34 - Blood pressure in different sections of the cardiovascular system. Arterial blood pressure- measuring methods and normal values. Factors determining the blood pressure levels.

sections

blood pressure

blood pressure in diff parts of cardiovascular system

pulmonary arteries

arterial blood pressure - measuring methods and normal values

arterial blood pressure

systolic, diastolic and pulse pressure

factors determining levels of arterial blood pressure

blood pressure

Blood pressure is the force exerted by the blood against the vessel wall. measured in mmHG

blood pressure in diff parts of cardiovascular system

• Blood in aorta - 100mmHg.

• The pumping of the blood is pulsable - there are periodic variations.

• Blood systolic pressure of avg 100-140mmHg – maximal bp during a cardiac cycle

• diastolic pressure 60-90mmHg- minimal bp value during a cardiac cycle

• As a whole blood pressure decreases progressively from leaving the aorta

  • The venous capillaries have a blood pressure range of 10mmHg-35 mmHg with the average being 17mmHg.

    • adapted to allow only a low pressure of blood to flow through.

    • This low pressure ensures Nutrients can still diffuse

    • The main blood pressure of the pulmonary capillaries is avg 7mmHg

pulmonary arteries

• The systolic pressure is 25 mmHg and the diastolic pressure is approx. 16mmHg

• The low pressure allow for the exchange of gases such as CO2 and oxygen between the pulmonary capillaries and pulmonary alveoli.

arterial blood pressure - measuring methods and normal values

• Sphygmomanometer- form of auscultation using stethoscope and cuff

• Oscillometric method involves the observation of oscillations in the sphygmomanometer cuff pressure

• also involves an electronic pressure sensor (transducer) to observe cuff pressure oscillations

• electronics to automatically interpret them.

describe steps of auscultatory blood pressure measurement using sphygmomanometer

• A cuff is wrapped around the upper arm, over the brachial artery.

• Air is pumped into the cuff to stop blood flow by squeezing the artery closed.

• A stethoscope is placed just below the cuff — no sound is heard because blood flow is blocked.

• As air is slowly released, cuff pressure drops.

• When cuff pressure equals systolic pressure, blood starts to spurt through — a tapping sound (Korotkoff sound) is heard.

• The pressure at this first sound is the systolic pressure (SP).

• As more air is released, sounds become louder, then fade and disappear.

• The pressure at which sounds disappear is the diastolic pressure (DP).

• Mean Arterial Pressure (MAP) — normal value is about 93 mm Hg.

arterial blood pressure

• Arterial blood pressure is most accurately measured using an invasive arterial line.

  • measurement of arterial pressure by measuring using a cannula mediate directly into an artery--(usually radial, femoral, dorsalis pedis or brachial).

  • The cannula must be connected to a sterile, fluid-filled system, which is connected to an electronic pressure transducer.

  • The advantage of this system is that pressure is constantly monitored beat-by-beat, and a waveform (a graph of pressure against time)

    • Systolic pressure (SP) is the maximum pressure reached during peak ventricular ejection.

    • Diastolic pressure (DP) is the minimum pressure reached during ventricular relaxation.

    • Pulse pressure (PP) is the difference between the systolic and diastolic pressure.

systolic, diastolic and pulse pressure

• Systolic pressure (SP) is the maximum pressure reached during peak ventricular ejection.

• Diastolic pressure (DP) is the minimum pressure reached during ventricular relaxation.

• Pulse pressure (PP) is the difference between the systolic and diastolic pressure.

factors determining levels of arterial blood pressure

• Mean arterial pressure = Cardiac output x Total peripheral resistance

• Total peripheral resistance (TPR)= is the sum total of all resistances in the systemic circulation and affects mainly diastolic pressure

• Cardiac Output =HR*SV

• difference between (EDV) - (ESV) mainly affects systolic pressure.

• There is also blood volume which affects both.

• the hormonal control (ADH)- vasopressin- causes constriction

• the hormonal control (aldosterone)

• the renin-angiotensin vasoconstricton mechanism

• the stress-relaxation changes in the blood vessels

• shift of fluids through the capillaries