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CMBM exam 3 > Micronutrients I - Minerals > Flashcards

Micronutrients I - Minerals Flashcards

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0
Q

Zinc excess

A 
gastric distress, dizziness, nausea 
Emetic effect at doses as low as 50 mg
Can reduce Cu absorption (Cu and Zn uptake related) 
implicated in alzheimer's disease 
can affect cholesterol and lower HDLs
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1
Q

Zinc deficiency

A

tissue damage - oxidative stress, apoptosis
immune deficiencies
late onset secondary sex chara.
growth reduction/ developmental changes
poor appetite - pts lose sense of taste
malabsorption disorders - inflammatory bowel disease

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2
Q

Iodine

A

require about 150 micrograms/day
concentrates in Thyroid
usually bound to tyrosine residues of proteins - regulates metabolic rates in cells

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3
Q

Iodine deficiency

A

spontaneous abortion
birth defects
irreversible impairment of brain and physical development
stimulates enlargement of thyroid (goiter)

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4
Q

Iodine excess

A 
Mild excess (up to 2 mg/day) no apparent effects 
chronic excess can disrupt thyroid function
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5
Q

Selenium

A 
enzyme cofactor for antioxidant defense
thyroid hormone and insulin function 
regulation of cell growth and fertility 
Exists as selenomethionine and selenocysteine 
adults require about 55ug/day
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6
Q

Selenium deficiency

A 
cardia failure
liver disease 
cancer 
atherosclerosis 
hair loss 
skin changes 
infertility
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7
Q

Selenium Excess

A 
>400 ug/day
peripheral neuropathy 
nausea
diarrhea
dermatitis 
hair loss 
nail deformities
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9
Q

Homeostatic mechanisms act to maintain;

A

Optimal ionic strength

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10
Q

How do you estimate total body water (TBW)?

A

TBW (liters) = body weight (lbs) / 4

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11
Q

What are some macronutrients?

A

Water and salts
Minerals
Vitamins

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12
Q

What is a cofactor?

A

Organic (vitamins) or inorganic (metal) aids to enzymes

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13
Q

Selenium is said to be an antioxidant, but what is an issue that can arise because of this belief?

A

Selenium is toxic at high levels

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14
Q

Transcellular refers to…

A

Luminal fluid of GI tracts and CNS, fluid in eyes and lubricating fluids of serous membrane surfaces

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15
Q

Interstitial refers to…

A

Space between cells

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16
Q

Which is higher in the resting cell; K+ or Na+?

A

K+ (140 mM)

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17
Q

Osmotic equilibrium;

A

Extracellular fluid (ECF) osmolality = Intracell (ICF)

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18
Q

What is the particle concentration of a fluid called and what are it’s units?

A

Osmolality Millosmoles per kg

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19
Q

Normal extracellular concentration of Na?

A

145 mM

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20
Q

Normal Intracellular concentration of Na?

A

12 mM

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21
Q

Normal Extracellular concentration of K?

A

4 mM

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22
Q

Normal Intracellular concentration of K?

A

140 mM

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23
Q

Major ECF solutes?

A

Na+, Cl- and HCO3

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24
Q

Major ICF solutes?

A

K+, organic phosphate esters (ATP, creatine phosphate, phospholipids)

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25
what molecule is responsible for most of the osmotic pressure in blood?
Albumin contributes to ~80%
26
whats a milliequivalent?
still not sure but slides say= milliMolar when only one ionizable group = 2x mMolar if there are TWO charges if there are multiple ionizable groups with diff. pK's, it is more pH dependent
27
what is the normal osmolality of plasma ?
275-290 mosmol/kg
28
what is the recommended intake of sodium?
2400 mg/day
29
In 20% of the population is Na sensitive and can lead to . . .
hypertension (ECF expansion)
30
Which molecules regulate the effective osmolality of the ECF and the ICF respectively?
Na+, K+
31
What are the main macromolecules?
Sodium and potassium
32
When food is ingested, your cells become _____ so if you vomit you ____ solutes.
Isotonic, solutes
33
The GI tract to the jejunum ____ water and the jejunum to the colon ____ water.
Secretes, absorbs
34
What are the other important macromolecules?
Calcium, phosphorous, sulfer and magnesium
35
What are the functions of calcium?
``` Regulation of intracellular enzyme activities Secretory processes Blood clotting Muscle contraction Bone growth Binds to proteins Acts as second messenger Hormone receptor interactions Calmodulin Binding - regulates muscle contraction and inflammation ```
36
Calcium concentration higher inside or outside of a cell?
Intracellular calcium is ~0.1 uM | which is about 10,000x lower than the ECF
37
Example of symport
diffusion of H+ along gradient pulls along Lactose
38
How much water is lost with feces ?
100ml/day
39
why do you lose solutes if you vomit or have diarrhea?
ingested food/water become isotonic | diarrheal fluid is also close to being isotonic and can lead to loss of liters
40
Recommended K+ intake
3500 mg/day
41
Excess K+
cardiac arrest | K:Na ratio linked to hypertension
42
K+ deficiency
heart arrhythmia muscle weakness increased blood pH (alkalosis)
43
Example of Calcium acting in hormone receptor interaction
epi "fight or flight" hormone released from adrenal medulla. Binds to alpha receptors in liver, activates glycogenolysis and inhibits glycogen synthesis mainly by raising Ca+ levels in the liver
44
what promotes Ca+ absorption?
``` Vitamin D Gastric acid Lactose Citrate, malate Protein and phosphorous Exercise ```
45
What inhibits Ca+ absorption?
``` Oxalic acid and Phytic acid from plants Dietary fiber Phosphate (combines with Ca+ to make insoluble precipitate - stones) steatorrhea (fatty feces) (soaps) increased rate of passage ```
46
what can occurs due to Calcium deficiencies?
rickets, osteomalacia - adult rickets Vitamin D prevents rickets - low leads to poor intestinal absoprtion/poor kidney reabsorption of Ca and Phosphate Osteoporosis
47
Many metal-phosphates are extremely ...
insoluble
48
Excessive Calcium intake leads to
risk of renal stone formation in some ppl
49
adult males should consume ~ _____ mg/day of calcium?
1000
50
What is the second most abundant mineral in the body?
Phosphate - (PO4)-3
51
where is most of the phosphate in the body ?
85% in bones and teeth | 15% elsewhere - like nucleic acids
52
What regulates phosphate?
Vitamin D
53
what are some functions of phosphate?
``` in structure of nucleic acids phospholipids activation of enzymes by phosphorylation ENERGY - ATP acid-base balance ```
54
what are some dietary sources of Phosphate?
Animal protein, milk, eggs Processed foods - tons of phosphate buffers Food additive for pH adjustment, to sequester some thing (like metals)
55
what is the recommended daily intake of Phosphate?
700-1250mg/day
56
A high Ca:P ration promotes?
Ca excretion | 15g/kg of diet is upper limit
57
What are some functions of Magnesium ?
``` Bone strength ATP hydrolysis - most enzymes need Mg+2 to stabilize ATP Enzyme cofactors Binds nucleic acids muscle relaxation after contractions ```
58
RDA for magnesium?
400mg/day male | 300mg/day female
59
What are sources of Mg?
vegetables, nuts, legumes | ~30-50% of intake is absorbed
60
Intracellular or extracellular Mg concentration higher?
intracellular
61
Mg deficiency
rare except with alcoholics | leads to hypertension, vascular disease. preeclampsia, osteoporosis
62
Mg excess
anaesthetic effect | diarrhea
63
function of sulfur?
sulfate in tissues in AA - cysteine, methionine key in disulfide bonds role in transfer groups (Acetyl CoA)
64
Key metals in enzymatic activites and protein structure?
Iron Zinc Iodine Selenium
65
Function of Iron
catalysis and electron transfer, oxygen transport
66
Why is Iron toxic in presence of oxygen ?
catalyzes Haber-Weiss-Fenton reactions
67
Haber-Weiss-Fenton reaction
Iron(II) + oxygen goes to Superoxide Superoxide reacts with Hydrogen ions to make Hydrogen peroxide and oxygen Iron(II) and hydrogen peroxide react to make hydroxyl radical (which attacks proteins) and hydroxide and Iron(III)
68
Zinc finger
protein domain that binds DNA for gene expression | cys, His, glutamate
69
Zinc
key role in many enzymes - catalysis and structure Zinc fingers Highly regulated by body lose about 1mg/day
70
Unlike Fe, Zinc is NOT
redox reactive
71
What increases zinc absorption?
by binding to His, Cys and nucleotides
72
What decreases zinc absorption?
Phytate - attracts + metals
73
Metallothionein
Cys rich proteins bind many metals at high capacity (12 atoms per protein) - liver, stomach, brain, tongue regulates Zn transfer in blood
74
what form of Zn is absorbed ?
Zn+2
75
Zinc storage
Men store 2.5 g women 1.5 g mainly in muscle and bone
76
Zinc turnover
300 days very slow In liver Zn-Mth is fast, ~2 weeks
77
units of trace metals in the body?
ppb - parts per billion = ug/liter | ppt - parts per trillion = ng/liter

CMBM exam 3 (24 decks)

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