Title: Anatomy and Physiology by Rod R Seeley 6th edition chapter 27 power-point
1 Anatomy and Physiology, Sixth Edition
Rod R. SeeleyIdaho State University Trent D.
StephensIdaho State University Philip
TatePhoenix College
Chapter 27 Lecture Outline
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2Chapter 27
- Water, Electrolytes, and
- Acid-Base Balance
3Body Fluids
- Intracellular
- All fluids inside cells of body
- About 40 of total body weight
- Extracellular
- All fluids outside cells
- About 20 of total body weight
- Subcompartments
- Interstitial fluid and plasma lymph, CSF,
synovial fluid
4Body Fluid Compartments
5Water Content Regulation
- Sources of water
- Ingestion
- Cellular metabolism
- Routes of water loss
- Urine
- Evaporation
- Perspiration
- Respiratory passages
- Feces
- Content regulated so total volume of water in
body remains constant - Kidneys primary regulator of water excretion
- Regulation processes
- Osmosis
- Osmolality
- Baroreceptors
- Learned behavior
- ???
6Extracellular Fluid Osmolality
- Osmolality
- Adding or removing water from a solution changes
this - Increased osmolality
- Triggers thirst and ADH secretion
- Decreased osmolality
- Inhibits thirst and ADH secretion
7Hormonal Regulation of Blood Osmolality
8Regulation of ECF Volume
- Increased ECF results in
- Decreased aldosterone secretion
- Increased ANH secretion
- Decreased ADH secretion
- Decreased sympathetic stimulation
- Decreased ECF results in
- Increased aldosterone secretion
- Decreased ANH secretion
- Increased ADH secretion
- Increased sympathetic stimulation
- Mechanisms
- Neural
- Renin-angiotensin-aldosterone
- Atrial natriuretic hormone (ANH)
- Antidiuretic hormone (ADH)
9Hormonal Regulation of Blood Volume
10Hormonal Regulation of Blood Volume
11Regulation of ECF Volume
12Regulation of ICF and ECF
13Regulation of Electrolytes in ECF
- Na Ions
- Dominant ECF cations
- Responsible for 90-95 of osmotic pressure
- Regulation of Na ions
- Kidneys major route of excretion
- Small quantities lost in sweat
- Terms
- Hypernatremia
- high sodium
- Hyponatremia
- low sodium
- Electrolytes
- Molecules or ions with an electrical charge
- Water ingestion adds electrolytes to body
- Kidneys, liver, skin, lungs remove from body
- Concentration changes only when growing, gaining
or losing weight
14Mechanisms Regulating Blood Sodium
15Mechanisms Regulating Blood Sodium
16Abnormal Plasma Levels of Sodium Ions
17Regulation of Chloride, Potassium, Magnesium Ions
- Potassium ions
- Maintained in narrow range
- Affect resting membrane potentials
- Aldosterone increases amount secreted
- Terms
- Hyperkalemia
- Hypokalemia
- Chloride ions
- Predominant anions in ECF
- Magnesium ions
- Capacity of kidney to reabsorb is limited
- Excess lost in urine
- Decreased extracellular magnesium results in
greater degree of reabsorption
18Potassium Ion Regulation in ECF
19Abnormal Concentration of Potassium Ions
20Abnormal Plasma Levels of Magnesium Ions
21Regulation of Blood Magnesium
22Regulation of Calcium Ions
- PTH increases Ca2 extracellular levels and
decreases extracellular phosphate levels - Vitamin D stimulates Ca2 uptake in intestines
- Calcitonin decreases extracellular Ca2 levels
- Regulated within narrow range
- Elevated extracellular levels prevent membrane
depolarization - Decreased levels lead to spontaneous action
potential generation - Terms
- Hypocalcemia
- Hypercalcemia
23Regulation of Calcium Ions
24Regulation of Phosphate Ions
- Under normal conditions, reabsorption of
phosphate occurs at maximum rate in the nephron - An increase in plasma phosphate increases amount
of phosphate in nephron beyond that which can be
reabsorbed excess is lost in urine
25Regulation of Blood Phosphate
26Acids and Basesand Buffers
- Buffers Resist changes in pH
- When H added, buffer removes
- When H removed, buffer replaces
- Types of buffer systems
- Carbonic acid/bicarbonate
- Protein
- Phosphate
- Acids
- Release H into solution
- Bases
- Remove H from solution
- Acids and bases
- Grouped as strong or weak
27Regulation of Acid-Base Balance
28Regulation of Acid-Base Balance
29Buffer Systems
30Respiratory Regulation ofAcid-Base Balance
- Respiratory regulation of pH is achieved through
carbonic acid/bicarbonate buffer system - As carbon dioxide levels increase, pH decreases
- As carbon dioxide levels decrease, pH increases
- Carbon dioxide levels and pH affect respiratory
centers - Hypoventilation increases blood carbon dioxide
levels - Hyperventilation decreases blood carbon dioxide
levels
31Respiratory Regulation ofAcid-Base Balance
32Renal Regulation of Acid-Base Balance
- Secretion of H into filtrate and reabsorption of
HCO3- into ECF cause extracellular pH to increase - HCO3- in filtrate reabsorbed
- Rate of H secretion increases as body fluid pH
decreases or as aldosterone levels increase - Secretion of H inhibited when urine pH falls
below 4.5
33Kidney Regulation of Acid-Base Balance
34Hydrogen Ion Buffering
35Acidosis and Alkalosis
- Acidosis pH body fluids below 7.35
- Respiratory Caused by inadequate ventilation
- Metabolic Results from all conditions other than
respiratory that decrease pH - Alkalosis pH body fluids above 7.45
- Respiratory Caused by hyperventilation
- Metabolic Results from all conditions other than
respiratory that increase pH - Compensatory mechanisms
36Acidosis and Alkalosis