Cellular and tissue responses and adaptations Flashcards
What are the different types of adaptations?
- Hypertrophy: swelling (cell size increases)
- Hyperplasia: need cells to divide, get some swelling (cell number increases)
- Atrophy: cells switch off/ undergo apoptosis (number of cells reduce)
- -Metaplasia: change- from simple columnar to squamous
What is the basic cause of hypertrophy/ hyperplasia/ atrophy/ metaplasia?
Hypertrophy: increase demand/ stimulation
Hyperplasia: increase demand/ stimulation
Atrophy: decrease nutrients/ stimulation
Metaplasia: chronic irritation
What are the 2 types of physiological hyperplasia?
- Hormonal
- Compensatory
What is the usual cause of pathologic hyperplasia?
Excesses of hormones or growth factors in certain viral infections (e.g. poxviruses and papillomaviruses
Give examples of physiologic and pathologic hyperplasia
Physiologic= dairy cow with enlarged mammary gland Pathologic= benign enlarged prostate/ congenital goitre/ Orf
Give some examples of pathologic atrophy?
- atrophy of disuse
- denervation atrophy (spinal muscular atrophy)
- inadequate nutrition
- diminished blood supply
What are the causes of metaplasia?
- Chronic irritation
- Deficiencies (e.g. vit A)
- Result of cell/ tissue injury
- oestrogen toxicity
In what cell type does hypertrophy normally occur?
-Stable or permanent
In what cell type does hyperplasia normally occur?
In labile cells
often only in epithelial
What are the definitions for labile/ stable/ permanent cells?
Labile: routinely proliferate (epidermis, intestinal epithelium/ bone marrow cells)
Stable cells: intermediate in ability to regenerate/ divide (bone/ cartilage/ smooth muscle)
Permanent: Very little capacity to regenerate (neurons/ cardiac/ skeletal muscle cells)
What is the name for a disorderly arrangement of cells?
Dysplasia (e.g. cancer cells)
What are the different types of disorders of growth?
- Agenesis
- Aplasia
- Atresia
- Hypoplasia
- Dysplasia
- Neoplasia
What is the definition of agenesis?
-complete failure of an organ to develop during embryonic stage due to absence of primordial tissue
What is the definition of aplasia?
lack of development of an organ (different is that in this case the precursor did exist at some point)… i.e. it started to develop but never fully formed
What is the definition of atresia?
absence or closure of a normal body orifice or tubular passage such as anus/ intestine.
What is the definition of hypoplasia in terms of growth?
Incomplete development of an organ
What is the definition of dysplasia in terms of growth?
Disordered growth
What is the definition of neoplasia in terms of growth?
Abnormal growth of cells- new formation (lump/ swelling)
What are the different types of intracellular accumulations?
Accumulations of normal cellular constituents
- Abnormal substance
- Pigment
typically lipids/ glycogen/ proteins
What is lipidosis?
Accumulation of triglycerides within parenchymal cells. Most commonly occurs in the liver.
Which animals are prone to glycogen intracellular accumulation?
- Animals with abnormal glucose levels or glycogen metabolism
- Diabetes mellitus, glycogen storage diseases, corticosteroid therapy
What are the causes of protein accumulation in cells?
- Proteinuria
- Excessive production of normal protein (Mott cells)
- Defects in protein folding (TSEs/ prion diseases)
What are the types of extracellular accumulations?
- Amyloid (generic term for a load of proteinaceous substances with a hyaline appearance)
- Gout (deposition of sodium urate crystals or urates in tissue-common in dehydrated birds/ reptiles)
- Cholesterol (by products of haemorrhage and necrosis)
What are the types of calcification?
- Dystrophic calcification (locally in necrotic tissue)
- Metastatic calcification ( normal tissue secondary to hypercalcaemia
What are the causes of metastatic calcification?
- Renal failure
- Vitamin D toxicosis
- PTH and PTH related protein (relleassed by types of neoplasia)
- Destruction of bone from primary/ metastatic neoplasms
Give an example of dystrophic pathologic calcification
-Myodegeneration (Vitamin E/ selecium deficiency)
What is an example of metastatic pathologic calcification?
- Pleural calfication secondary to renal failure
What are the different types of pigmentation?
- Exogenous (carbon/ carotenoid/ tetracyline)
- Endogenous (melanin/ lipofuscin-ceroid)
- Haematogenous (haemoglobin/ hemosiderin/ bilirubin)
