PATHO - Chapter 2 & 3

What is Atrophy?

Cellular adaptation where cells decrease/shrink in size. If enough cells shrink, the entire organ shrinks.

What is Hypertrophy?

Cellular adaptation where cells increase in size, increasing the overall size of the affected organ without making new cells.

What is Hyperplasia?

Cellular adaptation where there is an increase in the number of cells due to an increased rate of cellular division.

What is Metaplasia?

Cellular adaptation where one mature, differentiated cell type is replaced by another mature, differentiated cell type.

What is Dysplasia?

Abnormal changes in the size, shape, and organization of mature cells; often called atypical hyperplasia and is a precursor to cancer.

What is the difference between physiologic and pathologic atrophy?

Physiologic occurs with normal natural development (thymus shrinking). Pathologic occurs due to decreases in workload, pressure, blood supply, nutrition, or stimulation.

What is disuse atrophy and what is a classic example?

A type of pathologic atrophy that happens when skeletal muscles are not used for a prolonged period. Example: A patient's leg immobilized in a cast.

What is the most common cause of brain atrophy and how does blood flow play a role as we age?

Ischemia (reduced blood supply). As we age, progressive narrowing of blood vessels decreases blood flow and oxygen delivery to the brain, causing a gradual loss of neurons and brain shrinkage.

In what organs do we commonly see hypertrophy versus hyperplasia?

Hypertrophy (size) is common in cardiac and skeletal muscle. Hyperplasia (number) is common in the liver (compensatory regeneration) and the uterus/breasts (hormonal changes).

Is metaplasia reversible? What kind of cell types are seen, and are they differentiated?

Yes, it is fully reversible if the irritating stimulus is removed. It involves mature, fully differentiated cells replacing other mature cells to better survive an environmental stress.

What is the single most common cause of cellular injury?

Hypoxia (a lack of sufficient oxygen).

What kind of patterning affects a person's genetic predisposition to cancer, and what causes "silencing of genes" in cancer?

Epigenetic patterning. Gene silencing is caused by DNA hypermethylation and histone modification, which switch off tumor-suppressor genes.

What kind of injury occurs after ischemia when oxygen is re-established, and why?

Ischemia-Reperfusion Injury. When oxygen rushes back into previously ischemic tissues (like heart muscle during a heart attack), it reacts with damaged components to form massive amounts of destructive free radicals.

What are the definitions of the four types of asphyxial injuries?

1. Suffocation: Oxygen fails to reach blood. 2. Strangulation: Compression of neck blood vessels and airways. 3. Chemical Asphyxiants: Chemicals blocking oxygen delivery/utilization (CO, Cyanide). 4. Drowning: Liquid medium subverting breathing.

How do temperature extremes relate to climate change in cellular injury?

Climate change increases extreme weather events (heatwaves/freezes), causing spikes in hyperthermia (heat stroke, cramps) and hypothermia (vasoconstriction, cellular freezing/necrosis) in vulnerable populations.

What is the most common cause of asphyxial injuries and death in the pediatric population?

Foreign body aspiration (choking on small objects/food) and accidental suffocation in unsafe sleep environments.

Who are the common populations exposed to ionizing radiation?

Healthcare workers (X-ray techs, radiologists, orthopedic surgeons) and patient populations (those undergoing cancer radiation therapy or frequent diagnostic CT/X-ray imaging).

What is an illumination injury, its primary source, and its common symptoms?

Injury associated with fluorescent lamps or poor lighting, characteristically causing headaches and eyestrain.

What is the #1 systemic manifestation of cellular injury?

Fatigue and Malaise.

How does necrosis cause cell death, and what is its effect on surrounding tissue?

It is passive, accidental cell death where membranes rupture and leak intracellular contents. This leakage triggers a massive inflammatory response that damages surrounding healthy tissues.

What are the key features and locations of the four types of necrosis?

1. Coagulative (denatured proteins; Heart). 2. Liquefactive (hydrolases liquefy cells; Brain). 3. Caseous (clumpy, cheese-like; Lungs/TB). 4. Fat (lipases create chalky soap; Pancreas/Breast).

What is apoptosis and does it cause inflammation?

It is programmed cell death; an active, organized process of cellular self-destruction. It is NOT inflammatory because cell contents do not leak out.

What is sarcopenia and what is the primary clinical goal for geriatric patients experiencing it?

Sarcopenia is the age-related loss of skeletal muscle mass and strength. Because it impairs balance, the primary clinical goal is to PREVENT FALLS.

What is somatic death, and what are its four stages in chronological order?

The death of the entire person. The order is: 1. Algor mortis (cooling). 2. Livor mortis (purple pooling; takes several hours). 3. Rigor mortis (stiffening). 4. Postmortem autolysis (self-digestion).

What fraction of total body water is Intracellular Fluid (ICF) versus Extracellular Fluid (ECF)?

ICF makes up 2/3 of body water. ECF makes up 1/3 of body water.

Where specifically is Extracellular Fluid (ECF) found in the body?

Interstitial fluid, intravascularly (blood vessels), cerebrospinal fluid (CSF), lymphatic system, sweat, and urine.

What percentage of body weight is water in children?

60% to 65% of body weight.

What fluid loss occurs the most often and in the highest amounts?

Urine.

What are the key clinical signs/symptoms of dehydration in infants and children?

Sunken fontanel, dry mouth, dry cheeks, and dry gums.

Why can dehydration from diarrhea develop so rapidly and dangerously in infants?

Diarrheal fluid loss represents a massive proportion of an infant's total body weight, and their immature renal mechanisms cannot conserve fluid and electrolytes quickly enough to counter the losses.

Which electrolytes act as the primary osmotic forces for the ECF and ICF spaces?

Sodium (Na+) is the primary osmotic force for the ECF. Potassium (K+) is the primary osmotic force for the ICF.

Where do water, electrolytes, and small molecules exchange freely between the vascular and interstitial space?

At the site of capillaries and small venules.

What is the weight equivalent of 1 Liter of water?

1 Liter of water = 2.2 lbs = 1 kg.

What electrolyte makes up 90% of ECF cations and regulates its osmotic forces?

Sodium (Na+).

What are the five main causes of edema (SATA focus)?

1. Increased capillary hydrostatic pressure. 2. Decreased plasma oncotic pressure. 3. Increased capillary permeability. 4. Lymphatic obstruction. 5. Salt and water retention.

What are the steps of the Renin-Angiotensin-Aldosterone System (RAAS) pathway?

Low BP triggers Kidneys to release Renin -> Renin converts Angiotensinogen to Angiotensin I -> ACE converts Angiotensin I to Angiotensin II -> Angiotensin II causes vasoconstriction and triggers Aldosterone -> Aldosterone causes Sodium/Water retention to raise BP.

What happens to a cell's water movement and shape in an Isotonic solution?

There is no net movement of water; the cell retains its normal, healthy shape.

What happens to a cell's water movement and shape in a Hyponic solution?

Water rushes into the cell, causing it to swell and potentially burst (lyse).

What happens to a cell's water movement and shape in a Hypertonic solution?

Water is pulled out of the cell, causing the cell to shrink and shrivel (crenate).

What is the normal range for Potassium (K+), and how do you define hypo- and hyperkalemia?

Normal: 3.5 - 5.0 mEq/L. Hypokalemia is

What are the manifestations of hypokalemia, and what does its rhythm strip look like?

Weakness, muscle cramps, lethargy, decreased reflexes, and constipation. Rhythm strip shows flattened T waves, ST depression, and prominent U waves.

What does a hyperkalemic cardiac rhythm strip look like?

Tall, peaked T waves, prolonged PR interval, and a widened QRS complex.

What is the specific EXAM normal range for Calcium (Ca2+), and how do you define hypo- and hypercalcemia?

Normal: 9.0 - 10.5 mg/dL. Hypocalcemia is

What is the normal range for Magnesium (Mg2+), and how do you define hypo- and hypermagnesemia?

Normal: 1.5 - 3.0 mg/dL. Hypomagnesemia is

What three classic conditions cause hypomagnesemia (SATA focus)?

Malnutrition, chronic alcoholism (ETOH), and malabsorption syndromes.

What are the manifestations of hypermagnesemia?

Hypoactive reflexes, muscle weakness, respiratory depression, and hypotension.

What is normal human body pH and normal GI contents pH?

Normal body pH is 7.35 - 7.45. Normal GI contents pH is 1.0 - 3.0 (highly acidic).

What are the normal ABG reference values for pH, paCO2, and HCO3?

pH: 7.35 - 7.45 | paCO2: 35 - 45 mmHg | HCO3: 22 - 26 mEq/L.

What do pH values above 7.45 and below 7.35 indicate?

pH >7.45 indicates Alkalosis. pH

What does the ROME acronym stand for in ABG interpretation?

Respiratory Opposite (pH and paCO2 move in opposite directions) | Metabolic Equal (pH and HCO3 move in the same direction).