Cell Pathology Flashcards
Molecular Pathology
a science that encompasses all living phenomena and provide explanations for pathologic processes at the level of the molecules, atoms, and their elementary particles
in a resting cell, how are the essential components of the cell arranged?
components are arranged into aggregates chromatin
-a specialized organelle composed primarily of RNA known as the nucleolus
in dividing cells, how are the essential components of the cell arranged?
during mitosis - chromatin is restructured and the strands of DNA condense into chromosomes
what is an undiferentiated cell?
embryonic cells- not specialized yet
what does differential expression of genes allow to a cell?
to assume unique features and to perform specialized functions
describe protein synthesis
The genetic information encoded in the DNA is transcribed into the nuclear RNA
From the nuclear RNA, the message is transmitted by tRNA and mRNA into the cytoplasm
The ribosomal RNA (rRNA) serves as a template for translating the genetic messages into proteins
all human cells except these need a nucleus for survival
red blood cells and platelets
what is the nucleocytoplasmic (N:C) ratio
The ratio of the nucleus to the cytoplasm,
where is the N;C high
in undifferentiated embryonic cells, also in tumors - there is less cytoplasm and less organells
where is the N:C low
in differentiated cells of adult tissues- cytoplasm is more abundant and full of organelles
The cytoplasmic ground substance of all cells consists of an amorphous matrix called
hyaloplasm and a fibrillar meshwork called cytoskeleton
which is organelle is high in oxidative enzymes
mitochondria
what are small granules composed of RNA
ribosomes
ribosomes can be arranged into
aggregates that float freely in the cytoplasm, called polysomes or free ribosomes (make internal purpose)
attached to the membranes of the rough endoplasmic reticulum (RER) (to be delivered out of the cell
what is is endoplasmic reticulum
A meshwork of membranes that are in continuity with the outer plasma membranes on one side and the nuclear membrane on the other
what are the two form of the endoplasmic reticulum
rough: the site of protein synthesis
smooth: has complex functions, the most important of which are the catabolism (i.e., metabolic degradation) of drugs, hormones, and various nutrients, and the synthesis of steroid hormones
what is the golgi apparatus
proteins synthesized in the endoplasmic reticulum pass through the Golgi apparatus - are biochemically modified before being packaged into secretory granules or lysosomes
- Glycoprotein and lipoproteins (i.e., proteins linked to a carbohydrate or lipid) are formed in the Golgi apparatus
where do you find acid hydrolase
lysosomes: are digestive enzymes - active in an acidic milieu (i.e., at low pH levels)
what are secondary lysosomes
The primary lysosomes fuse with other cytoplasmic vesicles
what are heterophagosomes
2ndary lysosomes
Hyaloplasm
The ground substance of the cytoplasm: no distinct structure and appears as an “empty” space on electron microscopic studies
Biochemically, consists predominantly of water, but it also contains minerals, proteins, carbohydrates, and lipids
It is traversed by a network of filaments that form the cytoskeleton
what are the three filaments of the cytoskeleton
microfilaments, composed of actin and myosin (5 nm in diameter)
microtubules, which are 22 nm thick and composed of tubulin
intermediate filaments, named because their diameter (10 nm) is intermediate between that of microfilaments and microtubules
what is the plasma membrane made of
proteins, lipids, and carbohydrates that are arranged in a polarized complex bilayer that has an internal and external surface
at which level does the simplest form of integration occur
the single cell, example t lymphocytes
what is autocrine stimulation
T lymphocytes secrete interleukin-2 (IL-2), a cytokine, which serves as lymphocytes’ and some other cells’ own growth factor
what is paracrine stimulation
release of mediators from one cell and their uptake by another. this is done by hormonal signals for more complex integration- one cell to another
what is biogenic amines
mediates paracrine stimulation ex: epinephrine, neuropepride hormones (glucagon,gastrin)
what is endocrine stimulation
hormones released into the blood circulation: for higher intergration because it travels to several organs ex. insulin
the essential minerals for cell homeostasis are
na, cl,k,fe
the oligominerals for cell homeostasis are
zn,cu,se, mg
what is the steady state of a cell
When an equilibrium between the cells and their environment is achieved and maintained
what happens if the demand exceeds the capacity in a cell
it is irreparably damaged-die- usually cause by toxins, hypoxia/anoxia
what happens to the cell when there is a reversible injury
it may swell
what happens to a cells components when it swells
Swollen Mitochondria produce less energy
Switch to Anaerobic Metabolism (produces acid)
Degranulated RER produce less proteins
how can you tell if the cell is irreversasbily damaged
The most characteristic are nuclear changes -
what are the three forms of of nucleus damage
Pyknosis (Dense Chromatin)
Karyorrhexis (Nuclear Fragmentation)- all broken up-looks like cereal
Karyolysis (Nuclear dissolution
how do cell injuries occur
The most important are hypoxia, toxins, microbial pathogens, endogenous mediators of inflammation and immune reactions, and genetic/metabolic disturbances
hypoxia/anoxia occurs when…
Obstruction of the respiratory tubes (e.g. suffocation secondary to drowning)
Inadequate transport of oxygen across the respiratory surfaces of the lung (e.g. pneumonia)
Inadequate transport of oxygen in the blood (e.g. anemia)
An inability of the cell to use oxygen for cellular respiration (e.g. cyanide poisoning). Cyanide inhibits oxidative enzymes in the cell and prevents oxidative phosphorylation
also heart attack
what are reoxygenation injuries
Relative oversupply of Oxygen may cause release of “Oxygen Free Radicals”
Include H2O2 and Superoxide (O2-)
Thought to be mechanism of injury for many diseases
what do viruses do to a cell
Viruses
Disrupt Cellular processes
Disrupt Nuclear or Cytoplasmic membrane
Produce Foreign Antigen Immune attack
what are the examples of mediators of inflammation and immune reaction, how are they produced
lymphokines, cytokines, or complement proteins,
produced by the body in response to infection or in various immune reactions
how do genetic/metabolic disturbances cause cell injury
cause disturbances of intermediate metabolism and subsequent accumulation of toxic metabolites
can cells adapt to adverse stimuli
Once the cause is removed, most cells that have adapted to chronic stimulation revert to normalcy again
However, some forms of adaptation, especially those associated with cell loss
- e.g. bone loss in osteoporosis are irreversible
what is atrophy
cell adaptation: Decrease in size of cell
Physiologic (commonly with age) (Brains, Bone)
Pathologic
Ischemia (limit in blood supply
Denervation
Cachexia (Malignancy, Malnutrition)
what is hypertrophy
enlargement of cell, ex. Heart – Increase in bulk of Myocardium due to increased workload
High blood pressure
Outflow blockages (Aortic Stenosis)
Skeletal Muscle – Body Builders
hyperplasia
increase in number of cells, ex:Usually due to Hormonal stimulation (Uterus, Prostate)
Chronic Irritation
Callus, Corns (Thickening of skin)
what causes hypertrophy of the left ventricle
hypertension
what are intracellular accumulations
involve both an overload and underexcretion/ underutilization:
anthracosis
acuumulation of coal particles
hemosiderosis
accumulation of blood-derived brown pigment)
are heart or brain cells replacable
no
necrosis
meaning death Exogenously induced
apoptosis
programmed cell death
autolysis
death of cells after death
coagulative necrosis
Most common
Proteins are “Coagulated” (like a fried egg)
Marked by rapid inactivation of Hydrolytic enzymes
Heart, Liver, Kidneys
liquifactive necrosis
Dissolving of Tissue (“Liquefies”)
Common in Brain
Other Necrotic Organs may later liquefy (eg Myocardium
caseous necrosis
cheesy necrosis-tuberculosis
what are the two different types of gangrene
wet- 2ndary Infection of Necrotic Tissue 2ndary Liquefaction
“Dry”
Desiccated (Dried out) Necrotic Tissue (like Egyptian mummies)
the basic functional unit
a cell
what does the nuclear contian
dna rna and nuclear proteins
know 2-3 points on all cell organells
ok
what are lysosomes
Membrane-bound digestive cytoplasmic organelles that are rich in lytic enzymes. They originate as small vesicles budding from enzymes on the maturing face of the Golgi apparatus
These primary lysosomes contain acid hydrolases, which are digestive enzymes - active in an acidic milieu (i.e., at low pH levels)
what are the funtions of the cytoskeleton
The function of the cytoskeleton:
To maintain cell shape and enable the cell to adapt to external mechanical pressure
Also important for cell movement and the traffic of organelles
what is steady state
state of balance between opposing pressures operating in and around a cell or tissue
what does the cell produce
energy, waste, work/ end product
what are 2 microbial pathogens
bacteria-toxins and viruses
metaplasia
abnormal change in tissue
dysplasia
an elergement of the organ or tissue
apoptosis
Programmed cell death or “cell suicide”
Vital biological process – helps cell health and homeostasis
Complex signaling cascade induced
Caspase activation – caspase mediated protein cleavage – nucleosomal DNA fragmentation
Role in many disorders
Southern Blot
One way of analyzing the genetic pattern’s in a persons DNA
the thing were it moves up and compare who the killer is
