Exam 4 CH 27 Flashcards
Know the distribution of fluids in the human body.
Intracellular fluid compartment (All the fluid in the trillions of cells)
- About 40% of total body weight
- Major Cation: Potassium (K+)
- Major Anion: Phosphate
Extracellular fluid compartment (Includes the fluid outside all of the cells)
- About 20% of the total body weight
- Subcompartments
- Interstitial fluid (Found in the extracellular spaces outside the blood vessels)
- Anion= Cl-
- Cation= Na+
- Plasma (Extracellular fluid within the blood vessels) - Anion= Na+
- Cation= Cl-
- Interstitial fluid (Found in the extracellular spaces outside the blood vessels)
Understand how body build composition and concentrations are regulated, the sources of water, and routes of water loss,
-Regulated so the total volume of water in body remains constant.
- Kidneys are primary regulators of water excretion
- Gets rid of liquid waste
- Regulation processes
- Osmosis
- Osmolality
- Baroreceptors
- Learned behaviors
Sources of water
- Ingestion (drink & food)
- Cellular metabolism (metabloic water)
Routes of water loss
- Urine
- Evaporation
- Perspiration
- Respiratory passages - Feces (Looser the feces the more water it is. )
Understand osmolarity and how it is maintained.
Extracellular Fluid Osmolality
-Osmolality
-Measure of water vs solute concentration
-The higher the solute concentration the higher
the osmolality
-Adding or removing water from a solution changes
osmolality
-Increased osmolality
-Triggers thirst and ADH secretion (prevent water
loss)
-Decreased osmolality
-Inhibits thirst and ADH secretion (Lose water and
urination)
Know ICF and ECF levels are regulated.
Regulation of ICF
1. Large organic molecules, such as proteins, which cannot cross the plasma membrane, are synthesized inside cells and influence the concentration of solutes inside the cell.
- The transport of ions, such as Na+, K+, and Ca2+, across the plasma membrane, influences the concentration of ions inside and outside the cell.
- An electrical charge difference across the plasma membrane influences the distribution of ions inside and outside of the cell.
- The distribution of water inside and outside the cell is determined by osmosis
* If bicarbonate exists chloride enters
Regulation of ECF Volume
-Can increase or decrease even if osmolarity of extracellular fluid is maintained
-Monitored by
-Carotid sinus and aortic arch baroreceptors monitor
blood pressure
-Juxtaglomerular apparatus monitor pressure changes
-Receptors in walls of atria and large vessels respond
to small changes in BP
-These receptors activate these mechanisms
-Neural: increase in BP recognized by baroreceptors
-Decreased sympathetic stimulation of afferent
arteriole leads to increase pressure in the
glomerulus leading to increased filtration and
increased urine
output.
-Renin-angiotensin-aldosterone
-Atrial natriuretic hormone (ANH)
-Antidiuretic hormone (ADH)
Understand the levels of regulation, and consequences of the changes in the levels of sodium, chloride ions, potassium ions, and calcium.
Acids
-Release H+ into solution
Base
-Remove H+ from solution
Acids and Bases
-Grouped as strong or weak
Buffers (Change pH without changing itself)
- Resist change in pH
- When H+ added, buffer removes it
- When H+ removed, buffer replaces it
Types of buffer systems
- Carbonic acid/bicarbonate
- Protein
- Phosphate
*Carbonic acid
CO2+ H2O ↔CH2O3 (Acid) ↔CHO3- (Base) + H+
Left to Right Add H+
Right to Left Remove H+
*Protein
(Amino Acid) NH2–C–COOH (carboxyl end)
↓ ↓
(Weak base) NH3 COO (Weak acid) →H+
*Phosphate
HPO4 (Base) H2PO4
\+ ↓
H+ H+
---------- -----------
H2PO4 HPO4
Understand the mechanisms of acid-base balance
*Carbonic acid
CO2+ H2O ↔CH2O3 (Acid) ↔CHO3- (Base) + H+
Left to Right Add H+
Right to Left Remove H+
*Protein
(Amino Acid) NH2–C–COOH (carboxyl end)
↓ ↓
(Weak base) NH3 COO (Weak acid) →H+
*Phosphate
HPO4 (Base) H2PO4
\+ ↓
H+ H+
---------- -----------
H2PO4 HPO4
Understand how protein, bicarbonate, phosphate buffer systems function and where they contribute most to pH balance.
Buffers: If pH rises, buffers bind H+; If pH falls, buffers release H+
- Protein buffer
- Intracellular and plasma proteins absorb H+
- Provide % of buffering in the body. Ex: hemoglobin
- Bicarbonate buffering system
- Important in plasma
- Phosphate buffer system
- Important as an intercellular buffer
Understand how the respiratory system and urinary system aid in maintaining pH.
Respiratory center: If
- pH rises, respiratory rate decreases
- pH falls, respiratory rate increases
Achieved through the carbonic acid/bicarbonate buffer system.
-As carbon dioxide levels increase, pH decreases
-As carbon dioxide level decrease, pH increases
-Carbon dioxide levels and pH affect respiratory
centers
-Hypoventilation increases blood carbon dioxide
levels
-Hyperventilation decreases blood carbon dioxide
levels
Kidneys: If
- pH rises distal tubule decreases H+ secretion into the urine and decreases HCO3- absorption into the blood (more H2CO3 will dissociate into H+ and HCO3-)
- pH falls, distal tubule increases H+ secretion into the urine and increases HCO3- absorption into the blood.
Secretion of H+ into filtrate and reabsorption of HCO3 into ECF causes extracellular pH to increase
HCO3- in filtrate reabsorbed
Rate of H+ secretion increase as body fluid pH decreases or as aldosterone levels increase
Secretion of H+ inhibited when urine pH falls below 4.5 (Because it could damage the urethra)
Understand both types of acidosis and alkalosis and compensatory mechanisms.
Acidosis (too acidic)
-pH body fluids below 7.35
-Respiratory
-Caused by inadequate ventilation
-Metabolic
-Results from all conditions other than respiratory
that decrease pH
Alkalosis (too basic)
- pH body fluids above 7.45
- Respiratory
- Caused by hyperventilation
- Metabolic
- Results from all conditions other than respiratory that increase pH
- Compensatory mechanisms
