Question | Answer |
pulse and blood pressure, along with respiratory rate and body temperature | Vital signs |
pressure wave caused by the expansion and recoil of arteries | Pulse |
In systemic arterial blood pressure ,Pressure is increased in the cuff until it exceeds systolic pressure in the | biracial artery |
occur as blood starts to spurt through the artery (systolic pressure, normally 110–140 mm Hg) | Sounds first |
when the artery is no longer constricted and blood is flowing freely (diastolic pressure, normally 70–80 mm Hg) | Sounds disappear |
low blood pressure
Systolic pressure below 100 mm Hg | Hypotension |
temporary low BP and dizziness when suddenly rising from a sitting or reclining position | Orthostatic hypotension |
hint of poor nutrition and warning sign for Addison’s disease or hypothyroidism | Chronic hypotension |
important sign of circulatory shock. | Acute hypotension |
Primary or essential hypertension
90% of hypertensive conditions
Etiology unknown.
Due to several risk factors including heredity, diet, obesity, age, stress, diabetes mellitus, and smoking | Hypertension |
is less common
Due to identifiable disorders, including kidney disease, arteriosclerosis, and endocrine disorders such as hyperthyroidism and Cushing’s syndrome | Secondary hypertension |
Is fastest in the aorta, slowest in the capillaries, increases again in veins | velocity of blood flow |
Slow capillary flow allows adequate time for exchange between blood and | tissues |
Automatic adjustment of blood flow to each tissue in proportion to its requirements at any given point in time
Is controlled intrinsically by modifying the diameter of local arterioles feeding the capillaries | Autoregulation |
Two types of autoregulation | Metabolic: Vasodilation of SM via NO.
Myogenic : Increased stretch = constriction |
Vasodilation of arterioles and relaxation of precapillary sphincters occur in response to
Declining tissue O2 ( we need more oxygen !!!)
Substances from metabolically active tissues (H+, K+, adenosine, and prostaglandins) and inflammatory chemicals | Metabolic Controls |
NO is the major factor causing | vasodilation |
Myogenic responses of vascular smooth muscle keep tissue perfusion constant despite most fluctuations in | systemic pressure |
promotes increased tone and vasoconstriction | Passive stretch |
promotes vasodilation and increases blood flow to the tissue ( low pressure) | Reduced stretch |
Causes kidneys to conserve water. BP increases | ADH |
Causes BP increases | Angiotensin II |
Vasoconstriction. Released due to low blood flow. BP increases. | Endothelin |
A very potent vasodilator. Lowers BP | NO |
Vasodilator of the skin. Inhibits ADH. Lowers BP | Alcohol |
Antagonistic to aldosterone. Causes the kidneys to excrete Na. Lowers BP | ANP & BNP |
Occurs when short-term autoregulation cannot meet tissue nutrient requirements
The number of vessels to a region increases and existing vessels enlarge | Angiogenesis |
Blood flow to the brain is constant, as neurons are intolerant of | ischemia |
Supplies nutrients to cells (autoregulation in response to O2 need)
Helps maintain body temperature (neurally controlled)
Provides a blood reservoir (neurally controlled) | Blood flow through the skin |
Sweat also causes vasodilation via | bradykinin in perspiration
Bradykinin stimulates the release of NO |
Low O2 levels cause vasoconstriction; high levels promote | vasodilation |
Allows for proper O2 loading in the | lungs |
Lipid-soluble molecules diffuse directly through | endothelial membranes |
solutes pass through clefts and fenestrations. | Water-soluble |
such as proteins, are actively transported in pinocytotic vesicles or caveolae. | Larger molecules |
Tends to force fluids through the capillary walls
Is greater at the arterial end (35 mm Hg) of a bed than at the venule end (17 mm Hg) | Capillary hydrostatic pressure (HPc) (capillary blood pressure) |
Usually assumed to be zero because of lymphatic vessels | Interstitial fluid hydrostatic pressure (HPif) |
Created by nondiffusible plasma proteins, which draw water toward themselves | Capillary colloid osmotic pressure (oncotic pressure) (OPc) |
Low (~1 mm Hg) due to low protein content | Interstitial fluid osmotic pressure |
comprises all the forces acting on a capillary bed | Net Filtration Pressure |
At the arterial end of a bed | hydrostatic forces dominate |
At the venous end | osmotic forces dominate |
Excess fluid is returned to the blood via | lymphatic system |
Any condition in which
Blood vessels are inadequately filled
Blood cannot circulate normally
Results in inadequate blood flow to meet tissue needs | Circulatory Shock |
Hypovolemic shock | results from large-scale blood loss. Gun shot. |
Vascular shock | results from extreme vasodilation and decreased peripheral resistance. Bee stings |
Cardiogenic shock | results when an inefficient heart cannot sustain adequate circulation. Heart failure. |
short loop that runs from the heart to the lungs and back to the heart | Pulmonary circulation |
long loop to all parts of the body and back to the heart | Systemic circulation |