Cardiovascular System PDF

Cardiovascular System DR. SUROJIT SARKAR HPA ( PHYSIOLOGY) SAI, NSNIS, PATIALA  1. Hemodynamics: Circulation and its control Table of 2. Determinants of Blood Flow Contents 3. Cardiovascular Regulation Hemodynamics The branch of physiology dealing with the forces involved in the ci...

Cardiovascular System DR. SUROJIT SARKAR HPA ( PHYSIOLOGY) SAI, NSNIS, PATIALA  1. Hemodynamics: Circulation and its control Table of 2. Determinants of Blood Flow Contents 3. Cardiovascular Regulation Hemodynamics The branch of physiology dealing with the forces involved in the circulation of the blood. The study of movement of blood through circulatory system. The cardiovascular system is responsible for to pump the blood and to circulate it through different parts of the body. It is essential for the maintenance of pressure and other physical factors within the blood vessels. Circulation Schematic  a). Gaseous Exchange b). Gases in Circulation c). Tissue Perfusion Importance of Hemodynamics dd Blood Flow: It is defined as the volume of blood moving through a vessel, organ, or entire circulation in a given period (ml/min). Blood Flow is relatively constant under resting conditions but varies in different organs based on their immediate needs. Types of Flow: Streamline Flow Turbulent Flow Laminar Flow and Turbulent Flow Laminar Flow: Smooth and Orderly: Blood moves in parallel layers with minimal mixing. Velocity Profile: Highest at the center, decreasing towards the walls, forming a parabolic profile. Low Resistance: Efficient blood movement with less resistance. Turbulent Flow: Chaotic and Disordered: Blood moves irregularly with swirling patterns. Eddy Currents: Vortices disrupt the orderly layers. Increased Resistance: Higher resistance requires more energy to maintain flow.  Aspect Laminar Flow Turbulent Flow Ensures smooth delivery Impairs delivery, Efficient Oxygen and of oxygen and nutrients increasing resistance Nutrient Delivery to muscles, crucial for and energy loss endurance sports Importance of Cardiovascular Reduces cardiac Increases workload, Blood Flow in Efficiency workload, supporting sustained performance leading to quicker fatigue Sports Facilitates quick removal Performance and Hinders waste removal, of metabolic waste, Recovery slowing recovery enhancing recovery Promotes vascular Injury Prevention Increases risk of vascular health, minimizing and Management issues endothelial damage Determinants of Blood Flow: Volume of blood flow is determined by these factors: 1. Pressure gradient 2. Resistance to blood flow 3. Viscosity of blood 4. Diameter of blood vessels Pressure Gradient Volume of blood flowing through any blood vessel is directly proportional to the pressure gradient. The pressure gradient is the difference in blood pressure between two points in the circulatory system. It is the driving force for blood flow. Pressure gradient = P1 — P2 Where, P1 = Pressure at proximal end of the vessel P2 = Pressure at distal end of the vessel. Blood Pressure Blood pressure (BP), the force per unit area exerted on a vessel wall by the contained blood, is expressed in millimeters of mercury (mm Hg). It typically refers to systemic arterial blood pressure near the heart. Normal Blood Pressure Range: Systolic: 110 – 130 mmHg Diastolic: 70 – 90 mmHg  Importance of Blood Pressure in Sports: Serves as vital Physiological Marker in assessing Cardiovascular Health and Recovery Aspect BP Indicator Implications Establishes cardiovascular Cardiovascular Health Baseline BP status, detects issues Indicates potential Abnormal BP cardiovascular problems Immediate post-exercise Quick return to baseline Post-Exercise Recovery BP shows good recovery Persistent elevation Delayed post-exercise BP suggests inadequate recovery Overtraining and Fatigue Elevated resting BP Sign of overtraining Indicates need for rest Chronic high BP and recovery Hydration and Nutrition Low BP Sign of dehydration BP affected by electrolyte Highlights need for imbalances dietary adjustments Lower resting BP and Indicates effective American Heart Association: Blood Pressure Classification Training Adaptation efficient BP responses to training and improved exercise fitness Peripheral Resistance and Viscosity: Peripheral Resistance: Friction encountered as blood moves through vessels. Main sources: Blood viscosity, vessel length, vessel diameter. Viscosity: Internal resistance due to fluid thickness. Blood is more viscous than water (contains formed elements and plasma proteins). Conditions affecting viscosity: Polycythemia: High RBC count ↑ viscosity & resistance. Anemia: Low RBC count ↓ viscosity & resistance. Blood Vessel Diameter and Length: Blood Vessel Diameter: Smaller diameter → Higher resistance (more friction with vessel walls). Larger diameter → Lower resistance (less friction). Laminar flow: Fluid near vessel wall slows due to friction while blood at the center flows faster. Blood Vessel Length: Longer vessels → Greater resistance (more friction over distance). Example: As a child grows, blood vessel length and peripheral resistance increase. FACTORS MAINTAINING VELOCITY Three factors are responsible for the maintenance of the velocity of blood flow. 1. Cardiac output (C.O.) 2. Cross-sectional area of the blood vessel (affected by the diameter of the Blood Vessel) 3. Viscosity of the blood. Cardiac Output The amount of blood the heart pumps per minute is known cardiac output (Q) (measure in litres). The cardiac output is a product of stroke volume and heart rate. Cardiac Output (CO) = Stroke Volume (SV) × Heart Rate (HR) where: Stroke Volume (SV): The amount of blood ejected by the left ventricle of the heart in one contraction. Heart Rate (HR): The number of heartbeats per minute. Cardiac output varies widely with the level of activity of the body. Cardiac Output Resting Values: 1. Average heart rate = 70 bpm 2. Average stroke volume = 70—80 ml/beat 3. Average cardiac output = 5000 ml/minute (70 x 70 = 4900ml/4.9 L) Changes in Cardiac Output due to Exercise: Cardiac Output Heart Rate Stroke Volume Untrained 22,000 ml/min 195 b/min 113 ml Trained 22,000 ml/min 150 b/min 147 ml Factors affecting Cardiac Output: 1.Heart Rate (HR): 1. Increase in Heart Rate: Typically increases CO, as more beats per minute mean more blood is pumped. 2. Decrease in Heart Rate: Typically decreases CO. 2.Stroke Volume (SV): 1. Preload: The volume of blood in the ventricles at the end of diastole. Higher preload increases stroke volume due to the Frank-Starling mechanism. 2. Afterload: The resistance the heart must overcome to eject blood. Higher afterload can reduce stroke volume. 3. Contractility: The strength of the heart's contraction. Increased contractility increases stroke volume. Redistribution of blood flow during Exercise: Distribution of cardiac output during rest and maximal exercise. At rest, the cardiac output is 5 ℓ/min. (bottom of figure); during maximum exercise, the cardiac output increased five-fold to 25 ℓ/min (top of figure). Cardiovascular Regulation (Increased BP) CO = cardiac output; R = peripheral resistance; HR = heart rate; BP = blood pressure) Cardiovascular Regulation (Decreased BP) CO = cardiac output; R = peripheral resistance; HR = heart rate; BP = blood pressure) Cardiovascular Regulation Regulation Type Mechanism Effects on Heart Neural Regulation Sympathetic Nervous System (SNS) Increases heart rate and contractility Parasympathetic Nervous System (PNS) Decreases heart rate Baroreceptor Reflex Adjusts heart rate based on blood pressure Releases epinephrine/norepinephrine to Hormonal Regulation Adrenal Medulla increase heart rate and contractility Renin-Angiotensin-Aldosterone System Regulates blood volume and pressure (RAAS) Antidiuretic Hormone (ADH) Increases blood volume and pressure Increases stroke volume with increased Intrinsic Regulation Frank-Starling Mechanism venous return Coordinates heartbeats through electrical Cardiac Conduction System impulses Chemical Regulation Ion Concentration (Ca²⁺, K⁺, Na⁺) Affects electrical activity and contractility pH and CO₂ Levels Influences heart rate and contraction force Higher temperatures increase heart rate, Temperature Regulation Thermoregulation lower temperatures decrease it  Athletes Heart: An athlete's heart refers to the beneficial adaptations of the heart in response to regular, intense physical training. (LVWT : Left Ventricular Wall Thickness)  Cardiac Adaptations in Endurance and Resistance Athletes Aspect Endurance Athletes Resistance Athletes Eccentric (increased Concentric (increased Athletes Heart Cardiac Hypertrophy chamber size) wall thickness) An athlete's heart refers to the Prolonged aerobic High-intensity, short- beneficial adaptations of the heart in Primary Cause exercise duration efforts response to regular, intense physical training. Enhanced filling Stronger myocardial Physiological Effect (increased EDV) contractility Frank-Starling Adaptation to high Key Mechanism mechanism intrathoracic pressure Resting Heart Rate Lower No significant change Stroke Volume Increased Little change More efficient (aerobic Higher (anaerobic Energy Demand metabolism) metabolism) Sustained aerobic High-pressure Performance Benefit performance generation for lifting Athletes Heart An athlete's heart refers to the beneficial adaptations of the heart in response to regular, intense physical training. Structural Changes 1.Left Ventricular Hypertrophy (LVH): Increased size and wall thickness of the left ventricle. 2.Increased Heart Size: Symmetric enlargement of the heart chambers. 3.Increased Chamber Size: Larger heart chambers, particularly the left ventricle. Athletes Heart An athlete's heart refers to the beneficial adaptations of the heart in response to regular, intense physical training. Functional Changes 1.Bradycardia: Lower resting heart rate due to more efficient heart function. 2.Increased Stroke Volume: More blood pumped per beat. 3.Enhanced Cardiac Output: Increased blood volume pumped per minute. 4.Improved Diastolic Function: Better heart relaxation and filling. Athletes Heart An athlete's heart refers to the beneficial adaptations of the heart in response to regular, intense physical training. Electrical Changes 1.ECG Variations: Common benign changes like sinus bradycardia and early repolarization. 2.Increased Vagal Tone: Higher influence of the parasympathetic nervous system, leading to lower resting heart rates. Quiz: 1. What is haemodynamics? 2. What type of blood flow is smooth A) The study of blood composition and orderly, with blood moving in B) The study of blood movement through parallel layers? the circulatory system A) Turbulent flow C) The study of heart sounds B) Laminar flow C) Eddy currents D) The study of muscle contraction D) Vortical flow 3. Which factor directly affects the 4. What happens to blood flow volume of blood flow through a vessel? resistance as blood vessel diameter A) Blood color increases? B) Pressure gradient A) Resistance increases C) Blood pH B) Resistance decreases D) Vessel length C) Resistance stays the same D) Resistance fluctuates Quiz: 5. What is the main determinant of 6. What type of cardiac hypertrophy is cardiac output? typically seen in endurance athletes? A) Blood viscosity A) Concentric hypertrophy B) Stroke volume and heart rate B) Eccentric hypertrophy C) Blood vessel length C) Asymmetric hypertrophy D) Oxygen concentration D) Hypertrophic cardiomyopathy 7. Which mechanism increases stroke 8. What happens to the resting heart volume in endurance athletes? rate of endurance athletes? A) Valsalva maneuver A) It increases B) Frank-Starling mechanism B) It decreases C) Increased afterload C) It stays the same D) Decreased preload D) It becomes irregular Quiz: 9. Which type of metabolism is more 10. What long-term health benefit is efficient and primarily used by associated with regular cardiovascular endurance athletes? exercise? A) Anaerobic metabolism A) Decreased risk of hypertension B) Aerobic metabolism B) Increased risk of heart disease C) Glycolytic metabolism C) Lowered stroke volume D) Phosphagen metabolism D) Decreased parasympathetic tone