Block 9 Week 1 Flashcards
Which virulence factor of streptococcus pnuemoniae allows it to attach to the respiratory linings?
Surface adhesins
What are the causes of cardiogenic shock?
Myocardial infarction, arrythmia, pulmonary embolism with outflow obstruction
What is infarction?
Obstruction of blood supply to organ/tissue
What is the site of infection for streptococcus?
Nose, skin, pharynx
What happens following necrosis?
Classified based on 3 morphologies:
1)Liquefactive/colliquative necrosis
2) Coagulative necrosis
3) Necrosis
What is Liquefactive/ Collequative necrosis?
Digestion of necrotic cells by hydrolytic enzymes and activity of neutrophils, creating an abscess with liquid creamy tissue containing pus. This is associated with infection or brain infarction, with many cellular debris.
What is the gross morphology of liquefactive necrosis?
Liquid and creamy yellow pus
What is the micromorphology of liquefactive necrosis?
Neutrophils and debris
What is an abscess?
Necrotic cavity containing yellow pus.
What is pus?
Formed of necrotic cells and primarily dead neutrophils
What is coagulative necrosis?
Occurs due to infarction. Cells maintain their architecture initially during necrosis for first few days, but become dry/firm, hard and white with a preserved outline. May result in gangrenous necrosis if it progresses to entire limb.
Dermal papillae
Upward projections of dermis into epidermis
What is fibrinoid necrosis?
Necrosis in small blood vessels, resulting in immune complexes forming with fibrin, causing thickening of vessel walls.
What is gangrenous necrosis?
Loss of blood supply to entire limb due to coagulative nec
What is caesating necrosis?
Cell death that causes cheese like appearance, commonly found in tuberculosis with the formation of lung granulomas.
DNA of bacteria
Single circular chromosome and contains extracellular DNA in form of plasmid
What is a plasmid?
Small strand of circular DNA which replicates independently from the chromosome
Types of prokaryotes
Archae and bacteria
What is congestion?
Passive process where there is excess blood accummulation or reduced blood outflow
What causes congestion?
issue with heart pumping blood away from the area., venous obstruction such as mechanical compression.
No blood supply to the region of body
Infarction, associated with necrosis
Decreased/inadequate blood supply causing hypoxia
Ischaemia
Scaling
Shedding of cornified layer of skin
Saccular aneurysm
Aneurysm that bulges only on one side
What is purpura?
Intermediate sized haemhorrage under the skin caused by trauma or vasculitis. May be underlying cause for thrombocytopenia
What is petechia?
Smallest haemorrhage size caused by thrombocytopenia.
What is stenosis?
Narrowing of blood vessels
Ecchymosis
Subcutaneous haematoma due to breakdown of Hb -> Bilirubin and haemosiderin
Chronic pulmonary congestion
Excessive accumulation of blood in pulmonary artery. There is increased pressure on vessels which allow erythrocytes to leak out and macrophages to engulf erythrocytes and form a brownish haemosiderin
Neoplasia
Uncontrolled abnormal growth of cells associated with a tumour
Metaplasia
Environmental stimuli triggers benign change of replacement of mature cell type by different differentiated cell
Which stains react with anionic components?
Basic stains
ANeurysm
Enlargmeent of blood vessel caused by weakness in wall
Natural break down of blood clot
Fibrinolysis
Difference between fibrinolysis and thrombolysis
Fibrinolysis occurs in the body during healing process where fibrin in the clot is dissolved. Thrombolysis is the term for a group of medications to break down a clot
Using medication to break down clots
Thrombolysis
Sublethal changes to cell
Pale cyptoplasm, vacuolar degeneration, fatty changes
Conversion of one cell type to another
Transdifferentiation occurs in metaplasia
Serotyping
Identifiying antibodies based on their specificy
Acid fast bacteria
Kiehls- Neelsen stain is used because they resist decolourisation during typical staining due to presence of mycolic acid
Which sensation receptors are present in the skin?
Thermoreceptors, nociceptors, mechanoreceptors
Erosion
Loss of epidermis and papillary dermis
Infectioous eukaryotes
Fungi and parasites
Which glands secrete periodically?
Appocrine glands such as mamillry glands, axillae glands and groin glands. THey release via apocrine secretion into upper hair follicle, mixing with sebaceous secretion
Which glands secrete continuouslty?
Eccrine glands, releasing secretions of Na+ and H20.
Merocrine secretion
Eccrine glands- simple coiled tubular
Apocrine secretion
Apocrine glands - compound coiled tubular/ alveolar
Glands in mamillary, axillae and groin region
Apocrine gland
Antigenic variation
Bacteria change immunogenicity at high frequency
Which layer of the dermis does thermoregulation occur?
Papillary dermis
Desquamation
Shedding of dead corneoycytes
Which stage of wound healing is bacteria and damaged tissue removed?
Inflammation
Physical protection of skin
Against chemicals, water, infectious agents, mechanical damage
Superficial wound healing
Regenerate from basal layer
Action of lysozymes
Dissolve bacterial cell wall
Karyorrhexis
Fragmentation of cell nucleus due to cell necrosis
Pykyonosis
Shrinking/condensation of chromatin during cell necrosis
Lipid extrusion in epidermis
Occurs in stratum granulosum with the formation of lamellar bodies via enzymatic processing
which laer of epidermis do keratinocytes stop dividing?
Stratum spinosum, where they exit cell cycle and become tonofilaments
Late differentiation marker of keratinocytes in epidermal layer
Stratum granulosum
Thick skin
Contains more undulations in epidermal- dermal junction for attachment.
Cell type of stratum basale
Simple cuboidal
Decrease in number/size of cells
Atrophy
Dysplasia
Abnormal development of cells which is progressive, loss of cell polarity and nuclear hyperchromasia.
Site of hair regeneration
Hair papilla at the base of the follicle
Which dyes react with cationic components?
Acidic dyes
Composition of subcutis layer?
Loose connective tissue,
Hair cuticle
Plauqes which join together
LD50
Lethal does of bacteria which causes 50% animal mortaility
Toxin that is heat labile, produced by gram + and gram -
Exotoxin that has a specific target
Infarct
Area of necrosis caused by occlusion of arterial supply or venous drainage
What is the consequence of pulmonary embolism?
Cardiogenic shock
Bacterial cell envelope
Cell wall and cyptoplasmic membrane
What are the complication of aneurysm?
May rupture which causes internal bleeding. It is also a major site for clot formation or emoblisation which can lead to occlusion
What is a mural thrombi?
Arterial thrombi attached to the vessel wall
Thrombus formed under low shear-flow
Venous thrombi which is fibrin and erythrocyte rich
Role of peptidoglycan in gram negative bacteria
Forms periplasm to mantain bacterial shape
Which cell synthesises Vitamin D?
Keratinocytes in the presence of UV
Causes of thrombus formation
Endothelial injury, changes in intravascular pressure, hypercoagubility
Present of cell surface of peptidoglycan
Teichoic acid with phosphodiester bonds
Callus
Hyperplasia of peidermis due to pressure/friction
Peripheral arterial disease
Atheroma plaques in the arms and legs
Agar
Used as a preparation agent
Macconkey agar?
Differential agar to determine if bacteria can use lactose
Which bacteria are lactose positive?
Salmonella
Which bacteria are lactose negative?
E.coli
Karyorrhexis
Degeneration of the cell nucleus
Cauaes of decreased colloid oncotic pressure
Loss of protein through burns, urine due to issue with kidneys or faces in bowel disease
Athersoclerosis formation
Endothelial cell damage releases ROS and allows entry of LDL into tunica intima which become oxidised. This causes activation of macrophage receptors on LDL. Macrophages engulf oxidised LDL and become foam cells. These release chemokines to attract more LDL. They initiate smooth muscle migration via IgF-1 from tunica media which increases collagen generation and forms plaque. This plaque can rupture and result in coagulation and formation of clotl
Causes of haemhorrage?
Trauma
Atherosclerosis
Inflammation
Erosion of tumour
Obligate intracellular
Cannot reproduce outside the host cell and uses IC resources.
Extracellular
Can reproduce outside host cell
Ploidy
Number of sets of chromosomes
Hyperaemia?
Adaptive change where blood volume in tissues increases
Virulence
Ability to cause disease/degree of disease caused
Steatosis
Fatty liver
Which organ does metaplasia occur?
Pancreas from acinar -> duct cells
Which bacteria uses lactose as carbon source?
E.coli bacteria
Sepsis
Systemic release of IgF-1 causes vasodilation, activation of complement system of C3a and C5a with dysregulation of immune system
Virulence factors for salmonella
Endotoxins in LPS layer, exotoxin enterotxin that cause diarrhoea, O antigen, fibriae for adhesion
O antigen
Present in gram negative bacteria which prevents destruction by phagocytes
Cytotoxin
Inhibits host cell protein sysnthesis, causing calcium influx
Touch sensation of Merkel cells
DIscriminative fine touch
Type 3 molecules
Secreted by bacterium directly into host cell
Vibrio cholerae
Gram negative bacteria which increases adenylyate cyclase activitiy in the small intestine, affecting Na+ and CL- influx. Releases the enterotoxin
Free DNA taken up from environment
Transformation
Overload indicates irreversible cell damage
Ca2+
Where does energy production occur in bacteria?
Cyptoplasmic membrane
Types of acid fast bacterium
Mycobacterium, tuberculosis
Rete ridges
Downward projections of epidermis into dermis
Types of metaplsia
Squamous metaplasia in endocervix from cubodial, acinar-ductal in the pancreas and intestinal
Cardiogenic shock
Heart does not pump enough due to myocardial damage
Local congestion
Compression of blood vessels due to tumour or venous obstruction
Macule, patch, erythema
Lesion with skin colour issue due to melanocyte or blood flow
Precursor to dysplasia
Metaplasia
Cause of pulmonary embolus
DVT
Pathogens only associated with human disease
Overt/strict pathogens
Spores
Single celled reproductive bodies resistant to cell damage
Cause of sepsis
Bacteraemia (bacteria in bloodstream)
THromboembolsim
Blood clot which becomes stuck and occludes vessel
Nuclear atypia
Abnormal appearance of cell nuclei
Example of obligate intracellular parasite
Viruses
Shock caused by obstructive blood flow to heart or pulmonary artery
Obstructive shock
Cause of pitting oedema
Increased hydrostatic pressure
Most common infarct
Arterial occlusion
Vomiting, coughing, angina
Coronary artery blockage
Weakness, dysphea, facial numbness
Carotid artery blockage
What are the burn zones?
Coagulation zone, stasis zone, zone of hyperaemia
Coagulation zone
Region of burn where cell necrosis occurs which is irreversible
Stasis zone
Reduction in blood flow and perfusion which is reversible if oxygen supply is increased and nutrition
Zone of hyperaemia
Most external area which is inflammatory and has increased perfusion. Full recovery unless there is sepsis or ischaemia
What are the causes of lobar pneumonia?
Infection with streptoccus pneumonia that causes lung consolidation
What are the stages of lobar pneumonia?
Consolidation
Red hepatisization
Grey hepatization
Resolution
What is red hepatisation?
Lung becomes dry, airless with a liver-like consistency.RBC, WBC and debris clog the airways.
What is grey hepatization?
Fibrin, RBC and haemosiderin are broken down to fluid-like exudate, macrophages form and lungs turn grey.
Resolution in lobar pneumonia
Macrophages clear debris and leftover WBC and breakdown products are re-absorbed.
Alpha-haemolysin
Partial breakdown of Hb
Beta-haemolysin
Complete breakdown of Hb
What is immortalisation?
Cancer cells become immortalised and do not age due to increasing telomere production which prevents chromosomal shortening.
Dysplasia
Development of abnormal cell architecture, nuclear atypia and loss of cell polarity due to cytoskeletal changes. Occurs in HPV infection
What are the precursors to mast cells?
Basophils
Stratum spinosum
Contains tight intracellular junctions of desmosomes to attach to the cytoskeleton of cells
Downward projections in dermis
Rete ridges
Upward projections in dermis
Dermal papillae
Where do hair cells divide?
Papilla
What are the solid lesions?
Papule, plaque, nodule and wheal
What are the causes of decreased colloid osmotic pressure?
Liver cirrhosis and malnutrition
How can protein be lost?
Urine due to haemolytic disease
Faeces due to bowel disease
Skin due to burns
Which bacteria do not take up the gram stain?
Acid fast bacteria. Mycobacterium tuberculosis which has a thick waxy coat that prevents uptake
Conjugation
Transport of plasmid from one bacterium to another
Transduction
Use of bacteriophage to transmit genetic information
What are the stages of bacterial growth?
Lag
Exponential
Stationary
Death
Type 3 secreted molecule
Protein used by gram negative bacteria to inject effector proteins directly into the host cell cyptoplasm.
Endotoxins
Part of the LPS of gram negative bacteria which have weak toxic effects, released via cytolysis. It is generally heat labile.
Exotoxins
Highly toxic heat senstivie released extracellularly by gram positive and gram negative
What promotes the growth of clostridium dificile?
Primary bile acids promote germination of the spores. Secondary suppress growth.
