CHLORIDE, MAGNESIUM, POTASSIUM .... Flashcards
The major intracellular cation in the body.
● With a concentration 20 times greater inside the cells than
outside.
POTASSIUM
As a result, only _____ of the body’s total K+ circulates in the
plasma.
2% - POTASSIUM
Functions of K+ in the body include ___________, ___________, _______, __________
regulation of neuromuscular excitability, contraction of the heart,
ICF volume, and H+ concentration.
(RCIH)
The internal environment of the cell is negatively charged when at
rest.
Resting Membrane Potential
● Has a charge of -70 mv
Resting Membrane Potential
Passively and continuously leaks out potassium outside
Potassium Channel
When the cells receives a stimuli, and an action has to be
performed, the intracellular space must be positive
Excitation
During cell excitation, sodium enters the cell to create a
positive charge, rather than releasing ___________
potassium outside
In membrane potential has three (depolarization)
- Threshold of excitation
- Intracellular NA increases
- Extracellular K increases
the cell’s electrical charge becomes more positive and less negative
Depolarization
the process by which a cell returns to its resting electrical state
after a depolarization (change from negative to positive charge),
typically involving the efflux of potassium ions.
Happens when potassium is move out from the cell
○ Same reason with sodium, it is easier and faster for
potassium to be expelled outside the cell as the
concentration of the cell is less outside.
○ Aside from that the channels of plasma membrane favors
more potassium rather than sodium
Repolarization
is when a cell’s electrical charge becomes even more negative
than its usual resting state, making it less likely to fire an
electrical signal.
○ Happens as there is an increase of potassium outflow due
to the fact that potassium channels take time to close.
Hyperpolarization
The pump helps establish and maintain the resting membrane
potential of a cell.
○ By pumping three sodium ions out of the cell and two
potassium ions into the cell against their respective
concentration gradients.
○ This process ensures that there are more sodium ions
outside the cell and more potassium ions inside.
Sodium-Potassium Pump
The proximal tubules reabsorb nearly all the K+
○ Under the influence of aldosterone, additional K+ is
secreted into the urine in exchange for Na+ in both the
distal tubules and the collecting ducts
REGULATION OF POTASSIUM
○ Thus ___________ is the principal determinant of urinary
K+ excretion
Distal nephron
3 RENAL PROCESSES
Glomerular Filtration
Tubular Reabsorption
Tubular Secretion
Substances are filtered based on size and charge . Ions are
filtered
Glomerular Filtration:
Reabsorption of essential nutrients is being done, majority of
which happens at Proximal Convoluted Tubule (PCT)
● Direction: ______________
Tubular Reabsorption: Tubules to circulation
Direction: _____________
● Occurs in the Distal Convoluted Tubules (DCT) and Collecting
Ducts
Tubular Secretion: circulation to the tubules
It serves to eliminate waste products that were not filtered by the
glomerulus.
● High pressure in the glomerulus prevents all waste products from
being filtered, causing some to be returned to the blood vessels
around the nephron.
Tubular Secretion
The secretion of potassium in DCT and Collecting Ducts is under
the influence of _________
aldosterone
Aldosterone stimulates both parts of the ________ to
reabsorb sodium at the expense of potassium
nephron
The kidney reabsorbs filtered K+ in ____________ and _________
hypokalemic states and secretes K+ in hyperkalemic states
Also, only our _________ can eliminate potassium. Thus, it is very
important to know if your kidneys are working
kidneys
3 FACTORS THAT INFLUENCE THE DISTRIBUTION OF K+
BETWEEN CELLS AND ECF
Potassium, Insulin, Catecholamines
_____________ loss frequently occurs whenever the Na-K ATPase
pump is inhibited by conditions (hypoxia, hypomagnesemia,
*digoxin overdose)
Potassium
promotes acute entry of K ions into skeletal muscle and
liver by increasing Na-K ATPase activity
Insulin
_____________ promote cellular entry of K, whereas ___________
impairs cellular entry of K activity
Catecholamines; propranolol
_______________(adrenaline) & _____________
(noradrenaline)
Epinephrine
norepinephrine
■ Flight and fight
Epinephrine
Medication for the heart
■ Beta blocker
■ Possible that our potassium increases in our blood if it
cannot enter the cell
○ Propranolol
K is released from cells during _________
exercise
In exercise Increases K by __________ mmol/L
0.3 – 1.2 mmol/L
Reversed after several minutes of rest
exercise
● ____________ during venipuncture can cause erroneous high
plasma K concentrations or _____________
Forearm exercise - pseudohyperkalemia
______________ as with uncontrolled diabetes mellitus, causes
water to diffuse from the cells, carrying K+ with the water, which
leads to gradual depletion of K+ if kidney function is norma
HYPEROSMOLALITY
_________ into the ECF when cells are broken down
●___________, _______, __________
CELLULAR BREAKDOWN
Releases K
Severe trauma, tumor lysis syndrome, and massive blood
transfusions (STM)
● Low potassium in the blood
HYPOKALEMIA
HYPOKALEMIA DUE TO GASTROINTESTINAL LOSS (6)
(VDGIMC)
Vomiting
● Diarrhea
● Gastric suction
● Intestinal tumor
● Malabsorption
● Cancer therapy (chemotherapy, radiation therapy)
Inhibits Na-Cl co-transporter leading to the secretion of K
via potassium channels in the collecting duct
● Diuretics (Thiazides and Loop)
___________is the most common cause of
hypokalemia
(The use of ) diuretics
drugs that are promoting diaphoresis or excretion of water from the body
Diuretics
Inhibits the reabsorption of sodium
Thiazides
If you’re drinking these two diuretic, dapat may third
drug na ma add , si ________________
potassium sparing diuretics
Due to increased accumulation of acid in the body, more
bicarbonate ions will be excreted together with K+
● Renal Tubular Acidosis
pH of Blood: ______________
7.35-7.45
A condition in which the adrenal gland produces too much
aldosterone
○ More Na ions will be retained in exchange of K ions
○ You are reabsorbing more sodium
● Hyperaldosteronism
Low magnesium levels in the blood
○ Potassium channels or Renal Outer Medullary K+ (ROMK)
Channel are inhibited by magnesium
● Hypomagnesemia
In alkalemia (a condition where the blood becomes
more alkaline), cells take up more potassium (K+)
because alkalemia causes the cells to lose hydrogen
ions (H+) in order to balance and reduce their internal
pH level.
● Alkalosis
Low potassium in blood
● In healthy persons, an acute oral load of K+ will briefly increase
plasma K+ because most of the absorbed K+ rapidly moves
intracellularly
HYPOKALEMIA
CAUSES OF HYPERKALEMIA (DCIA)
DECREASED RENAL EXCRETION (4)
CELLULAR SIFT (5)
INCREASED INTAKE (1)
ARTIFICIAL (4)
DECREASED RENAL EXCRETION (AHAD)
Acute or chronic renal failure (GFR < 20 mL/min )
● Hypoaldosteronism
● Addison’s disease
● Diuretics
CELLULAR SIFT (AMCLH)
● Acidosis
● Muscle /Cellular injury
● Chemotherapy
● Leukemia
● Hemolysis
INCREASED INTAKE (O)
Oral or intravenous potassium replacement therapy
ARTIFICIAL (STGPR)
● Sample hemolysis
● Thrombocytosis
● Prolonged tourniquet use or excessive fist clenching
● GFR, glomerular filtration rate
● Major Extracellular Anion
CHLORIDE ION
Function of Chloride ○ Involved in maintaining _________, _______, _______
osmolality, blood volume, and electric neutrality
OBE
Physiology & Regulation
○ Main source: __________________
■ We get chloride from our food along with
other electrolytes that are absorbed in the
gastrointestinal system.
○ Kidney: _________ and __________
○ Excess chloride is excreted in ___________ and _______
DIET - GI absorption
filtration and reabsorption in PCT
urine and sweat
Excessive sweating stimulates aldosterone
secretion - _____________
sweat glands
○ Act as rate-limiting component
● Electrical Neutrality
CI- diffuses into the red blood cell to maintain
electroneutrality
○ The movement of chloride from the plasma into our
RBC (replacing the leaving bicarbonate which is also
an anion)
● Chloride shift
__________ it’s a byproduct of our body and has to be removed through
RBCs.
CO2
CO2 will bind to water via____________ to form_______________
Carbonic anhydrase to form Carbonic
acid (H2CO3)
Excess loss of HCO3
HYPERCHLOREMIA
Excess loss of Cl-
HYPOCHLOREMIA
HYPERCHLOREMIA as a result
of: (3)
● RBC will give off
chloride instead, since
bicarbonate is
insufficient (chloride
levels will increase)
● GI losses
● RTA or Metabolic
Aldosterone acidosis
HYPOCHLOREMIA (4)
● Prolonged vomiting
(will lead to a poor
absorption of our
electrolytes)
● Diabetic ketoacidosis
● Aldosterone deficiency
(sodium will not be
reabsorbed and
chloride will not also
be reabsorbed)
● Salt-losing
nephropathy
(pyelonephritis)
Fifth most common element and is the most prevalent cation in
the human body
CALCIUM
Sodium is prevalent in the __________ while calcium are
prevalent in our __________
plasma - bones
Majority of our calcium is stored in our _________, they
are not __________ and are not _________
bones
not physiologically active and not circulating
FUNCTIONS OF CALCIUM
Skeletal mineralization (stored as hydroxyapatite)
● Blood coagulation serves as Clotting Factor IV
● Neural transmission
○ calcium propagate signals down our axons
○ are also involved in dumping neurotransmitters like
acetylcholine, into our synapses (calcium is needed
by the acetylcholine to leave the terminal end of the
axon and enter the synaptic cleft, and bind to its
receptor)
● Pasma buffering capacity and enzyme activity
● Maintenance of normal muscle tone and excitability of skeletal
and cardiac muscle (because it has a connection with our signals
coming from the nerve cells)
DISTRIBUTION OF CALCIUM
_______ bone(as hydroxyapatite)
● ______ - circulation (blood) + ECF
● ______ is further divided into 3 different types of calcium:
○ ______ - bound to anions
○ _______- bound to protein (albumin)
○ ________-Free/ ionized Ca*+
99% > bone(as hydroxyapatite)
● 1% - circulation (blood) + ECF
● 1% is further divided into 3 different types of calcium:
○ 10% - bound to anions
○ 40% - bound to protein (albumin)
○ 50% -Free/ ionized Ca*+
In the laboratory, they are ____________
Calcium results will include calciums that are bound
to proteins and anions
hard to measure alone.
Some labs have separate tests for total calcium and
free/ionized calcium
○ Total calcium may look normal but free/ionized
calcium may be low, leading to _______ and _______
conditions and erroneous results
Decreased free calcium levels in the blood can cause muscle
spasms or uncontrolled muscle contractions called __________
tetany
3 HORMONES THAT REGULATE CALCIUM
- PTH: secreted in low calcium levels
- Vitamin D
- Calcitonin: secreted in high calcium levels
Trigger or stimulus to increase calcium levels
remember 99% of calcium is stored in bones
(meaning pwedeng kumuha doon sa bone ng excess
calcium) kasi only 1% of our calcium circulates on
plasma
● once you experience low calcium level on your body
it will release PTH, and this PTH will trigger bone
resorption meaning there is a breakdown of parts of
bone in order to release calcium from bone into
circulation thereby normalizing low calcium levels
- PTH: secreted in low calcium levels
Triggers to increase the absorption of calcium in our
diet and also help our PTH in bone resorption.
● Target: to increase calcium level in blood
- Vitamin D
Secreted by thyroid gland
● Secreted in high calcium level (opposite of both PTH
and Vit. D)
● If mataas ang calcium level sa blood, calcitonin will
be released by thyroid gland to excrete excess
calcium and will become normal level in blood)
● Meaning ginapababa niya ang calcium level
- Calcitonin: secreted in high calcium levels
an inactive substance in the skin
7-dehydrocholesterol
● still an inactive form of vitamin D
● Produced when 7-dehydrocholesterol is exposed to UV Light
- Cholecalciferol or vitamin D3
● Both of them, will enter liver and be converted to calcidiol
(25-hydroxyvitamin D)
● Still an inactive form of vit. D
● Will enter kidney and will form an active form of vitamin D
- Ergocalciferol or Vitamin D2
l (1, 25-dihydroxyvitamin D or 1,25-dihydroxycholecalciferol
(1,25-[OH]2 -D3 ) - has power to induce certain changes in our body to
increase calcium levels in plasma
The active form of Vitamin D
● To increase intestinal absorption of calcium in our diet
○ Induce to increase bone resorption, hence prompting
breakdown of the bone, causing the release of
calcium into circulation
○ Lastly, it decreases the excretion of calcium as well
as phosphate.
- Calcitriol
a reserve and will be activated by thyroid hormone
Inactive metabolite (24, 25-dihydroxyvitamin D
In summary
7-dehydrocholesterol → UV light exposure →
Cholecalciferol + Ergocalciferol (from diet) → Enter
together in the liver and undergo hydroxylation →
Calcidiol → Hydroxylated in the Kidney → Calcitriol
(Active form of Vitamin D)
○ Hence to make an active form of vitamin D
Cholecalciferol must undergo two hydroxylation
processes first from the liver second in the kidneys.
Increase the level of calcium in our blood and trigger or
stimulus is low in calcium levels
● To increase or to normalize low calcium level
PARATHYROID HORMONE
PARATHYROID HORMONE
● 3 MAJOR EFFECTS: (BCS)
○ Bone resorption
○ Conserves Ca2+ by increasing tubular reabsorption
○ Stimulates renal production of active vitamin D
____________ is not good because calcium tends to deposit in
our body
Hypercalcemia
Fourth most abundant cation
● Second most abundant intracellular ion
MAGNESIUM
MAGNESIUM
○ ______ - bone
○_______ - muscle and other organs and soft tissue
○ Less than ______ serum and erythrocytes
■ Protein-bound (primarily albumin)
■ Free or ionized form : major
■ Complexed with other ions
53%
46%
1%
Function of magnesium (5)
Functions:ETNSR
● Essential cofactor - example are ALP & ACP
● Transcellular ion transport- transports of ion from
apical surface to basolateral surface
● Neuromuscular transmission
● Synthesis of carbohydrates, proteins. Lipids, and
nucleic acid
● Release of and responds to certain hormones
MAGNESIUM
Controlled largely by the __________
● Non-protein-bound are filtered by the glomerulus
○ __________ is reabsorbed by the PCT
○ _______ is reabsorbed in ascending loop of
Henle
● Renal threshold: _________
Kidney
25-30%
50-60%
0.60-0.85 mmol/L
○ Increases renal reabsorption and intestinal
absorption
○ Main target is calcium and not magnesium, but it will initiate reabsorption and intestinal absorption of
calcium and madadamay ang si magnesium( so it is
moe in calcium than in magnesium)
PTH
○ Increases the renal excretion of magnesium
○ To eliminate magnesium in our bod
● Aldosterone and thyroxine
