintain a constant flow Long-Term Local Blood Flow Another example: ○ Metabolic activity of muscle increases (e.g., in athletes) ○ Therefore, the diameter and the number of capillaries in the tissue also increase ○ Local blood flow increases Short-Term Regulation of Blood Pressure Mechanisms include: ○ Baroreceptor reflexes ○ Adrenal medullary mechanism ○ Chemoreceptor reflexes ○ Central nervous system ischemic response Short-Term Regulation of Blood Pressure Baroreceptors ○ Sensory receptors sensitive to stretch ○ Found along the walls of most of the large arteries of the neck and thorax (eg., carotid sinus reflex, aortic arch reflex) Examples ○ If BP is high: Increased BP → Increased stretch → Dilation of blood vessels to maintain normal BP (prevent hypertension) ○ If BP is low: Decreased BP → Decreased stretch → Constriction of blood vessels to maintain normal BP (prevent hypotension) Short-Term Regulation of Blood Pressure Adrenal Medullary Mechanism ○ Activated by a substantial increase in sympathetic stimulation of the heart and blood vessels ○ Release of epinephrine and of norepinephrine into the bloodstream Activated during: ○ large decreases in blood pressure ○ Sudden and substantial increase in physical activity ○ Other stressful condictions Short-Term Regulation of Blood Pressure Chemoreceptor Reflexes ○ Located in carotid bodies, small organs approximately 1–2 mm in diameter, which lie near the carotid sinuses ○ Also located in in several aortic bodies lying adjacent to the aorta Examples ○ Increased blood CO2: Decreased blood pH → Increased breathing rate (to blow off CO2) Short-Term Regulation of Blood Pressure Short-Term Regulation of Blood Pressure CNS Ischemic Response ○ The increase in blood pressure in response to lack of blood flow to the medulla oblongata of the brain ○ Functions primarily in response to emergency situations E.g., when blood flow to the brain is severely restricted or when blood pressure falls below approximately 50 mm Hg Long-Term Regulation of Blood Pressure Mechanisms include: ○ Renin-angiotensin-aldosterone mechanism (RAAS) ○ Antidiuretic hormone (vasopressin) mechanism ○ Atrial natriuretic mechanism ○ Fluid shift mechanism ○ Stress-relaxation response Atherosclerosis deposition of material in the walls of arteries to form distinct plaques related to age and certain risk factors affects primarily medium and larger arteries, including the coronary arteries Plaques form when macrophages containing cholesterol accumulate in smooth muscle cells of the blood vessels After the plaques enlarge, they consist of smooth muscle cells, white blood cells, lipids (including cholesterol), and, in the largest plaques, fibrous connective tissue and calcium deposits Atherosclerosis Angina pectoris chest pain that results from a reduced blood supply to cardiac muscle pain is temporary and, if blood flow is restored, little permanent change or damage results characterized by chest discomfort deep to the sternum, often described as heaviness, pressure, or moderately severe pain CAUSE narrowed and hardened coronary arterial walls Reduced blood flow → reduced supply of O2 to cardiac muscle cells → limited anaerobic respiration of cardiac muscle → reduced pH in affected areas of the heart → stimulates pain receptors Myocardial Infarction results when there’s prolonged lack of blood flow to a part of the cardiac muscle leads to a lack of O2 and ultimately cellular death Symptoms of MI: ○ chest pain that radiates into the left shoulder and arm, shortness of breath, nausea, vomiting, and sweating Thank you!  UST General Santos School of Health Sciences Unit 8:The Cardiovascular SHS 120201: ANATOMY AND PHYSIOLOGY WITH PATHOPHYSIOLOGY System Dominican Blessing May God the Father bless us May God the Son heal us May God the Holy Spirit enlighten us Give us eyes to see with, ears to hear with, hands to do the work of God with, feet to walk with, and mouth to preach the word of salvation with; And may the angel of peace watch over us, and lead us at last by the Lord’s gift of the kingdom. Amen.