Blood pressure and Its measurement procedure

Blood Pressure

Blood pressure is determined by blood volume and cardiac output. The contraction of left ventricle is generates blood pressure so BP is highest in arota. Blood pressure is the pressure or force which exert in the wall of blood vessels. 

Blood pressure rises to about 110-120 mm Hg during ventricle contraction (systole) and fall to about 80-70 mm Hg during ventricle relaxation (diastole).   

Regulation of blood pressure.

• Baroreceptor is present on arota and help to regulate blood pressure.
• Renin enzyme is secreted from beta cells of kidney and cause hypertension.     
• Various hormones are maintains blood pressure in human body.

Factor Affecting Blood Pressure	Hormone	Effect on Blood Pressure
Cardiac output (increased heart rate and contractility)	Epinephrine, norepinephrine	BP Increase
Systemic vascular resistance           Vasodilation            Vasocontraction	Epinephrine, nitric oxide Angiotensin II, antidiuretic hormone (ADH)	BP Decrease BP Increase
Blood volume            Blood volume decrease            Blood volume increase	Atrial natriuretic peptide (ANP) Antidiuretic hormone (ADH) and aldosterone	BP Decrease BP Increase

• Physical changes may affect the blood pressure.
• Obesity is cause high blood pressure.
• Drinking alcohol is increase the blood pressure.

Measurement of Blood pressure

Measurement of Blood Pressure 

Blood pressure is measured by sphygmomanometer with help of stethoscope.

• Sphygmo means pulse 
• Manometer means instrument used to measure blood pressure 

Blood pressure is usually measured in the brachial artery (Left arm).   

The rubber cuff is tied round upper arm, rubber cuff connected to a rubber bulb. Pressure is raised to 250 mm Hg and than release pressure slowly. Listen sounds of heart valves closing. Chest piece of stethoscope is placing on the bronchial artery. 

Heard first sound through the stethoscope, this sound corresponds to systolic blood pressure (SBP). Second sound correspond to diastolic blood pressure (DBP).

Note:
Systolic blood pressure normal range around 100-120 mm Hg.
Diastolic blood pressure (DBP) normal range around 65-80 mm Hg.