Ess 3 Water Electrolytes, And Acid-Base Balance

Front 1

3 fluid compartments

Back 1

1. Intracellular fluid
2. Interstitial fluid
3. plasma

Front 2

Movement of water through fluid compartments

Back 2

Filtration occurs between plasma and interstitial
Osmosis occurs between cells and interstitial and interstitial and plasma
-osmosis is regulated by solute concentration b/t compartments

Front 3

Osmotic Gradients

Back 3

-differences of water concentration on both sides of a membrane
-water moves so easily through membranes the gradients don't last very long
-if osmolarity of interstitial fluid increases when water oves out of cells to the interstitital
-if osmolarity of ICF increases, water moves into the cells from interstitial

Front 4

Gender differences between water content

Back 4

Adult males 60% of body weight
Adult females 55% of body weight
-Main differences depends on body composition
Muscle has large water component
Fat has LOW water content

Front 5

Fluid Balance

Back 5

water is present in the correct amount (volume) and in the correct places (compartment)
-dependence on electrolyte balance b/t ICF and ECF b/c electrolytes are the primary factor for water movement
-osmosis depends on electrolyte balance
-if in balance fluid intake=fluid output

Front 6

Fluid Intake

Back 6

1. Ingested water
-liquids we drink
-food water content
2. Metabolic Water production
-electron transport chain
-other chemical reactions
TOTAL INTAKE PER DAY = 2500ml

Front 7

Fluid Output

Back 7

1. Kidneys excrete urine
2. Skin
-evaporation
-perspiration
-encironmental conditions may increase or decrease these values
3. Lungs
-water vapor expired with breathing
4. GI tract
-feces

Front 8

Electrolytes

Back 8

Functions:
-required minerals for body function
-control osmosis between compartments
-maintain acid-base balance (pH)
-carry an electrical current
Distribution:
ICF (K, HPO4, Protein anions)
ECF (Na, Cl, HCO3)

Front 9

Sodium (Na)

Back 9

most abundant ECF cation
Function:
1. maintaining electrical gradient b/t cell and ECF ( for action potentials)
2. maintaining osmotic pressure for transport across cell membranes for water and some solutesE
3. Transport of some solutes across membranes
Regulation
-kidneys through aldosterone

Front 10

Chloride (Cl)

Back 10

-most abundant ECF anion
Function
1. balance of osmotic pressure
2. formation of HCl for digestion (pH regulation)
Regulation
-indirectly by aldosterone since Cl follows Na

Front 11

Potassium (K)

Back 11

-most abundant ICF cation
Function
1. ICF osmotic pressure
2. Maintaining electrical gradient b/t ECF and cell
3. Regulate pH (K are exchanged for H)
Regulation
1. Aldosterone through the balance b/t K and Na

Front 12

Calcium (Ca)

Back 12

-most abundant ion in the body
1. stored in bones and teeth
2. small amounts in ECF
Function
1. strength of bones and teeth
2. muscle contraction
3. blood clotting
Regulation
1. PTH increases ECF Ca
2. Calcitonin decreases ECF Ca

Front 13

Phosphate (HPO4)

Back 13

-most is found in bones and teeth
-in fluids, most found in ICF
Function
1. strength of bones and teeth
2. formation of ATP and phosphocreatine
3. formation of phospholipids
4. intracellular buffer
Regulation
1. PTH increases ECF HPO4
2. Calcitonin removes HPO4 in blood to store with Ca

Front 14

Bicarbonate (HCO3)

Back 14

-found in ECF and ICF-more in ECF
Function
1. buffering H in blood, urine, and digestive secretions
Regulation
1. Respiration of CO2
2. Kidneys excretion and reabsorption

Front 15

Acid Base Balance

Back 15

Important part of homeostasis
1. Metabolism depends on enzymes (proteins) and are sensitive to pH
2. pH depends on free H ions in fluid compartments
Normal pH range of ECF is 7.35-7.45
Challenges to acid-base balance
1. metabolism continually produces acids

Front 16

Acid

Back 16

-a proton (H) donor
-acids dissociate in water to prduce H and a salt

strong acid has higher concentration of H ions

Front 17

Base

Back 17

H acceptors; can take the H out of a solution
the chemicals that take H out of solution are buffers-many are salts

Front 18

Maintaining pH

Back 18

1. Buffer systems
bicarbonate, phosphate, protein
2. Respiratory mechanism
3. Kidney excretion of H and reabsorption of HCO3

Front 19

Buffer systems

Back 19

any mechanism that changes the pH by converting a strong acid to a weaker acid
-can restore pH in seconds- fast but no powerful

Front 20

Bicarbonate Buffer System

Back 20

PRIMARY buffer system in BLOOD
-if lactic acid is produced the H dissociates from La and is picked up by the bicarbonate
-bicarbonate binds to H and forms carbonic acid (weaker acid)

Front 21

Phosphate Buffer system

Back 21

-most important in ICF and kidneys (renal tubule)
-mostly b/c the concentration of phosphates is higher in ICF than ECF
-accepts H

Front 22

Protein Buffer System

Back 22

Proteins act as buffers in both ICF and ECF
-more in ICF is better in ICF
-the carboxyl end of the protein is usually dissociated in physiological environments
-accepts H

Front 23

Respiratory mechanism- expiration of CO2

Back 23

-much stronger than buffer systems but not as fast
-if CO2 is exhaled at the lungs the body fluids will contain less H
-increase in CO2 and H stimulates the resp. center to inc. ventilation > this system is a well regulated means for controlling ECF pH

Front 24

Renal Control of pH

Back 24

-kidneys are STRONGEST mechanism to control pH but are slow and takes hours to days
1. Renal tubules excrete H in urine
2. Renal tubules regenerate more bicarbonate
3. Renal tubules also excrete fixed acids