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106 Cards in this Set
- Front
- Back
60% of the body's weight is made up of what? water
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Water
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What are the three compartments that water is stored in in the body?
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The intracellular, the extracellular and as a component of blood
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What is interstitial fluid responsible for?
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A medium for exchange between the cell and the outside, how things enter and exit cells
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Osmolarity
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Total solute concentration in a solution- osmoles/liter
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Which is more dilute a solution with an osmolarity of 100 or a solution with an osmolarity of 200?
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100
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Osmosis
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Net movement of water through a selectively permeable membrane that seperates two solutions with different solute concentrations.
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Elevated osmolarity is indicative of what?
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Increased solute (sodium) and decreased fluid (water)
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What are the two most important extracellular solutes?
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Sodium and protein
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What are the two most important intracellular solutes?
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Potassium and protein
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What would happen to a cell that has an intracellular osmolarity of 290 mOsM when it is placed in a solution with an osmolarity of 100 mOsM?
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It will swell because the solution with 100 mOsM has more water than the cell that has an osmolarity of 290 mOsM
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Where does all the exchange between plasma and interstitial space occur?
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The capillary level
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The goal of the body is to maintain what kind of osmolarity?
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Neutral
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What does isosmotic mean?
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Equal osmolarity
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What are the two components of extracelluar fluid?
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Plasma and interstitial fluid
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What is water directly regulated by?
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Antidiuretic hormone (ADH)
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What is water indirectly regulated by and how is it regulated?
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Aldosterone- because it regulates sodium and wherever sodium goes water follows
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What organs regulate water balance?
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Kidneys, GI tract, lungs, and to a lesser extent skin
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How is fluid balance regulated?
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By regulating intake (thirst) and output (kidneys)
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What we take in should be... (Equal to, less than, or more than)what goes out
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Equal to
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What pressure does the blood enter the capillary at?
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32 mmHg- hydrostatic pressure
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As the blood moves through the capillary to the venous end hydrostatic pressure changes to what and why?
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It decreases to 15 mmHg because of the loss of fluid to the interstitial spaces- remaining plasma solutes because concentrated.
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At the venous end, the net flow of water is where?
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Back into the capillary due to the increased osmolarity of the plasma at the venous end
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What is the increased osmolarity of the plasma at the venous end due to?
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Retained protein in the plasma- it does not leave the capillary
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What is the most abundant plasma protein?
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Albumin
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What does albumin do at the venous end of the capillary?
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It draws fluid back in, and is responsible for the osmotic effect
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Are the hydrostatic and osmotic pressures equal? (Meaning does all the fluid that goes in return?)
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No
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The excess fluid from the difference in pressures goes where?
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Into the interstitial space
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What happens to this excessive fluid in the interstitial space?
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It is returned to circulation by the lympatic system
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Edema
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Excess fluid in the interstitial space and/or body cavities
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What is exudate rich in?
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Protein and blood cells
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What is exudate type edema normally seen in?
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Inflammation
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What is purulent exudate?
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Pus
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What is transudate made of?
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Little or no protein and very few cells, it is an ultrafiltrate of plasma and it has a water like consistency.
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What is transudate normally found in?
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Edema of right heart failure
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What is the primary mechanism for formation of a transudate?
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Increased pressure at the level of the capillary
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True or False...
In transudate there is no vascular damage and there is no leakage of protein or cells into the interstitial space. |
True
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Transudate or exudate?
Increased hydrostatic pressure within blood vessels |
Transudate
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Transudate or exudate...
Increase permeability of the vessel wall |
Exudate
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What would happen if there was low albumin concentrations?
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There would be nothing to pull the fluid back in so edema would result.
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True or False...
Edema is usually multifactorial |
True
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Edema caused by chronic heart failure is usually a combination of what?
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hydrostatic (HTN) and hypervolemic
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Pitting edmea in right heart failure is prominent where and why?
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In the lower extermities due to gravity
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After a mastectomy patients may suffer from persistant edema for life- why?
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Because in a mastectomy they take out the lymph nodes and therefore it is unable to drain anymore resulting in edema.
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What is the principal regulator of water intake?
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Thirst
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What is thirst regulated by?
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The osmolarity of the plasma
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What cells monitor the osmolarity of the plasma?
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Osmoreceptors
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Increased osmolarity of the plasma activates what?
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Neural pathways that result in the conscious perception of thirst.
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Why are diabetics always thirsty?
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Because there is an increased plasma osmolarity because of the increased glucose so the regulators are always being stimulated
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What are the two mechanisms in the kidney that regulate output?
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What is filtered at the glomerulus and what is reabsorbed or secreted by the tubules.
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The amount of fluid filtered by the glomerulus is a function of what?
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Hydrostatic pressure- the pressure of the pump
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What are the tubules of the kidney are important for?
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Reabsorption and secretion of substances- modifying the filtrate.
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What is modified in the filtrate?
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Both solute and water
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What hormones are involved in the regulation of fluid balance?
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ADH, aldosterone, and atrial natriuretic peptide
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Where is ADH produced and stored?
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Produced by the neurons in the hypothalamus and stored in the axon terminals of the posterior pituitary.
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Increased osmolarity of the plasma causes what in regards to ADH?
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Results in action potential within the hypothalamic neurons and release of ADH into the plasma
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Where does ADH bind once it has been released?
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A receptor on the collecting duct cell (Found only in the kidney)
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When ADH binds to the receptor what does this stimulate?
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the formation of membrane channels in the collection duct cells to increase permeability of water from the filtrate back to the plasma.
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Lack of ADH secretion results in what?
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Copious dilute urine
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What is the only hormone that directly regulates water?
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ADH
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Where is aldosterone secreted?
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The adrenal cortex
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What does aldosterone act on?
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The renal cortical collecting duct cells to promote the movement of sodium from the filtrate back into the blood
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Movement of the sodium from the filtrate to the blood will result in what?
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Increased water retention because water follows sodium
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Where does atrial natriuretic peptide come from and what causes it to be released?
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Atrial cells in the heart in response to increased stretch.
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Increased stretch of the heart is caused by what?
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Increased venous return to the heart, caused by excess fluid volume
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What does ANP promote?
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Water and sodium loss through the kidneys
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Why is it important that aldosterone is a steroid hormone?
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Because it is a lipid itself so it crosses the plasma membrane easily.
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Where is the receptor for the aldosterone hormone?
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In the nucleus
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What stimulates the release of aldosterone?
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low plasma sodium/
high plasma potassium |
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Does aldosterone directly regulate plasma postassium concentration?
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yes
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What could cause hyperaldosterone secretion?
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tumor in the adrenal cortex causing hypokalemia
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Cardiac dysrhthmias from an inability of cells to conduct action potentials are associated with what electrolyte imbalance?
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hypokalemia
(low plasma postassium) |
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What could cause hypoaldosterone secretion?
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Addison's disease causing hyperkalemia
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What electrolye imbalance usually results from kidney dysfunction, and also results in cardiac dysfunction from hypoaldosterone secretion?
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hyperkalemia
(high plasma postassium) |
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When blood pressure drops, baroreceptors stimulate cells in the afferent arteriole to the kidney to release this.
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Renin
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A protein that acts like an enzyme and converts a plasma protein termed angiotensinogen into angiotensin I.
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Renin
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Angiontensin I is converted into angiontensin II, how?
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By an enzyme in the lung called the Angiotensin Converting Enzyme (ACE)
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A potent vasoconstrictor, this causes an increase in peripheral vascular resistance thatt raises blood pressure.
It is a potent stimulus for the release of aldosterone. |
Angiotensin II
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What is the purpose of stimulating the release of aldosterone with low BP, in general or low pressure through the kidney, specifically?
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To conserve water in order to increase plasma volume.
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What is one treatment for patients with fluid overload and hypertension?
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ACE inhibitors, diuretics
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1.excretion of wastes
2.regulation of body water, sodium, potassium 3.pH 4.secretion of hormones - erythropoetin, renin, vitamin D |
These are the 4 functions of the kidneys.
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What 2 major waste products are eliminated by the kidney?
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Blood Urea Nitrogen (BUN)
Creatinine |
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A nitrogen waste product that is the end result of protein and nucleic acid catabolism.Breaks down into ammonia.
Normal range: 6-19 mg/dl |
Blood Urea Nitrogen (BUN)
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A product of creatine metabolism in muscle.
Normal range is 0.5 - 1.4 mg/dl |
Creatinine
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1. vary the acidity of urine - normal pH ranges from 4.5 - 8.0
2. make and release into the interstitial space bicarbonate ion |
2 ways the kidney can help regulate pH
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What is the normal pH required in the ECF?
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7.35-7.45
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1. the bicarbonate system
2. phosphate and protein buffering systems |
How does the body maintain pH?
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Kidney can excrete hiydrogen ion into urine and return bicarbonate to the ECF.
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One mechanism to add new bicarbonate into blood.
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H ion elevated/bicarbonate ion decreased.
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acidosis
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H ion decreased/bicarbonate ion elevated.
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alkalosis
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In COPD - pt. cannot blow off CO2 as fast as it is produced. What can this cause?
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respiratory acidosis
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When CO2 is removed faster than it is produced (like in hyperventilation), it can cause this.
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respiratory alkalosis
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In the kidney, H ion is secreted and K ion is conserved.
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acidosis
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In the kidney, H ion is retained and K is secreted.
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alkalosis
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1. correction - the cause of the disturbance is repaired
2. compensation - physiological adjustments are made |
2 ways to return pH to normal
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kidney cells sense reduced O2 carrying capacity of blood and release this to stimulate the bone marrow to produce more red blood cells
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erythropoetin
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kidney activates this, which stimulates the GI tract to absord more dietary calcium
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vitamin D
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when blood pressure drops in the kidney, kidney cells release this, resulting in vasoconstriction, elevating BP
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renin
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elevated BUN and creatinine (from inability to produce urine)
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azotemia
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when azotemia becomes associated with clinical signs and symptoms, it is termed this.
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uremia (urine in the blood)
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prolonged signs and symptoms of uremia
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chronic renal failure (scarring/irreversible)
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kidney stone formation
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nephrolithiasis
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a clinical syndrome in which kidneys are unable to excrete waste products frequently it is reversible
increased serum BUN and creatinine caused by glomerular disease, ischemia, nephrotxicity, acute tubular necrosis |
acute renal failure
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characterized by destruction of tubular epithelial cells and clinically by acute suppression of renal function
most common cause of acute renal failure (when urine flow is <400 ml/day) reversible caused by ischemia from trauma, toxicity from chemicals |
acute tubular necrosis
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1.initiation - 36 hours - decline in urine output, w rise in BUN/creatinine
2.maintenance - 3 weeks - urine output only 50-400 ml/day, fluid overload 3.recovery - take up to 6 mos. - steady increase in urine output - pt usually becomes anemic from lack of erythropoetin |
3 stages of acute tubular necrosis
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Urinary outflow obstruction by renal stones.
More common in makes. Most important fator: increased urine concetration of the stone's constituents that exceed their solubility in urine. |
urolithiasis
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characterized morphologically by contracted kidneys with red-brown color and diffusely granular appearance
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end-stage kidney disease
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