6. Disordered Cell Growth Flashcards
Why are all cells not equivalent in their ability to proliferate?
Some divide often
Some divide infrequently
Some can “never” divide
What are examples of labile cells?
Skin
Gut epithelium
Endothelium
Bone marrow
What are examples of stable cells?
Liver
Pancreas
Bone
What are examples of permanent cells?
CNS
Cardiac muscle
What happens when labile or stable cells get injured?
Can often result in tissue regeneration and restoration of normal tissue and function
What happens when permanent cells get injured?
Often very little tissue renewal
What is the cellular response to altered physiological stimuli?
Hyperplasia
Hypertrophy
Atrophy
Metaplasia
What is hypertrophy?
Increase in the size of a cell without cell division
It can occur by itself but usually occurs in combination with an increase in cell number
What are examples of physiological hypertrophy?
Skeletal muscle that occurs with training in athletes
Myometrium of uterus during pregnancy
What are examples of pathological hypertrophy?
Cardiac muscle of the left ventricle after outflow obstruction
What is hyperplasia?
Hyperplasia is the increase in the number of cells in a tissue as a consequence of cell division
It can occur by itself but usually occurs in combination with an increase in cell size
What are the two types of hyperplasia?
Hormonal hyperplasia
Compensatory hyperplasia
What does hormonal hyperplasia do?
Increases the functional capacity of a tissue when needed
What does compensatory hyperplasia do?
Increases the tissue mass in response to some event such as resection
What is a physiological example of hyperplasia?
Adaptive increase in erthrocyte production leading to increased numbers of red cells in individuals living at high altitude
The low pO2 leads to increased erythroproietin production that stimulates bone marrow erythropoiesis
Increases red cell number and enhances O2 carriage
What are pathological examples of hyperplasia?
Psoriasis
Benign prostatic hyperplasia
Goitre
What is psoriasis?
Too many keratinocytes
Thick itchy skin
What is benign prostatic hypoerplasia?
Enlarged prostate
Urinary tract obstruction
What is goitre?
Hyperplasia of thyroid gland
What is the prostate gland?
Small gland found only in men, located in the pelvis, between penis and bladder - involved in production of semen
What happens when the prostate becomes enlarged?
Can place pressure on the bladder and urethra which can lead to:
Difficulty starting urination
A frequent need to urinate
difficulty fully emptying the bladder
What is the thyroid gland?
A small butterfly-shaped endocrine gland in the neck. just in front of the trachea
What happens when the thyroid gland swells?
Produces a lump in the neck known as a goitre this , although rarely, can increase significantly and affect breathing and swallowing
What is metaplasia?
The replacement one type of one mature differentiated cell type with another mature differentiated cell type, as an adaptive response to some insult or injury
What is meant by metamorphosis?
Change in form, structure, appearance etc
What is barrets oesophagus?
condition in which the tissue lining the oesophagus—the muscular tube that carries food and liquids from the mouth to the stomach—is replaced by tissue that is similar to the intestinal lining.
What is the process whereby barretts oesophagus is brought about?
Intestinal metaplasia
What is squamous metaplasia?
Can arise in the bladder secondary to chronic cytitsis indwelling catheters, urinary calculi or schistosomiasis
What does squamous metaplasia provide a risk factor for?
Subsequent development of a carcinoma
What is atrophy?
The decrease in the size of an organ and can be a consequence of reduction in cell size of number
How is atrophy mediated?
By reduced cell proliferation or by increased cell loss due to increased apoptosis
What is an example of atrophy?
Reduced muscle mass after immobilisation
What are the causes of atrophy?
Disuse (decreased workload) Loss of innervation Diminished blood supply Inadequate nutrition Loss of endocrine stimulation Ageing (senile atrophy) Pressure
