Cell Degranulation Flashcards
Which two types of cell form tissues?
Epithelial
Mesenchymal
What is atrophy?
Decrease in the size and number of cells, or a decrease in the size of an organ
Give the 4 types of cellular adaptation
Hypertrophy
Hyperplasia
Atrophy
Metaplasia
Define what is meant by a cellular adaptation
Achieving a new, altered state due to excessive physiological stresses or pathological stimuli
Define the following:
- Hypoplasia
2. Aplasia
- Reduced organ volume because of incomplete cell proliferation
- Organ absence because of defective cell proliferation
When does physiological atrophy occur?
- During early foetal development
- Uterus after parturition
- Thymus after puberty
- Age deterioration
Give some examples of pathological atrophy
- Disuse of skeletal muscle
- Reduced oxygen blood perfusion
- Inadequate nutrition on skeletal muscle
- Loss of endocrine stimulation in neutered animals
- Loss of innervation
- Ageing
What happens to the cells when they are atrophied?
- They are not dead
- There is a reduction of the cellular metabolism
- Reduction of cellular volume
What is hypertrophy?
Increase in the size of cells or the size of an organ
- no new cells just larger cells
- no cell division involved
When does hypertrophy occur?
When there is an increased functional demand
Response to an increase in nourishment
Give 2 examples of physiological hypertrophy
- Smooth muscle cells in a pregnant uterus
- Skeletal muscle cells with training
Give an example of pathological hypertrophy
Heart wall muscle thickens due to cardiac myocyte overload
Define hyperplasia
Increase in organ volume due to an increased number of cells
- only possible in cells which can divide
Give some examples of physiological hyperplasia
Hormonal:
- Proliferation of mammary epithelium during pregnancy
- Proliferation of uterine epithelium during pregnancy
Compensatory:
- Partial hepatectomy
Give some examples of pathological hyperplasia
- Excessive hormonal stimulation
- Attempt at regeneration
- Wound healing
Define metaplasia
Reversible change
Replacement of one adult cell type with another cell type
Give some examples of metaplasia
- Replacement of respiratory epithelium by squamous epithelium
- Reprogramming of stem cells
What are the 3 categories of intracellular accumulations?
- Normal cell constituents
- Abnormal substances
- Pigment
Give examples of the processes involved that lead to intracellular accumulations
- Normal or increased production but inadequate removal of normal endogenous substances
- Genetic/acquired defect in metabolism, packaging or transport of normal substances
- Deposition of abnormal exogenous substance
What is the name for an aggregation of lipids?
Chylomicron
Define steatosis
Abnormal accumulations of triglycerides within parenchymal cells
What are the causes of lipid accumulation?
- Toxins
- Protein malnutrition
- Diabetes
- Obesity
- Anorexia
- Alcohol abuse
How do protein accumulations in a cell usually appear?
Round, eosinophilic droplets, vacuoles or aggregates within the cytoplasm
What are the main reasons for protein accumulation?
- Excess protein presented to the cell beyond its cellular metabolism
- Defects in protein folding
What are the reasons that protein folding defects may occur?
- Defective intracellular transport and secretion of critical proteins
- Toxicity of abnormally folded proteins
- Genetic mutations
- Ageing
- Amyloidosis
What are the most common exogenous pigments that can accumulate in the body?
- Carbon
- Coal dust
- Tattooing
Name the 3 most common endogenous pigment accumulations
- Lipofuscin
- Melanin
- Hemosiderin (storage form of iron)
- Bilirubin
What condition is caused by an excessive of bilirubin?
Jaundice
What is bilirubin converted to at the end of an erythrocyte lifespan?
Bile
Where are the different %s of iron found in the body and in what forms?
80% - in haemoglobin, myoglobin and enzymes
20% - in a storage pool (haemosiderin, ferritin)
The level of what can be a used as a good indicator of body iron stores?
Plasma ferritin level
What are the 4 components of bile?
- Water
- Cholesterol
- Bile salts
- Bile pigments (bilirubin)
What are the 3 causes of jaundice?
- Excessive haemolysis
- Severe hepatic injury
- Obstructed bile flow
What is meant by pathological calcification?
Abnormal deposition of calcium salts
What are the 2 pathogenic phases of dystrophic calcification?
Initiation
- Intracellular: Ca accumulates in mitochondria of dying cells
- Extracellular: Initiated by the phospholipids in membrane bound vesicles
Propagation:
- Membrane facilitated calcification
- Ca binds to phospholipids in membrane which form groups
What is metastatic calcification?
Accumulation in normal tissues with hypercalcaemia
What is dystrophic calcification?
Local accumulation in dying tissues, areas of necrosis
Name 4 causes of hypercalcamia
- Increased parathyroid hormone
- Destruction of bone tissue
- Vitamin D intoxication
- Renal failure
What is an amyloid?
A pathological proteinaceous substance deposited between cells
Give examples of the most common amyloid proteins seen in veterinary medicine
- AA: synthesised in the liver, no immunoglobulin
- AL (amyloid light chain): derived from plasma cells
- Beta amyloid protein
- Islet amyloid protein
- Transthyretin
Compare primary and secondary amyloidosis
Primary - associated with immunocytic disorder
Secondary - complication of an underlying chronic inflammation
