Organ Function Tests

150 fill-in-the-blank practice flashcards covering liver, kidney, thyroid, and adrenal function tests based on lecture materials describing physiology and clinical markers.

Analysis of __________ parameters can aid in the diagnosis of diseases by identifying alterations in cellular homeostasis.

chemical

The term "__________" refers to a battery of investigations employed to identify abnormal functioning of a specific organ.

Organ Function Tests

Abnormal test results in organ function tests almost always result from a deranged __________ .

physiology

Injury to cells leads to the release of their contents into the __________ milieu, which then enters the plasma.

extracellular

Elevation of cardiac __________ ($cTnt$ and $cTnI$) and CK-MB are diagnostic markers for myocardial infarction.

troponins

The enzyme __________ ($LDH$) is elevated in serum during hemolysis due to its release from RBCs.

lactate dehydrogenase

Plasma enzymes with specific biological functions in the blood are classified as __________ plasma enzymes.

functional

Enzymes like lipoproteins lipase and complement system proteins are examples of __________ plasma enzymes.

functional

The absence of functional plasma enzymes like lipoprotein lipase can result in diseases such as __________ .

familial chylomicronemia

__________ plasma enzymes do not serve a physiological function in the plasma and enter only due to tissue turnover or disease.

Nonfunctional

Examples of nonfunctional plasma enzymes used diagnostically include amylase, lipase, $LDH$, and __________ .

CK-MB

Damage to either the __________ glands or the pancreas can lead to elevated plasma levels of amylase.

salivary

The liver acts as the __________ of metabolism in the human body.

hub

Many drugs and toxins entering via the oral route are metabolized in the liver in a process called __________ metabolism.

first-pass

The liver can regenerate to its original size even after the removal of __________ of its original tissue mass.

two-thirds

The parenchymal cells of the liver, known as __________ , account for nearly $60\%$ of total liver cells.

Hepatocytes

In carbohydrate metabolism, the liver performs glycogenesis, glycogenolysis, and __________ .

gluconeogenesis

Bile salts, important for the absorption of dietary lipids, are formed from the conversion of __________ into bile acids.

cholesterol

The liver is the primary site for the synthesis of purines and the formation of __________ .

uric acid

All major serum proteins except __________ are synthesized in the liver.

immunoglobulins

The serum protein __________ is vital for maintaining plasma volume and transporting molecules.

albumin

Hepatocytes synthesize all clotting factors except calcium, factor $VIII$, and __________ .

von Willebrand factor

Factor $VIII$ and von Willebrand factor are produced by hepatic __________ endothelial cells.

sinusoidal

Vitamin K cycle in the liver is involved in the $\\gamma$-carboxylation of __________ residues of factors $II$, $VII$, $IX$, and $X$.

glutamic acid

Vitamin A is stored in the liver as retinyl palmitate in specialized cells called __________ or Ito cells.

hepatic stellate cells

The liver is the only site for storage of the water-soluble vitamin __________ .

vitamin B12

Phase 1 reactions of xenobiotic metabolism typically involve inactivation by the microsomal __________ monooxygenase system.

cytochrome P450

Phase 2 reactions involve __________ (e.g., with glucuronic acid) to render compounds hydrophilic for excretion.

conjugation

The liver detoxifies ammonia into urea via the __________ cycle.

urea

__________ are tissue macrophages in the liver involved in phagocytosis and removal of senescent RBCs.

Kupfer cells

During intrauterine life, the liver acts as a site of __________ (production of blood cells).

hematopoiesis

The liver synthesizes __________ , which is a component of the renin-angiotensin-aldosterone system.

angiotensinogen

The majority of liver-related deaths worldwide occur as a complication of __________ .

cirrhosis

Hepatocellular damage is classically defined by elevated plasma levels of __________ ($ALT$) and aspartate aminotransferase ($AST$).

alanine aminotransferase

Both $ALT$ and $AST$ require __________ ($PLP$), the active form of vitamin $B_6$, as a coenzyme.

pyridoxal phosphate

The enzyme __________ is considered more "liver-specific" because substantial amounts of $AST$ are also found in the myocardium and skeletal muscle.

ALT

The ratio of $AST/ALT$ is known as the __________ ratio.

De Ritis

A De Ritis ratio ($AST/ALT$) of $>1$ is commonly seen in alcoholic hepatitis, cirrhosis, and __________ .

ischemic liver injury

Ischemic liver injury and paracetamol overdose cause __________ elevation of transaminases ($>15$ times URL).

severe

Alcoholic hepatitis usually causes only moderate transaminase elevation due to low levels of __________ in alcohol use disorder.

vitamin B6

A sudden massive drop in transaminase levels in a diseased liver may suggest __________ .

impending liver failure

Persistent low levels of transaminases can be seen in __________ deficiency.

vitamin B6

The mitochondrial enzyme __________ ($GDH$) is found in higher concentrations in the centrilobular areas of the liver.

glutamate dehydrogenase

Levels of $GDH$ in plasma are specifically elevated in __________ liver injury.

ischemic

__________ ($GSTs$) are uniformly distributed throughout the hepatic lobules and are involved in xenobiotic detoxification.

Glutathione S-transferases

__________ occurs when there is an obstruction to bile outflow, either intrahepatic or extrahepatic.

Cholestasis

Post-hepatic jaundice, also known as __________ jaundice, results from obstruction of larger bile ducts outside the liver.

obstructive

The biochemical markers of cholestasis include serum bilirubin, $ALP$, $GGT$, and __________ .

5'-nucleotidase

In intrahepatic cholestasis, both __________ and indirect bilirubin are typically elevated in the serum.

direct

Extrahepatic cholestasis is characterized by a predominant elevation of __________ bilirubin.

direct

Alkaline phosphatase ($ALP$) is an "__________" because it is anchored on the outer leaflet of the plasma membrane.

ectoenzyme

In cholestasis, __________ salts induce the production of $ALP$ and release it from the canalicular membrane.

bile

The reference interval for $ALP$ in adults is __________ $U/l$.

33-96

Levels of $ALP$ greater than $4$ times the URL are seen in extrahepatic obstruction and __________ .

primary biliary cholangitis

$\\gamma$-glutamyl transpeptidase ($GGT$) is involved in the synthesis of __________ and absorption of amino acids via Meister's cycle.

glutathione

Induction of microsomal __________ by alcohol makes it a useful marker for alcohol abuse and alcoholic liver disease.

GGT

Unlike $ALP$, the enzyme __________ ($5'-NT$) is relatively more specific to biliary obstruction as it is not increased in bone diseases.

5'-nucleotidase

The synthetic function of the liver is routinely assessed by measuring serum __________ and prothrombin time.

albumin

Albumin has a half-life of approximately __________ days.

14

Because of its long half-life, albumin levels are primarily used to assess __________ liver diseases.

chronic

The assessment of blood clotting factors $I$, $II$, $V$, $VII$, and $X$ is performed using the __________ ($PT$) test.

prothrombin time

Prothrombin time ($PT$) evaluates the __________ and common pathways of coagulation.

extrinsic

The reference interval for $PT$ is __________ seconds.

11-13

The __________ ($INR$) was introduced to standardize the estimation of $PT$ across different laboratories.

international normalized ratio

The calculation for $INR$ is $PT\,of\,Test / PT\,of\,Control$ raised to the power of __________ .

ISI

Prothrombin has a half-life of __________ hours, making $PT$ useful in both acute and chronic liver disease.

60

Diagnostic tests for hepatitis $A$ ($HAV$) primarily involve the detection of __________ via ELISA.

anti-HAV IgM

The presence of __________ in the blood is a marker of an acute viral infection.

IgM

The presence of __________ in the blood suggests chronic infection or recovery from a viral illness.

IgG

Hepatitis B infection is confirmed by ELISA for HBV surface antigen ($HBsAg$) and __________ .

anti-HBc IgM

Hepatitis $C$ ($HCV$) and Hepatitis $D$ ($HDV$) detection often utilizes __________ to identify viral RNA.

PCR

Hepatitis $D$ infection can only occur in a setting of __________ infection.

HBV

In liver failure, the blood level of __________ increases while the level of urea decreases.

ammonia

The normal reference interval for the albumin:globulin ($A:G$) ratio is __________ .

1.5-2.5:1

Reversal of the $A:G$ ratio is often seen in chronic __________ hepatitis.

viral

Wilson's disease is confirmed by an increase in __________ content in the liver and urinary excretion.

copper

Genetic testing for Wilson's disease focuses on detecting mutations in the __________ gene.

ATP7B

The functional unit of the kidney is the __________ .

nephron

The molecular weight cutoff for glomerular filtration is approximately __________ $kDa$.

70

Albumin, with a molecular weight of $66.5\,kDa$, is not filtered partly due to the __________ charge of the filtration barrier.

negative

The filtration barrier contains __________ proteoglycans that repel negatively charged molecules.

heparan sulfate

The kidneys maintain blood __________ by controlling bicarbonate reabsorption and hydrogen ion excretion.

pH

Apart from the liver, the __________ is the other major site for gluconeogenesis.

renal medulla

The Macula densa acts as a sensor for __________ levels in the tubular fluid to regulate renin production.

sodium

__________ is a hormone produced by the kidneys in response to hypoxia to stimulate RBC production.

Erythropoietin

Inactive vitamin D is converted to its active form, __________ , by the renal enzyme $1\text{-}\\alpha\text{-hydroxylase}$.

calcitriol

The enzyme $1\text{-}\\alpha\text{-hydroxylase}$ is induced by high levels of __________ .

parathyroid hormone

Temporary excess protein excretion in urine due to fever or exercise is called __________ proteinuria.

functional

The volume of fluid filtered by all glomeruli per unit time is the __________ ($GFR$).

glomerular filtration rate

The average $GFR$ in healthy males is approximately __________ $ml/min$.

130

Chronic kidney disease is defined as a renal abnormality that persists for more than __________ months.

3

The ideal exogenous substance for measuring $GFR$ is __________ .

inulin

Creatinine is a product of the dehydration and cyclization of __________ in the muscles.

creatine

The reference interval for serum creatinine in males is __________ $mg/dl$.

0.6-1.2

Creatinine clearance tends to __________ calculations of $GFR$ because some creatinine is secreted by the tubules.

overestimate

__________ is a low molecular weight protein synthesized by all nucleated cells that serves as a marker for $GFR$.

Cystatin C

Unlike creatinine, levels of Cystatin C are independent of __________ and diet.

muscle mass

The MDRD formula is used to calculate __________ based on serum creatinine, age, sex, and race.

eGFR

Urea clearance __________ the $GFR$ due to passive diffusion (reabsorption) into the renal interstitium.

underestimates

Passive transport of urea back into the interstitium is mediated by transporters activated by __________ .

ADH