Hydrodynamic pressure
the increment of pressure created by resistance to the flow of fluid in a closed system like plumbing pipes or the cardiovascular system
Blood pressure
the hydrodynamic pressure of moving blood
hydrostatic pressure
pressure caused by the weight of fluid
Osmotic pressure
a measure of the tendency of water to move by osmosis from an area of high water concentration across a semipermeable membrane to an area of low water concentration
Cardiac output
CO= SV x HR. Cardiac output is determined by heart rate and the volume of blood ejected with each beat (stroke volume)
Renin-angiotensin-aldosterone system
Decreased BP. -> Renin from Kidney converts Angiotensin to Angiotensin 1. -> Angiotensin converting enzyme in lung (Acetylcholinesterase ACE) converts Angiotensin 1 to Angiotensin II. -> Vasoconstriction & Aldosterone release from Adrenal Cortex = water r
Renin
Enzyme that initiates a cascade of events to maintain blood pressure.
Angiotensinogen
a protein made by the liver
Acetylcholinesterase
an enzyme made in the lungs. Converts Angiotensin 1 to Angiotensin II
Angiotensin II
increases blood pressure by increasing both peripheral resistance and cardiac output. It also stimulates secretion of Aldosterone from the adrenal cortex.
Aldosterone
a steroid that acts on the kidney to retain sodium and water, which expands blood volume and, therefore, cardiac output.
Fluid constiture _____% of body weight
60%
Two major body compartments fluids are divided into
Intracellular; is approximately 40 % of body weight (largest).Extracellular; is approximately 20% of body weight
3 compartments of Extracellular fluid
Interstitial fluid-(the largest). Plasma. transcellular fluid - fluid in synovial, peritoneal, pericardial, and intraocular spaces, as well as CSF
% of plasma and cells in blood
55% plasma and 45% cells
Effect of a high-sodium diet on blood pressure
Salt works on your kidneys to make your body hold on to more water. This extra stored water raises your blood pressure and puts strain on your kidneys, arteries, heart and brain.
Edema
abnormal accumultion of fluid in a tissue or body cavity such as the peritoneal cavity. It is always the result of some underlying condition.
2 main types of edema
Inflammatory edema and noninflammatory adema
Exudate
Inflammatory edema has a high protein content and is called exudate. It is created by the increased vascular permeability of inflammation that allows proteins to leak through capillary walls
Transudate
Low pressure edema caused by pressure imbalance. Diagnostic feature of transudate edema is "pitting edema".
Pleural effusion
Abnormal accumulation of fluid in the pleural space
Pericardial effusion
Accumulation of fluid in the pericardial space resulting from inflammation caused by acute pericarditis; fluid compresses the heart inhibiting cardiac filling
Ascites
Abnormal accumulation of fluid in the peritoneal cavity
Edema of increased fluid pressure (hydrostatic pressure)
Increased hydrostatic pressure prevents fluid return from the interstitial compartment to the venous end of the capillary or forces excessive amounts of fluid into the tissues
Albumin
A small protein molecule made by the liver and is a major determinant in plasma osmotic pressure
Edema of low osmotic pressure
Decreased osmotic pressue occurs when albumin falls; causing fluid to remain in the tissues
Edema of lymphatic obstruction
Edema resulting from lymphatic obstruction is termed lymphadema. Usually occurs in a limb. Common causes include tumor obliteration of lymph nodes, surgical interruption of lymph channels, and radiation scarring after tumor radiotherapy.
Forward effect of left ventricular failure
Decrease in Cardiac output leads to decrease blood pressure. Then decreased renal flow that lead to the increase of remin secreted by the kidney. That leads to the end factor of sodium and water retention causing edema
Backward effect of left ventricular failure
Buildup in the pulmonary circulation causing and increase in pulmonary venous pressure. This results in pulmonary edema
Dehydration
a deficiency of body water, which may be due to insufficient water intake, excess loss, or a combination of the two
Dehydration classification according to concentration of electrolytes in the fluid lost
Normotonic. hypotonic. hypertonic
Normotonic dehydration
refers to loss of a fluid roughly equivalent to normal plasma ex. sweat
Hypotonic dehydration
loss of a fluid with low electrolyte concetration. ex. urine
Hypertonic dehydration
loss of fluid with high electrolyte concentration
Causes of dehydration
insufficient water intake. excess loss. diarrhea. heavy sweating
Clinical signs of dehydration
Dry mucus membranes and thirst, pale, cool skin from peripheral vasoconstriction to maintain blood pressure; low urine output. Lost tissue elasticity (tissue turgor).
Third-spacing
A shift of fluid out of blood into another body space. examples are burns and peritonitis.
Why are sodium balance and blood pressure codependent?
...
Hyponatremia
Low plasma sodium. Usually due to excessive loss by sweating, vomiting or diarrhea, too much water intake and antidiuretics. It impairs nerve impulses and has osmotic effects that shift water from one compartment to another. Muscle cramps are common
Hypokalemia
Low plasma potassium. Can be caused by diarrhea. low dietary potassium with alcoholism. eating disorders. certain antihypertensive drugs that promote urine loss. by high plasma levels of aldosterone and cortisol that promote urine loss. high doses of insu
Effects of Hypokalemia
Most important effect is on the electrical activity of the heart. Shows distinctive changes on a EKG. Promotes electrical unstability, arrhythmias, interferes with muscle contraction and sensory nerve function.
How are sodium and potassium levels maintained?
Plasma levels of sodium are mainly maintained by aldosterone which acts on the kidneys to reduce urine sodium excretion. Blood levels potassium are also maintained by aldosterone, which acts on the kidneys to increase urine K+ excretion
Hypocalcemia
Low blood calcium. Causes include inadvertent surgical removal of parathyroid glands, high phosphate from renal failure, vitamin D deficiency. Hypocalcemia increases irritability of nerve cells which causes contractions of skeletal muscle either fasiculat
Hypercalcemia
Increased blood calcium. Hypercalcemia is usually caused by hyperparathyroidism with increased PTH
Also, malignant tumors may dissolve bone; excess vitamin D is another cause. Hypercalcemia depresses neuromuscular activity and leads to weakness and fatigu
Actions of the Parathyroid hormone (PTH)
Increases blood levels of calcium (stimulates breakdown of bone and rate at which calcium is removed from urine and absorbed from the gastrointestinal tract)
metabolic acidosis
Increased blood acidity resulting from fixed acids.
Cause: Shock with poor oxygenation and anaerobic metabolism, which generates fixed acids; diabetic ketoacidosis, kidney failure(less excretion). Effect: Decreased blood bicarbonate. Compensation: Rapid,
respiratory acidosis
CO2 accumulation in blood. Cause: Respiratory depression(e.g drugs, coma) or chronic pulmonary disease (emphysema). Effect: increased blood CO2. Compensation: Increased renal acid excretion and generation of new blood bicarbonate buffer
Fixed acids
Acids that cannot be exhaled. Also include ingested amino acids (especially from meat) and ketones produced from fatty acid metabolism.
Volatile acid
Acid that can be exhaled. CO2
3 buffer systems
Bicarbonate buffer system. Hemoglobin buffer. Phosphate buffer.
Bodies compensation for fixed acids
(1) the chemical acid-base buffer systems of the body fluids, which immediately combine with acid or base to prevent excessive changes in H+ concentration; (2) the respiratory center, which regulates the removal of CO2 (and, therefore, H2CO3) from the ext
Bicarbonate buffer system
Most important buffer. Combines hydrogen ions with bicarbonate to generate the weak acid carbonic acid
Hyperemia
Hyperemia is an active process associated with inflammation; arterioles dilate and the site turns red (erythema) with bright red, oxygenated blood
Congestion
Congestion is a passive process associated with impaired venous outflow. Chronic passive congestion occurs in the liver caused by chronic right heart failure the blood "dams up" in the vena cava
3 major elements that enable hemostasis
Activity of blood vessel endothelium, platelets, and plasma coagulation.
Immune thrombocytopenic purpura (ITP)
The immune system destroys its own platelets. Platelets become coated with antiplatelet antibodies and are quickly removed by the spleen.
Hemophilia A
Most serious inherited coagulation disorder. An x-linked gene defect that occurs almost exclusively in males. It is inherited from their mothers, most of whom are unaffected carriers.
Thrombosis
is the formation of a blood clot (thrombus) inside a blood vessel, obstructing the flow of blood through the circulatory system.
Clotting
Begins when plasma or platelets contact something they should not: extravascular tissue or foreign surface. Coagulation factors cause fibrinogen to polymerized into strands of fibrin which form a gel-like solid meshwork and plug the hole.
How can deep vein thrombosis become life-threatening.
Thrombophlebitis in a deep vein of the leg is very dangerous because the thrombus can break loose, and embolize (thromboembolism). Such emboli can be washed through the heart and completely occlude the pulmonary artery
4 conditions that increase tendency to form thrombosis
Endothelial injury. Abnormal blood flow. hypercoagulability. Some diseases also increase the tendency to form thrombosis
Embolus
intravascular object that travels in the bloodstream from one place to another. The main danger of an embolus is obstruction of blood flow.
Ischemia
lack of oxygen supply to tissue and is usually caused by obstructin of blood flow
Infarction
Area of ischemic necrosis. Most are caused by thrombotic occlusion of an artery.
How can shock become life-threatening
If left untreated will reach an irreversible stage. With progressively severe hypotension, hypoperfusion and acidosis. Decreased myocardial contractility. Leakage into blood of inflammatory mediatorss from dying cells that further compound metabolic diffi
Hypovolemic shock
Results from an underfilled vascular space, usually the result of hemorrhage. Hypovolemic shock may also be caused by fluid loss following burns or severe diarrhea
Cardiogenic shock
Pump failure. often occurs with myocardial infarction or other myocardial disease. In such cases, cardiac muscle simply lacks the mechanical power to maintain blood pressure
Septic shock
Associated with systemic microbial infection (sepsis). It ranks high as a cause of death in intensive care units---20% of affected patients die. Microbes release toxins, inflammatory mediators play a role, and damaged endothelium may induce DIC or hemorrh
Body's response to the initial stage of shock
Characterized by reflex reactions to re-establish perfusion. Low blood pressure stimulates the sympathetic nervous system: tachycardia increases cardiac output, and systemic vasoconstriction increases peripheral resistance to raise blood pressure and main
How is the second progressive stage of shock characterized?
more sever hypoperfusion and metabolic imbalances caused by hypoxia.
treatment of a child with anaphylaxis
Adrenaline. Early use of epinephorine