CH 24 HW & Quiz Flashcards
T of F: A newborn baby’s weight is as much as 75% water, whereas obese and elderly people’s weight is as little as 45% water
True
The blood, lymph, tissue fluid, and trans cellular fluid are all examples of which of the following?
Fluid compartments
How does water move from the digestive tract to the bloodstream?
Osmosis
If a local imbalance between the ICF and ECF occurs, water movement called _____ restores the balance. This depends on the relative concentration of solutes in each compartment.
Osmosis
When is a person in a state of fluid balance?
Daily fluid gains equal losses.
The total body water (TBW) of a 70kg (150lb) young male is about?
40L
% of TBW in ICF
65%
% of TBW in Interstitial Fluid
25%
% of TBW in Blood plasma and lymph
8%
% of TBW in Transcellular fluid
2%
Fluid intake is governed mainly by thirst. What is one thing that can make a person thirsty?
Reduced blood pressure
The 2 ways water can move from one fluid compartment to another?
Capillary filtration from the blood stream to the interstitial space and osmosis between other compartments
T or F: The only way to control water output significantly is through variations in urine volume.
True
Water balance is most directly tied to?
Electrolyte balance
How do hypovolemia and dehydration differ?
In dehydration water is lost, and in hypovolemia both water and electrolytes are lost
% of TBW that is water of a 70kg young male
55-60% water
What happens to ECF osmolarity during dehydration?
It increases
How is water intake regulated?
Osmoreceptors respond to angiotensin II and to rising osmolarity of ECF, Hypothalamic neurons produce antidiuretic hormone (ADH) promoting water conservation, and cerebral cortex produces a conscious sense of thirst
T or F: Cold weather has a dehydrating effect on the human body
True, cold air drier and absorbs more body water from the respiratory tract
The 2 types of fluid deficiency
Volume depletion and dehydration
What causes hypotonic hydration?
ADH Hypersecretion
T or F: In cases of volume depletion, TBW declines but fluid osmolarity is normal
True. Water and a proportional amount of its dissolved solutes are lost, therefore osmolarity is not affected
List the effects of dehydration
Increased blood osmolarity, reduced blood pressure, reduced salivation
In which form of fluid imbalance is TBW elevated while osmolarity is reduced?
Hypotonic Hydration (water intoxication)
Edema is the most common form of what?
Fluid sequestration
Reasons why infants are more vulnerable to dehydration to adults
Their kidneys are not fully developed to produce optimally concentrated urine, they have higher metabolic rates and produce toxic metabolites faster that are excreted with water, and they have a higher body surface to volume ratio than adults
Ions that are major cation electrolytes
Sodium and Calcium
What might happen if you lost large volumes of water and slat and then drank large quantities of plain water?
Hypotonic hydration (water intoxication) Nothing is replacing the lost electrolytes
What ion is the most significant solute in determine total body water and the distribution of water amount fluid compartments?
Sodium
What term is another name for volume depletion? Occurs when proportionate amounts of both water and sodium are lost
Hypovolemia
Which has the largest effect on plasma sodium concentration?
ADH because sodium is accompanied by a proportionate amount of water
In which form of fluid imbalance is TBW reduced while osmolarity remains normal?
Hypovolemia
What inhibits Na+ and water reabsorption and lowers the blood pressure?
Natriuretic peptides
Define fluid sequestration
A condition in which excess fluid accumulates in a particular location
What ion is the greatest determinant of intracellular osmolarity and cell volume?
Potassium
Ions that are major anion electrolytes
Cl- , HCO3- , Pi
Important functions of Sodium
It participates in muscle and nerve depolarization, it’s involved in generating body heat via the Na-K pump, and it participates in contra sport of glucose, K+, and Ca+
Imbalances of what ion are the most dangerous of all electrolyte imbalances?
Potassium (K+)
Even though aldosterone _____ the tubular reabsorption of sodium and water, this is offset by an ______ in GFR; thus there is only a small _____ in urine output.
Increases, increase, decrease
The atrial natriuretic peptides inhibit the secretion of what?
Renin and ADH
Functions of Calcium
Bone and teeth development, participates in muscle contraction, acts as a factor in the blood clotting cascade, acts as a second messenger and activates exocytosis during neurotransmission
What ion is the most abundant cation of the ICF?
Potassium K+
Functions of chloride ions
Play a major role in the regulation of body pH, important in osmotic balance, contributes to the formation of stomach acid (HCl) , and participates in the chloride shift that accompanies CO2 loading and unloading with RBCs
List compounds that phosphate is a necessary component of
ATP, GTP, cAMP, Phospholipids, Nucleic acids
Potassium imbalances are the most dangerous of all electrolyte imbalances. What is the most serious consequence of potassium imbalance?
Cardiac abnormalities
List all that are affected by aldosterone
Blood pressure, urine volume, and blood volume
Term for a compound that helps maintain a stable pH by binding protons if H+ concentration begins to rise, and releasing them into solution if H+ concentration falls
Chemical buffer
3 major chemical buffer systems of the body
Phosphate, protein, and bicarbonate buffer systems
What ion is the most abundant anion of the ECF?
Chloride (Cl-) , It is required for the formation of stomach acid and plays a major role in the regulation of body pH.
Bicarbonate Buffer System equation
H2O + CO2 <-> H2CO3 <-> HCO3- + H+
Properties of Phosphate
Exists in fluids as an equilibrium mixture of phosphate, monohydrogen and dihydrogen phosphate, it can be generated by the hydrolysis of ATP, and it is a component of nucleic acids, phospholipids, ATP, GTP, and cAMP
How can the respiratory system compensate for a drop in blood H+ concentrations?
Reduced pulmonary ventilation allows CO2 to accumulate, lowering pH back to normal
Acidosis
Tissue fluid below pH 7.35
What happens when body pH is below 6.8 or above 8.0?
This is quickly fatal as many of the body’s enzymes will become denatured
The most important buffer system in the blood is the bicarbonate buffer, which is a solution of ____ acid and bicarbonate ions
Weak
Alkalosis
Tissue fluid pH above 7.45
Lethal pH values
Above 7.7 or below 7.0
