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30 Cards in this Set
- Front
- Back
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Why can an organ be smaller than normal? |
1. Hypoplasia: never reached full size 2. Aplasia: never developed at all
*If it formed normally, reached full size and then shrunk = atrophy |
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Why could an organ be enlarged? |
Increased fluid or gas content -Edema -Vascular congestion -Blockage (bladder, intestine) -Accumulation (exudate, cellular accumulation) -Physiologic vascular engorgement (erectile) -Production/Storage of normal product (milk) Cellular Changes |
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Define Hypertrophy |
Increase in cell size such that an organ increases in size and weight. Cells are bigger because they synthesize more organelles |
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Define Hyperplasia |
Increase in cell number such that an organ increases in size and weight. Cells divide and become more numerous |
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Define Atrophy |
Decrease in cell size or number such that an organ decreases in size and weight. A regressive change, usually caused by gradual and continuous injury |
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Define Metaplasia |
One adult, fully-differentiated cell type is replaced by another adult cell type |
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Define Dysplasia |
Cells have a disorderly arrangement *most common in epithelial tissue |
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Which types of changes are sometimes preneoplastic changes (may progress to cancer)? |
Metaplasia and dysplasia |
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Causes of atrophy |
Decreased nutrition Decreased blood supply Disuse Denervation Pressure Loss of endocrine stimulation (Senility) |
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Atrophy is not a normal process, but ____________ is... Define this term |
Involution Organs who have previously attained full size, and shrinkage is a normal physiologic process |
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Examples of involution |
Uterus shrinking after pregnancy Mammary gland after lactation Thymus after maturity |
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Example of Hepatomegdaly (NOT hyperplasia/hypertrophy) |
Boar with brucellosis has a very enlarged liver due to inflammation (filled with neutrophils and lymphocytes) |
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3 Cell types that help determine if an organ is undergoing hypertrophy or hyperplasia |
Permanent: No longer divide and so can't undergo hyperplasia (ex. Striated skeletal/cardiac muscle, Neurons)
Labile: Readily divide to replace cells that are lost (ex. Epithelial cells of skin and intestine, Bone marrow cells)
Stable: Intermediate cells (ex. Hepatocytes, Bone cells, Smooth muscle cells) |
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Hyperplastic, hypertrophic and metaplastic changes can occur due to or in response to: (give examples) |
Increased workload or demand (body building) Compensate for loss of all or part of an organ (liver serosis) Hormonal stimulation (mammary gland growth) Chronic Irritation (Tracheal squamous metaplasia) |
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Hyperplastic, hypertrophic and metaplastic changes are generally |
Controlled and Reversible Protective Helpful |
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If you can't find a cause for the change, change seems excessive, or you withdraw the stimulus and the organ doesn't return to normal... then you might be dealing with __________ |
NEOPLASIA |
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Body Builder example: Skeletal muscle cells are ____________, which means that they undergo ____________, rather than ___________. |
Permanent Hypertrophy Hyperplasia |
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Obesity is considered an example of... |
Hypertrophy AND hyperplasia |
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Most common cardiac disease of cats; an example of hypertrophy |
Hypertrophic Cardiomyopathy (HCM) Found in 1-3yr old male cats, esp Maine Coons Inherited, genetic mutation Causes congestive heart failure Sudden death possible |
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Example of Atrophy |
Serous Atrophy of Fat A necropsy finding that indicates starvation Clear/Yellow-ish gelatinous material left Most evident in epicardial and perirenal fat but also in bone marrow |
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Example of Metaplasia |
Osseous Metaplasia (Dogs Dura Mater) Dural ossification that is bc of metaplastic aging Dura mater has plaques of well-differentiated bone that can form bone marrow Thoracolumbar pain may occur bc of compression of spinal roots |
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Examples of Hyperplasia |
Benign Prostatic Hyperplasia Parathyroid Gland Hyperplasia Viral Papillomas Nodular Hyperplasia in Liver or Spleen Gingival Hyperplasia |
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Benign Prostatic Hyperplasia |
Develops spontaneously with age in uncastrated dogs (castration can cause prostate to atrophy) Causes constipation, rarely urethral obstruction Enlargement is uniform and symmetrical |
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Parathyroid Gland Hyperplasia |
Commonly secondary to Renal Failure Renal failure leads to reduced urinary P --> Increased blood P --> Reduced blood Ca --> Stimulates parathyroid gland to produce PTH --> gland enlarges to meet demand --> Ca resorption from bone --> Renal osteodystrophy |
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Viral Papillomas |
Hyperplastic epithelium *can progress to neoplasia |
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Nodular hyperplasia in Liver |
Clinically insignificant Just important to distinguish them from something nasty |
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Nodular hyperplasia in Spleen |
Often an incidental finding No deleterious effect unless they rupture |
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Gingival hyperplasia |
Overgrowth of gum tissue (esp fibrous submucosa) |
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3 Main Causes of Adrenocortical Atrophy |
Iatrogenic - long term administration of corticosteroids Destructive pituitary gland lesion - decreased ACTH secretion Idiopathic - immune-mediated destruction of adrenal cortex |
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Squamous Metaplasia can be due to |
Smoking Vitamin A deficiency |
