Electrolytes and Water Balance Flashcards
What has chemo receptors that stimulate the adrenals? 
The hypothalamus
What are two cation electrolytes
Sodium (Na+)
Potassium (K+)
What are two anion electrolytes?
Chloride (Cl-)
Bicarbonate (HCO3-)
….
Anion gap
How does the body achieve neutrality? 
Balance between cations and anions 
Water always follows _________.
Sodium***
What does GFR stand for?
Glomerulus filtration rate
What is the functional unit of the kidney? 
Nephron***
Where does filtration happen in the nephron? 
Glomerulus
Where in the nephron is 80% of filtrate reabsorbed?
Proximal tubule
What part of the nephron runs from cortex to medulla of the kidney?
Loop of Henle
Which part of the loop of Henley is permeable to electrolytes and which part is permeable to water? 
Ascending- Electrolytes
Descending-Water
What controls aquaporin (water channels)?
ADH (vasopressin)
The nephron is impermeable to large molecules and cells that are greater than _________ in size.  anything equal to or less than this number can be filtered.
66 kilodaltons
What charge do proteins have? 
Negative charge
 what three things can we use to calculate osmolarity?
Na+
Glucose
Urea
In the renal cortex, the proximal tubule ____________ about 75 to 80% of filtrate volume.
Reabsorbs
(Water, HCO3-, Na+) 
 how much glucose does the proximal tubule reabsorb? 
All glucose up to threshold
What does the proximal tubule reabsorb?
-glucose
-Almost all amino acids, vitamins, proteins
-Varying amounts of urea, uric acid
-Varying amounts of ions (Mg+, Ca2+, P, K+) 
There is ______ Secretion at the proximal tubule. 
Some (Proximal tubule mostly reabsorbs)
H+, K+, NH3, and drugs
What is normal glucose levels?
80-120?
What does (mod SM) mean?
It means that it can contract and relax so blood flow can be regulated
?*** The Capillary tuft surrounded by Bowmans capsules (Extended end of Renal tubule) Is made of what two cells?
-endothelial cells
-mesangial cells (mod SM)
Water follows sodium all the way through tubular fluid to the _______
Blood
What moves sodium out and potassium in?
Sodium/potassium ATPase* 
Both sodium (+) and __________ Move into the cell together. 
Chloride (-)
Both monovalent
Bicarbonate can be _____________ and reabsorbed. 
Recycled
What does the adrenal cortex make?
Aldosterone (Steroid hormone)
What is the most abundant NPN?
Urea***
What are some NPN products?
-urea (Most abundant!)
-Creatine
-Uric acid
-and others 
What is the source of urea?
Ammonia NH3 (Processed by the liver) 
Urea cycle happens only in the ________.
Liver
(Ammonia —> urea —> Excreted) 
Urea can _________ pass through the glomerulus. 
Easily
Creatine is proportional to ____________. 
Muscle mass
(Be careful about data interpretation of this*)
Urea cannot be used for a GFR because? 
It is reabsorbed
What three characteristics are needed before a value can be used for GFR?
-stable
-Filter through
-No reabsorption
Increased uric acid can sometimes, but not always, be a clue for what?
Cancer
What does GFR stand for?
Glomerulus filtration rate
Where does filtration happen?
Glomerulus 
What controls aquapourin, water channels?
ADH (vasopressin) 
What part of the loop of Henlee will the osmolarity be back to normal?
The top of the ascending loop of Henlee
Where is urine the most concentrated?
The bottom of the distal loop of Henlee 
What connects proximal and distal tubules? 
Loop of Henle 
This completes small adjustments to achieve electrolyte and acid base homeostasis
DCT
DCT is under control of ____________.
Aldosterone and ADH
This stimulates sodium reabsorption and potassium secretion that will increase BP
Aldosterone
Aldosterone is regulated primarily by what mechanism?
Renin-angiotensinogen mechanism
-and by ACTH
What does the sympathetic nervous system stimulate?
Kidney’s juxtaglomerular cells to release renin 
What produces renin?
Kidney’s juxtaglomerular cells
What does renin activate? And where?
Angiotensinogen in liver 
What does angiotensinogen create?
Angiotensinogen I 
What converts angiotensin one to angiotensin two? 
ACE (Angiotensin converting enzyme)
Where is ACE found?
The surface of the lung and kidney endothelium
What does angiotensin 2 do?
Constricts smooth muscles of vessels and increases blood volume (by sodium and water reabsorption) 
What effect does angiotensin II have on the kidneys?
Helps the body keep sodium and water 
What effect does angiotensin II have on the adrenal cortex?
Stimulates the adrenal cortex to make aldosterone —-> Keep sodium and water and decreases potassium
What effect does angiotensin II have on the posterior pituitary gland?
Causes it to release ADH (Vasopressin) That helps the body retain water
What is the goal of the RAAS (Renin – angiotensin – aldosterone – system)?
To manage blood pressure especially when it drops. This is done by angiotensin II 
What are the two main overall effects of angiotensin II?
Increase blood volume and blood pressure
What does renin act on?
Angiotensinogen (produced by liver)
What will increase with decreased renal perfusion pressure and sodium levels?
Renin
Which ion is intracellular and which one is extracellular?
Extracellular- sodium
Intracellular-potassium 
(3 sodium out and 2 potassium in, More water out) 
What moves sodium out and potassium in? (One cation in and one cation out)
ATPase***
What moves into the cell WITH sodium?
Chloride Cl-
(Sodium is the driving force) 
-filters blood to form filtrate
-Consist of capillary tough surrounding Bowmans capsule (Extended end of renal tubule?)
-Supplied by and afferent arterial and efferent arteriole
Glomerulus 
What cells is the capillary tuff composed of?
*endothelial cells
*Mesangial cells (Modify smooth muscle, Can contract and relax so blood flow can be regulated)
What is the important function of Mesangial cells?
•They can modify smooth muscle by relaxing or contracting so blood flow can be regulated***
• phagocytic function- Take up molecules that block the space between the filter cells so filtration can continue*
What is the glomerulus impermeable to? 
Molecules and cells greater than 66 kg Dalton 
What is the threshold glucose level?
180 (units?)
-reabsorbs most (75 to 80%) of Filtrate volume; Water, HCO3, sodium) 
-All glucose up to threshold
-Almost all amino acids, vitamins, proteins
-Varying amounts of urea, uric acid
-Varying amounts of ions (Mg2+, Ca2+,P, K+)
-Some secretion at this location (Secretes H+, K+, NH3, and drugs
Proximal convoluted tubule (In renal cortex)
The GFR can tell you the renal __________.
Function
Albumin is _____ Kilodaltons and has a ______ charge. 
66, negative (things can attach to it like Na+) 
Filtration rate is _____ml/min
130
Hypothalamus hormones are stored in the…
Posterior pituitary gland
Where is ATH made? And where is it Stored and released from?
Hypothalamus
Posterior pituitary gland
What does the anterior pituitary do?
Make hormones 
What are the Surveillance functions of the hypothalamus?
- detect O2 levels
- Detect osmolarity
The loop of Henley facilitates reabsorption of _____, ______, ______. 
H2O, Na, Cl 
The descending limb of the loop of Henle is highly permeable to ______ And passively enters the medulla. 
Water
Urine is highly concentrated at what part of the loop of Henle? 
In the bottom of the loop
The ascending limb of the loop of Henley is relatively _________ To water, but actively reabsorbs…..
Impermeable 
Na+ and Cl- diluting the urine in the tubular lumen
-completes small adjustments to achieve electrolyte and acid-base homeostasis
-Under the control of aldosterone and ADH
Distal convoluted tubule
The distal convoluted tubule is under the control of…
Aldosterone and ADH 
What gets increased when there is a decrease renal perfusion pressure and sodium levels 
Renin (acts on angiotensinogen in liver) 
What can make the renin aldosterone system go up?
Decrease filtration and decrease sodium filtration
The renin angiotensin mechanism is connected to what systems? 
Para and sympathetic Nervous systems
-Final site for concentration or dilution of urine
-ADH controls water permeability
-ADH increases tubular permeability to water, increasing water reabsorption
Collecting duct (Collecting tubule) 
ADH (vasopressin) controls water permeability of the collecting tubule by expression of….
Aquaporin channels
What are the functions of the renal system? 
• homeostasis of body water
• Regulation of fluid and electrolyte balance
• Regulation of acid-base balance
• excretion of waste products of protein metabolism
The renal system excretes surplus of unwanted substances like…
-water
-Electrolytes
-Excessive glucose
-Drugs
-Some proteins
The kidney is an ___________ gland.
Endocrine
What is the threshold value of glucose?
180 mg/dL
What is the primary metabolic organ? The second?
Liver, kidneys 
Why can both the liver and the kidneys do glucogenesis?
They both have glucose-5-Phosphate
Phosphorylation, attaches protein to phosphate (ATP) 
Kinase???
Enzyme to detach phosphate. Dephosphorylation (?) 
Phosphatase (in liver and kidneys) 
Phorterlace?
…
Detach or attach hydrogen
Dehydrogenase
Three reasons why water is important?
-blood pressure to maintain brain functioning
-Biochemical reaction (Enzymes)
-Entra and extra cellular functioning
What is the percentage of water to total body weight?
Intracellular water?
Extracellular water? 
60%
2/3
1/3
Water that is enclosed by epithelial membranes. Not counted in the total body water
Transcellular water. Ex: Pleural fluid, humor and I, CSF, GUI, etc.
What influences the distribution of water in the various Compartments of the body? 
The concentration of the ions
Na+/Cl- > HCO3+ > K+, Ca+, Mg2+ 
What are three major components of the Nurohormonal regulation mechanism for body sodium and water?
-Renin
-Angiotensinogen
-Aldosterone
What are the natriuretic peptides?
-ANP (Type A from the atrium)
-BNP (Type B from the ventricle)
-CNP (Type C Brain vascular endothelial cells renal tubule) 
-Urodilation (kidney)
Natriuretic peptide that increases offloading of water, vasodilator
ANP
 what is important for CHF diagnosis? 
Increased BNP
What is average heart rate?
70 bpm
What measurement is proportional to vasculature width? 
Peripheral resistance
CO=
HR x SV*
MAP =
CO x PR*
SV =
EDV - ESV*
The amount of blood that can be pumped in one minute
Cardiac output (CO)
-around 4900ml 
Is osmolarity is osmolality more more thermodynamically stable?
Osmolality
of particles/kg of water
Osmolality*** absolute data
(evaluation of kidneys in fluid and electrolyte balance) 
of particles/ L
Osmolarity
-Govern the solvent movement across membrane
This is an indicator of the kidneys ability to conserve water
Urine osmolality
What is the most general target electrolyte?
Sodium (Na+) 
What is the normal values for sodium (Na+) 
135-145 mEq/L or mmol/L (because they are monovalent?) 
This is plasma concentration 
Normal values for potassium K+? 
3.5-5 mEq/L or mmol/L in plasma
what value is considered mild hyperkalemia?
(K+)
> 5.5 mM
Value is considered severe hyperkalemia? 
> 7.5 mM
Value is considered hypokalemia? 
< 3.5 mM
-maintains intracellular fluid volume
-Important and neuromuscular excitability, cardiac contraction (Normal values are essential to life) 
K+
H+ and _____ can swap inside and outside cell to maintain pH levels by hydrogen ion concentration
K+
What are the normal values for chloride (Cl-)? And where is this ion mostly found?
98-106 mEq/L or mmol/L
Major extracellular anion
What is the hamburger shift?
Chloride shift with bicarbonate (swap?)
 bicarbonate is a major ___________ anion.  primarily involved in acid base balance in carbonic acid dissociation
Extracellular
What are the three forms of carbon in the body? 
HCO3-, H2CO3, CO2
What is the normal value for total CO2?
HCO3-?
22-29 mEq/L
22-26 mEq/L
More than _____ % Of the carbon in the body is in the HCO3 form under normal conditions
60
(at a pH of 7.4 it’s H2CO3) 
What ions contribute to anion gap? 
All charged molecules contribute not just the major ones
When measuring the anion gap what ions are used? 
Cations: Na+, K+
Anions: Cl-, and CO2/HCO3-
How do you calculate the anion gap with and without potassium?***
• (Na + K) - (Cl + HCO3) = about 15 mmol/L (10-20)
•(Na) - (Cl + HCO3) = about 12 mmol/L (7-16)
What is the anion gap for metabolic acidosis? 
30 mmol/L or higher!
Calculating the anion gap is useful in assessing….
The accuracy of measured electrolyte results or signifying disease process (Metabolic acidosis) 
What should be done if you get an abnormal anion gap measurement?
Repeating of electrolyte measurements before reporting
What is the typical cause of an increased anion gap?
Increased Or decrease of unmeasured anions (like Lactic acid) 
What are three types of water and balances that cause a water deficit?
-diabetic acidosis (Osmotic Diuresis)
-Normal sodium Water imbalance
-Sodium imbalance

What are possible causes of water imbalance with normal sodium levels?
-dehydration: Water deficit
-adipsia (No sensation of thirst), Hypothalamic disorder
-Diabetes insipidus
The term used when a patient has no sensation of thirst
Adipsia
What are the two types of diabetes insipidus?
-Central: A.k.a. pituitary diabetes-ADH is not being released from pituitary gland
-Nephrogenic: Hypothalamus and pituitary function properly but kidneys do not respond to ADH
What can cause water imbalance by excess water and normal sodium levels?
-massive water intake usually psychiatric
-Excessive production of ADH (SIADH) 
Excess water but with sodium imbalance is usually due to…
Excess water with edema usually resulting from increased sodium
What causes plasma volume to increase, causing hypertension and cardiac overload and edema? 
Excess sodium (hypernatremia)
Hypernatremia (Excess sodium) Could result from…
Congestive heart failure, liver disease, renal disease, Renal nephrotic syndrome, Hyperaldosteronism (cushings)***, severe dehydration, nasogastric feeding of high-protein with not enough fluids 
Why could renal disease cause excess sodium (Hypernatremia)?
No filtration is happening (sodium stays in plasma due to decreased GFR)
What is the disease associated with hyperaldosteronism?
Cushing’s syndrome*** (Need to know!) 
What are the three main diseases associated with excess sodium (Hypernatremia)?
• renal disease
• Renal nephrotic syndrome
• hyperaldosteronism (cushings)
What is the number one function of the liver?
Protein synthesis
(can activate RAAS too) 
Sodium depletion (Hyponatremia)
Can be caused by…
-Hypoaldosteronism (Addison’s disease)***
-renal reabsorption disease
-Diabetes mellitus
-polyuria 
Potassium excess (hyperkalemia) Is fatal if it is over _____ mmol/L. Why?
7.5
Interferes with depolarization and resting membrane potential goes down?
Increase plasma levels (Hyperkalemia) Is seen in what diseases?
-hypoaldosteronism-adrenal insufficiency (Addison’s disease)
-Renal failure
-acidosis (increase in H+)
-Cellular breakdown (Potassium gets leaked out)*
-Insulin deficiency*
What can cause potassium depletion (Hypokalemia)? 
-vomiting, diarrhea
-Cushing syndrome (Hyperaldosteronism)
-renal absorptive disease
-Metabolic alkalosis
-Insulin access
Insulin can move potassium _______ cells.
Into
This generally coexists with hypernatremia
Hyperchloremia (Increase chloride)
Generally coexist with hyponatremia
Hypochloremia
What is an exception when there is normal sodium levels with abnormal chloride levels?
- metabolic acidosis- Increased chloride And decreased bicarbonate
* metabolic acidosis- Decreased chloride but increased bicarbonate
***”chloride shift” 
Evaluation of electrolyte balance may be examined in what specimens?
-serum/plasma of Electrolytes
-Urine measurement Of electrolytes
-Serum/urine osmolarity
Sweat electrolytes is mostly ___________.
Chloride
(cystic fibrosis Screening —> Sweat chloride) 
