Briefly describe the Adaptive and generally reversible types of cellular response to injury
Atrophy - decreased cell size e.g Atrophy in the pericardial fat.
Hypertrophy - increased cell size e.g increased size of myocardial cells due to stenotic heart valves
Hyperplasia - increased number of cells e.g goblet cell hyperplasia in bronchioles of lungs. This does not occur in all cell types - e.g neurons and cardiac cells can’t multiply
Explain why development during gestation is important by giving an example.
Cell division and differentiation involves several internal and external controls. In embryonic development timing is crucial for example, Cyclopia (one eye) is caused by ingesting a plant in ewes Day 14 of gestation and in rabbits day 6-9 of gestation. This is because the optical disc separates at D 14 in ewes and D6-9 in rabbits.
The optical disc separates at Day 14 in ewes and Day 6-9 in rabbits.
What can errors in growth and developmental disorders be classified as?
Minor (asymmetry of body parts) or major (malformations causing abortion or defects incompatible with life).
What are the two broad categories of cellular defects?
DNA/Chromosomal defects and Cellular microenvironment.
What are examples of DNA/Chromosomal defects?
Gene mutations (indels, substitution) and chromosomal issues such as translocations, duplications, and absences.
Examples include Down syndrome (trisomy 21) and Turner’s syndrome (Single X chromosome in females only 1 x sexchr.some).
What drives cells in the cellular microenvironment?
Internal and external signals.
What are the three categories of cells responding to injury?
Adaptive and generally reversible, Adaptive and potentially reversible, Not adaptable and not reversible.
What is atrophy?
Decreased cell size, e.g., muscle size decreased with decreased neural stimulation.
Example: Serous atrophy of fat in the pericardial area due to cachexia.- marked wasting of tissue
What is hypertrophy?
Increased cell size, e.g., increased size of myocardial cells due to stenotic heart valves.
Example: Hypertrophic cardiac myocytes appear large with irregular branches.
What is hyperplasia?
Increased number of cells, e.g., goblet cell hyperplasia in bronchioles of lungs.
What is metaplasia?
Change in one differentiated cell type to another mature differentiated cell type within the same embryonic lineage.
Example: Osseous metaplasia in the aorta due to chronic irritation.
What is dysplasia on a cellular level
Architectural/cellular disorder or absence of normal structure or differentiation.
Example: Squamous metaplasia and dysplasia in the trachea of smokers.
What are the pathological microscopic changes in cellular dysplasia?
Anisocytosis, Poikilocytosis, Hyperchromatism, and presence of increased mitotic figures.
What is the difference between cellular dysplasia and organ dysplasia? (LA)
Dysplasia is abnormal growth or development .
Cellular dysplasia is the disorder of cell layers and abnormal cell morphology - it can be reversible or may be preneoplastic. It has 4 pathological microscopic changes
Anisocytosis = unequal cell size
Poikilocytosis = abnormal cell shape
Hyperchromatism/hyperchromasia = dark nuclei
Presence of increased mitotic figure - unusual number of cells that are dividing
In contrast, organ dysplasia occurs at an organ level and causes malformation which is irreversible. Eg hip dysplasia (abnormal conformation of acetabulum), elbow dysplasia
Example: Hip dysplasia.
What are the three types of cell responses that are not adaptable and not reversible?
Apoptosis, Necrosis, and Neoplasia.
What are prenatal growth disorders?
Injuries to cells that have significant effects in the embryo due to primordial and pluripotent stem cell differentiation, max cell multiplication, and acute timing with controls.
What are the two types of prenatal growth disorders?
agnesis/aplasia - failure to develop
Hypoplasia - failure to attain normal size
Inherited malformations and congenital malformations.
What are inherited malformations?
What are congenital malformations?
Malformations that can be DNA-based or caused by other factors such as toxins or infections.
Describe Not adaptable and non-reversible cellular responses to injury
Apoptosis - programmed cell death (sublethally injured cells may undergo apoptosis i.e unrepairable DNA damage)
Necrosis - uncontrolled cell death (lethal injury results in uncontrolled cell death)
Neoplasia - DNA damage leads to uncontrolled abnormal cell proliferation and differentiation. This damage often needs to be significant and cumulative (more than 1 gene family damaged in most cases). - This is a cause of cancer as mutations accumulate over time and thus increases the rate of cancer with age.
Describe Adaptive and potentially reversible cell response to injury
Metaplasia - change in one differentiated cell type to another mature differentiated cell type within the same embryonic lineage. E.g osseous metaplasia in the aorta (transformation into bone with chronic irritation) - aorta contains CT and smooth m and bone is a type of CT (same lineage diff type of cell).
Dysplasia - architectural/cellular disorder or absence of normal structure or differentiation e.g squamous metaplasia and dysplasia in the trachea of smokers due to chronic irritation.
Both Metaplasia and Dysplasia may be reversed with removal of the irritant stimulus, however, prolonged stimulation can lead to neoplasia. (i.e preneoplastic in some circumstances)
Describe Prenatal growth disorders (Malformations) (LA)
Injuries to cells may have a more significant effect in the embryo since the following processes occur in the embryo:
-primordial and pluripotent stem cell differentiation
-max cell multiplication and differentiation
-acute timing with internal and external controls
Prenatal growth disorders can be inherited malformations or congenital malformations.
Inherited malformations: DNA based
Congenital malformations: (born with) Can be DNA based or based on other causes e.g toxins, infections, physical factors - actual cause may be difficult to determine if sporadic incidence
What is happening here
What is happening here
