Pathophysiology and Disease Concepts Review

Comprehensive practice flashcards reviewing core topics in pathophysiology including disease processes, cellular adaptation and injury, genetic disorders, neoplasia, and fluid, electrolyte, and acid-base imbalances.

What is the difference between physiology and pathophysiology?

Physiology is the study of normal body function, whereas pathophysiology is the study of the body's functional response to dysfunction or disease.

How do reliability and validity differ in diagnostic laboratory testing?

Reliability refers to the extent to which a repeated observation yields the same result, while validity refers to the extent to which a measurement tool measures what it is intended to measure.

What is the distinction between disease incidence and prevalence?

Incidence is the number of new cases of a disease in a population within a specific time period, whereas prevalence is the total number of both new and existing cases in a specific population within a given time period.

What are the three levels of disease prevention and an example of each?

Primary prevention removes risk factors before disease occurs (e.g., immunizations); secondary prevention detects early disease when curable (e.g., Pap smears); tertiary prevention prevents further deterioration or complications (e.g., antibiotic treatment).

How do dystrophic calcification and metastatic calcification differ?

Dystrophic calcification occurs in dead or damaged tissues despite normal serum calcium levels, whereas metastatic calcification occurs in normal tissues as a result of hypercalcemia.

What is the key difference between physiologic and pathologic atrophy?

Physiologic atrophy is a normal, expected reduction in cell size due to decreased activity or aging (e.g., thymus shrinking after puberty), while pathologic atrophy results from abnormal conditions or disease (e.g., disuse muscle loss from prolonged bed rest).

What differentiates dysplasia from metaplasia?

Metaplasia is the reversible replacement of one mature cell type by another mature cell type in response to chronic irritation, whereas dysplasia involves deranged, atypical cellular growth with variations in size, shape, and organization.

What causes the paradox of tissue damage during the reperfusion phase of ischemia-reperfusion injury?

The sudden influx of oxygenated blood to previously ischemic cells causes damaged mitochondria to produce a surge of reactive oxygen species (ROS), triggering severe oxidative stress, membrane lipid peroxidation, and accelerated cell death.

What are pyknosis, karyorrhexis, and karyolysis during cell necrosis?

Pyknosis is nuclear shrinkage into a dark, dense mass; karyorrhexis is nuclear fragmentation into pieces; karyolysis is nuclear dissolution where chromatin is digested by enzymes until the nucleus disappears.

Which type of necrosis is characterized by hydrolytic enzymes converting tissue into a liquid mass, commonly seen in the brain?

Liquefactive necrosis.

What is the difference in inheritance requirements between autosomal dominant and autosomal recessive single-gene disorders?

Autosomal dominant disorders require only one copy of the mutated allele from either parent, whereas autosomal recessive disorders require two copies of the mutated allele (one inherited from each heterozygous parent).

What gene mutation causes Marfan syndrome, and what are its primary clinical features?

It is caused by a mutation in the $FBN1$ gene affecting connective tissue; symptoms include arachnodactyly, heart valve defects, dislocation of the eye lens, and long limbs.

What chromosomal abnormalities characterize Turner syndrome and Klinefelter syndrome?

Turner syndrome is sex chromosome monosomy in females ($45,X$ or missing X chromosome), whereas Klinefelter syndrome involves individuals with at least two X chromosomes and one Y chromosome ($47,XXY$).

During which timeframe of intrauterine life is an embryo most susceptible to major structural abnormalities from teratogens?

The first trimester, specifically weeks $2$ to $8$ of embryonic development.

According to Table 6-2, how do benign and malignant neoplasms differ in cell differentiation, mode of growth, and metastatic capacity?

Benign tumors consist of well-differentiated cells, grow by expansion without invading surrounding tissue (often encapsulated), and do not metastasize. Malignant tumors consist of undifferentiated (anaplastic) cells, grow by infiltrating invasion, and metastasize via blood and lymph.

How are carcinomas and sarcomas defined based on their tissue of origin?

Carcinomas are malignant tumors arising from epithelial tissues, whereas sarcomas are malignant tumors arising from connective tissues.

How do proto-oncogenes, oncogenes, and tumor-suppressor genes function in cell growth regulation?

Proto-oncogenes are normal nonmutant genes coding for normal cell growth; oncogenes are mutated proto-oncogenes that promote excessive cell growth; tumor-suppressor genes (anti-oncogenes) prevent uncontrolled cell growth and maintain genomic stability.

What specific chromosomal translocations lead to Burkitt lymphoma and Chronic Myelogenous Leukemia (CML)?

In Burkitt lymphoma, the $myc$ proto-oncogene translocates from chromosome $8$ to $14$. In CML, translocation between chromosomes $9$ and $22$ forms the hybrid $bcr\text{-}abl$ oncogenic protein (Philadelphia chromosome).

What are the three stages of carcinogenesis?

Initiation (exposure to carcinogen causes DNA alteration), Promotion (growth factors or chemicals stimulate proliferation of mutated cells), and Progression (tumor cells acquire malignant phenotypic changes and increased aggressiveness).

Which specific tumor markers are associated with liver/germ cell tumors, prostate cancer, and ovarian epithelial tumors?

Alpha-fetoprotein (AFP) for liver and germ cell tumors; Prostate-Specific Antigen (PSA) for prostate tumors; Cancer Antigen 125 (CA-125) for ovarian epithelial tumors.

What role does the Epithelial-Mesenchymal Transition (EMT) play in cancer cell metastasis?

EMT is the process where epithelial cells lose polarity and adhesion, gain mesenchymal stem cell-like features, secrete proteases to degrade extracellular matrix, and increase migratory capacity and resistance to apoptosis.

What does the TNM designation T2N1M0 signify in cancer staging?

$T2$ indicates a moderate-sized primary tumor ($2{-}5\text{ cm}$), $N1$ indicates regional lymph node involvement, and $M0$ indicates no distant metastasis.

What is carcinoma in situ (CIS) and why is it categorized as Stage 0?

Carcinoma in situ is a pre-invasive lesion where abnormal cancer cells are localized strictly within the epithelial tissue of origin without penetrating the basement membrane.

What proportion of total body fluid is contained within the Intracellular Fluid (ICF) and Extracellular Fluid (ECF) compartments?

Intracellular Fluid (ICF) makes up $\frac{2}{3}$ of total body fluid, while Extracellular Fluid (ECF) makes up $\frac{1}{3}$ (composed of $80\%$ interstitial fluid and $20\%$ blood plasma).

How do Diabetes Insipidus and Syndrome of Inappropriate Antidiuretic Hormone (SIADH) differ regarding ADH activity and urine output?

Diabetes Insipidus involves a deficiency or insensitivity to ADH resulting in excretion of large volumes of dilute urine, whereas SIADH involves excess uninhibited ADH release resulting in fluid retention and concentrated, low-volume urine.

What are the four main physiological mechanisms that cause edema?

$1.$ Increased capillary hydrostatic pressure, $2.$ Decreased plasma osmotic pressure (loss of albumin), $3.$ Obstruction of lymphatic circulation, and $4.$ Increased capillary permeability (from inflammation or toxins).

What plasma sodium concentration levels define hyponatremia and hypernatremia?

Hyponatremia is defined as a plasma sodium level below $135\text{ mEq/L}$, while hypernatremia is defined as a level above $145\text{ mEq/L}$.

What characteristic electrocardiogram (EKG) changes are seen in severe hyperkalemia?

EKG changes include a prolonged PR interval, wide QRS complex, ST-segment depression, and tall, narrow/pointed T waves.

What are the three distinct forms of calcium present in the extracellular fluid (ECF)?

Protein-bound ($40\%$ bound to albumin), Complexed ($10\%$ chelated with citrate, phosphate, or sulfate), and Ionized/Free ($50\%$ active ionized form).

What is the normal physiological range of arterial blood pH, and what defines acidosis and alkalosis?

Normal arterial blood pH is $7.35{-}7.45$. Acidosis occurs when blood pH drops below $7.35$, and alkalosis occurs when blood pH rises above $7.45$.

In what sequential order does the body respond to compensate for acid-base imbalances?

$1.$ Chemical blood buffers (sodium bicarbonate-carbonic acid system), $2.$ Respiratory system changes in $CO_2$ retention/elimination, and $3.$ Renal modifications of $H^+$ excretion and $HCO_3^-$ reabsorption.

How do the primary chemical changes in respiratory acidosis compare to metabolic acidosis?

Respiratory acidosis is caused by hypercapnia (retention of $CO_2$ forming excess $H_2CO_3$), while metabolic acidosis is caused by an accumulation of metabolic acids ($H^+$) or a loss of bicarbonate ($HCO_3^-$).

What are the key clinical manifestations and compensatory mechanisms of metabolic acidosis?

Manifestations include headache, decreased BP, hyperkalemia, muscle twitching, warm flushed skin, nausea/vomiting, and Kussmaul respirations (compensatory hyperventilation to eliminate $CO_2$).

What are the common causes and clinical manifestations of metabolic alkalosis?

Causes include severe vomiting, GI suctioning, diuretics, and excessive antacids ($NaHCO_3$). Manifestations include restlessness, lethargy, dysrhythmias, hypokalemia, tremors, muscle cramps, tingling, and compensatory hypoventilation.