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minerals
cmbm exam II
113
Chemistry
Graduate
12/12/2009

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Term
what are major minerals?
Definition
major minerals - needed in amounts >100mg/day. Ca, P, Na, Cl, Mg, S
Term
what are trace minerals?
Definition
trace minerals - needed in amounts <100 mg/day. Fe, Zn, Cu, Mn, Fl, Cr, I, Se, Mo
Term
are minerals changed during digestion/use? destroyed by light, heat, or alkalinity?
Definition
no&no
Term
define bioavailability
Definition
bioavailability refers to how much of that we ingest that ends up in the bloodstream
Term
what kinds of things can change the absorption rate of minerals?
Definition
the body's need, other fiber & minerals can hamper other's absorption. some compounds such as phytic acid and oxalate bind some minerals
Term
what is the est. daily need for Na?
what does the AHA recommend? what is the recommendation for CHF pts?
Definition
500 mg. AHA recommends and CHF pts should be on 2.4 g
Term
what is the typical daily Na+ intake with the american diet? what % if this is naturally occuring?
Definition
6 g 10% of which is naturally occuring
Term
what organs does excess Na in our diets affect?
Definition
the kidneys are under a lot of pressure to excrete excess Na
Term
are Na deficiencies common? when might they happen?
Definition
Na deficiency is not common, they would only happen due to a disease or rx
Term
why is serum Na not a good assessment of body Na levels?
Definition
Na is a mostly extracellular ion
Term
what are the functions of Na?
Definition
regulates fluid balance, nerve impluse transmission, muscle function, regulates blood pH, allows absorption of glucose into small intestine, (thus low salt diet for diabetics)
Term
what is hyponatremia? why does it occur? what does it cause?
Definition
low blood Na levels. it usually occurs due to increase excretion of Na, (diarrhea, vomiting, intense prolonged sweating). it causes dehydration b/c water follows salt, (hypovalemia: water loss). this can cause edema from fluid movement into cells -> can lead to neurological problems in the elderly
Term
what is hyperatremia? what can it lead to?
Definition
high Na blood level. this can lead to increase in blood pressure, (arterial stretching activates Ca channels causing smooth muscle to contract and shorten the arterial diameter=HTN)
Term
what might hypernatramia be due to?
Definition
it can be due to CHF/kidney disease. w/CHF the contractility of the heart is decreased = ejection fraction is decreased. this can lead to kidney failure due to lower perfusion, which leads to lower capacity for excretion of wastes, (renin angiotensin system is upregulated)
Term
why would reading K levels for blood where hemolysis has occured be inaccurate?
Definition
K is an intracellular electrolyte
Term
what foods have high levels of K?
Definition
fruits and vegetables
Term
how does processing food affect Na, K levels?
Definition
processing food tends to lower K and raise Na levels
Term
what charge ion is important in membrane potential regulation?
Definition
cations, such as Na, K, Cl
Term
what does lack of K cause? what might cause this?
Definition
cramps. diuretics can cause these w/out a KCl rx
Term
how does K deficiency cause increased blood pressure?
Definition
lack of K causes muscle contraction which causes peripheral resistance in arteries
Term
what is an example of the nervous system being tightly regulated in terms of K?
Definition
the CNS will maintain adequate K levels even if blood and muscle levels decrease
Term
how do high K levels affect Na and blood pressure?
Definition
high K levels decreases Na levels and blood pressure
Term
what is hypokalemia? what can cause it?
Definition
low K. vomiting, diarrhea, bulimia, (cardiac rhythms can be disrupted by changes in ion levels), alcoholism, (decreased K intake/increase excretion). laxative abuse, (they target cells in large intestine where K/Mg is reabsorbed). cardiac rhythms can be disrupted by changes in ion levels. diabetics in ketoacidosis can be infused with insulin, which increases K influx into the cells
Term
what is hyperkalemia? what might cause it?
Definition
high K. rare, usually due to increased intake, important to monitor pts on diuretics. normal blood level: 3.5-5.5, heart attack: >7
Term
is Cl a extra or intracellular electrolyte?
Definition
extracellular
Term
how does Cl maintain a neutral environment in the blood?
Definition
Cl shift, it moves in and out of the RBCs
Term
where are lower Cl levels found in the CV system? higher?
Definition
Cl is lower in arterial blood, higher in venous
Term
what function does Cl perform in the stomach?
Definition
combines with H+ to form HCl
Term
when Cl is absorbed by the large intestine, what happens?
Definition
pH is raised, in conjunction with the kidneys/bicarb system
Term
what can cause hypochloremia? what does it do in the body?
Definition
frequent vomiting as well as sudden fright can cause low chloride levels. hypochloremia can lead to metabolic alkalosis, (high blood pH), and resp alkalosis which can result in abnormal cardiac rhythm/decreased flow to the brain. xanax, alcohol, GABA and benzos all have depressing effects on the CNS but increasing cellular Cl influx, causing excitation of inhibitory neurons
Term
what is hydroxyapatite?
Definition
a complex of Ca and P which binds to collagen protein matrix formed by osteoblasts for new bone growth.
Term
how much of body weight is made up by Ca? how much of that is in bone?
Definition
1-2% 99%
Term
when is mineralization of bone most active?
Definition
during linear growth
Term
how is bone strengthened? who is this important for especially?
Definition
repeated stress, (weight bearing exercise) caucasian women have lower rates of Ca absorption, so they are encouraged to do this
Term
how does Ca help with hormonal gene regulation?
Definition
Ca acts as a second messenger and helps with phosphorylation of gene expression enzymes
Term
is Ca needed for muscle contraction?
Definition
yes
Term
how does lack of Ca affect coagulation of blood?
Definition
its presence triggers clotting
Term
what is currently being attempted regarding the DV of Ca being 1000 mg/day?
Definition
most people do not receive enough, esp adolescents and senior citizens, (system of bone mineralization is slower), people on diets who cut out dairy are also at risk
Term
why are men at less of a risk for osteoporosis?
Definition
they have more muscle mass creating more tension which stimulates osteoblasts
Term
what does PTH overproduction cause?
Definition
demineralization of bone, possible hypercalcemia
Term
what is calcium absorption dependent on?
Definition
vitamin D which increases the transcription of Ca binding protein, enhancing the absorption of Ca into the intestine/system
Term
do phytates decrease Ca absorption?
Definition
yes
Term
why would pts in dialysis be at a higher risk for hypercalcemia?
Definition
phosphorous is usually high in pts on dialysis, and phosphorous stimulates higher PTH levels which in turn releases more Ca from the bone, raising Ca levels
Term
how can high levels of supplemental phosphorous and magnesium decrease Ca absorption?
Definition
phosphorous likes to bind to Ca, should be at a 1:2 ratio
Term
how does a decrease in estrogen levels affect Ca?
Definition
low estrogen can decrease Ca absorption, (direct affect on vit D)
Term
when are Ca supplements absorbed most efficiently?
Definition
between meals
Term
what % of mineral intake is usually absorbed? how can this be increased? what is this dependent upon?
Definition
usually about 35-40% is absorbed. absorption is increased by stomach acid which chelates minerals to AAs, increasing their solubility. (antacids can affect this)
Term
what does excessive Ca interfere with?
Definition
absorption of other minerals such as Zn, Mg, and I
Term
why is phosphorous important?
Definition
component of ATP, DNA, RNA, phospholipids, phosphorylation of enzymes via kinases, contributes to bone mass
Term
where is phosphorous found?
Definition
it is abundant in fruits, dairy products, (if people eat a high amount of bone marrow, they are at risk of high P which binds Ca)
Term
what enhances absorption of phosphorous along with Ca?
Definition
calcitriol, (vit D)
Term
what enhances urinary excretion of P?
Definition
PTH
Term
what is hypophosphatemia? what is is due to? what can happen long term?
Definition
low P levels in the blood, due to decreased absorption or increased excretion, (due to increased PTH), vit D deficicency, or overuse of P-binding antacids, (common in dialysis pts). long term: osteomalacia can result
Term
what is hyperphosphotemia?
Definition
high P levels, can be due to kidney disease, under active PTH, excessive vit D supplements, overuse of P-binding laxatives. high P w/low Ca increases risk for bone loss
Term
is there an accurate way to tell how much Mg is in the body? why?
Definition
not at the moment, b/c half the body's stores are in bone & half in soft tissue
Term
is it likely there is a sub-clinical Mg deficiency in the US diet?
Definition
yes, combined with increased excretion
Term
what is the first tx for pts with HTN?
Definition
MG2+
Term
what are some functions of Mg in the body?
Definition
coenzyme to DNA, protein synth, glycolysis, and ATP production. it stabilizes ATP, enhances insulin action, potentiates the action of some peptide hormones
Term
how does Mg affect muscles?
Definition
it is a muscle relaxant
Term
when pts are on loop diuretics, what are 2 important supplements?
Definition
Mg, vit B for muscle soreness, psychosis
Term
is Mg a safe supplement? what does its toxicity cause?
Definition
yes, toxicity will just cause diarrhea
Term
what are some foods containing Mg?
Definition
hard water, plants and refined foods
Term
what is the normal absorption rater for Mg? what are 2 things which can decrease its absorption rate?
Definition
normal absorption is 50%, high fiber and high Ca can affect bioavailability
Term
what accompanies hypomagnesemia?
Definition
low levels of Mg in the blood usually accompanies lower levels of K and P, (b/c they are all intracellular)
Term
what can cause hypomagnesemia?
Definition
kidney disease, alcoholics, (muscle cramps and bleeding problems - liver is where coagulation materials are made), diuretic use, and prolonged diarrhea
Term
can Mg help with tension headaches and restless leg syndrome?
Definition
yes, (restless leg syndrome is associated with increased PTH levels)
Term
what are the 2 states of iron?
Definition
ferrous 2+ and ferric 3+
Term
what does iron function as? is it a trace mineral?
Definition
iron is a trace mineral, which transports O2 on HB and myoglobin. it functions as a cofactor in enzymatic rxns, NT synthesis, and brain development
Term
what other minerals does the absorption of iron affect?
Definition
Mg, Zn, and Ca
Term
what is too much Fe associated with? how does Vit C play into this?
Definition
heart disease and Ca. Vit C can increase levels of iron absorption
Term
what transfers Fe? stores it? how can this information be used to determine iron levels in the body?
Definition
transferrin transfers Fe, and ferritin stores it in the liver. levels of transferrin correlate with iron binding capacity, (receptor # deptends on need)
Term
when does loss of iron occur?
Definition
Fe loss occurs in people with colitis or GI infections, due to intestinal cells sloughing off
Term
how does stomach acid help with iron absorption?
Definition
stomach acid solubilizes Fe and converts it to the ferrous state for absorption
Term
what is the most bioavailable iron? does anything affect this?
Definition
heme iron. Vit C enhances heme iron. steak blood/liver contains high levels of heme iron
Term
what can happen with dialysis pts in terms of Fe?
Definition
dialysis pts can develop atherosclerosis due to increased Fe
Term
what can malabsorption of iron be due to?
Definition
high phytic acid in diet, polyphenols (tannins) in tea and coffee, soy, oxalates, (spinach), fiber, Ca, Zn, (these minerals use the same transport so increases in one can negatively affect others)
Term
where does most iron for new RBCs come from?
Definition
breakdown of old RBCs
Term
how is iron lost during bowel movements?
Definition
some intestinal cells store Fe, and they are sloughed off during bowel movements
Term
why do women have a higher iron requirement? who else requires iron supplementation?
Definition
they have a lower muscle mass and loose some Fe through menstruation. atheletes also require Fe supplementation
Term
what is the most common nutritional deficiency in the world? for whom?
Definition
Fe, in children 6-24 mo
Term
what can Fe deficiency be due to?
Definition
diet, esp consuming binders or compounds that decrease/block absorption of Fe. it can also be due to hemorraging/acute infection - anything that causes RBC turnover
Term
what is a sign of Fe deficiency?
Definition
decreased serum ferritin
Term
how can inadequate protein intake in malnourished children affect iron storage?
Definition
pts may not be able to make enough transcripts for storage
Term
what is hemochromatosis? who is at risk for this?
Definition
chronic iron overload, caused by a genetic defect. african american males are at a higher risk, due to higher myoglobin
Term
what is zinc important for?
Definition
cell replication, maintenance of the immune system, DNA rep, sense of smell/taste, and apoptosis
Term
does zinc deficiency have severe consequences?
Definition
yes
Term
what things can negatively affect zinc absorption?
Definition
high Ca, Fe, (same trasport mech), also phytic acids, fiber
Term
how is excess Zn prevented from entering the blood?
Definition
metallothionine binds Zn in the intestinal cells
Term
how does Zn travel in the bloodstream?
Definition
Zn is bound to albumin, helps prevent it from being filtered in the kidney, though escape of large molecules such as glucose, (such as the case is in diabetes), can increase the excretion of smaller ones such as Zn
Term
why do deficiencies occur more easily with Zn?
Definition
it is not stored in high amounts
Term
what is Zn necessary for?
Definition
maintenance of hormones, particularly testosterone
Term
why does laxative use decrease Zn levels so fast?
Definition
digestive uses carry high amounts of Zn
Term
what can happen with Zn deficiency?
Definition
Zn deficiency can lead to hypogonadism, hair loss, skin lesions, growth retardation, impaired taste
Term
what can Zn be used to treat?
Definition
zinc can be used to treat wilson's disease, where hyperabsorption of Cu occurs, (Zn saturates the transport mech for Cu)
Term
what is Zn deficiency linked with?
Definition
heart disease, obesity, higher estradiol levels, (what testosterone converts to w/out Zn, also speeds up replication of Ca cells
Term
can alchol consumption cause Zn deficiency?
Definition
yes
Term
what can cause excessive Zn?
Definition
loss of libido, muscle spasms, menstrual cycle problems, sciatica. metallic taste
Term
is Zn a trace metal?
Definition
yes
Term
what is selenium, (a trace mineral), a component of that has antioxidant properties?
Definition
selenium is a component of gluathione peroxidase, which fights oxidation found in things like polyunsaturated fatty acids which oxidize in heat
Term
what is iodine, (a trace mineral), a component of? what if there is a deficiency of I?
Definition
thyroid hormones, T3+4, I deficiency can lead to short stature and mental retardation
Term
what is hypothyroidism? how is it related to iodine levels?
Definition
the thyroid enlarges when iodine is scarce to more efficiently trap iodine
Term
what happens with I/T3-4 deficiency?
Definition
premature graying, cardiomegaly, (increased heart size), heart failure, mental retardation in children, decreased sharpness of mind
Term
why are TSH levels high in a pt with hypothyroidism?
Definition
the tissue is not responding, more is produced, (conversely low TSH correlates with hyperthyroidism)
Term
what is chromium, (a trace mineral), important for?
Definition
glucose homeostasis. chromium is a part of a molecule called glucose tolerance factor, it potentiates the action of insulin, (glucophage acts similarly) -increases lean body mass
Term
how low should NaCl intake be lowered for a pt with a hx of HTN and CHF?
Definition
<2 g/day
Term
why would Mg be recommended for a pt with a hx of HTN and CHF?
Definition
Mg will decrease contractility of smooth muscle around arteries, essentially dialating them
Term
why would increased K be recommended for a pt with a hx of HTN and CHF?
Definition
K regulates blood pressure
Term
why would red yeast rice be recommended for a pt with a hx of HTN and CHF?
Definition
this particular yeast produces a compound that is statin, (HMG CoA reductase inhibitor)
Term
why would niacin be recommended for a pt with a hx of HTN and CHF?
Definition
niacin can lower LDLs
Term
why would B complex vitamins be recommended for a pt with a hx of HTN and CHF?
Definition
these will support and increase the rate of metabolism, maintain healthy skin and muscle tone, enhance immune and nervous system function, promote cell growth and division—including that of the red blood cells that help prevent anemia
Term
why green leafy vegetables not be recommended for a pt with a hx of HTN and CHF?
Definition
this is high in vitamin K, if the pt has coagulation tendencies, this will make it worse
Term
why restricted fluid intake be recommended for a pt with a hx of HTN and CHF?
Definition
this will reduce the amount of work the heart has to do
Term
why would omega 3 FAs/vit E recommended for a pt with a hx of HTN and CHF on metoprolol and ASA?
Definition
metoprolol can upregulate cholesterol synthesis in the liver, vitE can thin the blood, blocks absorption of vit K. omega 3 FA are precursors for prostaglandins, which are anti-inflammatory
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