Cell Pathology Flashcards
Nucleolus function
Makes rRNA
Na/K ATPase Pump
Purpose is to maintain high K inside and high Na outside Requires ATP (from the mitochondria) for energy Water follows sodium
Definition of ischemia, hypoxia, and anoxia
Ischemia: low blood supply
Hypoxia: low oxygen
Anoxia: no oxygen
Reversible cell injury
Happens if blood supply (oxygen and glucose) are restored and the cell returns to its original state
You get cell swelling originally
Irreversible cell injury
Happens if blood supply (oxygen and glucose) are restored and the cell does not return to its original state
Cell lyses and releases its contents
Nucleus lyses
Cell cannot recover = cell death
Cardiac troponin
Regulatory protein
You can test for it to determine if someone has had a heart attack
it is released if there is irreversible cell injury
What 3 compounds are released if a liver cell undergoes irreversible cell injury?
AST (aspartate aminotransferase)
ALT (alanine aminotransferase)
LDH (lactate dehydrogenase)
Infarction
Necrosis of a region of tissue caused by blood supply to that region
6 causes of cell injury (both reversible and irreversible)
- Ischemia (hypoxia/anoxia)
- Toxins
- Microbes
- Mediators of inflammation and immune reactions
- Genetic
- Metabolic disorders
How does cyanide work?
It blocks cytochrome C oxidase, which is one of the mitochondrial enzymes involved in production of ATP
Binds irreversibly
Irreversible cell death
Also blocks other enzymes
4 types of microbes that cause cell death
- Bacteria (ex: staphlyococcus aureus)
- Viruses (ex: RSV, HIV, Hep B)
- Fungus (ex: Candida)
- Parasites (ex: Giardia)
Exotoxin
Protein produced by bacteria that causes a toxic reaction
Staphylococcus aureus food poisoning
It contaminates food and replicated in the food, where it produces an exotoxin
The exotoxin is then ingested with the contaminated food
It crosses enterocytes and acts on T cells to cause violent inflammatory reactions (diarrhea and vomiting)
2 things Staph aureus causes
- Food poisoning
2. Impetigo
Directly cytopathic
The virus alone is killing the cell
Indirectly cytopathic
The damage is being caused by the host inflammatory cells in response to the infection
Cytopathic definition
Producing damage to the cell
Example of a directly and indirectly cytopathic virus
Directly: RSV
Indirectly: Hepatitis B
RSV infecting pneumocyte steps
Acquired by breathing in droplets containing virus from coughs/sneezes (effects infants)
RSV virus dumps viral RNA into cytoplasm and hijacks cell processes to make more viruses - also causes nuclear changes we can see
More RSV viruses - infected cell becomes multinucleated
Chronic viral Hepatitis B
Long standing inflammation of the liver caused by Hepatitis B virus
Chronic viral hepatitis B infection
Acquired by exposure to blood contaminated with Hep B virus (IV drug use, etc)
Virus enters hepatocyte and dumps viral DNA into nucleus
Hep B DNA makes more virus but does not kill cell
Hep B antigen on cell surface
T cell recognizes foreign viral antigen and gives signal to kill hepatocyte
Indirectly cytopathic (T cell is killing the hepatocyte)
HIV infection of T cells
Acquired by exposure to bodily fluids containing the virus (sex, exposure to blood)
HIV releases RNA and reverse transcriptase into cytoplasm
That makes RNA into DNA in cytoplasm, which enters nucleus
HIV hijacks cell processes to make more HIV virus and is directly cytopathic
Abscess definition
An infection becomes walled off from surrounding tissues
Reverse Transcriptase
A viral enzyme that converts RNA into DNA
Cytokines definition
Proteins secreted by immune cells that can act on other cells either near or far away
Complement proteins definition
Proteins in blood that can lyse both bacteria and cells
Tay-Sachs disease
Autosomal recessive
A type of lysosomal storage disease
Caused by a mutation in an enzyme called hexosaminidase A
Results in accumulation of material in lysosomes
5 types of intermediate filaments and where to find them
- Cytokeratins (epithelial tissue)
- Vimentin (mesenchymal tissue)
- Desmin (muscle tissue)
- GFAP - glial fibrillary acidic protein (glial tissue)
- Neurofilaments (neurons)
3 types of cytoskeletal filaments
- Intermediate filaments (5 types)
- Microfilaments (actin and myosin)
- Microtubules (tubulin)
Immunohistochemistry
A type of tissue stain that will turn certain substances brown, so that we can see them
Suicide genes
Genes that control apoptosis
Apoptosis requires energy and activates these genes
Physiologic definition
Normal process
Opposite = pathologic
How does the T cell kill a chronic hepatitis B infected hepatocyte?
(3 steps)
- T cell recognizes viral antigen and activates death receptor
- Death receptor activates apoptosis pathways in nucleus and cytoplasm
- Apoptotic hepatocyte with nuclear and cytoplasmic fragmentation
Graft versus host disease
When a patient receives a bone marrow transplantation for leukemia, the bone marrow transplant (graft) can recognize the patient’s tissues (host) as foreign and begin to attack them
Graft versus host disease is a serious complication of bone marrow transplantation
Bone marrow definition
The soft middle part of bone that contains the cells that form blood cells and participate in inflammation
Graft versus host disease
3 steps
- Donor T cell sees foreign antigen on enterocyte and activates death receptor
- Death receptor activates apoptosis pathways in nucleus and cytoplasm
- Apoptotic enterocyte with fragmented nucleus and cytoplasm
Happens because the match is not perfect
Bcl-2
A cytoplasmic protein that blocks apoptosis
Follicular lymphoma
B cells do not undergo apoptosis and you have too many B cells
Necrosis versus apoptosis
2 each
Necrosis: cell lysis, nuclear lysis
Apoptosis: cytoplasmic fragmentation, nuclear fragmentation
Atrophy
Decrease in size of cell/tissue/organ
Ex: brain with atrophy due to vascular disease
Hypertrophy
Increase in size of cell/tissue/organ
Ex: hypertrophy of left ventricle in high blood pressure
Hyperplasia
Increase in number of cells
Ex: hyperplasia of endometrium due to increased estrogen
Metaplasia
One mature cell type turns into another mature cell type
Ex: smoking turns respiratory columnar epithelium into squamous epithelium
Dysplasia
Abnormal proliferation, has an abnormal appearance under the microscope
Neoplasia
Abnormal proliferation that has formed a tumor
Hereditary hemochromatosis
Excess iron in liver due to genetic defect
Transport of iron is not regulated
Iron is toxic to liver
Nonalchoholic fatty liver disease
Occurs when hepatocytes receive excess glucose, usually due to poor diet
The cell will convert excess glucose into fat
Excess fat is toxic to liver
Gross definition
Macroscopic
Look at something with eyes
Microscopic
Histologic
Histopathologic
Look at something with microscope
Coagulative necrosis
Type of cell death caused by ischemia or infarction
Marked inactivation of cytoplasmic hydrolytic enzymes
Tissues do not lyse so they retain their form and consistency
Liquefactive necrosis
Can be caused by ischemia
Tissue is soft and liquified
Also in brain can be an infarct or stroke
Caseous necrosis
Caused by mycobacterium tuberculosis in the lung
Tissue is somewhat firm but falls apart as you handle it
Enzymatic fat necrosis
Caused by pancreatic enzymes digesting surrounding fat
Appears liquefied with calcified areas
Usually caused by acute pancreatitis (also trauma)
Fat degraded into glycerol and free fatty acids – free fatty acids bind calcium, forming calcium soaps – looks like liquified fat with whitish specks of calcium soap
Done by lipolytic enzymes
Consequences of diabetic glomerulosclerosis
Thickened vascular walls
Increased material in glomerulus
Due to hyperglycemia
