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CMBM exam 3 > Micronutrients I - Minerals > Flashcards

Micronutrients I - Minerals Flashcards

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
Q

what molecule is responsible for most of the osmotic pressure in blood?

A

Albumin contributes to ~80%

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26
Q

whats a milliequivalent?

A

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

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27
Q

what is the normal osmolality of plasma ?

A

275-290 mosmol/kg

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28
Q

what is the recommended intake of sodium?

A

2400 mg/day

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29
Q

In 20% of the population is Na sensitive and can lead to . . .

A

hypertension (ECF expansion)

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30
Q

Which molecules regulate the effective osmolality of the ECF and the ICF respectively?

A

Na+, K+

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31
Q

What are the main macromolecules?

A

Sodium and potassium

32
Q

When food is ingested, your cells become _____ so if you vomit you ____ solutes.

A

Isotonic, solutes

33
Q

The GI tract to the jejunum ____ water and the jejunum to the colon ____ water.

A

Secretes, absorbs

34
Q

What are the other important macromolecules?

A

Calcium, phosphorous, sulfer and magnesium

35
Q

What are the functions of calcium?

A 
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
Q

Calcium concentration higher inside or outside of a cell?

A

Intracellular calcium is ~0.1 uM

which is about 10,000x lower than the ECF

37
Q

Example of symport

A

diffusion of H+ along gradient pulls along Lactose

38
Q

How much water is lost with feces ?

A

100ml/day

39
Q

why do you lose solutes if you vomit or have diarrhea?

A

ingested food/water become isotonic

diarrheal fluid is also close to being isotonic and can lead to loss of liters

40
Q

Recommended K+ intake

A

3500 mg/day

41
Q

Excess K+

A

cardiac arrest

K:Na ratio linked to hypertension

42
Q

K+ deficiency

A

heart arrhythmia
muscle weakness
increased blood pH (alkalosis)

43
Q

Example of Calcium acting in hormone receptor interaction

A

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
Q

what promotes Ca+ absorption?

A 
Vitamin D
Gastric acid 
Lactose 
Citrate, malate 
Protein and phosphorous 
Exercise
45
Q

What inhibits Ca+ absorption?

A 
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
Q

what can occurs due to Calcium deficiencies?

A

rickets, osteomalacia - adult rickets
Vitamin D prevents rickets - low leads to poor intestinal absoprtion/poor kidney reabsorption of Ca and Phosphate
Osteoporosis

47
Q

Many metal-phosphates are extremely …

A

insoluble

48
Q

Excessive Calcium intake leads to

A

risk of renal stone formation in some ppl

49
Q

adult males should consume ~ _____ mg/day of calcium?

A

1000

50
Q

What is the second most abundant mineral in the body?

A

Phosphate - (PO4)-3

51
Q

where is most of the phosphate in the body ?

A

85% in bones and teeth

15% elsewhere - like nucleic acids

52
Q

What regulates phosphate?

A

Vitamin D

53
Q

what are some functions of phosphate?

A 
in structure of nucleic acids 
phospholipids 
activation of enzymes by phosphorylation 
ENERGY - ATP 
acid-base balance
54
Q

what are some dietary sources of Phosphate?

A

Animal protein, milk, eggs
Processed foods - tons of phosphate buffers
Food additive for pH adjustment, to sequester some thing (like metals)

55
Q

what is the recommended daily intake of Phosphate?

A

700-1250mg/day

56
Q

A high Ca:P ration promotes?

A

Ca excretion

15g/kg of diet is upper limit

57
Q

What are some functions of Magnesium ?

A 
Bone strength 
ATP hydrolysis - most enzymes need Mg+2 to stabilize ATP 
Enzyme cofactors 
Binds nucleic acids 
muscle relaxation after contractions
58
Q

RDA for magnesium?

A

400mg/day male

300mg/day female

59
Q

What are sources of Mg?

A

vegetables, nuts, legumes

~30-50% of intake is absorbed

60
Q

Intracellular or extracellular Mg concentration higher?

A

intracellular

61
Q

Mg deficiency

A

rare except with alcoholics

leads to hypertension, vascular disease. preeclampsia, osteoporosis

62
Q

Mg excess

A

anaesthetic effect

diarrhea

63
Q

function of sulfur?

A

sulfate in tissues
in AA - cysteine, methionine
key in disulfide bonds
role in transfer groups (Acetyl CoA)

64
Q

Key metals in enzymatic activites and protein structure?

A

Iron
Zinc
Iodine
Selenium

65
Q

Function of Iron

A

catalysis and electron transfer, oxygen transport

66
Q

Why is Iron toxic in presence of oxygen ?

A

catalyzes Haber-Weiss-Fenton reactions

67
Q

Haber-Weiss-Fenton reaction

A

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
Q

Zinc finger

A

protein domain that binds DNA for gene expression

cys, His, glutamate

69
Q

Zinc

A

key role in many enzymes - catalysis and structure
Zinc fingers
Highly regulated by body
lose about 1mg/day

70
Q

Unlike Fe, Zinc is NOT

A

redox reactive

71
Q

What increases zinc absorption?

A

by binding to His, Cys and nucleotides

72
Q

What decreases zinc absorption?

A

Phytate - attracts + metals

73
Q

Metallothionein

A

Cys rich proteins bind many metals at high capacity (12 atoms per protein) - liver, stomach, brain, tongue
regulates Zn transfer in blood

74
Q

what form of Zn is absorbed ?

A

Zn+2

75
Q

Zinc storage

A

Men store 2.5 g
women 1.5 g
mainly in muscle and bone

76
Q

Zinc turnover

A

300 days
very slow
In liver Zn-Mth is fast, ~2 weeks

77
Q

units of trace metals in the body?

A

ppb - parts per billion = ug/liter

ppt - parts per trillion = ng/liter

CMBM exam 3 (24 decks)

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