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Comprehensive Overview of Circulatory System and Blood Pressure Regulation

Detailed exploration of blood circulation, blood vessel structure, blood pressure measurement, regulation, and physiological factors affecting cardiovascular health.

Health & Medicine◦
Related topics:
Blood Pressure Insights•
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PRESENTED TO: Dr. ASIF ALI BUKHARI
CARDIAC CARE ASSOCIA TE Presented By: • MINAHILSALEEM • ROMANNAVEED • BISMAASGHAR • KAINATHAFEEZ • AYMANHAMEED • KHIZRABASHEER • MAHNOORINTIZAR
CIRCULATION
OUR OBJECTIVE  Basic theory of circulatory.  Structure and function of blood vessels  Blood Pressure intro and methods  Regulations of blood pressure.  Factor and physiology variation  Total peripheral resistance  Atrial Pressure
BASIC THEORY OF CIRCULATION
 CIRCULATION Circulation is how the body moves blood, oxygen, and nutrients to every part of the body. • The heart works like a pump. It beats to push blood around the body. • Blood travels through tubes called blood vessels — arteries, veins, and capillaries. • Arteries carry fresh, oxygen-rich blood away from the heart to the body. • Veins carry blood back to the heart after the oxygen has been used. • Capillaries are tiny vessels where oxygen and nutrients pass into body cells, and waste (like carbon dioxide) is picked up.
STRUCTURE AND FUNCTION OF BLOOD VESSELS
 BLOOD VESSELS Blood vessels are a closed network of tubes that transport blood throughout the body, delivering oxygen and nutrients to tissues while removing metabolic waste.  General Structure of Blood Vessel Walls Most major blood vessels consist of three distinct tissue layers (tunics) surrounding a central hollow space called the lumen: • Tunica Intima (Inner Layer): Made of a smooth layer of endothelial cells that minimize friction as blood flows through. • Tunica Media (Middle Layer): Composed of smooth muscle fibers and elastic tissue; controls vessel diameter through contraction (vasoconstriction) and relaxation (vasodilation). • Tunica Externa / Adventitia (Outer Layer): Made of strong collagen fibers that protect and anchor the vessel to surrounding tissues.
TYPES STRUCTURE FUNCTION ATERIES • Thick • Elastic • Muscular walls with a narrow lumen • Lacks valves. Carry oxygenated blood away from the heart under high pressure (exception: pulmonary artery carries deoxygenated blood). CAPILLARIES • Network with extremely thin walls made of only a single layer of endothelial cells .Facilitate the exchange of oxygen, nutrients, carbon dioxide, and waste products between blood and body tissues. VEINS • Thin muscular walls with a large lumen • One-way valves to prevent backflow Return deoxygenated blood back to the heart under low pressure (exception: pulmonary vein carries oxygenated blood).
Blood vessels have specialized structural features tailored to their specific roles in blood circulation, pressure regulation, and exchange. • Arterioles: Precapillary Sphincters • Veins: One-Way Valves & Skeletal Muscle Pump • Capillaries: Special Structural Variations  Continuous Capillaries (Tightest)  Fenestrated Capillaries (Pores)  Sinusoid Capillaries (Gaps)
Another terminology Vasa Vasorum (Vessels of the Vessels)A network of tiny blood vessels located inside the outer layer (tunica externa) of very large arteries and veins (like the Aorta and Vena Cava). Function • Large vessel walls are too thick for oxygen to diffuse all the way through from the inside. • The vasa vasorum acts as a personal blood supply to nourish the outer layers of these massive vessels.
BLOOD RESSURE
Blood pressure (BP)* is the pressure exerted by circulating blood against the walls of blood vessels, especially arteries.  It is generated primarily by the pumping action of the left ventricle.  Blood pressure is essential for maintaining adequate blood flow to: • Brain • Heart • Kidneys • Muscles • Other tissues  BP varies continuously throughout the cardiac cycle.
 It is conventionally expressed as: Systolic BP / Diastolic BP Example: 120/80 mmHg*
 Systolic BP (SBP): • Maximum arterial pressure during ventricular contraction. • Represents the peak pressure generated by the heart.  Diastolic BP (DBP): • Minimum arterial pressure during ventricular relaxation. • Represents the pressure maintained in arteries between heartbeats.
 Pulse Pressure Difference between systolic and diastolic pressure. • Formula PP = SBP − DBP • Example:* PP = 120 − 80 = 40 mmHg
 Mean Arterial Pressure (MAP) Approximate average pressure driving blood through the systemic circulation during one cardiac cycle.* • At normal heart rates: MAP ≈ DBP + ⅓(PP) • Example: MAP ≈ 80 + ⅓(40) = 93 mmHg
CATEGORY SYSTOLIC DIASYTOLIC *Normal <120 mmHg <120 mmHg Elevated 120-129mmHg <80mmHg Stage 1 hypertension 130-139mmHg 80-89mmHg Stage 2 hypertension ≥140 ≥90 Severe hypertension >180 >120
 Basic Blood Pressure Equation The fundamental relationship is: Blood Pressure = Cardiac Output × Systemic Vascular Resistance BP ≈ CO × SVR Where: • BP = arterial blood pressure • CO = cardiac output • SVR = systemic vascular resistance
 More precisely for mean arterial pressure: MAP = (CO × SVR) + CVP Where: MAP = mean arterial pressure • CO = cardiac output • SVR = systemic vascular resistance • CVP = central venous pressure Because CVP is normally small, it is often simplified to: MAP ≈ CO × SVR
 Cardiac Output Equation Cardiac output is the amount of blood pumped by the heart per minute. CO = Heart Rate × Stroke Volume Or CO = HR × SV Where: CO = cardiac output, L/min HR = heart rate, beats/min SV = stroke volume, mL/beat • Example If: HR = 70 beats/min SV = 70 mL/beat
 Pulse Pressure & Mean Arterial Pressure Equations • Pulse Pressure PP = SBP − DBP • Example: 120/80 mmHg PP = 120 − 80 PP = 40 mmHg*
 MEASUREMENT OF BLOOD PRESSURE Blood pressure by the Sphygmomanometer. It is also called B.P apparatus. There are three types: • Mercury B.P apparatus • Digital B.P apparatus • Android B.P apparatus  Why Was Mercury Used in Sphygmomanometers? • Mercury is a metal, but it is unusual because it is liquid at room temperature. • A mercury sphygmomanometer uses the height of a mercury column to represent pressure.
METHOD PRINCIPLE MAIN ADVANTAGE MAIN LIMITATION Mercury sphygmomanometer Mercury column + auscultation Excellent reference technique historically Mercury toxicity; being phased out Aneroid sphygmomanometer Mechanical gauge + auscultation Mercury-free, portable Can lose calibration Automated oscillometric Detects cuff pressure oscillations | Easy and rapid Algorithm-dependent; validation important
REGULATION AND CONTROL BP
Blood pressure management has two types 1.life style modification 2.medication  Life style modification • Reduce salt intake • Regular physical activity • Maintain healthy body weight • Eat a balance diet • Reduce stress • Get adequate sleep
 Medication • Ace inhibitor • Beta blockers • Calcium channel blockers • Diuretic  FACTORS OF BLOOD PRESSURE • Cardiac Output • Stroke Volume • Venous return • Preload • Afterload
 CARDIAC OUTPUT Cardiac output is the amount of blood pumped by the heart per minute. CO = Heart Rate × Stroke Volume  STROKE VOLUME Stroke volume is the amount of blood pumped by the heart per beat.  HEART RATE Heart rate is the no. of beat per minute. Normal HR= 70-75 times per minute
 VENOUS RETURN Venous return is the rate of blood flow back to the heart.  Preload Amount of blood filling the heart before contraction Afterload Resistance against the heart which pumps blood
FACTORS AFFECTING THE HEART RATE
 AUTONOMIC INNERVATION The autonomic nervous system regulates the heart rate, contraction force, and electrical conduction through the Cardiac Plexus, which contains both • sympathetic • parasympathetic fibers.
 EFFECTS OF SYMAPATHETIC STIMULATION • Rate of rhythm of SA node Heart rate (Chronotropic Effect) • Excitability of AV junctional fibers ( Bathmotropic Effect) • Conduction velocity (Dromotropic Effect) • Force of Contraction (Inotropic)
 EFFECTS OF PARASYMPATHETIC STIMULATION • Rate of rhythm of SA node Heart Rate • Excitability of AV junctional fibers • Conduction velocity • Force of Contraction
 PHYSIOLOGICAL VARIATIONS OF BLOOD PRESSURE Physiological variation of blood pressure refers to the normal, healthy ups and downs in blood pressure caused by daily activities, age, and body functions. Blood pressure is not fixed; it changes all the time to match what your body needs.
 HYPERTENSION Hypertension, or high blood pressure, occurs when the force of blood pushing against your artery walls is consistently too high (at or above 130/80 mm Hg). Often called the "silent killer," it usually has no warning signs, but if left untreated, it can cause heart attacks, strokes, and kidney damage.
ATRIAL PRESSURE REFLEX
 ATRIAL PRESSURE REFLEX The atrial pressure reflex, commonly known as the Bainbridge Reflex, is a physiological mechanism that increases heart rate in response to an elevated blood volume and increased pressure within the right atrium of the heart. How the Reflex Works •Stimulus: High blood volume increases venous return, which stretches the walls of the right atrium. •Receptors: Low-pressure stretch mechanoreceptors in the atrial walls detect this tension. •Afferent Pathway: Signals travel via the vagus nerve to the brainstem (medulla oblongata). •Efferent Response: The brain decreases parasympathetic (vagal) tone and increases sympathetic nervous system activity to the heart's sinoatrial (SA) node. •Result: Heart rate speeds up (tachycardia) to pump the extra volume forward
TOTAL PERIPHERAL RESISTANCE
 TOTAL PERPHERAL RESISTANCE The resistance that blood must overcome to move through the systemic blood vessels. • It is a major factor in setting your blood pressure. • Small muscular arteries called arterioles control most of this resistance by changing their size.  Factors •Vessel Radius: A smaller opening makes high resistance. A larger opening makes low resistance. •Blood Viscosity: Thicker blood increases resistance. Thinner blood decreases it. •Vessel Length: Longer blood vessels increase total resistance.
 MATHEMATICAL RELATIONSHIP TPR connects to blood pressure and heart output through this basic formula: MAP=CO×TPR •MAP: Mean arterial pressure (average blood pressure) •CO: Cardiac output (blood pumped by the heart per minute) •TPR: Total peripheral resistance  Body Control •Vasoconstriction: Blood vessels get narrower. This raises TPR and raises blood pressure. •Vasodilation: Blood vessels get wider. This lowers TPR and lowers blood pressure
OUTTEAM • MINAHILSALEEM • ROMANNA VEED • BISMAASGHAR • KAINA THAFEEZ • AYMANHAMEED • KHIZRABASHEER • MAHNOORINTIZAR • AREEBA • AYESHATAHIR • FA TIMAAMJAD • AYESHA • KHALIDA
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