Cellular Pathology Flashcards
Plasma membrane
➢ phospholipid bilayer with embedded proteins / glycoproteins / glycolipids (eg
ion pumps, receptors, adhesion molecules, etc)
➢ semipermeable membrane with pumps for ionic / osmotic homeostasis
Nucleus
➢ chromatin (euchromatin vs heterochromatin)
➢ nucleolus (synthesis of ribosomal RNA/subunits)
➢ transcription of genes
Mitochondria
➢ inner & outer membrane, cristae
➢ intermembranous and inner matrix compartments
➢ oxidative phosphorylation (main source of ATP)
Endoplasmic reticulum (ER), Ribosomes, & Golgi Apparatus
➢ RER & Golgi - synthesis & packaging of proteins for export. Membranes,
lysosomes
➢ SER - lipid biosynthesis (eg membranes, steroids)
- Detoxification of harmful compounds (via P450’s)
- Sequestration of Ca 2+ ions
Chaperones & Proteasomes
➢ Chaperones assist proper folding of proteins and transport across organelle
membranes.
➢ Proteasomes degrade both excess proteins and incorrectly folded (misfolded)
proteins.
Lysosomes
➢ Enzymatic digestion (acid hydrolases) of materials in the cell
➢ Primary vs secondary lysosomes; residual bodies
➢ Autophagy vs heterophagy/endocytosis
➢ Phagocytosis/phagosome; pinocytosis/pinocytic vesicle; receptor-mediated
endocytosis
Cytoskeleton
➢ Structure and movement of cells/organelles/ granules/ surface molecules/
phagocytosis
: actin in various forms – cell shape and movement
Microfilaments
: polymers of tubulin – organelle movement/flagella/cilia/ mitotic
spindle
Microtubules
Intermediate filaments:
cytokeratin, vimentin, desmin, GFAP, neurofilament
proteins
Peroxisomes
➢ Enzymes (eg catalase, oxidases) – metabolism of hydrogen peroxide and fatty
acids
– metabolism of hydrogen peroxide and fatty
acids
Enzymes (eg catalase, oxidases)
CELLULAR INJURY CELL ADAPTATION AND CELL DEATH
The __________ are in constant fight for living from all kinds of aggressions
that could cause injury, and provided the operating environment is appropriate, could adapt to almost all situations. All these aggressions are called ______, and injury alters
the preceding normal steady state of the cell.
tissues and cells
stress
If the injury is acute, one of two possible
things can happen to the cell:
- It can either survive in a damaged state and adapt to the injury (reversible
injury) or; - It can die (irreversible injury or cell death). If the injury is of a chronic nature,
the cell may be able to adapt to it, resulting in a variety of cellular changes
known as adaptations. These include atrophy, hypertrophy, hyperplasia,
intracellular accumulations, metaplasia and dysplasia, that will be described
later
Homeostasis
cells are able to maintain normal structure and function (eg ion balance,
pH, energy metabolism) in response to normal physiologic demands
Stress –
any stimulus or succession of stimuli of such magnitude that tend to
disrupt the homeostasis of the organism.
Cellular adaptation
▪
as cells encounter some stresses (eg excessive physiologic demand or
some mild pathologic stimuli) they may make functional or structural
adaptations to maintain viability/ homeostasis.
cells may respond to these stimuli by either ___________ or __________
their content of specific organelles.
increasing or decreasing
adaptive processes:
atrophy, hypertrophy, hyperplasia and metaplasia
are forms of adaptation
Cell injury
▪ if the limits of adaptive response are exceeded, or in certain instances
when adaptation is not possible (eg with severe injurious stimulus), a
sequence of events called _______ occurs.
cell injury
Cell injury
A. Reversible cell injury
B. Irreversible cell injury / cell death
*removal of stress / injurious stimulus results in complete restoration
of structural and functional integrity.
a) Reversible cell injury
*if stimulus persists (or severe enough from the star) the cell will
suffer irreversible cell injury and death
b) Irreversible cell injury / cell death
- is one of the most crucial events in pathology and can
affect any type of cell.
cell death
Two principle morphologic patterns that are indicative of cell death:
Necrosis
Apoptosis
– type of cell death characterized by sever membrane
injury and enzymatic degradation; always a
pathologic process.
Necrosis
– regulated form of cell death; can be a physiologic
or pathologic process.
Apoptosis
CAUSES OF CELLULAR INJURY
- Hypoxia (Oxygen Deficiency)
- Physical agents
- Chemical, Drugs & toxins
- Infectious agents
- Immunologic Reactions
- Genetic Abnormalities
- Nutritional Imbalances
- Workload Imbalances
- Cell Aging
one of the most important and common causes of cell injury and cell
death.
Hypoxia (Oxygen Deficiency)
causes impairment of oxidative respiration, ie it interferes with
energy production.
hypoxia
Hypoxia (Oxygen Deficiency)
occurs with:
a) Deficient blood supply
b) Reduced oxygen-carrying capacity of the blood
c) Interference with respiratory chain / oxidative phosphorylation
= deficiency of blood supply from impeded
arterial flow or reduced venous drainage = hypoxia +
↓ delivery of nutrients and ↓ removal of metabolites.
ischemia
= localized area of ischemic necrosis.
infarction
Reduced oxygen-carrying capacity of the blood
due to anemia
due to Hb dysfunction
= reduction in numbers or volume of
erythrocytes or quantity of hemoglobin (Hb).
due to anemia
eg methaemoglobinemia - nitrate / nitrite poisoning,
carboxyhaemoglobinemia-carbon monoxide
poisoning
due to Hb dysfunction
- nitrate / nitrite poisoning,
eg methaemoglobinemia
-carbon monoxide
poisoning
carboxyhaemoglobinemia
eg, cyanide poisoning inactivates cytochrome oxidase in
mitochondria → blocks oxidative phosphorylation.
________ may be increased by tissue hypoxia due to
associated local vascular injury.
physical injury