Flashcards in Pathology 1, 2 and 3 - Mechanisms of disease, tissues and cell injury, inflammation 1 Deck (73)
What are all diseases caused by a problem with one of?
VascularInfection/ inflammatoryNeoplasticDrugs/ toxinsIntervention/ IatrogenicCongenital/ developmentAutoimmuneTraumaEndocrine/ metbaolism
What chemical is used to fix and preserve biological specimens when the first arrive at the lab?
Formalin (formaldehyde)- then dehydrated and prepared for histology by paraffin
What must occur before the paraffin can be added to specimens?
Must be dehydrated
What histological stains are used to look at specimens? - colour of these
Eosin (red)Haematoxylin (blue)
Why do environmental changes result in changes at the organ and cellular level?
To adapt and help maintain homeostasis (alterations can become abnormal = pathological)
What cellular changes can increased demand lead to?
What cellular change can decreased demand lead to?
What cellular change can altered demand lead to?
What is hyperplasia?
Increase in cell number
What is hyperplasia due to?
Always due to an external stimulus (will regress on withdrawal of the stimulus)
Is hyperplasia physiological and/or pathological
Can be physiological or pathological
Give 2 examples of hyperplasia?
Changes in breast tissue at pubertyHyperplasia of endometrial lining at pregnancy(both stimulated by hormones)
What type of hyperplasia occurs due to loss of tissue?
Compensatory (reactive) hyperplasia e.g. in liver and bone marrow (if bleeding a lot)
What are the mechanism behind hyperplasia? (3)
Production of increased growth factorsIncreased growth factor receptorsSwitch on of genes encoding cell cycle regulators to promote new cell growth
Pathological hyperplasia examples caused by hormones?
Excess oestrogen leads to endometrial hyperplasia and abnormal menstrual bleeding (often post-menopausal)Hormonally induced prostatic hyperplasia in response to androgens
Pathological hyperplasia example caused by infection?
Lymph nodes become hyper plastic in response to an infection
What happens when the stimulus causing hyperplasia is withdrawn?
The hyperplasia will regress (cancer keeps growing in the absence of a stimulus)
Is hyperplastic tissue at risk of developing cancer?
Yes e.g. endometrial cancer is much more common in obese individuals
What is hypertrophy?
Increase in cell size
What 2 cellular changes often occur together?
Hyperplasia and hypertrophy
In what type of cells does hyperplasia normally occur in isolation in?
Non-dividing cells e.g. cardiac myocytes and skeletal muscles
What type of stress tends to cause hypertrophy?
When does hypertrophy in the heart become pathological?
When the heart can no longer function and requires more blood supply, etc. that it is supplied (same principle for skeletal muscle)
What is atrophy?
Reduction in cell size
Is atrophy pathological and/or physiological?
Can be pathological or physiological
Examples of physiological atrophy? (2)
Embryological structures (can remain = pathological)Uterus undergoes rapid atrophy after parturition
Causes of pathological atrophy? (7)
Decreased workload e.g. cast for broken limbLoss of innervationBlocked blood supply Ageing (usually in cells that have no replicating ability)Inadequate nutritionLoss of hormonal stimulus (e.g. post-menopausal uterus)Pressure (e.g. can be seen in normal tissue adjacent to tumours)
Mechanisms of atrophy? (3)
Reduced cellular componentsProtein degradation- "digestion" in lysosomes and degraded
What is the name of the pathway which leads to atrophy by digestion in lysosomes?
The ubiquitin proteasome pathway (principle mechanism of protein catabolism in the mammalian cytosol and nucleus