p.1
Cellular Adaptation Mechanisms
What are cells capable of adapting to within defined limits?
A variety of stimuli which may upset normality.
p.1
Cellular Adaptation Mechanisms
What is cellular adaptation?
The state between a normal unstressed cell and the overstressed injured cell.
p.2
Normal Cell Growth and Regeneration
What is regeneration in the context of normal cell growth?
Regeneration is the process where cells that are lost through death or injury are replaced.
p.1
Cellular Adaptation Mechanisms
Is the adaptive process reversible?
Yes, the adaptive process is potentially reversible.
p.2
Normal Cell Growth and Regeneration
What does normal growth of tissues depend on?
Normal growth of tissues depends on a balance between the number of cells actively dividing and the number of cells dying.
p.2
Normal Cell Growth and Regeneration
What type of cells are capable of repeated mitotic activity in tissues?
Stem cells are capable of repeated mitotic activity in tissues.
p.2
Normal Cell Growth and Regeneration
Can differentiated cells return to the cell cycle and divide?
Yes, sometimes differentiated cells can return to the cell cycle and divide to produce daughter cells.
p.3
Normal Cell Growth and Regeneration
What happens to permanent cells when they are lost?
Permanent cells cannot divide and replace lost cells by the same cell type. Instead, repair by fibrosis occurs.
p.3
Normal Cell Growth and Regeneration
What is the process of repair by fibrosis?
In this process, dead tissue is removed and scar tissues (collagen-rich fibrous tissue) fill the defect.
What do cells and tissues need to maintain in order to function appropriately?
A steady state (homeostasis).
p.11
Hypertrophy and Hyperplasia in Physiological Conditions
What is hyperplasia?
Hyperplasia is the increase in the number of cells.
p.12
Hypertrophy and Hyperplasia in Physiological Conditions
What physiological changes occur in the myometrial smooth muscle during pregnancy?
Hypertrophy and hyperplasia causing enlargement of the pregnant uterus.
p.9
Pathological Causes of Atrophy
How does reduced blood supply lead to pathological atrophy?
Reduced blood supply, such as the shrinkage of the brain caused by atherosclerosis of carotid arteries, leads to pathological atrophy.
What is the G1 phase of the cell cycle?
Gap 1, the preparation for S phase.
p.8
Adaptive States: Atrophy, Hypertrophy, Hyperplasia, Metaplasia
What is atrophy?
Atrophy is a reduction in the mass of cells leading to a reduction in size of the tissue or organ.
p.3
Normal Cell Growth and Regeneration
When is repair rather than regeneration likely to occur?
Repair rather than regeneration is likely when labile or stable tissue shows extensive injury.
p.6
Types of Tissues: Labile, Stable, and Permanent
What are labile tissues?
Labile tissues are continuously changeable and have a short life span, such as bone marrow and gut epithelium.
p.6
Types of Tissues: Labile, Stable, and Permanent
What characterizes stable tissues?
Stable tissues have a slow turnover and long-lived differentiation, such as liver and kidney tissues.
p.7
Cellular Adaptation Mechanisms
What are the four main adaptive states in cellular adaptation?
Atrophy, Hypertrophy, Hyperplasia, and Metaplasia.
p.14
Metaplasia and Its Reversibility
What is metaplasia?
Metaplasia is the term used when one differentiated tissue is replaced by another. It is a potentially reversible change; if the cause of metaplasia is removed, the tissue may revert to normal.
p.10
Hypertrophy and Hyperplasia in Physiological Conditions
What is hypertrophy?
Hypertrophy is an increase in mass due to an increase in cell size.
p.7
Cellular Adaptation Mechanisms
Are the adaptive states of cells reversible?
In general, they are potentially reversible.
p.13
Pathological Conditions Leading to Hypertrophy and Hyperplasia
What pathological condition is associated with cardiac muscle in hypertension?
Cardiac muscle hypertrophy.
p.9
Pathological Causes of Atrophy
What is the effect of inadequate nutrition on muscles and major organs?
Inadequate nutrition can cause the wasting of muscles and major organs, as seen in starvation.
p.14
Metaplasia and Its Reversibility
What happens to bronchial epithelium in smokers?
Bronchial (pseudo-stratified ciliated columnar) epithelium changes to squamous epithelium in smokers.
p.7
Adaptive States: Atrophy, Hypertrophy, Hyperplasia, Metaplasia
What is metaplasia?
Change in tissue type as a result of replacement of one differentiated cell type by another.
p.11
Hypertrophy and Hyperplasia in Physiological Conditions
What is hypertrophy?
Hypertrophy is the increase in the size of cells.
What are the four main stages of the cell cycle?
M phase, G1 phase, S phase, G2 phase.
p.12
Hypertrophy and Hyperplasia in Physiological Conditions
What compensatory changes occur in the remaining kidney after the other kidney is removed?
Hypertrophy and hyperplasia.
p.7
Adaptive States: Atrophy, Hypertrophy, Hyperplasia, Metaplasia
What is hypertrophy?
Enlargement of an organ as a result of increased cell size.
p.9
Pathological Causes of Atrophy
What is pressure atrophy and what causes it?
Pressure atrophy is caused by adjacent tumors or cysts.
p.10
Hypertrophy and Hyperplasia in Physiological Conditions
What is hyperplasia?
Hyperplasia is an increase in mass due to an increase in cell number.
What are the two main controls of the cell cycle?
Growth factors and cyclins.
p.8
Pathological Causes of Atrophy
In what conditions does atrophy occur?
Atrophy occurs in physiological conditions, during normal growth and development, generally due to loss of endocrine stimulation.
p.11
Hypertrophy and Hyperplasia in Physiological Conditions
How do hypertrophy and hyperplasia differ?
Hypertrophy involves an increase in cell size, while hyperplasia involves an increase in cell number.
p.6
Types of Tissues: Labile, Stable, and Permanent
What are examples of labile tissues?
Bone marrow and gut epithelium.
p.6
Types of Tissues: Labile, Stable, and Permanent
What are examples of stable tissues?
Liver and kidney tissues.
p.7
Adaptive States: Atrophy, Hypertrophy, Hyperplasia, Metaplasia
What is atrophy?
Shrinkage of an organ as a result of decrease in cell size and/or number.
p.13
Pathological Conditions Leading to Hypertrophy and Hyperplasia
What is the cause of hyperplasia of the prostate gland in pathological conditions?
An abnormal response of androgens.
p.14
Metaplasia and Its Reversibility
What type of metaplasia occurs in the bladder due to stones and infection?
Transitional bladder epithelium changes to squamous epithelium in bladder stones and infection.
Can cells in the G0 phase re-enter the cell cycle?
Yes, they may re-enter at G1 and regain the proliferative state.
p.10
Hypertrophy and Hyperplasia in Physiological Conditions
Can permanent cell populations undergo hyperplasia?
No, permanent cell populations can only enlarge by hypertrophy.
p.12
Hypertrophy and Hyperplasia in Physiological Conditions
What causes skeletal muscle hypertrophy in bodybuilders or athletes?
Physiological conditions.
p.12
Hypertrophy and Hyperplasia in Physiological Conditions
What happens to the breasts during lactation in terms of physiological changes?
Hypertrophy and hyperplasia.
p.13
Pathological Conditions Leading to Hypertrophy and Hyperplasia
What causes hyperplasia of the adrenal gland in pathological conditions?
Excess of ACTH hormone by a pituitary neoplasm.
p.9
Pathological Causes of Atrophy
How does loss of endocrine stimulation result in pathological atrophy?
Loss of endocrine stimulation, such as infarction of the pituitary, results in atrophy of the thyroid and adrenal glands.
What occurs during the G2 phase of the cell cycle?
Gap 2, distribution of chromosomes takes place.
p.10
Hypertrophy and Hyperplasia in Physiological Conditions
Do hypertrophy and hyperplasia commonly occur together?
Yes, in practice hypertrophy and hyperplasia commonly occur together.
p.10
Hypertrophy and Hyperplasia in Physiological Conditions
Are hypertrophy and hyperplasia reversible conditions?
Yes, both hypertrophy and hyperplasia are reversible conditions. If the cause is removed, the tissue can return towards normal.
p.3
Normal Cell Growth and Regeneration
What does the scar tissue provide to the damaged tissue?
The scar provides continuity and strength to the tissue but results in the loss of original function.
What occurs during the M phase of the cell cycle?
Mitosis, when the cell divides (about 1 hour).
p.6
Types of Tissues: Labile, Stable, and Permanent
What are examples of permanent tissues?
Neurons and cardiac muscle cells.
p.10
Hypertrophy and Hyperplasia in Physiological Conditions
What are the two ways an organ or tissue can enlarge?
An organ or tissue can enlarge due to an increase in the number of constituent cells or an increase in the size of the cells.
What is the G0 phase in the cell cycle?
A non-proliferative or growth arrest phase.
p.8
Adaptive States: Atrophy, Hypertrophy, Hyperplasia, Metaplasia
What are the two mechanisms involved in atrophy?
A reduction in the number of cells through apoptosis and a reduction in the size of cells.
p.9
Pathological Causes of Atrophy
What is denervation and how does it cause pathological atrophy?
Denervation is the wasting of muscle caused by lack of nerve stimulation, for example, Poliomyelitis.
p.6
Types of Tissues: Labile, Stable, and Permanent
What are permanent tissues?
Permanent tissues contain cells capable of division only in fetal life, and cell loss after birth cannot be replaced, such as neurons and cardiac muscle cells.
p.13
Pathological Conditions Leading to Hypertrophy and Hyperplasia
What causes bladder smooth muscle hypertrophy and hyperplasia in pathological conditions?
Enlargement of the prostatic gland.
p.7
Cellular Adaptation Mechanisms
What factors control the adaptive states of cells?
A complex web of genetic and environmental factors that control normal growth and development.
p.10
Hypertrophy and Hyperplasia in Physiological Conditions
What is required for hyperplasia to occur?
Hyperplasia requires that the cells be capable of division and can occur only in labile and stable cell populations.
p.7
Adaptive States: Atrophy, Hypertrophy, Hyperplasia, Metaplasia
What is hyperplasia?
Enlargement of an organ through an increase in cell number.
p.14
Metaplasia and Its Reversibility
What type of metaplasia occurs in the lower oesophagus in patients with gastro-oesophageal reflux?
Stratified squamous epithelium changes into glandular epithelium in the lower oesophagus in patients with gastro-oesophageal reflux.
