Chapter 29 Flashcards
what does body water depend on?
age and gender
what amount of the total body water does the intracellular fluid make up?
2/3 of total body water
what makes up 1/3 of total body water?
extracellular fluid
what is Edema?
Accumulation of IF which leads to tissue swelling
what causes lymph edema?
removal or blockage of lymph vessels that disrupts drainage
what does electrolyte balance usually refer to?
salt balance
the most abundant cation in the ECF
sodium
what is calcitonin released in response to what?
increased calcium levels
what is PTH released in response to?
low calcium levels
total body water content of infants
75%
total body water content of adults
55%
solutes that dissociate into ions
electrolytes
why do electrolytes have greater osmotic power than non electrolytes?
they are much more numerous
the major anion of the ECF
Cl
what is the major cation inside cells?
potassium
what is the major anion inside cells?
HPO4
what is the bulk of nonelectrolytes made up of?
proteins
phospholipids
cholesterol
neutral fats
the 2 main fluid compartments
intracellular fluid
extracellular fluid
fluid divisions of extracellular fluid with percents
plasma (20%) interstitial fluid (80%)
what is fluid movement across capillaries determined by?
hydrostatic and colloid osmotic forces
what is fluid movement across cell membranes determined by?
osmotic forces
the ability of a solution to cause water inflow into the cell or outflow of the cell
tonicity
the number of solutes in 1 liter of solution
osmolarity
the number of solutes in 1 kg of solvent
osmolality
increased Pco2
hypercapnia
decrease Pco2
hypocapnia
3 mechanisms that help keep the pH within normal limits
chemical buffer systems
brain stem respiratory centers
renal mechanisms
what are salts important for?
controlling fluid movements
excitability of muscle and nerve cells
secretory activity
membrane permeability
what effect do estrogens have on Na balance?
they increase Na re-absorption leading to water retention during the menstrual cycle and pregnancy
what effect does progesterone have on Na balance?
decreases Na reabsorption and promotes loss of Na and water
what would a decrease in the osmolarity of the extracellular fluid cause?
it would cause water to move into the cells
the area of the brain that plays a major role in electrolyte balance
hypothalamus
what is the driving force of water intake?
thirst
solute that plays the biggest role in water reabsorption
sodium ions
the hallmark symptom of hypotonic hydration
hyponatremia
which part of the nephron does aldosterone target?
distal convoluted tubule
the only ion that exerts significant osmotic pressure
sodium ion
what does ANP promote?
sodium excretion
the most imporant buffer in our plasma
bicarbonate
Hydrogen ions are secreted into the filtrate mainly by the…
proximal convoluted tubule
the most important urine buffer
phosphate
ion that is reabsorbed when hydrogen ions are secreted
sodium
what does parathyroid hormone enhance reabsorption of ?
calcium ions
what condition can hypoproteinemia lead to?
edema
molecules that can act as either an acid or a base
Amphoteric molecules
what will hyperventilation lead to?
respiratory alkalosis
functions of water
- Maintain Body Temperature
- Protective cushioning
- Lubricant, Reactant, Solvent
- Transportation
average Percent body water content in elderly
45%
average percent body water content in women
50%
average percent body water content in men
60%
why do men has a higher water content than women?
because they have more muscle mass
where is Intracellular fluid (ICF)?
INSIDE CELL
where is Extracellular fluid (ECF)?
OUTSIDE CELL
What is the link between the external and internal environments?
plasma
what regulates fluid movement across the membranes
by osmotic and hydrostatic pressures (forces)
the major hormone released when we are thirsty
ADH
R- term for too much sodium in the blood
hypernatremia
R- term for too little sodium in the blood
hyponatremia
the driving force of water intake
thirst
what would a decrease in the osmolarity of the extracellular fluid cause water to do?
move into the cells
ways to eliminate H+ from the body
exhaling carbon dioxide and excretion by the kidneys
the main regulators of calcium in the blood
calcitonin
vitamin D
PTH
the major hormone that regulates water loss
ADH
what can inadequate exhalation of carbon dioxide cause?
respiratory acidosis
3 chemical buffer systems
Bicarbonate buffer system
Phosphate buffer system
Protein buffer system
what causes release of aldosterone from the adrenal cortex?
increased K+ levels
pH levels that cause acidosis
< 7.35
pH levels that cause alkalosis
> 7.45
Pco2 durring metabolic acidosis and metabolic alkalosis
35-45
Pco2 durring respiratory acidosis
> 45
Pco2 durring respiratory alkalosis
<35
most important buffer system
bicarbonate buffer system
how is the thirst center activiated?
via the osmoreceptors when the osmolality exceeds the norm by 2-3%
where are osmoreceptors located?
in the hypothalamus
what is the antagonist to aldosterone?
ANP
where is ANP produced from?
the heart
what acid-base abnormality does vomitting cause?
metabolic alkalosis
what acid-base abnormality can excessive alcohol cause?
metabolic acidosis
how does the kidney respond to respiratory imbalances?
by increases or decreasing bicarbonate levels
how does the body respond to metabolic alkalosis?
the respiratory system will allow CO2 to accumulate in the blood and breathing breathing rate will slow
how does the body respond to metabolic acidosis?
respiratory system will remove as much CO2 as possible
breathing increased
where is the protein buffer system important?
inside the cell and in the blood
the only important buffer system of the ECF
bicarbonate buffer system
where does the bicarbonate buffer system work?
inside and outside the cell
what does each of the 3 buffer systems contain?
a weak acid and weak base
what releases when CO2 is converted to HCO3?
h+
function of chloride in the ECF?
helps maintain osmotic pressure of blood
where is calcitonin released from?
the thyroid
how do K+ and H+ maintain cation balance?
by moving in opposite directions
where is potassium balance controlled?
in the collecting duct by principal cells
what will increased K+ cause the release of?
aldosterone
function of aldosterone
to increase Na+ reabsorption and secretion of K+
what are glucocorticoids close to structurally?
aldosterone
what part of the nephron does aldosterone target?
the DCT and the collecting duct
speed of the effects of aldoesterone
hours to days
most common causes of edema
high blood pressure
blockage of blood vessels
high blood volume
increased capillary permeability
what does drinking large amounts of water in a short period of time lead to?
hypotonic hydration
what is facultative water loss caused by?
activities and emotional state
how does obligatory water loss happen
lungs
sin
feces
urine
most important intracellular buffer?
protein buffer
