Pathology: cells and cell death Flashcards
Necrosis
exogenously induced cell death due to irreversible cell injury caused by toxins anoxia, etc.
- Coagulative necrosis: Most common, happens when cell proteins are altered or denatured, rapid inactivation of cytoplasmic hydrolytic enzymes which prevents lysis of tissue
- Liquefactive necrosis: Dead cells liquefy under the influence of certain enzymes, mostly seen in the brain. Coagulative necrosis may liquefy, secondary liquefaction
- Caseous necrosis: typically found in tuberculosis/fungal infection, center of a tuberculous granuloma becomes necrotic and the cell becomes cheesy, yellow-white
- Fat necrosis: special form of liquefactive necrosis limited to fat tissue especially around the pancreas caused by the action of lipolytic enzymes. Pancreatic enzymes reliease into the fat tissue degrade fat into glycerol and free fatty acid
Apoptosis
endogenously (from within) programmed cell death
Required ATP, genes and enzymes
Initial event can be endogenous or exogenous
Affect single cell
Lack of apoptosis may cause pathology
Webb of hands and feet, menstruation
Gangrene
Dead tissue
Necrotic tissue can undergo secondary changes such as calcification
Diagnosis
Identification of a specific disease through evaluation of signs, symptoms, lab findings
Etiology
The causative factors in a particular disease, e.g. congenital, virus, malignancy
Idiopathic
the cause is unkonw
latrogenic
caused by treatment, procedure, error
pathogenesis
the development of the disease or the sequence of events involved in the specific disease process
Onset
Acute- sudden and obvious, short term
Gradual - milder conditions, developing over time
Insidious - gradual progress with vague or mild signs
Manifestations
the clinical evidence or effects
signs - objective indicators
symptoms - subjective indicators
Syndrome
collection of signs and symptoms that usually occurs together in response to a certain condition
Complications
secondary or additional problems that arise after the original disease begins
Prognosis
the probability or likelihood for recovery
Communicable
infections that can be spread from one person to another
Contatious
easily transmittable
contamination
in any health care setting, hand hygiene after patient contact can do more than any other intervention to limit the spread of pathogenic microorganisms
Cell structure and function
Plasma membrane Nucleus Cytoplasm cytosol organelles
Plasma membrane
- outer surface of the cell, consists of a lipid bilayer
- Membrane proteins functions as cannel, carriers, receptors, ligands, enzymes, linkers, identity markers.
- require active expenditure of energy
- selectively permeable
- integrity is a prerequisite for the maintenance of all essential cellular functions
- rupture or damage that can not be repaired inevitable leades to cell death
Cytoplasm
- consists of cytosol, organelles, cytoskeleton
- volume of cytoplasm varies
- N: C Ratio Nucleocytoplasmic ratio - higher in undifferentiated adult cells, fetal cells, tumour cells
Cellular organelles
Nucleus Mitochondria Ribosomes Endoplasmic reticulum Golgi complex Lysosomes
Necleus
Essential part of most human cells
Separated from the rest of the cell by nuclear membrane
Consists of DNA organized into chromatin
Condenses into Chromosomes during cell division
Blue print for protein synthesis
Mitochondria
Double membrane involved in cellular energy production
Energy demanding cells (liver, nerve) are mitochondrial rich
Undifferentiated cells, including may malignant tumour cells have few mitochondria
Ribosomes
Small RNA granules found free floating or on RER
Involved in protein synthesis
Proteins for internal purposes - free ribosommes
Export or luxury proteins - RER
Endoplasmic Retinulum
Meshwork of membranes continuous with plasma membrane and nuclear membrane
Rough ER involved in protein synthesis, studded with ribosomes.
Smooth ER involved in catabolism of drugs, hormones, nutrients doesn’t contain ribosomes
Golgi apparatus
Adjacent to nucles
Composed of membrane bound cisternas
Biochemically modifies, sorts and packages
Lysosome
Membrane bound digestive organelle Rich in lytic enzymes Fused with vesicles to digest material E.g. worn out structures, bacteria, etc Can release its content into the cell to lyse cell
Cell projectsion
passive projections Microvilli (e.g. intestine) do not require ATP, function to increase the surface are of the cell Active projections Require ATP (expenditure of energy) 1. Cilia 2. Flagella
Integration
- Autocrine stimulation - cell secretes substance that stimulate itself, simplest form
- Paracrine stimulation - cell secretes a substance that stimulates a nearby cell
- Endocrine stimulation - cell releases a substance into the bloodstream that is then able to stimulation a fa way cell. Highest form of integration of cell function, can involve cells of anatomically distinct organs
Causes of cell injury
Hypoxia, ischemia, anoxia
Physical agents (temp/vibration/radiation)
Mechanical damage (trauma)
Abnormal metabolite accumulation
Fluid or electrolyte imbalance
Chemicals
Microbiological agents (bacteria/viruses)
Immunological reactions (autoimmune/host cells)
Genetic defects
Nutritional imbalances
Aging
cellular response to injury
Reversible : within range of homeostasis, membrane left relatively intact. Mitochondria able to sustain energy demands
Irreversible: accumulation of amorphous, Ca-rich densities in the mitochondrial matrix
extensive plasma membrane damage
Lysosomal swell
Nuclear change, Decrease energy production, metabolism, in ph
Atrophy
Decrease in the size of cels resulting in reduced tissue mass, can be caused by poor nutrition, again, immobility
Hypertrophy
increase in the size of individual cells resulting in enlarged tissue mass, can be due to extra work on the tissue
Working out striated muscle, cardiovascular diseases - cardiac muscle
Hyperplasia
increased number of cells resulting in enlarged tissue mass, can occur in conjunction with hypertrophy - endometrial thickening of the uterus
Metaplasia
occurs when one mature cell type is replaced by a different mature cell type: e.g. in smokers, ciliated columnar epithelia of the respiratory tract changes to stratified squamous epithelia
Dysplasia
cells of a tissue vary in size and shape, large nuclei area present and the rate of mitosis increases, may indicate a precancerous state
Intercellular accumulations
May occur as a result of an overload of various metabolites or exogenous material or may be due to prevention of excretion of metabolic byproducts or normal secretions
Black lung - accumulation of coal particles
Fatty liver - damage to liver cells, causes decrease in lipoprotein production, therefore an increase in lipid storage
