Chapter 25 Fluid/Electrolytes Flashcards
What two classifications are solutes divided???
Electrolytes: can break down to ions
NonElectrolytes: do not break down
Electrolytes have greater osmotic pressure power than non electrolytes…Why?
Water moves according to osmotic gradients, in what direction?
Elec have 2X the amount of solute because the breakdown of ions into more total particles.
High OP pulls H2O so…
High solute pulls H2O.
What is the distinctive electrolyte pattern of both extra and intracellular compartments?
EXTRA- Sodium chief CATION Chloride major ANION INTRA- Potassium chief CATION Phosphate chief ANION
What is substantial in the movement of fluid among compartments? How does this move?
Water
Passive osmosis
Ion fluxes are restricted and move selectively by _______ _______.
Nutrients, resp. gases, and wastes move ____________.
________ is the only fluid circulating thru out and links inter w/ external environm.
Osmolalities of all body fluids are _______.
active transport
unidirectionnaly (passive transport)
Plasma
EQUAL
To remain properly hydrated, water ______ must ________ water _______. The intake sources are:
intake equal output
Ingested fluid 60% food 30%
metabolic water 10%
Water output is in what forms?
Urine 60%, feces 4%
Insensible losses 28%, sweat 8%
Increases in plasma osmolarity trigger thirst and release of _____. Why?
ADH
Loss of water because plasma has high solute
Water occupies what two compartments of the body? And what two major subdivisions of one of those?
Intracellular Fluid (ICF):2/3, cells
Extracellular Fluid (ECF):
~Plasma-blood fluid
~Interstitial fluid (IF)-between cells
When is the hypothalamic thirst center stimulated?
low blood vol (low h20)
increase plasma osmo (high solute)
baroreceptor input, angio II, other stimuli
What feedback inhibits thirst center?
moistened mucosa (mouth/throat) activated stomach and stretch receptors
What triggers or inhibits ADH release?
Hypothalamic osmoreceptors (nerve monitoring plasma osmo)
TRIGGERS:
fever, vomiting, diarrhea, high sweating, blood loss, burns
What makes a hypotonic hydration occur?
What is the sodium content in the ECF?
What condition can be caused, which does?
Excess in water (or renal insuff)
Sodium normal, water high.
Hyponatremia-low solute con because high water, net osmosis into tissue causing swelling
What is atypical accumulation of fluid in the interstitial space, leading to tissue swelling?
Edema
What is hypoproteinemia? What does it force?
How can this happen?
Lack of plasma protein.
fluid out of cap beds at the arterial ends
protein malnutrition, liver dz, glomerulonephritis
What is compartment syndrome? What causes this?
Interstitial fluid accumulation resulting in low BP and low circulation.
Blocked lymph vessels causing proteins to leak into Interst. fluid.
Salts are important for:
Neuromuscular excitability
Secretory activity (neurotrans)
Membrane permeability (ionic pres)
Controlling fluid movements
What electrolyte (solute) accounts for 90% of all ECF solutes, is the single most abundant cation in ECF, and is the ONLY cation exerting significant osmotic pressure?
Sodium
When water is down, so is sodium.
Sodium ions leak into cells and are pumped out against their electrochemical gradient.
*sodiums role in controlling ECF volume and water distribution.
What triggers the release of aldosterone?
(Renin-angiotensin mech)
Renin catalyzes the production of angiotensin II which prompts aldosterone.
Adrenal cortical cells directly stimulates also.
Explain how aldosterone is involved and what occurs when K+ levels are high in ECF.
If K+ is high, then its just high OR water is too low making K+ concentration appear high. Low water means low sodium.
Aldos. stim kidneys to secrete K+ and hold (reabsorb) sodium and water, decreasing urine output.
When blood volume increases, what is alerted? This causes what 4 occurrences once alerted? What is this whole process called?
Carotid artery baroreceptors. SNS impulses to kidney slow. Arterioles dilate. Glomerular filtration increases Sodium/water output increases
PRESSURE DIURESIS
ANP is released in response to? and does what?
Stretch in the heart atria (higher BP)
Inhibits angio II, releasing sodium and water. Lowers BP!
(similar to ace inhib)
Estrogens cause what?
Enhance NaCl reabsorp by renal tubules.
Water retention during menstrual cycle.
Edema during pregnancy.
Progesterone and glucocorticoids cause?
Prog-decrease Na+ reabsorp./acts as diuretic, na+ and h20 loss.
GC-enhance reabsorp of sodium and promote edema (cushings)
Potassium ion concentration affects cells _____ ______.
Excessive ECF pot. does?
Too little K+ causes?
Such K+ can lead to what 2 deadly conditions?
membrane potential
decreases membrane potential
hyperpolarizations (non responsiveness)
HYPERKALEMIA
HYPOKALEMIA
Where is K+ balance controlled? and controls its own ECF via?
Cortical collecting ducts (for each Na reabsor, a K+ is secreted)
Feedback regulation of aldosterone release
Ionic calcium in ECF is important for:
What does hypo and hyper calcemia do?
Calcium balance is controlled by?
Blood clotting, cell membrane permeability, secretory behavior.
Hypo-increases excitability, muscle tentany.
Hyper-inhibits neurons and muscle cells. cause heart arrhythmias.
PTH (reg. cal) and CALCITONIN (antag)
PTH promotes increase in calcium levels by targeting:
Bones-break down
Small intestine-food absorp
Kidney-cal reabsorp, decrease phos reabsorp.
Calcitonin is released in response to high calcium levels. What is its job, and relevance?
PTH antagonist (prevents cal levels rise)
Minor
Define alkalosis and acidosis.
arterial blood ph rises above 7.45
below 7.35
How are hydrogen ions regulated (in order)?
1-Chemical buffer system-within seconds
(co2 and water to carbonic acid to bicarbonate and then backward)
2-Resp center in brain (for lung breathing)-minutes
3-Kidney- (urinating) days
Explain the diff of weak/strong acids/bases.
Strong acid-all H+ dissassoc completely in water
Weak acid-partially dissa/efficiently prevents ph changes
Strong base-diss easily and grabs H+ quickly
Weak base-accept H slower
What are the three major chemical buffer systems?
Bicarbonate
Phosphate
Protein
*Any drifts in Ph are resisted by the entire chemical buffering system.
What occurs in the bicarbonate buffer system when strong acid/base is added?
acid-H+ released combine with bicarb and form carbonic acid
ph slightly decreases
base-reacts with carbonic acid to form sodium bicarb. ph rises slightly
*ECF ONLY BUFFER
How will the phosphate buffer system work?
Same as bicarb buff
*effective in urine and ICF
How does the most plentiful and powerful buffer, the protein buffer work?
Can bind or release H+ ions based on ph levels
Physiological buffers regulate ph by:
Chemical buffers regulate ph by:
Kidneys regulate ph by:
Lung reg co2/o2…ridding of co2
chemical tie up acids/bases but not remove
kidneys rid through urine and prevent *ultimate acid/base reg organ
What is the most important renal mechanism for regulating acid/base balance?
reabsorbing or generating new bicarbonate, or excreting bicarb.
(losing bicarb is same as gaining H+, reabsorb bicarb is same as losing H+)
If ph cannot be explained by CO2 level, then acidosis/alkalosis is not:
respiratory, (its metabolic)
CO2 combines with water in tubule forming _______.
Carbonic acid splits into _____ and ________.
For each H+ secreted, a ______ and ________ are reabsorbed by PCT.
Secreted H+ form _______, thus, bicarbonate disappears from filtrate at the same rate that it enters the Peritubular cap blood.
Carbonic acid (H2CO3)
Hydrogen and bicarbonate (H+ + HCO3-)
Hydrogen and sodium
carbonic acid
Carbonic acid (H2CO3) formed in filtrate dissociates to release \_\_\_\_\_\_ \_\_\_\_\_\_ and \_\_\_\_\_\_\_. Carbon dioxide then diffuses into tubule cells, where it acts to trigger further \_\_\_\_\_\_\_ secretion.
carbon dioxide water
hydrogen
Respiratory acidosis is the most common cause of acid/base imbalance. What occurs in pt?
What is the most important indicator of resp. inadequacy?
Pt breaths shallow, or gas exchange bad due to emphysema, pneumonia, cystic fibrosis.
co2
resp. alka common result of hyperventilation (co2 removal high from heavy breaths, low co2 in blood)
If in metabolic acidosis/alkalosis then…
Metab acidosis 2nd most common, causes?
bicarbonate levels too high/low
too much alcohol, excessive loss of bicarb. lactid acid accum., shock, ketosis (diabetic),starvation, renal failure.
What are some causes of metabolic alkalosis?
(rising blood ph/bicarb levels)
- vomiting (acid contents)
- ingesting too much base (antacids)
- constipation (excessive bicarb reabsorb)
