LG 6.13 - Cell Adaptations

Question 1

What is cell adaptation?

Answer 1

• Prolonged exposure of cells to adverse or exaggerated normal stimuli which evokes various changes at the level of individual cells, tissues, or whole organs.

Question 2

What is atrophy? Classify it? Examples?

Answer 2

• Atropy: decrease in size of a tissue, organ or the entire body.
• physiologic vs. pathologic atrophy
• Ex: physiologic = thymus, or womanly parts due to later life menopause.
  pathologic = ischemic organs are typically small (kidneys with arteriosclerosis), testicular atrophy, alzheimer dementia (brain shrinks).

Question 3

What is hypertrophy? Classify it? Examples?

Answer 3

• Hypertrophy: increase size in tissues or organs due to enlargement of individual cells.
• Physiologic vs. pathologic.
• Ex: physiologic = enlargement of skeletal muscles in body builders due to weights. pathologic = hypertrophy of heart (increase in work load, ^BP).

Question 4

What is hyperplasia? Examples? Can hyperplasia and hypertrophy be seen together?

Answer 4

• Hyperplasia: Adaptive increase in number of cells that can cause enlargement of tissues or organs.
• Ex: endometrial hyperplasia due to estrogens. Hyperplastic polyps of colon or stomach.
• Yes. Pregnancy, hypertrophy of uterus, with hyperplasia. BPH.

Question 5

What is metaplasia? Examples? Reversible? Can it progress to a more detrimental growth?

Answer 5

• Metaplasia: adaptive change of one cell type for another to suit the environment.
• Ex: squamous metaplasia of the bronchial epithelium due to smoking. gastric or glandular metaplasia of GE junction in Barrett Esophagus (from esophagus cells to gastric stomach cells)
• Yes.
• Yes, it can progress to dysplasia.

Question 6

What is dysplasia? Is there an association with cancer? Example?

Answer 6

• Dysplasia: disordered growth of tissues resulting from chronic irritation or infection.
• Yes, it is considered a precancerous condition.
• Ex: detection of cervical dysplasia ( cervical intraepithelial neoplasia or CIN) based on PAP smears. Stratified squamous -> non. Association with HPV.

Question 7

What is anaplasia? Other names for it? Examples?

Answer 7

• Anaplasia: undifferentiated and uncontrolled growth of cells - the hallmark of malignant transformation.
• Malignancy; carcinoma; cancer; neoplasm.
• Ex: squamous cells carcinoma of the cervix, cancer of the lung, malignant melanoma, renal cell carcinoma.

Question 8

When is cell injury seen?

Answer 8

• Seen when environmental changes exceed the capacity of cell to maintain normal homeostasis.

Question 9

What characterizes reversible cell injury? Example?

Answer 9

• Mild or short-lived. cellular swelling (hydropic degeneration), increased influx of water in cytoplasm and mito. NO NUCLEAR DAMAGE.
• Ex: hypoxia, dysfunction of ATP- NA+/K+ pump, once ATP function restored, cell pumps out water and NA+ and is good.

Question 10

What constitutes irreversible cell injury? How can these changes be diagnosed?

Answer 10

• If acute stress to which cell must react exceeds its ability to adapt, the changes result to cell death. Recognize by changes in nucleus or by rupture of cell membrane.
• Most of these can be seen by light microscopy and ultrasound.

Question 11

What are the three forms that damage to the nucleus can present?

Answer 11

• Pyknosis
• Karyorrhexis
• Karyolysis

Question 12

What is pyknosis, karyorrhexis, karyolysis?

Answer 12

• Pyknosis: condensation of the chromatin.
• Karyorrhexis: fragmentation of the nucleus into small particles (nuclear dust).
• Karyolysis: involves dissolution of nucleus and lysis of chromatin by enzymes.

Question 13

What are other irreversible cellular changes, regarding cytoplasm? Can these be diagnosed?

Answer 13

• Cytoplasm is fragmented and lost. Dead cell, clinically, releases their cellular enzymes into ECF and eventually the circulation.
• AST or LDH can be measured in the blood where they are useful signs of cell injury.

Question 14

What is anthracosis? What does it refer to? Is this normal? When does disease occur?

Answer 14

• Anthracosis: accumulation of coal particles.
• Storage of this indigestible material in the alveolar histiocytes of the lungs and regional hilar and mediastinal lymph nodes.
• Entirely normal, seen in city dwellers.
• Occurs when there is an overabundance of inhaled coal dust, causing black pulmonary lesions.

Question 15

Where is fat normally stored, in what form? Found in whom usually? Why?

Answer 15

• Normally stored in liver cells in the form of triglycerides.
• Found in chronic alcoholics commonly.
• Alcohol has high caloric content and serves as substrate for new fat formation in liver cells.
  Also inhibits several digestive enzymes and utilization of fat. inhibits both protein synthesis and export of fat from liver in form of lipoproteins.

Question 16

What is hemosiderosis? How can it damage organs? What stain is used to see?

Answer 16

• Hemosiderosis: accumulation of blood-derived brown pigment hemosiderin, iron storage protein normally found in spleen, BM and Kupffer cells in liver.
• Excess iron stored intracellularly as ferritin and hemosiderin in skin, pancreas, heart, and kidneys can cause damage if severe enough.
• Prussian-blue stain.

Question 17

Where is lipofuscin predominately found? is it normal? can it interfere with cell function?

Answer 17

• Composed of golden-brouwn granules found predominantly in neurons, myocardial cells and hepatocytes.
• Normal in many cells, increases with age.
• Does not interfere.

Question 18

How do inherited lysosomal storage diseases affect the body? Examples?

Answer 18

• Breakdown of certain complex lipids, mucopolysaccharides and glycogens are accomplished by a sequence of enzymatic steps.
• These enzymes are located in lysososomes of the cells, their absence substrate accumulates in the lysosomes causing functional derangements of cells tissues and organs.
• Ex: Tay-Sachs, Gauchers, Hurlers.

Question 19

What cells cannot undergo hyperplasia? Why?

Answer 19

• Skeletal muscle, myocytes (heart cells), nerve cells.

- These are permanent and do not have stem cells that can create new cells.