Blood Pressure -Blood pressure is the force exerted by the blood against the walls of the blood vessels as if flow through them.

 

Blood pressure :

       Blood   pressure is the force exerted by the blood against the walls of the blood vessels as if flow through them. 

·         Systolic pressure is the highest degree of pressure exerted by the blood against the walls of the blood vessels during the ventricle is forcing the blood into the aorta.

·         Diastolic pressure is the lower pressure that occur  when the heart is in its resting period just before the contraction of the left ventricle pulse pressure is the difference between the systolic and diastolic pressure and represents the volume output of the left ventricle.

·         The average blood pressure for a healthy adult is usually bout 120/80 mm Hg

   

 A systolic pressure above 150 or below 90mm hg.

 

 Is considered  abnormal venous pressure may vary from 40 to 110mm of water

 

·         Hypertension is a condition of abnormally high blood pressure hypertension is condition hypertension is a condition of abnormally low blood pressure.

              Factor Causing Variation in blood pressure :

                                 I.            Age: Blood pressure is lower in children than in adults pressure gradually increase until 45to 50 year after it accelerates sharply.

                              II.            Sex: There is no difference in B.P values between boys in persons of the same age with normal weight. Weight reduction usually decreases the blood pressure.

                           III.            Race: Certain race e.g. Negroes will have higher B.P reading than other races.

                           IV.            Climate: Pressure norms are lower in tropical climates than temperature and highest in polar climates.

                              V.            Time of the day : In all persons B.P is lower in the early morning and than rise to a peak in the evening then it declines.

                           VI.            Exercise: Muscular exertion will raise the blood pressure.

                        VII.            Pain : Sever pain may cause temporary and marked increase the blood pressure.

                     VIII.            Emotion : Fear ,worry excitement and other emotional factor will raise the blood pressure to greeter level. Blood pressure is more likely to be  raised in prsons who live stressful urban environment or who have with constant mental tension than in persons leading relaxed tranquil lives.

                           IX.            Posture :  It is often stated that B.P  is lower when lying down than when sitting or standing .when the B.P. is decreased suddenly on standing posture it is called orthostatic hypotension.

                              X.            Disease conditions: Disease affecting the circulatory system and kidney may increase the blood pressure disease that  weaken the heart action may lower the blood pressure.

                           XI.            Drugs: The drugs such as amyl nitrite and nitro glycerin cause a decrease in the blood  pressure certain drugs increase the blood pressure .

                        XII.            Hemorrhage :Hemorrhage causes a low blood pressure by decreasing the volume of blood in the blood vessels.

                     XIII.            Increased intracranial pressure :

        Pressure in the cranium usually produce a rise in the blood pressure e.g. ,head injury and intra cranial tumors.

 

Instrument used in measuring the blood pressure:

    The standard instrument used to measure the blood  pressure is called a sphygmomanometer.

·         There are two types of pressure manometer mercury and aneroid both give accurate readings when they are function property

·         The use of a proper size cuff is necessary to get an accurate  reading if the cuff is too narrow or not overlapping the reading will be false.

·         A cuff that is too wide for the extremity gives a lower than the diameter of the extremity on which it will be used encircle the extremity .

 

Blood pressure :

    Blood pressure is the force exerted by the blood against the wall off blood vessels as it flows through them. It includes to measurement.

·         Systolic blood pressure  is force exerted by arterial walls during against systole it is the maximum pressure during ventricle contraction.

·         Diastolic blood pressure is the force exerted by blood   against arterial wall during diastole it is the minimum pressure when the ventricle are relaxed .

                       Unit of measuring blood pressure is (mmHg) millimeters normal blood pressure is 120/80 mmHg here systolic pressure is 80mmHg.

·         Pulse pressure is the difference between systolic and the diastolic pressure normally the pulse pressure is 40mmHg.

Physiology of Blood pressure :

BP=Cardiac output (CO)+peripheral resistance.

Blood output =stroke volume x heart rate .

·         Blood pressure has very close relationship with the cardiac output peripheral vascular resistance blood volume viscosity and the elasticity of arterial wall.

·         Cardiac output is the amount of blood ejected by heart in one cycle.

·         Stroke volume is the amount of blood ejected by heart in one cycle.

Blood pressure basically depends upon cardiac output and peripheral vascular resistance

·         Normally heart eject 70-80ml blood in one cycle. If client has 72 heart rate then cardiac output is 70O72 5040ml.