Cellular Pathology (Lec. 03) Flashcards
cells are able to maintain normal structure and function (e.g. ion balance, pH, energy metabolism) in response to normal physiologic demands
homeostasis
any stimulus or succession of stimuli of such magnitude that tends to disrupt the homeostasis of the organism
stress
as cells encounter some stresses they may make functional or structural adaptations to maintain viability/ homeostasis
cellular adaptation
What is cell injury?
Cell injury occurs if the limits of adaptive response are exceeded, or in certain instances when adaptation is not possible.
What is reversible cell injury?
Reversible cell injury is the removal of stress or injurious stimulus that results in complete restoration of structural and functional integrity.
If severe stimulus persists in a cell, what will happen?
Irreversible cell injury
It is a type of cell death characterized by severe membrane injury and enzymatic degradation; always a pathologic process
Necrosis
What is apoptosis?
A regulated form of cell death. Can be physiologic or pathologic process.
one of the most important and common causes of cell injury and cell death
hypoxia
- oxygen deficiency
- blood supply deficiency
- hypoxia
- ischemia
Hypoxia occurs with? (3)
- Deficient blood supply (Ischemia)
- Reduced oxygen-carrying capacity of the blood
- Interference with respiratory chain / oxidative phosphorylation
What are some infectious agents that can cause cell injury?
a. Viruses
b. Bacteria / rickettsiae / chlamydia
c. Fungi
d. Protozoa
e. Metazoan parasite
cell injury occurs if stimulus prolonged and/or exceeds ability to adapt
overworked cells
prolonged lack of stimulation (e.g. disuse, denervation, lack of trophic hormones) can lead to atrophy and eventually the loss of cells
underworked cells
the cumulative effects of a lifetime of cell damage (chemical, infectious, nutrition, etc) lead to a diminished capacity of aged cells / tissues to maintain homeostasis and adapt to harmful stimuli
cell aging
What are the 2 types of nutritional imbalance?
deficiency and overnutrition
combined effects of environmental factors and 2 or more mutated genes (eg neoplasia, hypertension, coronary artery disease)
multifactorial inheritance
What are the different chemical, drugs and toxins that can cause cell injury?
- Inorganic poisons
- Organic poisons
- Manufactured chemicals
- Physiologic compounds
- Plant toxins
- Animal toxins
- Bacterial toxins / Mycotoxins
What are the three types of immunologic reactions that can cause cell injury?
- Immune response
- Hypersensitivity reactions
- Autoimmune diseases
What are the four intracellular system that are particularly vulnerable to injury?
- cell membranes
- mitochondria
- protein synthesis, folding and packaging
- genetic apparatus
chemical species with a single unpaired electron in outer orbit (donate or steal electrons, extremely unstable)
free radicals
Generation of free radicals (4)
- Cellular metabolism
- Enzymatic metabolism of exogenous chemicals
- Ionizing radiation
- Divalent metals
Where are the main sites of damage of Free radicals? (3)
- Damage of membranes
- Damage of proteins
- Damage to DNA
What are the protective mechanism of the cell against free radicals?
- Storage and transport proteins
- Antioxidants
- Enzymes involved in neutralizing free radicals