1 - Adaptive Changes Flashcards
Which of the following is/are most likely to undergo hypertrophy as an adaptive response?
(a) Bone marrow
(b) Cardiac muscle
(c) Gingival epithelium
(d) Intestinal epithelium
(e) Skeletal muscle
(b) and (e); Cardiac and skeletal muscle
Define the term hypertrophy and give one example of a veterinary condition in which hypertrophy is a prominent feature.
Hypertrophy is a cellular change in which an organ enlarges due to the size of its constituent cells increasing (typically due increased to synthesis of cytoplasmic organelles).
Hypertrophy is prominent in:
- Hypertrophic cardiomyopathy
- Increased skeletal muscle mass due to exercise
Give three reasons why a tissue or organ might undergo atrophy.
Atrophy of an organ can be due to (accept any three):
- Decreased nutrition or blood supply
- Disuse
- Loss of innervation
- Pressure / compression
- Loss of endocrine stimulation
FILL IN THE BLANKS. You examine a dog with heart disease. Its pulmonic valve is stenotic, meaning the heart has to work harder to eject blood from the (a) [heart chamber] into the (b) [blood vessel]. The myocardial cells will most likely undergo (c) [adaptive process] to cope with the extra workload.
(a) Right ventricle; (b) Pulmonary trunk; (c) Hypertrophy
Define the term metaplasia and give one example of a veterinary condition in which metaplasia is a prominent feature.
Metaplasia is a cellular change in which one fully differentiated adult cell type converts to a different adult cell type. It is often, but not always, a protective response to continued injury. Examples include:
- Squamous metaplasia in vitamin A deficiency
- Osseous metaplasia in the lungs of old dogs
- Osseous metaplasia in the dura mater of old dogs.
Name the process whereby a uterus returns to its normal size after parturition.
Involution
Give an example of organ or tissue involution in domestic animals.
Any of the following:
- Uterus returns to its normal size after parturition
- Mammary gland returns to its normal size after weaning
- Thymus withers at maturity
Choose any that apply. Lack of hormonal stimulation of an organ tends to cause …
(a) atrophy
(b) dysplasia
(c) hyperplasia
(d) hypertrophy
(e) metaplasia
(a) atrophy
Clearly explain the key difference(s) between hyperplasia and neoplasia.
Hyperplasia is generally protective, helpful, controlled and reversible. It has a clear stimulus, and will stop once this stimulus is removed. Neoplasia, on the other hand, is harmful and uncontrolled cell division. There is no clear stimulus that can be withdrawn to stop it; it progresses autonomously.
Define the term hyperplasia and give one example of a veterinary condition in which hyperplasia is a prominent feature.
Hyperplasia is a cellular change in which an organ enlarges due to an increase in the number of its constituent cells. Hyperplasia is prominent in:
- Benign prostatic hyperplasia in uncastrated dogs
- Renal secondary hyperparathyroidism
- Nodular hyperplasia of the spleen
- Nodular hyperplasia of the liver
- Gingival hyperplasia in brachycephalic dogs
- Mammary fibroadenomatous hyperplasia in young, unspayed cats
- Pretty much any healing response (including the bone marrow hyperplasia seen when there is increased demand for red or white blood cells)
Fibrous tissue in chronic, non-healing wounds can sometimes turn to cartilage. This is an example of chondroid …
(a) atrophy
(b) dysplasia
(c) hyperplasia
(d) involution
(e) metaplasia
(e) metaplasia
Hypoplasia and atrophy both result in structures that are smaller than normal. Explain the difference between the two.
Hypoplasia means that an organ or structure never reached full size during development. Atrophy, on the other hand, means that an organ or structure reached full size but then shrunk under the influence of some pathologic process.
Atrophy and agenesis both result in structures that are smaller than normal. Explain the difference between the two.
Agenesis means that an organ or structure never formed during development. Atrophy, on the other hand, means that an organ or structure reached full size but then shrunk under the influence of some pathologic process.
Define the term atrophy.
Atrophy is a decrease in the size or amount of a cell, tissue, or organ after normal size has been reached. It is caused by a decreased number and/or size of cells. The general cause is inadequate cellular nutrition for any reason, where synthesis of proteins is exceeded by degradation or loss. Cells regress to a smaller cell size and survive, but with decreased function.
What is the term for a decrease in the size or amount of a cell, tissue, or organ after normal size has been reached?
Atrophy
