Define blood pressure & list its types. Describe the factors on which

cbse-class-11

#1

Define blood pressure & list its types. Describe the factors on which B.E relies.


#2

Blood Pressure : Blood pressure is the pressure exerted by the blood on the blood-vessel walls. This is due to the pumping action of the heart and is necessary for the flow of blood through various blood vessels. This force is absorbed by the friction of the blood with the blood vessels. By the time blood reaches the capillaries, its pressure falls considerably. Blood pressure is of three types :

  1. Systolic pressure or pressure during the systole of the heart.
  2. Diastolic pressure or pressure during the diastole of the heart.
  3. Pulse pressure which is the different between systolic and diastolic pressure.
    Normal blood pressure or B.E in adult males is :
    Systolic : 125-130 mm Hg (Mercury) Diastolic : 70-90 mm Hg (Mercury)
    Blood pressure varies with :
    (i) Age : It rises with age. In infants, B.E is between 70-90 mm Hg.
    (ii) Sex : In females, B.E is slightly lower than males.
    (iii) Build : In overweight persons, B.E is on the higher side.
    (iv) Posture : The diastolic B.E is slightly higher in a standing position.
    (v) Sleep : In sleep, the systolic pressure falls by 15-20 mm Hg.
    (vi) Emotions : Emotions result in increase in systolic blood pressure.
    (vii) Food : After the intake of food, B.E rises slightly.
    (viii) Exercise : In exercise, B.E rises and in strenuous exercise the systolic B.E may rise to 180 mm Hg.