Blood pressure

Blood pressure (BP) is the pressure exerted by circulating blood upon the walls of blood vessels. When used without further specification, "blood pressure" usually refers to the arterial pressure in the systemic circulation. It is usually measured at a person's upper arm. Blood pressure is usually expressed in terms of the systolic (maximum) pressure over diastolic (minimum) pressure and is measured in millimeters of mercury (mm Hg). It is one of the vital signs along with respiratory rate, heart rate, oxygen saturation, and body temperature. Normal resting blood pressure in an adult is approximately 120/80 mm Hg.

Blood pressure varies depending on situation, activity, and disease states. It is regulated by the nervous and endocrine systems. Blood pressure that is low due to a disease state is called hypotension, and pressure that is consistently high is hypertension. Both have many causes which can range from mild to severe. Both may be of sudden onset or of long duration. Long term hypertension is a risk factor for many diseases, including kidney failure, heart disease, and stroke. Long term hypertension is more common than long term hypotension in Western countries. Long term hypertension often goes undetected because of infrequent monitoring and the absence of symptoms.

David Riley

David Sidney Riley (born 8 December 1960) is an English former footballer who played as a midfielder and striker, making 190 league appearances in a nine-year career in the Football League, scoring 40 goals.

He began his career at Nottingham Forest in 1983, and had loan spells at Darlington and Peterborough United, before joining Port Vale for £20,000 in October 1987. In March 1990 he was sold on to Peterborough United for £40,000, and helped the club to two successive promotions into the Second Division. He later played for Kettering Town, Ponsonby (in New Zealand), Boston United, and King's Lynn.

Playing career

Riley played for Keyworth United before turning professional with Brian Clough's Nottingham Forest in June 1983. He played 12 First Division games for the club between April 1984 and 1987, scoring two goals. He was loaned out to Darlington in February 1987, and played six Third Division games for Cyril Knowles' side, scoring two goals. He joined Fourth Division side Peterborough United on loan in 1987, and played twelve league games under Noel Cantwell, scoring two goals.

David

David (/ˈdeɪvɪd/; Hebrew: דָּוִד, Modern David, Tiberian Dāwîḏ;ISO 259-3 Dawid; Arabic: داوُد‎ Dāwūd; Syriac: ܕܘܝܕ‎ Dawid; Ancient Greek: Δαυίδ; Latin: Davidus, David; Strong's: Daveed) was, according to the Books of Samuel, the second king of the United Kingdom of Israel, and according to the New Testament, an ancestor of Jesus. His life is conventionally dated to c. 1040 – 970 BCE, his reign over Judah c. 1010–970 BCE.

The Books of Samuel, 1 Kings, and 1 Chronicles are the only Old Testament sources of information on David, although the Tel Dan Stele (dated c. 850–835 BCE) contains the phrase בית דוד (bytdwd), read as "House of David", which many scholars confirm to be a likely plausible match to the existence in the mid-9th century BCE of a Judean royal dynasty called the House of David.

Depicted as a valorous warrior of great renown, and a poet and musician credited for composing much of the psalms contained in the Book of Psalms, King David is widely viewed as a righteous and effective king in battle and civil justice. He is described as a man after God's own heart in 1 Samuel 13:14 and Acts 13:22.

Blood

Blood is a bodily fluid in humans and other animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells. When it reaches the lungs, gas exchange occurs when carbon dioxide is diffused out of the blood into the pulmonary alveoli and oxygen is diffused into the blood. This oxygenated blood is pumped to the left hand side of the heart in the pulmonary vein and enters the left atrium. From here it passes through the mitral valve, through the ventricle and taken all around the body by the aorta. Blood contains antibodies, nutrients, oxygen and much more to help the body work.

In vertebrates, it is composed of blood cells suspended in blood plasma. Plasma, which constitutes 55% of blood fluid, is mostly water (92% by volume), and contains dissipated proteins, glucose, mineral ions, hormones, carbon dioxide (plasma being the main medium for excretory product transportation), and blood cells themselves. Albumin is the main protein in plasma, and it functions to regulate the colloidal osmotic pressure of blood. The blood cells are mainly red blood cells (also called RBCs or erythrocytes), white blood cells (also called WBCs or leukocytes) and platelets. The most abundant cells in vertebrate blood are red blood cells. These contain hemoglobin, an iron-containing protein, which facilitates oxygen transport by reversibly binding to this respiratory gas and greatly increasing its solubility in blood. In contrast, carbon dioxide is almost entirely transported extracellularly dissolved in plasma as bicarbonate ion.

Pressure

Pressure (symbol: p or P) is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled gage pressure) is the pressure relative to the ambient pressure.

Various units are used to express pressure. Some of these derive from a unit of force divided by a unit of area; the SI unit of pressure, the pascal (Pa), for example, is one newton per square metre; similarly, the pound-force per square inch (psi) is the traditional unit of pressure in the imperial and US customary systems. Pressure may also be expressed in terms of standard atmospheric pressure; the atmosphere (atm) is equal to this pressure and the torr is defined as ¹⁄₇₆₀ of this. Manometric units such as the centimetre of water, millimetre of mercury and inch of mercury are used to express pressures in terms of the height of column of a particular fluid in a manometer.

Definition

Pressure is the amount of force acting per unit area. The symbol for pressure is p or P. The IUPAC recommendation for pressure is a lower-case p. However, upper-case P is widely used. The usage of P vs p depends on the field in which one is working, on the nearby presence of other symbols for quantities such as power and momentum, and on writing style.