C. Chem Lecture Exam 3

Understand what compensated and uncompensated means with metabolic or respiratory acidosis and alkalosis. * Uncompensated the pH will still be abnormal* How would the lab values look?

Normal ABG values

Normal range

pH- 7.35-7.45

PaCO₂- 35-45 mmHg

HCO₃⁻ - 22-26 mEq/L

Increased CO₂ = more acidic (↓ pH).

Decreased CO₂ = more alkaline (↑ pH).

Increased HCO₃⁻ = more alkaline (↑ pH).

Decreased HCO₃⁻ = more acidic (↓ pH).

Which Lipoprotein is good for you?

High Density Lipoprotein (HDL)

Which statement best describes plasma levels of lipoprotein(a) [Lp(a)]?

Plasma levels of Lp(a) vary widely among individuals in population but remain relatively constant within a person.

Elevated Lp(a) à increase the risk of premature coronary heart disease (CHD) and stroke

Remember the formula to calculate LDL with total cholesterol, triglycerides, and HDL. (you will need a calculator for the test)

LDL = TC - HDL - (Trig/5)

Most abundant cation that determines plasma osmolality.

Sodium

What is the role of HDL?

removes excess cholesterol from peripheral cells and carries it back toward the liver (reverse cholesterol transport)

synthesized by the liver and intestine

Albumin serves as what for drugs and hormones?

transport/carrier protein that binds drugs and hormones in blood. (maybe)

Lipoprotein X (Lp-X) levels are increased in which condition?

Biliary cirrhosis, cholestasis (liver disease, when flow of bile from liver is reduced or blocked) , and LCAT mutations

After aerobic cellular metabolism, hydrogen ions are carried out to the lungs with what type of hemoglobin?

Deoxyhemoglobin (HHb) binds/buffers H⁺ as CO₂ is transported toward the lungs.

Know how to distinguish between respiratory and metabolic acidosis and alkalosis and when it is compensated or uncompensated.

Respiratory disorders: pCO₂ changes opposite to pH. Metabolic disorders: HCO₃⁻ changes in the same direction as pH. Check whether the other system has changed appropriately to compensate;

Remember the formula for anion gap both the one with potassium and the one with potassium.

AG = (Na + K) - (Cl + CO2)

or

AG = Na - (Cl + CO2)

An elevated anion gap means what?

Increase in unmeasured anions, often from accumulation of acids;

leads to ketoacidois, lactic acidosis, metabolic acidosis)

How is bicarbonate recovered?

recovered from glomerular filtrate & converted to CO2 when H ions are excreted in urine

Kidneys reclaim filtered HCO₃⁻, mainly in proximal tubules, through H⁺ secretion and conversion of filtered HCO₃⁻ to CO₂ and H₂O, followed by reformation of HCO₃⁻ in tubular cells

Bile acids from the liver are derived from what?

Cholesterol

What assay does bilirubin and vitamin C interfere with?

The routine enzymatic total cholesterol colorimetric assay

Calcitonin does what to PTH and vitamin D?

decreases PTH activity and decreases vitamin D activation.

Changes in CO2 levels modify what?

ventilation (respiration) rate

What organ compensates pH slowly BUT completely when there is an acid-base disturbance?

Kidneys

Hypoventilation causes what acid-base disturbance?

respiratory acidosis

A patient presents with increased chylomicrons, triglycerides, lipemia( milky serum), abdomen pain and eruptive xanthomas. Which dyslipidemia is most likely?

Hyperchylomicronemia Type 1

What is elevated in Type IIa dyslipidemia?

Increased LDL and cholesterol.

Triglycerides are usually normal.

What is elevated in Type IIb dyslipidemia?

Increased LDL and VLDL.

Both cholesterol and triglycerides are elevated.

What is elevated in Type III dyslipidemia?

Increased IDL and VLDL.

Associated with elevated cholesterol, triglycerides, and palmar xanthomas.

What is elevated in Type IV dyslipidemia?

Increased VLDL and triglycerides.

Often associated with obesity and diabetes.

What is elevated in Type V dyslipidemia?

Increased chylomicrons and VLDL.

Causes very high triglycerides and increases the risk of pancreatitis.

Bicarbonate leaves the cell and what electrolyte enters the RBC in exchange?

Chloride

Too much bicarbonate causes what acid-base disturbance?

Metabolic ALKALOSIS

What hormones are involved in calcium regulation?

Parathyroid hormone (PTH), vitamin D (calcitriol), and calcitonin.

Remember the exogenous pathway, endogenous pathway, and reverse cholesterol transport pathway.

Exogenous: intestinal chylomicrons carry dietary triglycerides; LPL releases fatty acids; remnants go to liver.

Endogenous: liver releases VLDL, which becomes IDL and then LDL, delivering cholesterol.

Reverse transport: HDL removes peripheral cholesterol and carries it toward liver; ABCA1 assists efflux. [Ch 10, slides 26-31]

Process where dietary lipids are digested by lipase and bile acids and absorbed by the intestines?

Lipid Absorption

Potassium is regulated by aldosterone. When sodium is being reabsorbed what needs to be excreted?

Potassium

PTH (parathyroid hormone) regulates calcium by acting on?

bone , kidneys, and small intestine

to increase calcium

CO2 diffused into the blood and forms H2CO3 and that dissociates into H+ and H2CO3

CO₂ + H₂O ⇌ H₂CO₃ ⇌ H⁺ + HCO₃⁻.

What is the most common method to measure sodium, potassium, and chloride?

Ion-selective electrode (ISE) methods.

What is metabolic acidosis in terms of pH, bicarbonate, and CO2 levels?

Metabolic acidosis: ↓pH (

What hormone is secreted first when there is low blood volume and blood pressure?

Renin

The amount of oxygen being loaded to hemoglobin depends on what?

Availability/concentration of O₂, hemoglobin amount/type, competing molecules such as CO, pH, temperature, pCO₂, and 2,3-BPG.

Why does the bicarbonate-carbonic acid system have a low buffering capacity?

Because carbonic acid is a weak acid that does not dissociate completely; it remains the principal plasma buffer because lungs regulate CO₂ and kidneys regulate HCO₃⁻.

What is the membrane substance used in potassium ion selective electrodes?

Valinomycin

What enzyme is used in the method for quantifying serum triglycerides?

Lipase

What causes the serum/plasma to appear milky?

chylomicrons

Quantifying HDL level is thought to be a significant risk assessment level if low for what disease?

Coronary heart disease (CHD)/coronary artery disease risk; low HDL is a risk marker.

What is the main function of ADH?

increases renal water reabsorption, conserving water and helping regulate osmolality/blood volume.

Which electrolyte is the major component of the blood's buffering system?

Bicarbonate

What electrolyte determines plasma's osmolality?

Sodium

If sodium is low what will the osmolality (increased or decreased)?

Decreased

When the plasma osmolality is high what does the body activate?

Thirst and ADH/vasopressin release, promoting water intake and reabsorption.

What type of acid-base disturbance is where bicarbonate is low?

Metabolic acidosis.

What is the chloride shift?

Chloride/Hamburger shift: as HCO₃⁻ exits rbc into plasma, Cl⁻ enters rbcs to preserve electroneutrality. Reverse occurs in lungs

What substance is the precursor to all steroid hormones?

Cholesterol

What is the function of HDL, LDL, VLDL, and chylomicrons?

HDL: returns excess cholesterol to liver.

LDL: delivers cholesterol to peripheral cells (atherogenic when elevated).

VLDL: transports endogenous hepatic triglycerides.

Chylomicrons: carry absorbed dietary triglycerides from intestine to tissues and ultimately liver as remnants.

What is the specimen of choice for acid-base disturbances involving pulmonary dysfunction?

Arterial whole blood

What is the major intracellular cation?

Potassium

Anticoagulant of choice of blood gas analysis?

Sodium Heparin

What happens to blood's pH when lungs remove CO2 too fast?

pH increases, producing respiratory alkalosis from excess CO₂ elimination.

Acid-base disturbance when bicarbonate is not being reabsorbed by the kidneys?

Metabolic acidosis

What accumulates in the blood when lungs cannot remove CO2?

Carbon dioxide (CO₂), increasing pCO₂ and H

If a blood gas specimen is left exposed to air, which of the following changes will occur?

PO 2 and pH increase; PCO 2 decreases

What hormone acts on the distal tubules of the kidney to retain Na and H2O?

Aldosterone

Which is the most predominant buffer system in the body?

Bicarbonate-carbonic acid system

What lipoprotein infiltrates extracellular space and forms plaques?

LDL (low-density lipoprotein)

Respiratory acidosis in regard to CO2 level.

Increased pCO₂

What electrolytes will be increased if the blood is hemolyzed?

Potassium and phosphate can be falsely elevated with hemolysi

What causes metabolic alkalosis?

Loss of gastric acid from vomiting/NG suction; excess bicarbonate or alkali; prolonged diuretic use; hypokalemia and hypochloremia.

Know the process of chylomicrons.

Dietary lipids are absorbed by intestinal cells, re-esterified and packaged into chylomicrons; they circulate and deliver triglycerides via LPL (activated by Apo C-II); chylomicron remnants are taken up by liver.

What is the process in the kidney when there is respiratory alkalosis?

by excreting HCO₃⁻ and retaining H⁺ (reducing Na⁺/H⁺ exchange).

When burn patients experience water loss what happens to their electrolytes?

• Sodium: Decreases due to fluid and sodium loss (hyponatremia).

• Potassium: Initially increases because damaged cells release potassium into the blood (hyperkalemia).

What lipoprotein has the most protein?

HDL

What is high and what is low in regard to HDL and total cholesterol in people with high-risk coronary heart disease?

Higher-risk pattern:

low HDL

high total cholesterol (especially elevated LDL).

What is the sweat chloride test for?

Diagnosis of cystic fibrosis: abnormally high sweat chloride

Low Na, Cl, and K are seen in which condition?

Combined GI losses (e.g., prolonged vomiting with fluid/electrolyte depletion) are a possible clinical example ???? (maybe)

Anticoagulant of choice for testing plasma calcium?

Lithium heparin

What conditions are needed for adequate tissue oxygenation?

1.Available atmospheric oxygen

2.Adequate ventilation

3.Gas exchange between lungs and arterial blood

4.Loading of O2 onto hemoglobin

5.Adequate hemoglobin

6.Adequate transport

7.Release of O2 to tissue

Which lipoprotein if increased increases the risk for acute myocardial infarction and stroke?

Lp(a), lipoprotein(a)

Which lipoprotein is seen in patients with biliary cirrhosis or cholestasis?

Lipoprotein X

Which dyslipidemia will NOT increase the risk for CHD?

Type I hypertriglyceridemia

What methods are used (previously and currently) to quantify HDL?

Previously: two-step chemical precipitation.

Currently: direct/homogeneous automated HDL assays using selective reagents (polymers, detergents, modified enzymes).

What happens when angiotensin is released in terms of blood pressure, blood volume, aldosterone, and blood vessels?

raises blood pressure by constricting blood vessels and increasing aldosterone, which causes the kidneys to retain sodium and water.

Aldosterone effect on potassium?

increases renal potassium secretion/excretion as sodium is reabsorbed

What are the causes for anion gap elevation?

Ketoacidosis DM

lactic acidosis

Metabolic Acidosis

ACIDOSIS

uremia/renal failure

glycol poisoning

lactic acidosis

Hypernatremia

Error of instrument

Loss of HCO3

Diarrhea, tubular acidosis

What is the hamburger shift?

HCO₃⁻ exits RBCs and Cl⁻ enters to preserve electrical neutrality.

Remember the Henderson-Hasselbalch Equation and what is used to compensate metabolic or respiratory acid-base disturbances. Remember the correct significant figures for pH.

Henderson-Hasselbalch:

pH = 6.1 + log₁₀([HCO₃⁻] / (0.0307 × pCO₂)),

with HCO₃⁻ in mmol/L and pCO₂ in mmHg.

Normal ratio ≈20:1 → pH ≈7.40.

Metabolic disorders compensated by lungs (CO₂ change);

respiratory disorders compensated by kidneys (HCO₃⁻ change).

Report pH to two decimal places, e.g., 7.40