increased fluid and sodium loss with strenuous exercise and high environmental temperature, inadequate intake of fluid and electrolytes as well as those who are ill
Potential and actual disorders of fluid and electrolyte balance occur in every setting, with every disorder, and with a variety of changes that affect healthy people including?
60%
____% of a typical adult's weight consists of fluid (water and electrolytes)?
Age, gender and body fat
What are some factors that influence the amount of body fluid?
younger, older; men, women
____ people have a higher percentage of body fluid than ____ people; and ____ have proportionately more body fluid than ____.
False, obese people have less fluid than those who are thin because fat cells contain little water
True or False: Obese people have more fluid than those who are thin?
highest
The skeleton has a low water content and the muscle, skin and blood contain the ____ amounts of water?
intracellular space (fluid in the cells) and the extracellular space (fluid outside the cells)
Body fluid is located in what two fluid compartments?
two thirds, located primarily in the skeletal muscle mass
Approximately how much of body fluid is in the intracellular fluid (ICF) compartment?
one third
Approximately how much of body fluid is in the extracellular(ECF) compartment?
the intravascular, interstitial, and transcellular fluid spaces
What 3 further compartments is the extracellular fluid (ECF) divided into?
the intravascular space (the fluid within the blood vessels)
Contains plasma, the effective circulating volume...
plasma
Approximately 3 L of the average 6 L of blood volume in adults is made up of...
erythrocytes, leukocytes and thrombocytes
The remaining 3 L of blood volume in adults is made up of...
interstitial space
Space containing the fluid that surrounds the cell and totals about 11 to 12 L in an adult is know as the...
lymph
____ in an interstitial fluid...
potassium and phosphate
What are the two major electrolytes in the ICF?
trauma to the cells and tissues because the ECF has a low concentration of potassium and can only tolerate small changes in potassium concentration
What typically causes the release of large stores of intracellular potassium and why is this so dangerous?
hydrostatic pressure, at both the arterial and venous ends of the vessel and the osmotic pressure, exerted by the protein plasma -- the direction of fluid movement depends on the differences in these two opposing forces
Normal movement of fluids through the capillary wall into the tissue depends on ____ and ____
Osmotic pressure
The amount of hydrostatic pressure needed to stop the flow of water by osmosis - primarily determined by the number of solutes
Oncotic pressure
The osmotic pressure exerted by proteins (e.g. albumin)
Osmotic diuresis
The increase in urine output caused by the excretion of substances such as glucose, mannitol, or contrast agents in the urine
180
The kidneys filter approximately ____L of plasma per day
high, low
hydrostatic pressure in the capillaries tends to filter fluid out of the intravascular compartment into the interstitial fluid
In filtration, a form of passive transport, movement of water and solutes occurs from an area of ____ hydrostatic pressure to an area of ____ hydrostatic pressure
1 to 2 L
general rule of thumb is that the output is approximately 1 mL of urine per kilogram of body weight per hour in all age groups
What is the volume of urine in liters for adults daily?
sodium, chloride, and potassium
actual sweat losses can vary from 0 to 1,000 mL or more every hour, depending on factors such as temperature. Fevers greatly increase insensible water loss through lungs and skin
Continuous water loss by evaporation (approximately 500mL/day) occurs through skin as insensible perspiration, what are the chief solutes in sweat?
300 mL
abnormal conditions such as hyperpnea (abnormally deep respirations) or continuous coughing; increase this loss - the lungs play a major role in acid-base balance
The lungs eliminate water vapor (insensible loss) at a rate of approximately ____ mL every day
100 - 200 mL
approximately 8 L of fluid circulates through the GI system every 24 hours, because the bulk of fluid is normally reabsorbed in the small intestine, diarrhea and fistulas cause large losses
What is the usual loss of fluid through the GI tract daily?
kidneys, skin, GI and lungs
What are the organs of fluid loss?
urea, creatinine and uric acid
when measured with serum osmolality, urine osmolality is the most reliable indicator of urine concentration
What substances determine urine osmolality?
sodium
although blood urea nitrogen (BUN) and glucose also play a major role in determining serum osmolality
Serum osmolality primarily reflects the concentration of ____
270 to 300 mOsm/kg
sodium predominates in ECF osmolality and holds water in this compartment
Normal serum osmolality in healthy adults is?
0
What is the formula for serum osmolality and how is it measured?
1.010 to 1.025
measured at the bedside by placing a calibrated hydrometer or urinometer in a cylinder of approximately 20 mL of urine
also assessed with a refractometer or dipstick with reagent
Urine specific gravity measures the kidneys ability to excrete or conserve water, what is the normal range?
larger, lower
The ____ the volume of urine, the ____ the specific gravity is
True
True or False: Specific gravity is a less reliable indicator of concentration than urine osmolality: increased glucose or protein in urine can cause falsely elevated specific gravity.
kidenys, lungs, heart, pituitary gland, adrenal glands, and parathyroid glands
To keep the composition and volume of body fluid within narrow limits of normal, which main organs are involved to maintain this homeostatic range?
urea, an end product of the metabolism of protein(from both muscle and dietary intake) by the liver
What makes up BUN?
decreased renal function, GI bleeding, dehydration, increased protein intake, fever, and sepsis
What are factors that increase BUN?
end-stage liver disease, a low protein diet, starvation, and any condition that results in expanded fluid volume (e.g. pregnancy)
What are factors that decrease BUN?
amino acids and ammonia molecules
The breakdown of ? produces large amounts of ? molecules, which are absorbed into the bloodstream. These molecules are then converted to urea and excreted in the bloodstream
10 to 20 mg/dL
What is a normal BUN range?
creatinine, better indicator of renal function than BUN because it does not vary with protein intake and metabolic state
What is the end product of muscle metabolism?
0.7 to 1.4 mg/dL (62 to 124 mmol/L, its concentration depends on lean body mass and varies from person to person
What is the normal serum creatinine?
increase
When renal function decreases, serum creatinine levels increase or decrease?
the volume percentage of RBCs (erythrocytes) in whole blood
males 42% to 52%
females 35% to 47%
What does hematocrit measure and what is the nornmal range fro males and females?
dehydration and polycythemia (too many red blood cells. The opposite of anemia. polycythemia formally exists when the hemoglobin, RBC count, and total RBC volume are all above normal)
Conditions that increase the hematocrit level
over-hydration and anemia
Conditions that decrease the hematocrit level
increases, conserved
Urine sodium values change with sodium intake and the status of fluid volume, as sodium intake increases, excretion ____, as the circulating fluid volume decreases, sodium is _____
aldosterone and antidiuretic hormone (ADH)
The kidneys normally filter 180 L of plasma daily in the adult and excrete 1 to 2 L of urine. They act both autonomously and in response to which bloodborne messengers?
-regulation of ECF volume and osmolality by selective retention and excretion of body fluids
-regulation of normal electrolyte levels in the ECF by selective electrolyte retention and excretion
-regulation of pH of the ECF by retention of hydrogen ions
-e
What are the major functions of the kidneys in maintaining normal fluid balance?
hypothalamus, posterior pituitary gland
to conserve water
Where is ADH made and stored? Why is it released?
maintain osmotic pressure of cells by controlling the retention or excretion of water by the kidneys
regulate blood volume
What are the functions of ADH?
aldosterone
What is the mineralocorticoid (group of hormones that regulates the balance of water and electrolytes (ions such as sodium and potassium) in the body and act specifically on the tubules of the kidney) secreted by the zona glomerulosa (outer zone) of the a
loss, retention
Increased secretion of aldosterone causes sodium retention (and thus water retention) and potassium loss; decreased secretion of aldosterone causes sodium and water ____ and potassium ____
cortisol
What is another adrenocortical hormone that can also produce sodium and fluid retention but has less mineralcorticoid action?
regulate calcium and phosphate balance by means of parathyroid hormone (PTH)
What is the role of the parathyroid glands?
-influence bone reabsorption, calcium absorption from the intestines and calcium reabsorption from the renal tubules
What are the roles of parathyroid hormone (PTH)?
aldosterone, antidiuretic hormone (ADH), angiotensin I and angiotensin II
Hormones that work to retain water and sodium, therefore increasing blood pressure are?
the liver
Where is the substance angiotensinogen secreted?
renin
What enzyme converts angiotensinogen into angiotensin I?
angiotensin-converting enzyme (ACE)
What enzyme converts angiotensin I to angiotensin II?
atrial natriuretic peptide
Which hormone decreases blood volume by excreting sodium and water?
the atrial myocardium with tissue distribution in the cardiac atria and ventricles specifically when blood pressure is high and the myocardium stretches
What produces atrial natriuretic peptide?
sympathetic nervous system
this stimulates the granular cells (juxtaglomerular cells) which stimulates the release of renin (the enzyme that converts angiotensinogen to angiotensin I) in response to decreased renal perfusion
-angiotensin converting enzyme
Which system is activated when baroreceptors sense a decrease in blood pressure?
aldosterone
increasing BP
Angiotensin II, a major vasoconstrictor, increases arterial perfusion and stimulates the thirst center in the brain, causing us to drink more water, increasing plasma volume which all increase blood pressure. It also stimulates the adrenal cortex to relea
this increases muscle therefore increases in contraction and results in the increase of blood pressure
Angiotensin II causes cardiac vascular hypertrophy, how doe this cause an increase in blood pressure?
atrial natriuretic peptide (renin angiotensin aldosterone system inhibitor)
this causes vasodilation, decreasing BP, inhibiting the release of renin and therefore the production of angiotensin II
If blood pressure is high, the stimulation of atrial myocytes will decrease blood pressure by releasing what hormone?
the left atrium and carotid and aortic arches
they respond to changes in blood volume and regulate sympathetic and parasympathetic neural activity as well as endocrine activities
Where are baroreceptors located and what is their role?
sympathetic and parasympathetic
increases cardiac rate, conduction, and contractility
increases the circulating blood volume (as well as BP)
-sympathetic stimulation constricts renal arterioles; this increases the release of aldosterone, decreases glomeru
As arterial pressure decreases, baroreceptors transmit fewer impulses from the carotid and aortic arches to the vasomotor center. A decrease in impulses stimulates the _____ nervous system and inhibits the ____ nervous system, what is the outcome of this
aldosterone
a volume regulator also released as serum potassium increases, serum sodium decreases, or adrenocorticotropic hormone (ACTH) increases - A hormone produced by the anterior lobe of the pituitary gland that stimulates the secretion of cortisol a
As the sympathetic nervous system is stimulated, which hormone is released in response to an increased release of renin
ADH and thirst mechanism - maintain sodium concentration and oral intake of fluids. Oral intake is controlled by the thirst center located in the hypothalamus. A serum concentration or osmolality increases or blood volume decreases, neurons in the hypotha
The presence or absence of which hormone is the most significant factor in determining whether urine that is excreted is concentrated or dilute?
surface of the hypothalamus
they sense changes in sodium concentration
as osmotic pressure increases, neurons become dehydrated and quickly release impulses to the posterior pituitary, which increases the release of ADH, which then travels in the blood to
Where are osmoreceptors located and how do they increase the reabsorption of water and decrease urine output?
natriuretic peptides
1. atrial natriuretic peptide 2. brain natriuretic peptide 3. C-type natriuretic peptide 4. D-type natriuretic peptide
What hormones affect the fluid volume and cardiovascular function through the excretion of sodium (natriuresis) direct vasodilation, and the opposition of the renin-angiotensin-aldosterone system? What are the four peptides identified?
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