Lecture 25 Flashcards
What determines the fate of a cell when exposed to a stimulus?
- type of stimulus
- duration of the stimulus
- magnitude of the stimulus
- vulnerability of the cell
What is the physiological response to cell stress/injury
adaptation to the stimulus within the normal range
What is the pathological response to cell stress/injury?
adaptation to the stimulus outside of the normal range
or
may result in cellular malfunction, damage, or death
What are the common causes of cell injury?
- metabolic
- chemical
- physical
- biological
- immunological
- genetic
- aging
Metabolic causes of cell injury?
oxygen deprivation (hypoxia and ischemia)
nutritional (deficiency and excess)
Chemical causes of cell injury?
drugs, alcohol, and poisons
physical causes of cell injury?
trauma, extreme temps, and radiation
biological causes of cell injury?
viruses, bacteria, and parasites
immunological causes of cell injury?
allergic reactions and autoimmune disease
genetic causes of cell injury?
chromosomal abnormalities
mutations
How does aging lead to cell injury?
cellular senescence
What are the four major intracellular systems impacted by cell injury?
- Membrane integrity
- ATP production
- protein synthesis
- genomic or chromosomal integrity
explain reversible and irreversible cell injury?
reversible = mild damage
cell can be repaired
irreversible = severe or progressive damage
membrane damage
dna damage
leads to cell death (necrosis or apoptosis)
What are the early cellular responses to injury?
- cloudy swelling- swelling of organelles
- hydropic degeneration- vacuoles appear in cytoplasm
- fatty change - accumulation of fatty acids in cytoplasm (common in liver)
Explain hypertrophy? Cause?
This is when the size of the cells increase, which could also increase the size of an organ
This is caused by increased functional demand and specific hormone stimulation
what tissues are commonly impacted by hypertrophy?
cardiac muscle (hypertension)
skeletal muscle (exercise)
uterus (pregnancy)
Does cell number in hypertrophy change?
No
What is hyperplasia? What causes it?
Increase in the number of cells (reversible)
It is caused by: increased functional demand and hormonal stimulation
What tissues are normally affected by hyperplasia?
endometrium (hormonal stim)
prostate gland (hormonal stim)
RBC ( high altitude)
glandular epithelium of breast (hormonal stim)
uterine enlargement (pregnancy)
What is atrophy? What causes it?
atrophy is a decrease in functional cell mass
decreased size and function
reversible
causes: decreased functional demand decreased blood supply loss of innervation loss of hormone stimulation nutritional deficiency aging
tissues normally affected by atrophy?
- testes
- skeletal muscle
- brain
What is involution?
It is the process, by which, an organ shrinks or returns to its formal size
What are examples of involution?
- The uterus returning to normal size after pregnancy
2. mammary glands changing back to pre-lactational state after breastfeeding
What is metaplasia? what causes it?
There is a change in cell differentiation (reversible)
cause:
smoking and acid reflux
What tissues are normally impacted by metaplasia?
respiratory epithelium
cervical epithelium
esophageal epithelium
What is dysplasia? what causes it?
The failure of differentiation and maturation cellular atypia (structurally abnormal, high nuclear to cyto ratio, and large nuclei with dark staining)
cause?
rapid multiplication of cells
may demonstrate genetic abnormalities
What tissues are most affected by dysplasia?
cervix and skin
