[FMS] NAM - metals Flashcards
Where is sodium found and excreted?
- Mostly found in blood and in ECF (extracellular fluid)
- Mostly excreted in urine
What is a sodium-associated disease?
Osteoporosis
What is too low Na in serum known as?
Too low Na in serum = Hyponatremia
- Electrolyte abnormality
- cells swell
- decrease in total body water
What is too high Na in serum known as?
Too high Na in serum= Hypernatremia
-cause: limited access to water or impaired thirst mechanism
-decrease in total body water relative to electrolytes
-water problem
-water leaves cells and enters blood aiming to dilute it and lowering Na levels
What does too much Na in the diet lead to?
-too much Na= facial puffiness, high bp, heart disease and stroke
-can cause Ca loss- increase in Ca excretion some can be from bone
Where is potassium found and excreted?
- Mostly inside the cells than outside; present in all body tissues
- Mostly excreted in urine, 10% in sweat and stool
- K has a strong relationship with Na
What is low levels of K in the blood known as?
Hypokalemia
- Cause 1: excessive K loss in urine (due to medications that increase urination)
- These medications are often prescribed for high blood pressure or heart disease
- Cause 2: Low K intake; associated with increased blood pressure and higher risk stroke
- If you have low K levels, you may have a heart problem, such as an irregular heartbeat
What is high levels of K in the blood known as?
Hyperkalemia
- Can be life-threatening
- Heart muscle activity may be reduced, weakness, paralysis in feet or respiratory
Where is magnesium found?
- 50% of body’s magnesium is in bone
- Very little in blood
What are the physiological functions of magnesium?
- Cofactor
- Protein synthesis
- muscle and nerve function
- blood pressure regulation
- oxidative phosphorylation, and glycolysis, and DNA, RNA and glutathione
- Regulates insulin secretion
- Contributes to formation of bone and teeth
What is too low levels of magnesium known as?
Hypomagnesemia
- Low Mg impairs the Mg-dependent adenyl cyclase generation of cAMP
- This decreases release of parathyroid hormone (PTH)
- Since PTH regulates Ca levels, Ca levels are decreased
^ Hypomagnesemia patients are at risk of cardiac arrhythmias
What is too high levels of magnesium known as?
- Major cause is renal failure
- Cardiovascular and neurological complications
Where is calcium found?
- About 99% of body’s calcium is stored in bones and teeth
- Cells (muscle cells) and blood also contain ca (bound to albumin or exist as ionised Ca).
What are the physiological functions of calcium?
- Formation of bone and teeth
- Small fraction of Ca in blood, ECF, and other tissues -
- mediates blood vessel contraction/dilation
- muscle contraction
- blood clotting
- nerve transmission, and hormonal secretion.
What are diseases associated with calcium?
- osteoporosis
- dental changes
- cataracts
- Familial hypocalciuric hypercalcemia (FHH): inherited disorder - FHH-usually do not show symptoms
what are low levels of Ca in blood called
Hypocalcemia
what are high levels of Ca in blood called
Hypercalcemia
What are trace elements?
essential for life; for numerous metal-dependent enzyme and protein activities
how many trace elements are there
13
which trace element has an established role
iron, zinc, iodine, copper, selenium, chromium, manganese, molybdenum
which trace element has a controversial role
vanadium, silicon, boron, nickel
which trace element has no know proven role in health
Arsenic
Where is iron found?
- In the circulation –e.g bound to haemoglobin, ferritin (iron storage protein) and transferrin (iron-carrier protein)
- Also, deposited in higher amounts in tissues during disease states
What are the functions of iron?
- component of hemoglobin
- myglobin
- neuro/physio development
How is iron regulated at high systemic levels by hepcidin?
-If you have high systemic/tissue iron levels, your liver hepatocytes sense this and they produce the hormone, hepcidin.
- This hepcidin binds on to the ferroportin molecules.
- Ferroportin is a transmembrane ion exporter which is uni-directional.
- If that is degraded then iron cannot come out into the circulation.
- And so by iron levels not coming out into the circulation, iron levels are maintained under normal physiological conditions.
- The body also has high levels of systemic ion present, we don’t want more iron to come out from the cells into the circulation.
How is iron regulated at low levels and by what molecule?
REGULATED BY HEPCIDIN
When iron levels iron levels are low, hepcidin secretion decreases.
- Less hepcidin is able to bind to ferroportin.
- These ferroportin molecules are functional and not degraded.
- Therefore they allow the exist of iron from inside the cells to the outside of the cell which isn’t part of the systemic circulation.
- So it brings an iron into the circulation to prevent anaemia.
What is primary iron overload and its treatment?
- Primary iron overload (inherited)-
^ Haemochromatosis - mutations in genes that regulate hepcidin or ferroportin (cellular iron exporter)
Treatment-Phlebotomy
what is secondary iron overload and its treatment
Secondary iron overload – Mild to moderate, due to other conditions e.g alcohol-associated liver disease or transfusion or excessive dietary consumption
Treatment-iron chelating agents e.g deferoxamine (intramuscular, subcutaneous, intravenous), deferiprone (oral)
what is iron deficiency anaemia and its treatments
Low RBC count or low haemoglobin
Treatment: Ferrous sulphate, ferrous gluconate, IV
where is zinc found
Present in blood, in all tissues- highest in muscle, bone, then liver
What is the role of zinc in the human body?
how is zinc regulated and distributed?
- regulated by its intestinal absorption
- Distribution is controlled at cellular and systemic levels through coordinated regulation through ZIP family and ZnT family of transporters
what is the zinc deficiency disorder called, and what causes it?
Acrodermatitis enteropathica (AE)
defective ZIP-4= transmembrane zinc uptake protein
Rare autosomal recessive condition resulting in severe zinc deficiency
what happens in zinc overload
- neuronal defects
- headaches
- nausea
- vomiting
- diarrhea
- respiratory stress
What are the functions of copper?
- Required for growth, cardiovascular integrity, lung elasticity, neovascularization, neuroendocrine function, iron metabolism
Essential cofactor for enzymes:
- cytochrome c oxidase
- lysyl oxidase
- dopamine monooxygenase
- ceruloplasmin
what is the disease for copper deficiency called? whats the cause and treatment?
Menkes Disease-X-linked recessive pattern
Mutations in ATP7A (regulates copper levels)= poor distribution of copper
Copper accumulates in small intestine, kidneys, but low in brain and other tissues
Treatment: copper injections
what is the disease for copper overload called? how is it caused and whats the treatment?
Wilson disease- rare genetic disorder, impairs copper transport
Mutation inATP7B, Decreased copper secretion into bile, Body cannot get rid of extra copper. Copper accumulates in liver, other organs, eyes and brain.
Treatment: copper chelation therapy or high doses of zinc can prevent permanent organ damage (results in decreased copper absorption from diet)
what is the physoilogical functions of sodium
homeostasis
bp
fluid electrolyte balance
regulates ecf volume
transport nutrients
excitability of muscle and nerve cells
what is the physiological functions of potassium
normal cell function
intracellular volume
transmembrane electrochemical gradients
acid-base balance
maintain isotonicity
activates enzymes
nerve impulsrs
contraction of cardiac muscles
