chem exam 2 315

Glucose

the body’s main energy source, especially critical for the brain and nervous system, which rely almost exclusively on extracellular glucose

Glycolysis

produce ATP & pyruvate/lactate for immediate energy

Glycogenesis

stores glucose as glycogen(mainly in liver n muscle)

Gluconeogenesis

(formation of G6P from non-carb sources)- liver synthesize glucose from non-carb sources like a.a,lactate, glycerol Liver,pancreas,adrenal glands regulate homeostasis of blood glucos

Glycogenolysis

breakdown of glycogen to glucose for use as energy

ex of monosaccharide

glucose, galactose, fructose

ex of disaccharide

sucrose, lactose

Oligosaccharide

3 to 10 units(glycoproteins)

Polysaccharide

>10 units (glycogen,starch)

Entry step of glucose metabolism

Glucose phosphorylated to glucose 6 phosphate using ATP

saturated lipids

(no double bonds)(straight eq)

unsaturated lipids

(1 or more double bonds)

Triglyceride

3 fatty acids esterified to glycerol backbone

Body's main energy storage form in adipose tissue 

Provide insulation n protection of organs

Severely high triglycerides lead to?

acute pancreatitis & atherosclerosis (build up of plaque in arteries)

Phospholipids

Glycerol backbone w/ 2 fatty acids, phosphate group n polar head

Phosphatidylcholine (lecithin-mix of fatty substances)- most common, &phosphatidylethanolamine, sphingomyelin 

Hydrophobic tails, hydrophilic head

Structure molecules, forms membranes n lipoprotein surfaces

Cholesterol

4 ringed struc

Amphipathic hydrophobic nucleus n small hydrophilic hydroxyl group→ allows alignment w/ phospholipids(in mem n lipoproteins)

Free cholesterol- in membranes n lipoprotein surfaces

Cholesteryl esters- esterified w/ fatty acids→stored in cells , packed in lipoproteins 

Synthesized mainly in liver n intestines from acetyl-CoA

Chylomicrons structure

Sphere w/ core- triglycerides n cholesteryl esters

chylomicrons function

Transports (exogenous)dietary triglycerides from intestines →liver,muscle,adipose tissue

;Hydrolyzed by lipoprotein lipase (LPL), releasing free fatty acids for storage or energy.

whats the chylomicrons surface made of

apolipoproteins, phospholipids, free cholesterol

ApoC-II

(activates LPL)

Apolipoproteins

bind lipids to lipoproteins- enables transport of fats

ApoB-48

(structural)

hyperchylomicronemia

→creamy serum layer after refrigeration

Very low density lipoproteins(VLDL)

Produced by liver to transport endogenous triglycerides(from excess carbs)

[eating too much carbs→liver turn extra verbs into triglycerides→pack in vldl→shipped out]

Delivers triglycerides to muscle(for energy) n adipose tissue(for storage)

Elevated VLDL

→hypertriglyceridemia

IDL

Remnants of VLDL after triglyceride removal by lipoprotein lipase

Normally found briefly in blood(transitional particles (teen stage))

Formed when LPL removes triglycerides from vldl→particle shrinks

elevated idl is uncommon but when it occurs, what is the cause

defective ApoE

LDL

Final version after most triglycerides have been removed, formed from vldl→idl metabolism(sum of chem rxns)

Most of triglyceride is removed , rich in cholesterol esters

Transport cholesterol to peripheral tissue , for mem synthesis n hormone production

Diff sizes n densities , small n dense → atherogenic

lipoprotein(a)

Particles resembles LDL j w/ an additionally ApoA covalently attached to ApoB-100

ApoA has kringles(repeated peptide loops) structurally similar to plasminogen(protease dissolves fibrin clots) interferes w/fibrinolysis; trouble w/ clot break down

Genetically determined unaffected w/ diet or lifestyle

Elevated LpA

→ higher risk of myocardial infarction, stroke, aortic stenosis(narrowing of aortic valve)

HDL

Removes excess cholesterol from tissues n transports back to liver thro reverse cholesterol transport

Smallest n most dense lipoprotein, has more proteins n less lipids

Apo protein A1, A-II, C

Synthesized in liver n intestine

HDL2

larger, rich in cholesterol

HDL3

smaller,denser,less cholesterol

LpX

Abnormal lipoprotein non-atherogenic, rich in phospholipids

Lil triglyceride

In cholestatic liver disease 

can produce high cholesterol results

In LCAT deficiency(inability to esterify cholesterol)

when does LpX accumulate

elevated plasma cholesterol which could mislead clinicals; important to differentiate from LDL(contributes to plaque)

what can LpX cause that makes it a problem clinically

gray topped that contain sodium fluoride

specimen collection using what tube

contains an anticoagulant and preservative that inhibits glycolytic enzymes, specifically enolase

whats special with gray topped tubes

Even with fluoride, what must be done ASAP with the plasma

must be separated from cells because the glucose decline in the first hour is virtually identical to tubes without it.

it has a diurnal variation (glucose value can b higher in the morning compared to afternoon)

whats special ab fasting plasma

HbA1c

Formed when glucose binds irreversibly to RBC hemoglobin; a value > 6.5 confirms diabetes.

Fasting Plasma Glucose (FPG)

Normal is 70–99 mg/dL

 Prediabetes FPG is

100–125 mg/dL

diabetes FPG is

126 mg/dL.

2-hr oral glucose tolerance test

A value >200 mg/dL indicates diabetes.

Gestational diabetes

Pregnancy hormones (cortisol, estrogen, human placental lactogen, progesterone) antagonize insulin action. Screened via a 1-step (75g) or 2-step (100g) method.

increased insulin resistance

pregnancy leads to what resistance

Diabetes mellitus(DM)

Disorders that r chronic hyperglycemia due to defects in insulin secretion or action

Hexose Monophosphate Shunt(HMP Shunt)

Generates NADPH (for biosynthesis and antioxidant defense) and ribose-5-phosphate (for nucleic acids).

Glucose Oxidase Method

A coupled reaction where peroxidase catalyzes a reaction between hydrogenperoxide(H2O2) and a dye to form a colored compound.

whats significant about Apo A-1 (the primary protein in HDL) in regards to CHD

decreases the risk of coronary heart disease

whats significant about Apo B-100 (found in LDL and VLDL) in regards to CHD

increases risk.

Increased chylomicrons appearance in tube

creamy serum layer; after fatty meal gives plasma milky/turbid appearance

increased VLDL appearance in tube

Cause turbid/cloudy plasma in hyperlipidemia  but no creamy layer

a quinoneimine dye

end product of glucose oxidase method

method to measure electrolyte activity

ion selective electrodes (ISE)

Direct ISE

measures undiluted sample (e.g.,blood gas analyzers).

Indirect ISE

measures diluted sample; affected by high lipids/proteins → pseudohyponatremia.

Osmolality

# of dissolved solute particles per kg of solvent, 275–295 mOsm/kg.

dictates water rentention and renin release

normal osmol gap

<10 mOsm/kg

toxic alcohols

an elevated osmol gap indicates unmeasured osmotically active substances in the blood, such as

osmol calculation

2 Na + glucose/20 + BUN/3

Anion gap

Diff of unmeasured anions n cations

High AG=

bicarbonate is being replaced by unmeasured anions; acidosis stuff

ref 8-16mmol/L

AG=Na-(Cl+HCO3)

ref 12-20mmol/L

AG=(NA+K)-(Cl+HCO3)

causes of hypokalemia

Due to GI loss (vomiting, diarrhea)

renal loss (diuretics, Cushing's),

cellular shifts (alkalosis, insulin)

decreased intake

Causes muscle weakness, cramps, and arrhythmias.

Hypokalemia

plasma K con <3.5 mmol/L

causes of hyperkalemia

Due to decreased renal excretion (renal failure, Addison's)

cellular shifts (acidosis, tissue injury)

artifactual errors (hemolyzed sample, prolonged tourniquet, fist clenching).

hyperkalemia

plasma K con >5.1 mmol/L

Pseudohyperkalemia

is a pre-analytical error caused by a hemolyzed sample, prolonged tourniquet use, or fist clenching

high osmolality

Na is high n water is low

low osmol

Na is low n water is high

Hyponatremia

Caused by losing sodium or retaining too much water.

kidney disease

heart failure

diuretics

vomit, diarrhea

Hypernatremia

caused by excess water loss, decreased water intake, or increased sodium retention

dehydration

sweating

diarrhea

chloride

what electrolyte is always evaluated alongside bicarbonate to maintain electroneutrality

Hypochloremia

Strongly associated with prolonged vomiting (loss of gastric HCl) or high bicarbonate states (metabolic alkalosis)

Hyperchloremia

Associated with GI bicarbonate loss (diarrhea) or renal tubular acidosis(metabolic acidosis)

henderson hasselbach

what eq defines the relationship between pH, the metabolic component (bicarbonate), and the respiratory component (pCO2).

the pancreatic islets of Langerhans

insulin is produced by beta cells of

anaerobic glycolysis

Severe anemia decreases oxygen to tissues, leading to

high anion gap metabolic acidosis

anaerobic glycolysis this generates lactic acid, resulting in a

Intravenous (IV) Fluid Therapy

Drawing blood proximal to (above) a running IV line causes massive pre-analytical errors. The sample is contaminated by the IV fluid, causing the analytes in the fluid (like Na and Cl in normal saline) to read critically high, while all other analytes are artificially diluted

collecting sample before giving patient IV to not impact electrolytes

Pediatric dyslipidemia

is an important predictor of future cardiovascular disease

dyslipidemia

abnormal level of lipids

calcium and phosphorus

Parathyroid hormone (PTH) directly controls

PTH in kidney does what

it promotes Ca reabsorption in distal tubule

excretion of HPO4

activation of renal 1-alpha-hydroxylase

these actions are direct

P

to be excreted by the kidneys

role of PTH for Mg

enhances renal reabsorption and intestinal absorption

RAAS (blood vol regulation)

Renin (kidney) → Angiotensin II (vasoconstrictor) → Aldosterone (Na reabsorption, water follows

severe anemia

In addition, the accuracy of pulse oximetry can be compromised by many factors, including poor perfusion and

greater

As lipoprotein particles become smaller and denser, their relative protein content generally becomes

ABCA1 transporter

active transfer of cholesterol to ApoA-1

LCAT enzyme (lecithin-cholesterol acyltransferase)

esterifies free cholesterol so it can b stored in HDL

chol value

<200mg/dL

LDL value

100

HDL value

>40 for men

>50 for women

triglycerides value

<150

Secondary dyslipidemia

Caused by another disease, lifestyle factor, or medication.

Tangier disease

a rare inherited disorder involving defects in the ABCA1 transporter, which normally transfers cholesterol to Apo A-I. (impairment of HDL formation)