blood pressure overview

• Blood Flow


  Volume of blood passing through a vessel in a given time
• Cardiac Output


  Total blood flow from the heart per minute
• Peripheral Resistance


  Friction opposing blood flow in vessels
• Blood Pressure


  Force per unit area exerted by blood on vessel walls
• Total Blood Flow


  Sum of blood flow through entire circulation
• Blood Viscosity


  Thickness or stickiness of blood affecting flow
• Hematocrit


  Percentage of blood volume occupied by red blood cells
• Blood Vessel Length


  Directly proportional to resistance encountered
• Blood Vessel Diameter


  Major determinant of peripheral resistance
• Pulse Pressure


  Difference between systolic and diastolic blood pressure
• Mean Arterial Pressure (MAP)

  Average pressure driving blood into tissues
• Compliance


  Elastic artery ability to stretch
• Pulsatility


  Volume of blood entering vessels at any time
• Arterial Blood Pressure


  Reflects compliance and pulsatility in arteries
• Atherosclerosis


  Buildup of fatty plaques causing increased resistance
• Systemic Blood Pressure


  Pressure gradient from aorta to right atrium
• Blood Pressure Regulation


  Mechanisms controlling vessel diameter, heart rate, and contractility
• Short-term Mechanisms


  Neural and hormonal controls for immediate blood pressure adjustments
• Long-term Mechanisms


  Kidney regulation of blood volume for sustained blood pressure control
• Venous Return


  Blood flow back to the heart through veins
• Hypovolemic Shock


  Shock due to low blood volume causing inadequate tissue perfusion
• Elastic Arteries


  Arteries that dampen blood pressure fluctuations
• Muscular Arteries


  Arteries active in vasoconstriction
• Baroreceptors


  Stretch receptors in arteries detecting blood pressure changes
• Carotid sinus


  Location where baroreceptors in the carotid artery are located
• Vasomotor center


  Brain region controlling blood vessel diameter
• Cardioinhibitory center


  Brain region inhibiting heart rate
• Cardioacceleratory center


  Brain region stimulating heart rate
• Epinephrine


  Hormone increasing heart rate, contractility, and vasoconstriction
• Norepinephrine


  Hormone increasing heart rate, contractility, and vasoconstriction
• Antidiuretic hormone (ADH)


  Hormone causing intense vasoconstriction in low blood pressure
• Endothelium-derived factors


  Vasoconstrictors like endothelin and prostaglandin-derived growth factor
• α1-adrenoceptor agonists


  Agents like methoxamine & phenylephrine treating hypotension
• Atrial natriuretic peptide (ANP)

  Hormone causing blood volume & pressure decrease
• Nitric oxide (NO)


  Brief but potent vasodilator
• Renin


  Enzyme released by kidney's glomerular cells to regulate blood pressure
• Angiotensin II


  Hormone causing vasoconstriction and aldosterone release
• Aldosterone


  Hormone promoting sodium reabsorption
• Venous return


  Blood flow back to the heart aided by respiratory and muscular pumps
• Cardiac reserve


  Heart's ability to respond to increased demand for output