Tag: human body and organ system

Pulse pressure is calculated as the difference between the systolic pressure and the diastolic pressure. Here, 120 - 80 = 40 mm Hg.

The pulse pressure is the difference between systolic and diastolic pressure. For a standard 120/80 reading, the difference is 120 - 80 = 40 mm Hg.

In a healthy adult man, the normal diastolic pressure is typically 80 mm Hg. This is the pressure in the arteries when the heart is at rest.

A blood pressure reading of 140/90 mm Hg is considered elevated and is classified as hypertension. Normal is typically 120/80.

The pulmonary artery carries deoxygenated blood from the heart to the lungs. Its pressure is higher than that of the pulmonary vein, which carries oxygenated blood back to the heart at a much lower pressure.

• Blood pressure is the pressure which is exerted by blood against the wall of the arteries. 
  
• The average pressure produced in the ventricles when they contract and the blood is pumped into the aorta and the pulmonary artery is known as the systolic pressure, it is equal to the pressure exerted by a column of 120 mm of mercury. 
  
• The average pressure produced in the ventricles when they relax and are filled with blood is known as the diastolic pressure, it is about 80 mm of mercury. Hence the value of blood pressure in an adult is about 120/80.
  
• The blood pressure is measured by an instrument known as the sphygmomanometer.
  

The ejection of blood into the arteries causes the pressure within the arteries to rise, so the ventricular blood pressure is the highest in contracting arteries.

Adrenal medulla secrets adrenaline in response to stress and emergency condition. These hormones increase alertness, pupillary dilation, sweating etc. Both the hormones increase the heartbeat, the strength of heart contraction, blood pressure, rate of respiration.

Noradrenaline are rapidly secreted in response to the stress of any kind and during emergency situations and are called emergency hormones. In the rest of the  body, norepinephrine increases the heart rate and blood pressure.

When renal blood flow is reduced, the enzyme renin is secreted by the kidney cells. This promotes the conversion of angiotensinogen, produced by the liver, to angiotensin, which stimulates the production of aldosterone by the adrenal cortex. Aldosterone increases the reabsorption of sodium and water and the excretion of potassium by the kidneys. This raises the blood volume and the flow of blood through the kidneys, suppressing renin production and reducing aldosterone secretion.