Lecture 1-Body Fluid Compartments Flashcards
Daily intake of water—oral intake = ___ ml/day + synthesized by the body = ___ ml/day
Oral intake = 2100 ml/day + synthesized by the body = 200 ml/day
Total water intake = 2300 ml/day
Loss of body water = ____ loss, ___ loss, loss in ___, loss by ___
Insensible loss, sweat loss, loss in feces, loss by kidneys
Insensible loss = ___ ml/day
700 ml/day—350 ml lost via skin + 350 ml lost via lungs
Loss in sweat = ___ ml/day
100 ml/day
Loss in feces = ___ ml/day
100 ml/day
Loss in urine = ___ ml/day
1400 ml/day
Total body fluid is distributed mainly between two compartments: the ___ fluid and the ___ fluid; ___ fluid is divided into the ___ fluid and blood ___
The extracellular fluid and the intracellular fluid; extracellular fluid is divided into the interstitial fluid and blood plasma
___ fluid = this compartment includes fluid in the synovial, peritoneal, pericardial, and intraocular spaces, as well as the cerebrospinal fluid; it is usually considered to be a specialized type of ___ fluid, although in some cases its composition may differ markedly from that of the plasma or interstitial fluid; this compartment constitutes ~ ___ to ___ liters
Transcellular fluid; it is usually considered to be a specialized type of extracellular fluid; all the transcellular fluids together constitute ~1-2 liters
In a 70 kg adult man, the total body water is about ___% of the body weight, or about ___ liters
60% of the body weight, or about 42 liters
Total body water depends on age, gender, and degree of obesity—T/F?
True
As a person grows older, the percentage of total body weight that is fluid gradually ___ (increases/decreases); this is due in part to the fact that aging is usually associated with an increased percentage of the body weight being ___
The percentage of total body weight that is fluid gradually decreases; this is due in part to the fact that aging is usually associated with an increased percentage of the body weight being fat (so this decreases the percentage of water in the body)
Body fluid compartments—intracellular fluid = ___ L
28 L
Body fluid compartments—extracellular fluid = ___ L
14 L
Body fluid compartments—interstitial fluid = ___ L
11 L
Body fluid compartments—plasma = ___ L
3 L
Fluid composition—extracellular vs. intracellular—plasma and interstitial fluids are ___ (similar/different) in composition; there is a highly permeable ___ (cell/capillary) membrane inbetween plasma and interstitial fluids; protein level is greater in the ___ (plasma or interstitial fluid) because of ___ (low/high) membrane permeability
Plasma and interstitial fluids are similar in composition; there is a highly permeable capillary membrane inbetween plasma and interstitial fluids; protein level is greater in the plasma because of low [capillary] membrane permeability
Fluid composition—extracellular vs. intracellular—intracellular fluid is separated from extracellular fluid by ___ membrane; the cell membrane is highly permeable to ___, not ____, making it ___-permeable
Intracellular fluid is separated from extracellular fluid by cell membrane; the cell membrane is highly permeable to water, not electrolytes, making it semi-permeable
Extracellular fluid has high concentrations of what two ions?
Sodium and chloride
Intracellular fluid has high concentration of what (3) things?
Potassium, phosphate, and protein
Gibbs Donnan Equilibrium—when two solutions containing ions are separated by a membrane that is permeable to some of the ions and not to others, a/an ___ is established; electrical and chemical energies on either side of the membrane are ___ and ___ to each other
An electrochemical equilibrium is established; electrical and chemical energies on either side of the membrane are equal and opposite to each other
Fluid exchange and osmotic equilibrium—distribution of fluid between intracellular and extracellular compartments is determined by osmotic effect of ___
Small solutes
Fluid exchange and osmotic equilibrium—___ or ___ (i.e.: sodium and chloride) determine distribution of fluids across the semi-permeable cell membrane [inbetween intracellular/extracellular compartments]
Electrolytes or small ions (i.e.: sodium and chloride)
Fluid exchange and osmotic equilibrium—___ factors cause fluids to shift between intra/extracellular compartments; the reason for this is that the cell membranes are highly permeable to ___ but relatively impermeable to ___
Osmotic factors; the reason for this is that the cell membranes are highly permeable to water but relatively impermeable to small ions such as sodium and chloride
The relative amounts of EXTRACELLULAR fluid distributed between the plasma and interstitial spaces are determined mainly by the balance of ___ and ___ forces across the capillary membrane
Hydrostatic and colloid osmotic forces across the capillary membrane
Rate of osmosis—because cell membranes are relatively ___ to most solutes but are ___ to water (i.e.: they are selectively permeable), whenever there is a higher concentration of solute on one side of the cell membrane, ___ diffuses across the membrane toward the region of higher solute concentration
Because cell membranes are relatively impermeable to most solutes but are highly permeable to water (i.e.: they are selectively permeable), whenever there is a higher concentration of solute on one side of the cell membrane, water diffuses across the membrane toward the region of higher solute concentration
If a solute such as sodium chloride is added to the extracellular fluid water rapidly diffuses from the cells through the cell membranes into the ___ fluid until the water concentration on both sides of the membrane becomes equal
Extracellular fluid
If a solute such as sodium chloride is removed from the extracellular fluid, water diffuses from the extracellular fluid through the cell membranes and into the ___
Cells
The rate of diffusion of water is called the rate of ___
Osmosis
Mole is the term defining a specific quantity of ___
Molecules
Osmole refers to the number of particles in ___, rather than molar concentration
Osmole refers to the number of particles in solution, rather than molar concentration
One osmole (osm) = ___
1 mole (mol) 6.02 x 10^23
Total number of particles in a solution is measured in ___
Osmole
Osmolality = osmoles/___ of water
Osmoles/kg of water
^ Not really applicable to us
Osmolarity = osmoles/___ of solution
Osmoles/liter of solution
^ More applicable to us
Osmosis is the net diffusion of ___ across a selective membrane
Water
Water moves from ___ water concentration to ___ water concentration
High water concentration to low water concentration
___ refers to the amount of pressure required to prevent osmosis (pressure applied in opposite direction of osmosis)
Osmotic pressure
Osmotic pressure of a solution is proportional to the concentration of osmotically active particles, independent of molecular size (big or small)—T/F?
True
Molecules which dissociate when dissolved into solution have more osmotic effect—T/F?
True
Osmolarity of body fluids—80% of the osmolarity of interstitial fluid and plasma is due to ___ and ___
Sodium and chloride
Osmolarity of body fluids—plasma is 1 mOsm/L ___ (less than/greater than) interstitial fluid…why?
Plasma is 1 mOsm/L greater than interstitial fluid because plasma proteins maintain 20 mmHg greater pressure in capillaries than surrounding tissues
Osmolarity of intracellular fluid is almost 50% due to ___ ions; remainder divided among other intracellular substances
Potassium ions
Total osmolarity of each compartment is ___ mOsm/L
300 mOsm/L
Because the plasma and interstitial fluid are separated only by highly permeable capillary membranes, their ionic composition is similar—T/F?
True
The most important difference between the plasma and interstitial fluid is that there is a ___ (lower/higher) concentration of protein in the plasma
Higher concentration of protein in the plasma
Because the capillaries have a ___ (low/high) permeability to plasma proteins, ___ (small/large) amounts of proteins are leaked into the interstitial spaces in most tissues
Because the capillaries have a low permeability to plasma proteins, small amounts of proteins are leaked into the interstitial spaces in most tissues
Extracellular fluid osmolarity (interstitial fluid + plasma) is mostly due to ___ and ___ ions
Sodium and chloride ions (account for 80% of the total osmolarity in the interstitial/plasma compartments)
Intracellular fluid osmolarity is mostly due to ___ ions
Potassium ions (account for 50%—the remainder is divided among many other intracellular substances)
Large osmotic pressures can develop across cell membranes with relatively small changes in solute concentrations—T/F?
True
Small changes in concentration of impermeable solutes cause little changes in cell volume—T/F?
False—can cause TREMENDOUS changes in cell volume
If isotonic saline is added to the extracellular fluid compartment, the osmolarity of the extracellular fluid ___ (increases/decreases/does not change); therefore, ___ (osmosis/no osmosis) occurs through the cell membranes; the effect is a/an ___ (increase/decrease/no change) in extracellular fluid volume
If isotonic saline is added to the extracellular fluid compartment, the osmolarity of the extracellular fluid does not change; therefore, no osmosis occurs through the cell membranes; the effect is an increase in extracellular fluid volume
If a hypertonic solution is added to the extracellular fluid, the extracellular osmolarity ___ (increases/decreases/does not change); therefore, ___ (osmosis/no osmosis) occurs and water moves into the ___ compartment; almost all the added sodium chloride remains in the ___ compartment and fluid diffuses from cells into the ___ space to achieve ___; the net effect is a/an ___ (increase/decrease/no change) in extracellular volume, a/an ___ (increase/decrease/no change) in intracellular volume, and a ___ (rise/decline) in osmolarity in both compartments
If a hypertonic solution is added to the extracellular fluid, the extracellular osmolarity increases; therefore, osmosis occurs and water moves into the extracellular compartment; almost all the added sodium chloride remains in the extracellular compartment and fluid diffuses from cells into the extracellular space to achieve osmotic equilibrium; the net effect is an increase in extracellular volume (greater than the volume of fluid added), a decrease in intracellular volume, and a rise in osmolarity in both compartments
If a hypotonic solution is added to the extracellular fluid, the osmolarity of the extracellular fluid ___ (increases/decreases/does not change); extracellular water diffuses into the ___ until the intracellular and extracellular compartments have the same ___; both the intracellular and extracellular volumes are ___ (increased/decreased/unchanged) by the addition of hypotonic fluid, although the ___ (intracellular/extracellular) volume increases to a greater extent
If a hypotonic solution is added to the extracellular fluid, the osmolarity of the extracellular fluid decreases; extracellular water diffuses into the cells until the intracellular and extracellular compartments have the same osmolarity; both the intracellular and extracellular volumes are increased by the addition of hypotonic fluid, although the intracellular volume increases to a greater extent
Sodium concentration abnormalities—hyponatremia = excess ___, loss of ___
Excess water, loss of sodium
Conditions that can cause hyponatremia—___ and ___; ___ abuse; ___ disease; excess ___ retention (from what hormone?)
Diarrhea and vomiting; diuretic abuse; Addison’s disease (inadequate mineralocorticoid—Aldosterone/glucocorticoid secretion); excess water retention (from oversecretion of ADH/vasopressin)
Sodium concentration abnormalities—hypernatremia = loss of ___, excess ___
Loss of water, excess sodium
Conditions that can cause hypernatremia—lack of ___ (what hormone?); ___ (endocrine condition); ___hydration; ___ secretion (what hormone?)
Lack of ADH; diabetes insipidus; dehydration; aldosterone secretion
Rapid changes in cell volume as a result of hyponatremia can have profound effects on tissue and organ function, especially the ___
Brain
A rapid reduction in plasma sodium concentration, for example, can cause brain cell edema and neurological symptoms, including headache, nausea, lethargy, and disorientation—T/F?
True
If plasma sodium concentration rapidly falls below ___ to ___ mmol/L, brain swelling may lead to seizures, coma, permanent brain damage, and death
Below 115 to 120 mmol/L
Because the skull is rigid, the brain cannot increase its volume by more than about ___% without it being forced down the neck (herniation), which can lead to permanent brain injury and death
10%
Hypernatremia can be caused by ___ loss or excess ___
Water loss or excess sodium
Hypernatremia from primary loss of water can occur from an inability to secrete ___ hormone
An inability to secrete antidiuretic hormone—needed for the kidneys to conserve water
Hypernatremia—as a result of lack of ADH, the kidneys excrete large amounts of ___ (dilute/concentrated) urine (a disorder referred to as ___), causing ___ and ___ (increased/decreased) concentration of sodium chloride in the extracellular fluid
As a result of lack of ADH, the kidneys excrete large amounts of dilute urine (a disorder referred to as “central” diabetes insipidus), causing dehydration and increased concentration of sodium chloride in the extracellular fluid
Hypernatremia—in certain types of renal diseases, the kidneys cannot respond to antidiuretic hormone, causing a type of ___
“Nephrogenic” diabetes insipidus
Hypernatremia d/t excessive sodium chloride in the extracellular fluid—this often results in ___hydration (de/over) because excess extracellular sodium chloride is usually associated with at least some degree of ___ retention by the kidneys
This often results in over hydration because excess extracellular sodium chloride is usually associated with at least some degree of water retention by the kidneys
Hypernatremia—excessive secretion of the sodium-retaining hormone ___ can cause a mild degree of hypernatremia and overhydration
Aldosterone
Sodium retention caused by increased aldosterone secretion also stimulates secretion of ___ hormone and causes the kidneys to reabsorb greater amounts of ___
Water
Hypernatremia is much ___ (more/less) common than hyponatremia…why?
Much less common—because hypernatremia promotes intense thirst and stimulates secretion of antidiuretic hormone, which protects against a large increase in plasma and extracellular fluid sodium
Severe symptoms of hypernatremia usually occur only with rapid and large increases in the plasma sodium concentration above ___ to ___ mmol/L
Above 158 to 160 mmol/L
Correction of hypernatremia can be achieved by administering ___ or ___ solutions
Hypotonic or dextrose solutions
It is prudent to correct hyper/hyponatremia ___ (slowly or quickly)
SLOWLY
Edema = presence of excess fluid in ___; occurs mostly in the ___ fluid compartment
Presence of excess fluid in body tissue; occurs mostly in the extracellular fluid compartment
Intracellular edema can occur in certain conditions—inflammation has a direct effect on ___ (increasing/decreasing) cell membrane permeability; ___ (increase/decrease) in cellular metabolic function; lack of ___ to cells; ___ (increased/decreased) blood flow, reducing oxygen and nutrient supply
Inflammation has a direct effect on increasing cell membrane permeability; decrease in cellular metabolic function; lack of nutrition to cells; decreased blood flow, reducing oxygen and nutrient supply
Extracellular edema (excess fluid accumulation in extracellular spaces)—two general causes: 1) abnormal leakage from ___; 2) lymphatic failure to return fluids to ___
1) abnormal leakage from plasma
2) lymphatic failure to return fluids to blood
Extracellular edema—abnormal leakage from plasma can result from excessive ___ filtration rate; filtration is dependent on ___ity and ___ of capillary; starling factors—___ pressure and ___ pressure
Excessive capillary filtration rate; filtration is dependent on permeability and surface area of capillary; starling factors—hydrostatic pressure and colloid osmotic pressure
Extracellular edema—lymphatic failure to return fluids to blood can result from lymphatic ___, preventing return of ___ to plasma; ___ (increased/decreased) interstitial colloid osmotic pressure; cancer, surgery, infection (i.e.: ___)
Lymphatic blockage, preventing return of proteins to plasma; increased interstitial colloid osmotic pressure; cancer, surgery, infection (i.e.: filaria nematodes)
Causes of extracellular edema—___ (increased/decreased) capillary pressure from excessive kidney retention of ___ and ___; ___ (low/high) venous pressure and venous constriction; ___ (increased/decreased) arteriolar resistance
Increased capillary pressure from excessive kidney retention of salt and water; high venous pressure and venous constriction; decreased arteriolar resistance
Causes of extracellular edema—___ (increased/decreased) plasma proteins from loss in ___ (i.e.: ___ syndrome); denuded skin (i.e.: ___ and ___); failure to produce proteins (i.e.: ___ disease, ___nutrition)
Decreased plasma proteins from loss in urine (i.e.: nephrotic syndrome); denuded skin (i.e.: burns and wounds); failure to produce proteins (i.e.: liver disease, malnutrition)
One of the most important causes of decreased plasma protein concentration is loss of proteins in the ___ in certain kidney diseases, a condition referred to as ___ syndrome
Loss of proteins in the urine in certain kidney diseases, a condition referred to as nephrotic syndrome
Causes of extracellular edema—___ (increased/decreased) capillary permeability from immune reactions that cause release of histamine and other immune products; toxins; bacterial infections; vitamin deficiency, especially vitamin C; prolonged ischemia; burns
Increased capillary permeability
Causes of extracellular edema—___ of lymph return—i.e.: cancer, infections (i.e.: filaria nematodes), surgery, congenital absence or abnormality of lymphatic vessels
Blockage of lymph return
Edema caused by heart failure—the heart fails to pump blood normally from the ___ into the arteries, which raises ___ pressure and ___ pressure, causing ___ (increased/decreased) capillary filtration; the arterial pressure tends to ___ (rise/drop), causing decreased excretion of ___ and __ by the kidneys, which causes still more edema
The heart fails to pump blood normally from the veins into the arteries, which raises venous pressure and capillary pressure, causing increased capillary filtration; the arterial pressure tends to drop, causing decreased excretion of salt and water by the kidneys, which causes still more edema
Edema caused by heart failure—blood flow to the kidneys is ___ (increased/decreased), which stimulates secretion of ___, causing increased formation of ___ and increased secretion of ___, both of which cause additional ___ and ___ retention by the kidneys
Blood flow to the kidneys is decreased, which stimulates secretion of renin, causing increased formation of angiotensin II and increased secretion of aldosterone, both of which cause additional salt and water retention by the kidneys
Extracellular edema—summary of causes—___ (increased/decreased) capillary pressure; ___ (increased/decreased) plasma proteins; ___ (increased/decreased) capillary permeability; ___ of lymphatic return
Increased capillary pressure; decreased plasma proteins; increased capillary permeability; blockage of lymphatic return
Virtually all the fluid in the interstitium is in the ___ form
Gel form
Summary of safety factors that prevent edema—1) low interstitial ___; 2) ___ (increased/decreased) lymph flow; 3) “wash down” of interstitial fluid ___—as lymphatic flow ___ (increases/decreases), proteins are washed away
1) low interstitial compliance
2) increased lymph flow
3) “wash down” of interstitial fluid proteins—as lymphatic flow increases, proteins are washed away
The total safety factor against edema is about ___ mm Hg; therefore, capillary pressure can ___ before significant edema occurs
Total safety factor = 17 mm Hg; capillary pressure can double before significant edema occurs
Total safety factor— -3 mm Hg from interstitial compliance; 7 mm Hg from lymph flow; 7 mm Hg from “wash down” of proteins from interstitial spaces
3+7+7 = 17 mm Hg
The right kidney rests slightly lower than the left one d/t the presence of the liver on the right side—T/F?
True
The ___ is the functional unit of the kidney
Nephron
Plasma filtration occurs in the ___
Glomerulus
Renal blood flow = ___% of cardiac output (___ ml/min)
22% of cardiac output (1100 ml/min)
Renal blood flow—oxygen consumption in the kidneys varies directly with active transport of ___
Na+
Highest metabolism occurs in the renal ___
Cortex
On a per gram basis, renal blood flow is the highest of any organ—T/F?
True—because renal tissue makes up only 0.4% of body weight but receives 25% of cardiac output
The kidneys are the most highly perfused major organs in the body—T/F?
True
The high perfusion to the kidneys facilitates plasma filtration at rates as high as ___ to ___ ml/min in young adults
125 to 140 ml/min
___ is the functional unit of the kidney
Nephron
Each kidney has 1.25 million nephrons
Two types of nephrons = ___ and ___
Cortical and juxtamedullary
Cortical nephrons = ___ (short/long) loops of Henle, extend to outer medulla; outnumber juxtamedullary nephrons ___:___
Short loops of Henle, extend to outer medulla; outnumber juxtamedullary nephrons 7:1
Juxtamedullary nephrons—extend deep into the medulla with ___ (short/long) loops of Henle; play a big role in ___ urine
Long loops of Henle; play a big role in concentrating urine
The kidney can regenerate new nephrons—T/F?
False—the kidney CANNOT regenerate new nephrons
With renal injury, disease, or normal aging, the number of nephrons gradually ___ (increases/decreases)
Decreases
After age 40 years, the number of functioning nephrons usually decreases about ___% every 10 years; thus, at age 80 years, many people have ___% fewer functioning nephrons than they did at age 40 years
After age 40 years, the number of functioning nephrons usually decreases about 10% every 10 years; thus, at age 80 years, many people have 40% fewer functioning nephrons than they did at age 40 years
The nephron begins with ___ space
Bowman’s space
The distal convoluted tubule comes into very close contact with the ___ (afferent/efferent) glomerular arteriole, and the modified cells of each form the ___ apparatus, a complex physiologic feedback control mechanism contributing in part to the precise control of intra- and extra-renal hemodynamics that is a hallmark feature of the normally functioning kidney
Afferent arteriole, and the modified cells of each form the juxtaglomerular apparatus
Superficial cortical nephrons have their glomeruli in the ___ (inner/outer) cortex; they have ___ (shorter/longer) loops of Henle, which dip only into the ___ (inner/outer) medulla
Superficial cortical nephrons have their glomeruli in the outer cortex; they have shorter loops of Henle, which dip only into the outer medulla
Juxtamedullary nephrons have their glomeruli near the corticomedullary border; they have ___ (smaller/larger) glomeruli, and thus have ___ (lower/higher) glomerular filtration rates (GFR); their loops of Henle dip deeper into the ___ (inner/outer) medulla and papilla, and are vital in the ___ of urine
They have larger glomeruli, and thus have higher glomerular filtration rates (GFR); their loops of Henle dip deeper into the inner medulla and papilla, and are vital in the concentration of urine
___ = high-pressure capillary bed; the site of blood filtration
Glomerulus
___ = funnel-like structure; ‘beginning’ of the nephron
Bowman’s capsule
Each nephron has its own independent blood supply (renal arterioles and veins)—T/F?
True
Where in the nephron is urine is formed, concentrated, and conveyed to the ureters? (4) parts
- Proximal convoluted tubule
- Loop of Henle
- Distal convoluted tubule
- Collecting duct
