Module 10 - Fluid Balance Flashcards
Water
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
Fluid compartment
Fluid compartment – body fluid named after location – separated by physical barrier
Intracellular Fluid (ICF)
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
Extracellular Fluid (ECF)
Extracellular Fluid (ECF) – surrounds all cells – two components
1/3 body water
Plasma
Interstitial Fluid (IF)
Plasma - Extracellular Fluid
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
Interstitial Fluid (IF) - Extracellular Fluid
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
Fluid Balance
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
Osmosis
Osmosis – transfer of water – concentration gradient – in and out of compartments
Electrolytes
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
Solute concentration
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
Body’s Water Content
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
Water Gain and Loss
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
ADH
ADH – adjusts output – increases water permeability of cells – aquaporins come
ANP and aldosterone
ANP and aldosterone – regulate urine production
Diuretic
Diuretic – increases urine production – decreases water conservation
Thirst Response
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
Blood Concentrated - Thirst response
Blood is highly concentrated – increase blood osmolarity
Dry mouth – salivatory glands stim by
sympathetic – conserve
Trigger osmoreceptors in hypothalamus
Decreased Volume & Pressure - Thirst Response
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
Osmoreceptors - Thirst Response
Osmoreceptors – hypothalamus – signal water reabsorption
Trigger thirst – voluntary intake of fluids
Trigger ADH – conserve water
Decreases osmolarity
Increase blood volume and pressure
Electrolyte Function
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
Extracellular Ions
Extracellular
Na+, Ca2+, Cl-, HCO3- (bicarbonate)
Concentration will be same for plasma and interstitial fluid – constantly exchanging
Intracellular Ions
Intracellular
K+, Mg+, Phosphate, and negatively charge proteins
Ion Concentration
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
Sodium Na+
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
Potassium K+
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
Chloride Cl-
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
Calcium Ca+
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
Maintaining pH
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
Buffer System
Buffer System – neutralization
Weak acid or weak base balance hydrogen or hydroxide in a fluid
Respiratory Regulation
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
Renal Regulation
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
Chemical Buffer Systems
Protein
Carbonic acid Bicarbonate System
Phosphate system
Carbonic acid Bicarbonate buffer
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
Protein Buffer System
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
Phosphate Buffer System
Phosphate buffer
Its self if a buffer ion – neutralizing acids and bases
Internal fluids of cells
Dihydrogen phosphate (acid) & hydrogen phosphate (base)
RECAP - Chemical Buffer System
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
Maintaining pH – Exhalation
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
Maintain pH – Kidneys
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
Acidosis
Acidosis – Blood pH <7.35 – high H+ levels
Depression of CNS – depression of synaptic transmission
Alkalosis
Alkalosis – Blood pH >7.45 – high levels of OH- and little H+
Overexcited CNS
Metabolic Acidosis & Alkalosis
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
Respiratory - Acidosis & Alkalosis
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
