Lecture 16: Body Fluids Flashcards
What are the major cations in the extracellular compartment?
Na+
Ca++
What are the major anions in the extracellular compartment?
Cl-
HCO3-
What are the major cations in the intracellular compartment?
K+
Mg++
What are the major anions in the intracellular compartment?
PO4
proteins
What is osmolarity?
mOsm/ L = concentration of particles per liter of solution
What is osmolality?
mOsm/ kg = concentration fo particles per kg solven
What is an effective osmoles?
refers to a solute that does not easily cross a membrane
creates an osmotic force for water
Proteins are effective osmoles
Where does daily fluid intake come from?
ingestion: 2100 ml/ day
metabolism: 200 ml/ day
Where does daily fluid loss come from?
insensible evaporation: 350 ml/day through skin and 350 ml/ day via lungs
sweat: 100 ml/day
feces: 100ml/day
urine: 1400 ml/day
What is the total daily fluid intake? loss?
2300 ml/ day for both
What is the average total body water?
42 liters
What makes up the basic metabolic profile and the values for each?
Na+: 140 mEq/L K+: 4 mEq/L Cl-: 104 mEq/L HCO3-: 24 mEq/L BUN:. mg/dl Cr: 1 mg/dl Glucose: 80 mg/dl
What is the osmolar gap?
difference between the measured osmolarity and the estimated osmolarity
or difference between measured and estimated osmolality
What are common things that can elevate the osmolar gap?
ethanol methanol ethylene glycol acetone mannitol
How do you calculate potential osmotic pressure?
osmolarity/ osmotic pressure
Major ions that determine most of the total osmolarity of interstitial fluid
sodium and chloride ions
Major ions that determine most of total osmolarity of intracellular fluid
potassium ions
What happens when adding isotonic saline to extracellular fluid compartment?
extracellular osmolarity does not change
extracellular volume increases
What happens when adding a hypertonic saline to extracellular fluid compartment?
intracellular volume decreases
extracellular volume increases
osmolarity in both compartments increases
A solution of implement solutes having an osmolarity of 282 mOsm/L is isotonic, what does that mean?
water cannot enter or leave cell
A solution of impermeant solutes having an osmolarity of > 282 mOsm/L is hypertonic, what does this mean?
water will diffuse out of the cell
Addition of a hypotonic saline to extracellular fluid compartment results in….?
volume of both compartments increases
osmolarity in both compartments decreases
A solution of impermeant solutes having an osmolarity <282 mOsm/L is hypotonic, what does this mean?
water will diffuse into the cell
What are the causes and consequences of hyponatremia?
causes: serum sodium concentration <135 mmol/L or excess watering causing brain to swell
consequences: seizures, coma, permanent brain damage, death
What are the causes and consequences of hypernatremia?
cause: deficit in total body water in relation to total body sodium
consequence: cognitive effects, other illnesses
Causes of extracellular edema
(1) abnormal leakage of fluid from the plasma to the interstitial spaces across the capillaries
(2) failure of the lymphatics to return fluid from the interstitium back into the blood, often called lymphedema
What is the anatomical organization of the kidney?
- capsule
- renal cortex: bowman’s capsules and proximal and distal convoluted tubules
- renal medulla: renal pyramids
- penal pelvis: minor and major calyces
Describe cortical nephrons
have glomeruli located in outer cortex and have short loops of Henle
Describe juxtamedullary nephrons
have glomeruli deep in renal cortex near medulla and have long loops of Henle.
Have long efferent arterioles associated with peritubular capillaries
Kidneys receive ____ of total cardiac output
22% ( 1100 ml/min)
What does high hydrostatic pressure in glomerular capillaries causes?
rapid fluid filtration
What does low hydrostatic pressure in peritubular capillaries cause?
permits rapid fluid reabsorption
What is the path of blood flow to the kidneys?
renal artery interloper arteries arcuate arteries interlobular arteries afferent arterioles glomerular capillaries efferent arterioles
What is the path of blood flow from kidneys?
peritubular capillaries interlobular veins arcuate veins interlobar veins renal veins
