Blood pressure

A healthcare worker measuring blood pressure using a sphygmomanometer.
A digital sphygmomanometer used for measuring blood pressure
Overview of main complications of persistent high blood pressure
Cardiac systole and diastole
Blood flow velocity waveforms in the central retinal artery (red) and vein (blue), measured by laser Doppler imaging in the eye fundus of a healthy volunteer.
Schematic of pressures in the circulation
A schematic representation of the arterial pressure waveform over one cardiac cycle. The notch in the curve is associated with closing of the aortic valve.
Taking blood pressure with a sphygmomanometer

Pressure of circulating blood against the walls of blood vessels.

- Blood pressure
A healthcare worker measuring blood pressure using a sphygmomanometer.

77 related topics

Alpha

Emission spectrum for sodium, showing the D line.

Sodium

Chemical element with the symbol Na and atomic number 11.

Chemical element with the symbol Na and atomic number 11.

Emission spectrum for sodium, showing the D line.
A positive flame test for sodium has a bright yellow color.
The structure of sodium chloride, showing octahedral coordination around Na+ and Cl− centres. This framework disintegrates when dissolved in water and reassembles when the water evaporates.
Two equivalent images of the chemical structure of sodium stearate, a typical soap.
The structure of the complex of sodium (Na+, shown in yellow) and the antibiotic monensin-A.
NaK phase diagram, showing the melting point of sodium as a function of potassium concentration. NaK with 77% potassium is eutectic and has the lowest melting point of the NaK alloys at −12.6 °C.

Studies have found that lowering sodium intake by 2 g per day tends to lower systolic blood pressure by about two to four mm Hg. It has been estimated that such a decrease in sodium intake would lead to between 9 and 17% fewer cases of hypertension.

Hypotension

Low blood pressure.

Low blood pressure.

Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood.

Anterior (frontal) view of the opened heart. White arrows indicate normal blood flow. (Pulmonary artery labeled at upper right.)

Pulmonary artery

Artery in the pulmonary circulation that carries deoxygenated blood from the right side of the heart to the lungs.

Artery in the pulmonary circulation that carries deoxygenated blood from the right side of the heart to the lungs.

Anterior (frontal) view of the opened heart. White arrows indicate normal blood flow. (Pulmonary artery labeled at upper right.)
Volume rendering of a high resolution CT scan of the thorax. The anterior thoracic wall, the airways and the pulmonary vessels anterior to the root of the lung have been digitally removed to visualize the different levels of the pulmonary circulation.
At the far end, pulmonary arteries (labelled at the bottom) become capillaries at the pulmonary alveoli.
Image showing main pulmonary artery coursing ventrally to the aortic root and trachea, and the right pulmonary artery passes dorsally to the ascending aorta, while the left pulmonary artery passes ventrally to the descending aorta.
Pulmonary circuit
Transverse section of thorax, showing relations of pulmonary artery.
Pulmonary artery
Pulmonary artery.Deep dissection.Anterior view.
CT scan of a normal lung, with different levels of pulmonary arteries.
Bronchial anatomy

The pulmonary artery pressure (PA pressure) is a measure of the blood pressure found in the main pulmonary artery.

Autonomic nervous system innervation.

Autonomic nervous system

Division of the peripheral nervous system that supplies smooth muscle and glands, and thus influences the function of internal organs.

Division of the peripheral nervous system that supplies smooth muscle and glands, and thus influences the function of internal organs.

Autonomic nervous system innervation.
Autonomic nervous system, showing splanchnic nerves in middle, and the vagus nerve as "X" in blue. The heart and organs below in list to right are regarded as viscera.
Function of the autonomic nervous system
A flow diagram showing the process of stimulation of adrenal medulla that makes it release adrenaline, that further acts on adrenoreceptors, indirectly mediating or mimicking sympathetic activity.

Short-term physiological effects of caffeine include increased blood pressure and sympathetic nerve outflow.

Valves of the heart in motion, the front wall of the heart is removed in this image.

Heart valve

One-way valve that allows blood to flow in one direction through the chambers of the heart.

One-way valve that allows blood to flow in one direction through the chambers of the heart.

Valves of the heart in motion, the front wall of the heart is removed in this image.
Structure of the heart valves
Blood flow through the valves
3D - loop of a heart viewed from the apex, with the apical part of the ventricles removed and the mitral valve clearly visible. Due to missing data, the leaflets of the tricuspid and aortic valves are not clearly visible, but the openings are; the pulmonary valve is not visible. On the left are two standard 2D views (taken from the 3D dataset) showing tricuspid and mitral valves (above) and aortal valve (below).
Wiggers diagram, showing various events during a cardiac cycle, with closures and openings of the aortic and mitral marked in the pressure curves.
This is further explanation of the echocardiogram above. MV: Mitral valve, TV: Tricuspid valve, AV: Aortic valve, Septum: Interventricular septum. Continuous lines demarcate septum and free wall seen in echocardiogram, dotted line is a suggestion of where the free wall of the right ventricle should be. The red line represents where the upper left loop in the echocardiogram transects the 3D-loop, the blue line represents the lower loop.
Illustration of the valves of the heart when the ventricles are contracting.

A heart valve opens or closes according to differential blood pressure on each side.

Arteries of the neck. The carotid sinus is at the origin of the internal carotid artery.

Baroreceptor

Baroreceptors (or archaically, pressoreceptors) are sensors located in the carotid sinus (at the bifurcation of external and internal carotids) and in the aortic arch.

Baroreceptors (or archaically, pressoreceptors) are sensors located in the carotid sinus (at the bifurcation of external and internal carotids) and in the aortic arch.

Arteries of the neck. The carotid sinus is at the origin of the internal carotid artery.

They sense the blood pressure and relay the information to the brain, so that a proper blood pressure can be maintained.

The cardiac cycle at the point of beginning a ventricular systole, or contraction: 1) newly oxygenated blood (red arrow) in the left ventricle begins pulsing through the aortic valve to supply all body systems; 2) oxygen-depleted blood (blue arrow) in the right ventricle begins pulsing through the pulmonic (pulmonary) valve en route to the lungs for reoxygenation.

Systole

Part of the cardiac cycle during which some chambers of the heart muscle contract after refilling with blood.

Part of the cardiac cycle during which some chambers of the heart muscle contract after refilling with blood.

The cardiac cycle at the point of beginning a ventricular systole, or contraction: 1) newly oxygenated blood (red arrow) in the left ventricle begins pulsing through the aortic valve to supply all body systems; 2) oxygen-depleted blood (blue arrow) in the right ventricle begins pulsing through the pulmonic (pulmonary) valve en route to the lungs for reoxygenation.
Electrical waves track a systole (a contraction) of the heart. The end-point of the P wave depolarization is the start-point of the atrial stage of systole. The ventricular stage of systole begins at the R peak of the QRS wave complex; the T wave indicates the end of ventricular contraction, after which ventricular relaxation (ventricular diastole) begins.
The cardiac cycle at beginning of atrial systole: The left (red) and right (blue) ventricles begin to fill during ventricular diastole. Then, after tracing the P wave of the ECG, the two atria begin contracting (systole), pulsing blood under pressure into the ventricles.
A Wiggers diagram, showing various events during systole (here primarily displayed as ventricular systole, or ventricular contraction). The very short interval (about 0.03 second) of isovolumetric, or fixed-volume, contraction begins (see upper left) at the R peak of the QRS complex on the electrocardiogram graph-line. + Ejection phase begins immediately after isovolumetric contraction—ventricular volume (red graph-line) begins to decrease as ventricular pressure (light blue graph-line) continues to increase; then pressure drops as it enters diastole.

The left ventricular systole enables blood pressure to be routinely measured in the larger arteries of the left ventricle of the heart.

Spironolactone, the most widely used antimineralocorticoid.

Antimineralocorticoid

Diuretic drug which antagonizes the action of aldosterone at mineralocorticoid receptors.

Diuretic drug which antagonizes the action of aldosterone at mineralocorticoid receptors.

Spironolactone, the most widely used antimineralocorticoid.
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Antimineralocorticoids and highlighted groups that are important for activity. The y-lactone ring shown in red and the C-7 substituent in pink.
Skeletal formulae of aldosterone antagonists.

By regulating water excretion, mineralocorticoid receptor antagonists lower blood pressure and reduce fluid around the heart which can be very beneficial in some cardiovascular conditions.

Furosemide 125mg vials for intravenous application

Diuretic

Any substance that promotes diuresis, the increased production of urine.

Any substance that promotes diuresis, the increased production of urine.

Furosemide 125mg vials for intravenous application

First, they effectively reduce blood pressure.

Example of the widely used Bourdon pressure gauge

Pressure measurement

Analysis of an applied force by a fluid on a surface.

Analysis of an applied force by a fluid on a surface.

Example of the widely used Bourdon pressure gauge
Checking tire pressure with a spring and piston tire-pressure gauge
Natural gas pressure gauge
A pressure gauge reading in psi (red scale) and kPa (black scale)
A pressure gauge in action
The difference in fluid height in a liquid-column manometer is proportional to the pressure difference:
Ring balance manometer
A McLeod gauge, drained of mercury
Membrane-type manometer
An original 19th century Eugene Bourdon compound gauge, reading pressure both below and above ambient with great sensitivity
Indicator side with card and dial
Mechanical side with Bourdon tube
Mechanical details
A pile of pressure capsules with corrugated diaphragms in an aneroid barograph
Application Schematic
Pirani vacuum gauge (open)
Bayard–Alpert hot-cathode ionization gauge
Penning vacuum gauge (open)
Dead-weight tester. This uses known calibrated weights on a piston to generate a known pressure.

Blood pressure is measured in millimetres of mercury (see torr) in most of the world, central venous pressure and lung pressures in centimeters of water are still common, as in settings for CPAP machines.