Blood pressure (BP) is the pressure exerted by circulating blood upon the walls of blood vessels and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation, usually measured at a person's upper arm. A person’s blood pressure is usually expressed in terms of the systolic pressure over diastolic pressure and is measured in millimeters of mercury (mm Hg). Normal resting blood pressure for an adult is approximately 120/80 mm Hg.
Blood pressure (BP) is the pressure exerted by circulating blood upon the walls of blood vessels and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation, usually measured at a person's upper arm. A person’s blood pressure is usually expressed in terms of the systolic pressure over diastolic pressure and is measured in millimeters of mercury (mm Hg). Normal resting blood pressure for an adult is approximately 120/80 mm Hg.
Cardiac output (The Guyton and Hall Physiology)Maryam Fida
The volume of blood pumped by each ventricle per minute is called cardiac output
Cardiac output = Stroke Volume X Heart Rate
Normal value = 5 Liters /Minute
Cardiac output = Stroke Volume X Heart Rate
The factors which regulate stroke volume and Heart rate are basically regulating Cardiac output
Volume of blood ejected by each ventricle in single systole; Normal Value = 70 ml/beat
Stroke Volume = End diastolic Volume – End Systolic Volume
So stroke volume is mainly controlled by
EDV
ESV
VENOUS RETURN: What ever blood volume returns to the heart, same is pumped forward through the Frank’s Starlings Law. According to this law 13- 15 liters of blood volume can be pumped out without cardiac stimulation.
DURATION OF DIASTOLE OR FILLING TIME: ventricular filling occurs during diastole, so there must be adequate ventricular filling time.
DISTENSIBILITY OF THE VENTRICLES: Normally ventricles are distensible to accommodate adequate blood volume. Infarction decreases the distensibility which decreases the EDV.
ATRIAL CONTRACTION: There must be adequate atrial contraction to have adequate EDV. If atrial function is not adequate then EDV will decrease.
E.S.V is basically CONTROLLED BY MYOCARDIAL CONTRACTION
FORCE OF MYOCARDIAL CONTRACTION: It depends upon the initial length of muscle fibers according to frank’s starlings law.
PRELOAD: The effect of EDV on initial length is called preload. So EDV also effects the ESV.
AFTER LOAD: Force of contraction is also dependant upon the resistance against which the ventricles have to pump
CONDITION OF THE MYOCARDIUM : It also effects the force of contraction.
AUTONOMIC NERVES : Sympathetic stimulation increases and parasympathetic stimulation decreases force of contraction
HORMONES: Catecholamines, thyroxine, glucagon, digitalis, calcium, increased temp, caffeine, theophyline increase the force.
Force decreases by hypoxia, acidosis, barniturates, procainamide and quinidine decrease the force of contraction.
Blood pressure is the multiply of cardiac output and peripheral resistance.
Blood pressure = Cardiac Output x Peripheral Resistance
Cardiac output is the multi[ply of heart rate and stroke volume.
Normal heart rate in humans is 72 beats/min.
Stroke volume is the volume of blood pumped by heart during one beat.
Cardiac Output = Stroke volume x Heart Rate
FULL WEB Interactive version
http://www.scribd.com/doc/182401977/Physiologic-and-Pathophysiologic-Function-of-the-Heart-Cardiac-Cycle-Graphs-Curves-Loops-and-CO-Calculations
Cardiac output (The Guyton and Hall Physiology)Maryam Fida
The volume of blood pumped by each ventricle per minute is called cardiac output
Cardiac output = Stroke Volume X Heart Rate
Normal value = 5 Liters /Minute
Cardiac output = Stroke Volume X Heart Rate
The factors which regulate stroke volume and Heart rate are basically regulating Cardiac output
Volume of blood ejected by each ventricle in single systole; Normal Value = 70 ml/beat
Stroke Volume = End diastolic Volume – End Systolic Volume
So stroke volume is mainly controlled by
EDV
ESV
VENOUS RETURN: What ever blood volume returns to the heart, same is pumped forward through the Frank’s Starlings Law. According to this law 13- 15 liters of blood volume can be pumped out without cardiac stimulation.
DURATION OF DIASTOLE OR FILLING TIME: ventricular filling occurs during diastole, so there must be adequate ventricular filling time.
DISTENSIBILITY OF THE VENTRICLES: Normally ventricles are distensible to accommodate adequate blood volume. Infarction decreases the distensibility which decreases the EDV.
ATRIAL CONTRACTION: There must be adequate atrial contraction to have adequate EDV. If atrial function is not adequate then EDV will decrease.
E.S.V is basically CONTROLLED BY MYOCARDIAL CONTRACTION
FORCE OF MYOCARDIAL CONTRACTION: It depends upon the initial length of muscle fibers according to frank’s starlings law.
PRELOAD: The effect of EDV on initial length is called preload. So EDV also effects the ESV.
AFTER LOAD: Force of contraction is also dependant upon the resistance against which the ventricles have to pump
CONDITION OF THE MYOCARDIUM : It also effects the force of contraction.
AUTONOMIC NERVES : Sympathetic stimulation increases and parasympathetic stimulation decreases force of contraction
HORMONES: Catecholamines, thyroxine, glucagon, digitalis, calcium, increased temp, caffeine, theophyline increase the force.
Force decreases by hypoxia, acidosis, barniturates, procainamide and quinidine decrease the force of contraction.
Blood pressure is the multiply of cardiac output and peripheral resistance.
Blood pressure = Cardiac Output x Peripheral Resistance
Cardiac output is the multi[ply of heart rate and stroke volume.
Normal heart rate in humans is 72 beats/min.
Stroke volume is the volume of blood pumped by heart during one beat.
Cardiac Output = Stroke volume x Heart Rate
FULL WEB Interactive version
http://www.scribd.com/doc/182401977/Physiologic-and-Pathophysiologic-Function-of-the-Heart-Cardiac-Cycle-Graphs-Curves-Loops-and-CO-Calculations
Cardiovascular system (blood pressure, hypertension) Pharmacy Universe
The circulatory system, also called the cardiovascular system or the vascular system, is an organ system that permits blood to circulate and transport nutrients (such as amino acids and electrolytes), oxygen, carbon dioxide, hormones, and blood cells to and from the cells in the body to provide nourishment and help in fighting diseases, stabilize temperature and pH, and maintain homeostasis.
The circulatory system includes the lymphatic system, which circulates lymph.[1] The passage of lymph for example takes much longer than that of blood.[2] Blood is a fluid consisting of plasma, red blood cells, white blood cells, and platelets that is circulated by the heart through the vertebrate vascular system, carrying oxygen and nutrients to and waste materials away from all body tissues. Lymph is essentially recycled excess blood plasma after it has been filtered from the interstitial fluid (between cells) and returned to the lymphatic system. The cardiovascular (from Latin words meaning "heart" and "vessel") system comprises the blood, heart, and blood vessels.[3] The lymph, lymph nodes, and lymph vessels form the lymphatic system, which returns filtered blood plasma from the interstitial fluid (between cells) as lymph.
8. END- DIASTOLIC VOLUME - volume of blood filling the ventricle During rapid filling = 110ml to 120ml - 130 ml STROKE VOLUME - volume of blood ejected as he ventricles contract During systole = 70ml to 90 ml END -SYSTOLIC VOLUME - remaining volume in each ventricle = 40 - 50 ml PRELOAD - degree of tension on the muscle when it begins to contract End Diastolic Volume = 110 to 120 - 130ml EJECTION FRACTION - fraction of the end -diastolic volume that is ejected = 60% to 65% volume
9. AFTERLOAD - load against which the muscle exerts its contractile force - pressure in the artery leading from the ventricle ABSOLUTE REFRACTORY PERIOD Ventricle - 0.25 to 0.3 second Atrium - 0.15 second RELATIVE REFRACTORY PERIOD - 0.05 second Causes of Plateau in Cardiac Action Potential 1. Opening of slow calcium - sodium channels 2. Decreased potassium permeability CARDIAC OUTPUT - the quantity of blood pumped into the aorta each minute by the heart VENOUS RETURN- quantity of blood flowing from the veins into the right atrium each minute
10. CARDIAC CYCLE EVENTS I. LATE DIASTOLE A. Rapid Filling - 70 to 80% from atria to ventricle B. Slow Filling - Diastasis C. Atrial Systole - 30 to 20% from atria to ventricle II. SYSTOLE (Ventricular) A. Isometric Ventricular Contraction Right ventricle pressure above 10 mmHg Left ventricular pressure above 80 mmHg B. Rapid Ejection - 70% of blood from ventricle to aorta and pulmonary artery C. Slow Ejection - 30% of blood from ventricle to aorta and pulmonary artery
11. III. EARLY DIASTOLE A. Protodiastole B. Isometric Ventricular Relaxation ATRIAL PRESSURE WAVES a wave - caused by atrial contraction Right atrial pressure increases 4 to 6 mmHg Left atrial pressure increases 7 to 8 mmHg c wave - back bulging of A - V valves when ventricles contract v wave - slow flow of blood into the atria from the veins while A-V valves are closed during ventricular contraction Efficiency of the Heart or Efficiency of cardiac Contraction - ratio of work output to total chemical energy expenditure Normal Heart - 20 to 25 %
12. VARIATION IN LENGTH OF ACTION POTENTIAL AND ASSOCIATED PHENOMENA WITH CARDIAC RATE
13. EFFECT OF VARIOUS CONDITIONS ON CARDIAC OUTPUT. APPROXIMATE PERCENTAGE CHANGES ARE SHOWN IN PARENTHESIS
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15. REGULATION OF CARDIAC PUMPING A. BASIC MEANS of regulating volume pumped by the heart. 1. Intrinsic Cardiac Regulation of pumping in response to changes of volume of blood flowing to the hear. FRANK - STARLING MECHANISM - the greater the heart is stretched during filling, the greater the force of contraction and the greater the quantity of blood pumped into the aorta HETEROMETRIC REGULATION - regulation of cardiac output as a result of changes in cardiac muscle fiber length. 2. Control of the Heart by the Sympathetic and Parasympathetic nerves
16. Changes in Cardiac output caused by nerve stimulation result from changes in heart rate and from changes in contractile strength of the heart Chronotropic Action - cardiac accelerator action of catecholamines Inotropic Action - effect on strength of cardiac contraction Homometric Regulation - regulation due to changes in contractility independent of length.
17. B. Other Factors: 1. Effect of Potassium and Calcium Ions Excess potassium in the ECF causes the heart to become dilated and flacid and slows the heart rate Excess calcium ions causes the heart to go into Spastic contraction 2. Effect of temperature on Heart Function Increased temperature caused greatly increased heart rate
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21. Catecholamines exert their inotropic effect by activation of adenylyl cyclase and increase intracellular cAMP Xanthines such as caffeine and theophylline - inhibit the breakdown of cAMP Glucagon - increases the formation of cAMP - is positively inotropic Digitalis - inhibitory effect on Na + - K + ATPase in the myocardium - is positively inotropic Hypercapnia,hypoxia, acidosis, barbiturates - decrease myocardial contractility - are positively inotropic.