CELL INJURY, ADAPTATIONS AND DEATH - 1 Flashcards
Covers ppts - Part 1 and Part 2 i.e. Cell adaptations and mechanisms & morphology of cell injury
List instances of atrophy occuring due to loss of endocrine stimulation
i. Atrophy of the endometrium, vaginal epithelium, and breast following loss of estrogen stimulation as in menopause
ii. Hypopituitarism - atrophy of target organs, such as the thyroid and adrenal cortex; Sheehan Syndrome
1. Identify the pattern of cell adaptation described below.
Change from columnar to squamous epithelium in the respiratory tract in response to chronic irritation from cigarette smoke
2. List 3 other examples for the same
- Squamous metaplasia
-
Other examples of squamous metaplasia are:
a. Stones in the excretory ducts of the salivary glands, pancreas, or bile ducts
b. deficiency of vitamin A (retinoic acid) induces squamous metaplasia in the respiratory epithelium
c. Mucus-secreting endocervical cells (ECCs) encountering the acid pH of the vagina undergo squamous metaplasia
Identify the pattern of hypertrophy described:
- New sarcomeres are predominantly assembled in parallel to the long axes of cells
- Myocytes thicken
- •Wall thickness increases without proportional chamber dilatation
Concentric hypertrophy
List 1 word that best describes the following
•reversible change in which one differentiated cell type (epithelial or mesenchymal) is replaced by another cell type
Metaplasia
Identify the molecular mechanisms repsonsible for the adaptation seen in the attached image.
In this case of Alzheimer’s disease, there is more marked atrophy seen superiorly and laterally, with sparing of the occipital region.
The mechanism is:
- Decrease in cell number through apoptosis
- Decrease in cell size through increased degradation of proteins via the ubiquitin-proteasome pathway and consumption of cell organelles through autophagy
Given the clinical scenario below, identify the molecular mechanism responsible for the cell adaptation described
Transformation of pseudostratified ciliated columnar epithelium to squamous epithelium in the respiratory tract in an individual deficient in Vitamin A
reprogramming of stem cells
List 1 word that best describes the following:
An increase in the number of cells in an organ or tissue in response to a stimulus
Hyperplasia
Identify the molecular mechanisms repsonsible for the adaptation seen in the attached image.
- Increased production of cellular proteins.
- switch of contractile proteins from adult to fetal or neonatal forms
Identify the pattern of cell adaptation shown in the attached image.
Dysplasia
List 3 microscopic features of dysplasia
a. Disorderly proliferation of cells occurs with loss of cell maturation as the cells progress to the surface
b. ↑mitotic activity (normal spindles)
c. ↑nuclear size/chromatin
- Identify the finding shown in the attached image
- What is the most likely etiology?
- Red neurons
- Hypoxia
Portions of the kidney that are at most risk for ischemic damage
early proximal tubule and the thick ascending limb of the loop of Henle
How is superoxide inactivated?
Superoxide dismutase which converts it to H2O2 and O2
List 1 word that describes the following:
•an increase in the size of cells, that results in an increase in the size of the affected organ
Hypertrophy
List 1 word that means the following:
‘steady state’
Homeostasis
What pattern of cell adaptation would occur in a patient with chronic hemodynamic overload due to hypertension or faulty valves?
Hypertrophy
3 mechanisms via which free radicals cause damage
a. Lipid peroxidation in membranes
b. Oxidative modification of proteins
c. Lesions in DNA
Which is more dangerous, Ischemia or hypoxia in the absence of ischemia?
Ischemia
What is the mechanism of mucus gland hyperplasia in smokers?
Chronic irritation
Identify the pattern of cell adaptation likely to have occured in the scenario described below
bone formation in muscle after intramuscular hemorrhage
The scenario is myositis ossificans. The cell adaptation is connective tissue metaplasia
See the attached image.
- Identify the pigment accumulated within cells.
- What cell eating process is this pigment associated with?
1. Lipofuscin
2. Autophagy
Note: Increased autophagy is seen in severe atrophy. Lipofuscin granules represent the residual bodies that accumulate as a result of autophagy. Excessive accumulation imparts a brown color to tissue. In the setting of atrophy, it is called brown atrophy – common age-related finding.
Refer Slide 18 of the ppt
Identify the molecular mechanisms repsonsible for the adaptation seen in the attached photmicrograph of the prostate.
increased output of new cells from tissue stem cells
- What would be the clinical consequence of ischemia in the splenic flexure area?
- List the 2 vessels supplying this area.
- Ischemic colitis
- SMA and IMA
The attached image is a section of the pancreas in a patient with cystic fibrosis.
1. Identify the cellular adaptation likely to have occured.
2. What is the mechanism?
- Pathologic atrophy
- Increased pressure due to thick duct secretions—> atrophy of exocrine glands in Cystic Fibrosis
List the 6 mechanisms of pathologic atrophy
Decreased workload (atrophy of disuse)
Loss of innervation (denervation atrophy)
Diminished blood supply
Inadequate nutrition
Loss of endocrine stimulation
Increased pressure
First visible sign of tissue hypoxia detected by the light microscope
Cellular swelling/Hydropic change
Pattern of hypertrophy likley to be encountered in chronic mitral or aortic regurgitation
Eccentric Hypertrophy
List 2 examples of physiologic hypertrophy
a. increased functional demand - Skeletal muscle weight training
b. massive physiologic growth of the uterus during pregnancy
What term best defines the description below?
Loss of cells in addition to the cells that are irreversibly damaged at the end of ischemia, following restoration of blood flow
Ischemia-Reperfusion Injury
Identify the finding shown in the image below
What is the mechanism?
- Hydropic change
- Failure of energy-dependent ion pumps in the plasma membrane
List 1 word that describes the following:
reversible functional and structural responses to changes in physiologic states and some pathologic stimuli, during which new but altered steady states are achieved
Adaptations
List one word that means the following:
reduction in the size of an organ or tissue due to a decrease in cell size and number.
Atrophy
- See attached image of an endometrial biopsy specimen and identify the type of cell adaptation seen.
- List one other pathologic condition** where the same type of cell adaptation is encountered **due to the same mechanism
- Endometrial hyperplasia
- Benign prostatic hyperplasia
List 1 word that best describes the following:
reduction in the size of an organ or tissue due to a decrease in cell size and number.
Atrophy
Consequences of membrane damage to the following:
a. Mitochondria
b. Plasma membrane
c. Lysosomes
a. Apoptotic death
b. cell swelling, leakage of cell contents
c. enzymatic digestion of proteins, RNA, DNA, and glycogen
2 consistent features of irreversibility of cell injury
a. Inability to reverse mitochondrial dysfunction (lack of oxidative phosphorylation and ATP generation)
b. Profound disturbances in membrane function
The zone of hepatocytes most susceptible to hypoxia.
Why?
Zone III
Zone III hepatocytes constitute the zone that is located farthest from the portal triad and receives the least amount of oxygen and nutrients.
List the 4 mechanisms of ischemic-reperfusion injury
- Oxidative stress
- Intracellular calcium overload
- Inflammation
- Activation of the complement system
List one term that best fits the description given below:
a. excess of oxygen derived free radicals
b. chemical species that have a single unpaired electron in an outer orbit.
a. Oxidative stress
b. Free radicals
List 2 examples of physiologic atrophy
During fetal development- notochord and thyroglossal duct regression
Decrease in the size of the uterus that occurs shortly after parturition
What cell adaptation is likely to have occured in the attached image?
Columnar metaplasia
1 example of metaplasia that is NOT associated with an increased risk of cancer
Apocrine metaplasia in the breast
