Chapter 1 Flashcards
What are the two ways that an organ can increase in size?
Hyperplasia and hypertrophy
Steps involved in hypertrophy?
Gene activation, protein synthesis, production or organelles
What kind of growth is undergone by permanent tissues?
Only hypertrophy in cardiac muscle, skeletal muscles, and nerves
What can pathologic hyperplasia lead to?
Dysplasia and possibly cancer
What tissue hyperplasia has no increased risk of cancer?
BPH
What are the two forms of atrophy?
Decrease in cell number via apoptosis
Decrease in cell size via ubiquitin proteosome degradation of the cytoskeleton or autophagy.
How does ubitquitin proteosome degradation occur?
intermediate filaments of the cytoskeleton are tagged with ubiquitin and destroyed by proteosomes
Autophagy
autophagic vacuoles fuse with lysosomes containing hydrolytic enzymes to breakdown cellular components
a increase in stress leads to _________
a decrease in stress leads to ___________
a change in stress leads to ___________
an increase in size
a decrease in size
a change in cell type
most common cells to undergo metaplasia?
surface epithelium
Barret’s esophagus is an example of metaplasia?
esophagus is normally lined by nonkeratinizing squamous epithelium and acid reflux causes it to change to nonciliated mucin–producing columnar cells
metaplasia occurs via_______ ≈
reprogramming cells
Is metaplasia reversible?
Yes, with removal of stressor
what is one tissue that can become metaplastic with no increased risk of cancer?
apocrine metaplasia of the breast (fibrocystic change)
vitamin A deficiency can cause metaplasia in ____
thin squamous lining of the conjunctiva– becomes stratified keratinizing squamous epithelium= keratomalcia
Mesenchymal(connective tissue) metaplasia example?
Myositis ossifican in which CT in muscle changes to bone during healing after trauma.
dysplasia
disordered cell growth, most often refers to proliferation of precancerous cells
is dysplasia reversible?
in theory, it is reversible with alleviation of inciting stress, if it persists, dysplasia becomes carcinoma
Aplasia vs hypoplasia
Aplasia: failure of cell production during embryogenesis
Hypoplasia: decrease in cell production during embryogenesis, resulting in small organ
what occurs when a stress exceeds the cells ability to adapt?
cellular injury
slowly vs. acutely developing ischemia
Slow= atrophy: renal atherosclerosis Acute= ischemia: renal artery embolus
What is the final electron acceptor in the electron transport chain?
Oxygen
How does decreased oxygen lead to lack of ATP?
Impairment of Oxidative phosphorylation
3 causes of ischemia
Decreased arterial perfusion- arteriosclerosis
Decreased venous drainage- budd chiari- PV thrombosis seen with polycythemia vera
Shock- generalized hypotension= poor perfusion
hypoxemia
PaO2 <60 mmHg, SaO2 < 90%,low partial pressure of oxygen in the blood
Causes of Hypoemia
High altitude, hypoventilation, difusion defect, V/Q mismatch
cherry–red appearance of the skin and headache
CO poisoning, leads to coma and death
cyanosis with chocolate colored blood
Methemogolinemia
Why can’t heme bind O2 in methemoglobin
Fe3+ is present, only Fe2+ binds O2.
Treatment for methemoglobin
methylene blue
Labs in Carbon Monoxide posioning
Normal PaO2, decreased Sao2
Labs in Methemoglobinemia
PaO2 normal, Sao2 decreased
why do newborns get methemoglobinemia
there is oxidant stress (sulfa or nitratae drugs) and adults have enzymes to reduce but newborns are immature.
broad effects of low ATP on cellular functioning
Na–K pump dysfunction: water and sodium buildup in the cell
Ca pump: calcium build up in the cell
anaerobic glycolysis impaired– switch to anaerobic causing lactic acidosis, which denatures proteins and precipitates DNA
What is the hallmark of reversible injury?
Swelling
What happens with cellular swelling?
cytosol swells: loss o microvilli and membrane blebbing and swelling of RER, causing the dissociation of ER and ribosomes and decreased protein synthesis