Module 10 - Fluid Balance

Question 1

Water

Answer 1

Water is the main component of all body fluid – all reactions take place in an aqueous solution
Moves through semi-permeable membranes of cells by Osmosis
Simple diffusion w/ concentration gradient

Question 2

Fluid compartment

Answer 2

Fluid compartment – body fluid named after location – separated by physical barrier

Question 3

Intracellular Fluid (ICF)

Answer 3

Intracellular Fluid (ICF) – all fluid enclosed in cells by plasma membrane
Principle component of cytosol/cytoplasm
60% of total water – 2/3 of body
Institital fluid particles travel thru bilayer

Question 4

Extracellular Fluid (ECF)

Answer 4

Extracellular Fluid (ECF) – surrounds all cells – two components
1/3 body water
Plasma
Interstitial Fluid (IF)

Question 5

Plasma - Extracellular Fluid

Answer 5

Plasma – fluid component of blood – 20% of 1/3
Travels in blood vessels
Transports materials – blood cells, proteins, electrolytes, nutrients, & etc.
Diffuses through capillaries – semi perm

Question 6

Interstitial Fluid (IF) - Extracellular Fluid

Answer 6

Interstitial Fluid (IF) – materials travel b/w cells – 80% of 1/3
Gases, nutrients, and waste travel b/w capillaries and cells
Separated by cells’ bilayer
CSF, lymph, synovial fluid in joints, & pleural fluid in pleural cavities

Question 7

Fluid Balance

Answer 7

Fluid Balance
Each fluid carries different concentrations of ions, proteins – driving water needs

Fluid balance – compartments water needs are met
Water balance and electrolyte balance must be maintained

Osmosis

Solute concentration

Composition of IF and plasma are similar – different from ICF
Needed or else fluids would be able to mix – they need different balance so they don’t cross the membranes

Question 8

Osmosis

Answer 8

Osmosis – transfer of water – concentration gradient – in and out of compartments

Question 9

Electrolytes

Answer 9

Electrolytes – compounds that dissociate into ions
Na+, Cl-, K+, Mg2+, Ca2+
Bound molecules that have balanced themselves – hydrolysis
they will dissolve their connection once in water – send electrical charge –
b/c water is a polar molecule – pulls anion to hydrogen – pulls cation to oxygen

Question 10

Solute concentration

Answer 10

Solute concentration – major determinant of fluid balance – some solutes drive water in and out – concentration of solutes needs to be managed – water balances this concentration
Electrolytes

Question 11

Body’s Water Content

Answer 11

Body’s Water Content
Fluid in = fluid out – constant volume
Age and fat presence (less fluid) play role
Infant – 75% water
Adult – 50-60% - females have less
Elderly – 45%
Brain and kidneys – 80-85% of their mass is water
Teeth – 8-10% of mass is water

Question 12

Water Gain and Loss

Answer 12

Water Gain and Loss
H2O – Intake from digestive tract – food and drink – 2100ml/day

H2O – generated by carbon metabolic reactions – last steps of aerobic respiration – electron transport chain – 200ml/day

Loss – insensible = exhaled air – feces & skin as sweat increases with exercise – Urine – extracted from blood plasma
Out of balance – thirst response triggered

Question 13

ADH

Answer 13

ADH – adjusts output – increases water permeability of cells – aquaporins come

Question 14

ANP and aldosterone

Answer 14

ANP and aldosterone – regulate urine production

Question 15

Diuretic

Answer 15

Diuretic – increases urine production – decreases water conservation

Question 16

Thirst Response

Answer 16

Thirst Response – hypothalamus – trigger body to adjust water intake to
maintain balance
Insufficient H20
Blood is highly concentrated – increase blood osmolarity
Decreased volume and pressure

Osmoreceptors – hypothalamus – signal water reabsorption

Question 17

Blood Concentrated - Thirst response

Answer 17

Blood is highly concentrated – increase blood osmolarity
Dry mouth – salivatory glands stim by
sympathetic – conserve
Trigger osmoreceptors in hypothalamus

Question 18

Decreased Volume & Pressure - Thirst Response

Answer 18

Decreased volume and pressure – baroreceptors in
aorta and carotid arteries
Heart triggered increase HR and stretch
of contraction
Triggers RAAS in kidneys, adrenal glands,
and nephrons
Nephrons reabsorb sodium – Water
follows sodium
Stim Hypothalamus

Question 19

Osmoreceptors - Thirst Response

Answer 19

Osmoreceptors – hypothalamus – signal water reabsorption
Trigger thirst – voluntary intake of fluids
Trigger ADH – conserve water
Decreases osmolarity
Increase blood volume and pressure

Question 20

Electrolyte Function

Answer 20

Electrolyte Function
Assist in electrical impulse transmission along cell membranes - Enable action potentials

Aid in releasing hormones from endocrine glands

Stabilize protein structures in enzymes – cofactors

Osmotic balance – control movement of water b/w compartments

Maintain acid-base balance

Question 21

Extracellular Ions

Answer 21

Extracellular
Na+, Ca2+, Cl-, HCO3- (bicarbonate)
Concentration will be same for plasma and interstitial fluid – constantly exchanging

Question 22

Intracellular Ions

Answer 22

Intracellular
K+, Mg+, Phosphate, and negatively charge proteins

Question 23

Ion Concentration

Answer 23

H20 can exchange b/w each – via osmosis – balancing solute concentration
Concentration of solutes in 1 liter of fluid could be the same inside and outside the cell – solute type doesn’t make a difference – 290mOsm/L

Question 24

Sodium Na+

Answer 24

Sodium Na+
Excites neurons – causes depolarization
Most abundant extracellular ion
Pulls water – affects osmotic pressure – fluid and electrolyte balancing

Aldosterone reabsorbs sodium in distal tube – pulling water with it

ADH – pulls water – sodium follows

ANP – decreases sodium reabsorption – lowers blood pressure

Excretion by kidneys in urine
Hyponatremia – low levels
Hypernatremia – high levels

Question 25

Potassium K+

Answer 25

Potassium K+ Intracellular fluid cation - most abundant Maintains fluid volume and regulates pH Involved in impulse conduction and muscle contraction Controlled by mineralocorticoids – mainly aldosterone Controlled excretion into urine

Question 26

Chloride Cl-

Answer 26

Chloride Cl- Extracellular anion (negative charge) Regulates osmotic pressure b/w compartments Forms HCl in stomach – digestive acid Aldosterone – indirect control – it pulls sodium (positive charge), chloride follows (negative charge) – electrical attraction

Question 27

Calcium Ca+

Answer 27

Calcium Ca+ Most abundant ion in body High levels in ECF Component of bones and teeth Blood coagulation Calcium releases neurotransmitters on nervous cell membranes - Major role in conduction of nerve impulses – triggering muscle contractions and maintains muscle tone – excited nerves tissue Regulated by parathyroid hormone, calcitonin and calcitriol – regulate Ca+ in blood – pulls from bones if needed

Question 28

Maintaining pH

Answer 28

Maintaining pH pH – concentration of Hydrogen ions – lower number = high hydrogen body is constantly releasing Hydrogen ions – result of metabolic reactions – example Krebs cycle damaging while in blood – till excreted Normal pH of blood – 7.35 - 7.45 – constant need to maintain 0 = acidic – lots of hydrogen – vinegar 14 = alkaline – lots of hydroxide – ammonia Body must control hydrogen Buffer System – neutralization Respiratory Regulation Renal Regulation

Question 29

Buffer System

Answer 29

Buffer System – neutralization Weak acid or weak base balance hydrogen or hydroxide in a fluid

Question 30

Respiratory Regulation

Answer 30

Respiratory Regulation Exhaling CO2 – controlled by lungs C02 combines with H20 = carbonic acid – dissociates into H+ and Bicarbonate ions Excess body function – increases metabolism reactions – acids breaking down to make energy = increased hydrogen ions – body from increasing breathing rate

Question 31

Renal Regulation

Answer 31

Renal Regulation Kidneys filter – excrete acids and reabsorb bases Excrete H+ Absorb bicarbonate – HCO3- If H+ is low – kidneys will just inhibit both – till it rises thru metabolic reactions

Question 32

Chemical Buffer Systems

Answer 32

Protein Carbonic acid Bicarbonate System Phosphate system

Question 32

Carbonic acid Bicarbonate buffer

Answer 32

Carbonic acid Bicarbonate buffer will decrease H+ - picks up H+ ions Fluid around body cells Reaction of sodium bicarbonate w/ hydrochloric acid = carbonic acid & sodium chloride H+ + HCO3- = H2C03 – carbonic acid H2CO3 can spilt into H20 + CO2 CO2 dissolves in blood = carbonic acid Carbonic acid & water form hydronium ions & bicarbonate Bicarbonate & carbonic acid – work together to gain/lose protons

Question 32

Protein Buffer System

Answer 32

Protein system – in cells and plasma Proteins = amino acids Amino acids = positively charged amino groups (weak bases) and negatively charged carboxyl groups (weak acid) Charged regions bind to hydrogen and hydroxyl ions Hemoglobin – buffer for carbonic aid Binds to hydrogen ions release when CO2 is converted to bicarbonate Proteins in blood plasma bind to H+ when pH drops Releases hydrogen when pH rises Cells Proteins in cells bind to H+ when pH drops – release hydrogen when pH rises

Question 32

Phosphate Buffer System

Answer 32

Phosphate buffer Its self if a buffer ion – neutralizing acids and bases Internal fluids of cells Dihydrogen phosphate (acid) & hydrogen phosphate (base)

Question 33

RECAP - Chemical Buffer System

Answer 33

Recap Protein buffer – in cells and plasma Hemoglobin buffers carbonic acid Carbonic acid-bicarbonate – regulates blood pH Carbonic acid = H20 + CO2 CO2 – exhaled H20 – stays Phosphate – regulates pH – RBCs and kidney tubules Watches fluids in kidneys Actives or inhibits excretion and reabsorption

Question 34

Maintaining pH – Exhalation

Answer 34

Maintaining pH – Exhalation Regulation in lungs – blood travels through pulmonary capillaries When C02 in present in blood – reacts with water = carbonic acid – releasing hydrogen ions – acidic blood CO2 + H20 = carbonic acid CO2 rises – increase carbonic acid – increase reactions with H20 – Lower pH Resp rate & depth increases & decreases according to amount of C02 Increase = C02 out – reduces blood levels of carbonic acid – pH increases to normal Decrease = C02 moderate Chemoreceptors – aorta & carotid sense increased levels of C02 Signal brain to adjust resp Excessive breathing – too much CO2 out – reduces carbonic acid – too alkaline – breath in paper bag to retake C02 – balancing Hypercapnia – high levels of C02 in blood Hypocapnia – low levels of C02 in blood

Question 35

Maintain pH – Kidneys

Answer 35

Maintain pH – Kidneys Break down of carbonic acid to bicarbonate and h+ will increase pH Metabolic product increases – energy is being used – reactions increase to synthesis more body products Kidneys control secretion and reabsorption High levels of H+ from increase reactions Excrete of excess H+ Reabsorption of bicarbonate – will bind with floating h+ to back carbonic acid Levels lower because no excess H+ Ammonia will bind to H+ in urine – excreted Phosphate binds with H+ in urine – excreted

Question 36

Acidosis

Answer 36

Acidosis – Blood pH <7.35 – high H+ levels Depression of CNS – depression of synaptic transmission

Question 37

Alkalosis

Answer 37

Alkalosis – Blood pH >7.45 – high levels of OH- and little H+ Overexcited CNS

Question 38

Metabolic Acidosis & Alkalosis

Answer 38

Metabolic – issue with kidney levels of bicarbonate Acidosis – decreased bicarbonate & decrease pH Increase or can’t excrete H+ ions Abnormal increase in acid metabolism Alkalosis – high levels of bicarbonate – loss of acid – vomiting, diarrhea

Question 39

Respiratory - Acidosis & Alkalosis

Answer 39

Respiratory – issue balancing C02 thru exhalation Acidosis – high levels of C02 & low pH – hypoventilation or b/c gas exchange issue Alkalosis – low levels of C02 & high pH – hyperventilation – breathing out too much C02