Formative Flashcards
List the categories of microorganism that cause disease
Bacteria Viruses Fungi Parasites Prions
What is the role of microscopy in the diagnosis of bacterial infection?
Allows for staining and quick detection (but not identification) of bacteria in samples
What is the role of culture in the diagnosis of bacterial infection?
Strains can be identified by colonial appearance and growth patterns
What is the difference between sterile and non-sterile sites?
Sterile sites contain no microorganisms, commensal or otherwise, while non-sterile sites can contain commensal microbes that may not harm the body but show up in testing
What are some sterile sites? 4
Blood
CSF
Bladder
Lungs
What are some non-sterile sites? 4
Skin
Nasopharynx
Urethra
Gut
How are viruses detected?
Cell line must be innoculated, and electron microscopes used
Antigen election and nucleic acid amplificated used
What is the function of bacterial ribosomes?
Protein synthesis
What is the function of the plasma membrane in bacterial cells?
Allows diffusion
What is the function of the bacterial cell wall?
Cell structure and support
What is the function of the bacterial capsule?
Defence mechanism
What is the function of the flagellum?
Motility
What is the function of the fimbriae?
Allows adherence
What are the main structures of a bacterial cell surface? 4
Plasma membrane
Penicillin binding proteins
Peptidoglycans
Lipopolysaccharides (only in gram negative)
What is the function of penicillin binding proteins in the bacterial cell surface?
Synthesizes peptidoglycans
What is the function of peptidoglycan in the bacterial cell surface?
Give the cell strength and shape
What is the structure of peptidoglycan?
Carbohydrate polymers cross linked with amino acids
What are the two shapes bacteria can be in?
Cocci= spherical Bacilli= bacilli
Wha is the difference in structure between staph and strep?
Staph= clusters Strep= chains
What can virus families be classified according to?
Virion shape/symmetry
Presence/ absence of envelope
Genome structure
Mode of replication
How are viruses cultured?
In living cells (cell lines, tissues or intact animals)
Cell lines are grown in a nutrient containing medium with 5% CO2
What respiratory infections are of major importance? 3
Influenza A
Rhinovirus
Respiratory syncytial virus
What gastrointestinal virus is of major importance?
Rotavirus
What neurological viruses are of major importance? 2
Enterovirus
Herpes simplex
What are the 3 classifications of fungi?
Basidomycetes
Ascomycetes
Zygomycetes
What are basidiomycetes?
Mainly mould and mushrooms, a few yeasts
What are ascomycetes?
Moulds and yeasts, some mushrooms
What are zygomycetes?
Moulds
What are dermatophytes?
Fungi that use keratin as a nutrient source and attack the skin and mucous membranes
What are systemic fungi?
Yeasts responsible for oral, skin, nail, and many other forms of infections
What are the main types of parasites? 3
Protozoa
Helminths
Ectoparasites
What is a protozoa?
A single celled organism that can only multiply in the host
What are helminths?
Worm parasites e.g. roundworm, tapeworm
What are ectoparasites?
Parasites that live on, as opposed to in, the host e.g. lice
What is active immunisation?
Production of antibodies in the immune system in response to the presence of an antigen, creating immunological memory
What is used to immunise in active immunisation?
Attenuated organism Dead organism Toxoid Recombinant Conjugate
What is passive immunisation?
Patient is immunised with antibodies specific to the pathogen, providing immediate protecting but no immunological memory
What are the advantages of using passive immunisation?
Easily stored and transported
Safer- can be used on even immunocompromised
What are the gram positive coagulase positive bacteria?
Staphylococcus aureus
What are the gram positive coagulase negative bacteria?
Staphylococcus epidermis
Staphylococcus saprophyticus
What are the gram positive aerobic non spore forming bacteria?
Listeria monocytogenes
Corynebacterium diptheriae
What are the gram positive aerobic spore forming bacteria?
Bacillus species
What are the gram positive anaerobic spore forming bacteria?
Clostridium species
What are the gram positive partially haemolytic bacteria?
Streptococcus pneumonia
Viridans streptococci
What are the gram positive completely haemolytic bacteria?
Streptococcus pyogenes
Streptococcus agalactiae
What are the gram positive non haemolytic bacteria?
Enterococci
What are the gram negative cocci?
Moraxella catarrhalis
Neisseria gonorrhoeae
Neisseria meningitidus
What are the gram negative bacilli lactose fermenters that show growth on MacConkey’s?
Escherchia coli
Klebsiella species
What are the gram negative bacilli lactose non-fermenters that show growth on MacConkey’s?
Proteus species
Salmonella species
Shigella species
Pseudomonas species
What are the gram negative anaerobic bacilli bacteria?
Bacteriodes species
Prevotilla species
Porphyromonas species
What are the gram negative curved bacilli?
Campylobacter species
Vibrio species
Helicobacter species
What are the gram negative cocci-bacilli?
Haemophilus influenzae
What is virulence?
A quantitive measure of the likelihood of a pathogen to cause disease
What are some of the virulence factors of bacteria?
Colonisation
Immunoevasion
Immunosuppression
Bacterial toxins
What is pathogenesis?
The process by which a pathogen causes a disease in the host
What is minimal inhibitory concentration?
Minimum concentration of antimicrobial required to inhibit visible growth of an organism
What is the minimal bactericidal concentration?
The minimum concentration of the antimicrobial needed to kill the arganism
What is a sensitive organism?
An organism that is inhibited or killed by levels of the antimicrobial that are available at the site of infection
What is a resistant organism?
An organism that is not killed or inhibited by the concentration of antimicrobial at the site of infection
What is a bactericidal?
An antimicrobial that kills bacteria
What is a bacteriostatic?
An antimicrobial that inhibits the growth of a bacteria
Explain the term ‘synergy’
Two or more structures, agents or processes working together to create a combined action greater than the sum of each acting separately
Explain the term ‘antagonistic’
Two or more structures, agents or processed working against each other to create a combined action less than the sum of each acting separately
What are the 3 methods by which antibacterials act?
Inhibition of cell wall synthesis
Inhibition of protein synthesis
Inhibition of nucleic acid synthesis
What antibacterials act by inhibiting cell wall synthesis?
Penicillin and cephalosporins
Glycopeptides
How to penicillins act as antibacterials?
Inhibit cell wall synthesis by inhibiting the enzymes responsible for cross linking carbohydrates to form peptidoglycans
Contain beta lactams
How to glycopeptides act as antibacterials?
Inhibit cell wall synthesis by inhibiting production of the peptidoglycan precursor in gram positive bacteria
Give examples of glycopeptide antibacterials
Vancomycin and teicoplanin
What types of antibacterials act by inhibiting protein synthesis?
Aminoglycosides
Macrolides and tetracycline
Oxazolidiones
What type of bacteria do aminoglycosides act on and give an example of one
Gram negative
Gentamicin
What type of bacteria do macrolides and tetracycline act on and give examples
Gram positive
Erythromycin and clairithromycin
What infection are oxazolidiones used to treat and give an example
MRSA
Linezolid
What types of antibacterials act by inhibiting nucleic acid synthesis?
Trimethoprim and sulphamethoxazole
Fluoroquinones
How do trimethoprim and sulphamethoxazole work?
Inhibit nucleic acid synthesis by inhibiting different steps in purine synthesis
What is the combined form of trimethoprim and sulphamethoxazole and what is it and trimethoprim individually used to treat?
Co-trimoxazole used to treat chest infections
Trimethoprim used to treat UTIs
What type of bacteria are fluoroquinolones effective against?
Gram negative
Give an example of a fluoroquinolone and explain why it cannot be used to treat children
Ciprofixacin
Interferes with cartilage growth
What types of antifungal are there?
Polyenes
Azoles
Allylamines
Echnocandins
How do polyenes act as an anti fungal?
Bind to ergosterol and make the cell wall more permeable
Name two polyene antifungals and what they are used to treat
Amphotericin B- serious fungal and yeast infections
Nyastatin- candida infections of the skin
How do azoles act as an antifungal?
Inhibit ergosterol synthesis
Name two azoles and what they are used to treat
Fluconazole- yeast infection
Voriconazole and itraconazole- aspergillosis
How do allylamines work as antifungals?
Suppress ergosterol synthesis
What allylamine is in use and what is it used to treat?
Terbinafine
Dermatophytes
How do echnocandins act as antifungals?
inhibit production of glucan polysaccharide
What organisms combat B-lactam activity and how do they do this?
Staph aureus
Produces B-lactamas enzymes to break down penicillins and cephalosporins
What are the causes of acute inflammation?
Microorganisms Mechanical trauma Chemical changes Extreme physical conditions Dead tissue Hypersensitivity
What are the cardinal signs of inflammation?
Dolor- pain
Calor- heat
Rubour- redness
Tumour- swelling
What are the benefits of acute inflammation?
Rapid response
Protects site
Neutrophils deal with damage
Plasma proteina localise process
Describe the change in blood vessel radius during acute inflammation
Transient arteriolar constriction followed by local arteriolar dilation (flush and flare)
Describe the change in vessel permeability during acute inflammation
Chemical mediators cause the vessel walls to become more permeable, allowing exudation of plasma proteins such as immunoglobulin and fibrinogen
Describe the movement of neutrophils during acute inflammation
Neutrophils move from the centre to the endothelial aspect of the lumen- margination
Neutrophils then adhere to endothelium- pavementing
Neutrophils squeeze between endothelium to outside tissue- emigration
List the systemic effects of acute inflammation
Pyrexia
General malaise
Neutrophilia
Septic shock
How can acute inflammation be detrimental to the patient?
Spread t the bloodstream causing sepsis
Bacteraemia
Septicaemia
Toxaemia
What cell types are involved in chronic inflammation?
Lymphocytes
Macrophages
Plasma cells
Fibroblasts
What are the major causes of chronic inflammation?
Arising from acute inflammation
Arising as primary lesion
How can chronic inflammation arise from acute inflammation?
Large volume of damage
Inability to remove debris
Fails to resolve
How can chronic inflammation arise as a primary lesion?
Autoimmune disorder
Material resistant to cellular digestion
Exogenous substances
Endogenous substances
What are the effects of chronic inflammation?
Scarring and fibrosis
Granuloma formation
What factors promote healing and repair?
Cleanliness Apposition of edges Sound nutrition Metabolic stability and normality Normal inflammatory and coagulation mechanisms
What factors impair healing and repair?
Dirty gaping wound Large haemotoma Poor nourishment- lack of vitamins A and C Abnormal CHO metabolism Inhinition of angiogenesis
What kind of reaction is type I sensitivity?
Allergic reaction
Describe the process of a type I hypersensitivity reaction?
B cells stimulated to produce IgE to a specific antigen, triggering a mast cell response and sensitising it to the antigen
What is a type II hyper sensitivity reaction?
The antibodies bind to antigens on the patient’s own cell surface
What immunoglobulins are involved in type II hypersensitivity?
IgG and IgM
When do type III hypersensitivity reactions occur?
When there is an accumulation of immune complexes that cannot be cleared from the circulation
How long do type IV hypersensitivity reactions take to develop?
2-3 days
How are type IV hypersensitivity reactions mediated?
Through CD4 helper T cells
What is the process of a type IV hypersensitivity reaction?
CD4 cells recognise the antigen and produce cytokines, leading to an inflammatory response
What is an early phase response?
A response occurring within minutes performed by mast cell mediators
What is a late phase response?
Takes longer to respond with newly synthesised mediators
What is the difference between localised and systemic hypersensitivity?
Localised- causes localised inflammation and can be cleared away by macriphages
Systemic- Immune complexes deposited in skin, joints, kidneys, blood vessels etc
What is an autoimmune disease?
A large group pf clinical disorderes characterised by tissue or organ damage mediated by incorrect immune mechanisms targertted at self-antigens
What factors are involved in the aetiology of the immune system?
Genetic factors
Immune regulatory factors
Hormonal factors
Environmental factors
What pathogenic mechanisms are involved in autoimmune disease?
Cell mediated Antibody mediated Antibody+ complement Immune complex mediated Recruitment of innate compounds
What are the 2 types of autoimmune disease?
Organ specific
Non-organ specific
What is the difference between organ specific and non-organ specific autoimmune disease?
organ specific- immune response directed towards antigens in one organ only
Non specific- attacks antigens in several organs
Describe ionisation of drugs and how this affects their uptake
Most drugs are weak acids or bases and the degree of dissociation depends on the pH of the environment
Ionised drugs to do not cross the membrane
Unionised drugs diffuse until equilibrium is reached
How does lipid solubility affect drug transport across a membrane?
For a drug tp be able to cross a membrane, it must be lipid soluble
How does the drug structure affect active transport?
In order to be able to be absorbed by active transport, the drug must resemble naturally occurring molecules
What factors affect the absorption of a drug from the GI tract?
Gut motility
Food
Illness
How do food and illness affect drug absorption from the GI tract?
Food- some food impair or enhance the ability of a drug to be absorbed
Illness- Malabsorption caused by illness can impair the absorption rate of certain drugs
What is first pass metabolism?
Metabolism of the drug prior to it reaching the site of absorption
Where does first pass metabolism mainly occur?
Gut lumen (acid enzymes) Gut wall (metabolic enzymes) Liver (hepatic enzymes)
How can first pass metabolism be avoided?
Using different delivery methods
What are the benefits of administering drugs IV?
100% bioavailability
Avoids first pass metabolism
What are the benefits of administering drugs topically?
Controlled, sustained doses of drug
Avoids first pass metabolism
What are the benefits of administering drugs via inhalation?
Drug delivered directly to site of action Rapid effect Small doses Little systemic absorption Reduced adverse effects
What is the bioavailability of a drug?
Amount of drug which reaches the circulation and is available for action
What factors affect bioavailability?
Formulation
Drug’s ability to pass physiological carriers
Gastrointestinal effects
First pass metabolism
What affects a drug’s ability to pass physiological barriers?
Particle size
Lipid solubility
pH and ionisation
What factors affect drug distribution?
Tissue perfusion Membrane characteristics Transport mechanisms Disease/other drugs Elimination
What membrane characteristics affect drug distribution?
Blood brain barrier
Blood testes/ovaries barrier
What factors does renal filtration depend on?
Glomerular filtration
Passive tubular reabsorption
Active tubular reabsorption
What is glomerular filtration?
All unbound drugs are filtered at the glomerulus provided their size or charge doesn’t prevent this
What is passive tubular reabsorption?
As the filtrate moves down the kidney tubules, it becomes more concentrated and unionised drugs can be reabsorbed by diffusion
What is active tubular reabsorption?
Some drugs are actively secreted into the proximal tubules of the kidneys for excretion
What is drug metabolism?
Biochemical modification of pharmaceutical substances by living organisms usually through specialised enzymatic activity
What 3 reactions can be involved in phase 1 metabolism?
Oxidation
Reduction
Hydrolysis
What is the process of phase 1 metabolism?
Polar groups are exposed on or introduced to a molecule, providing an active site for phase 2
What enzymes carry out phase 1 metabolism?
Cytochroms P450
What reaction is involved in phase 2 metabolism?
Conjugation
How does conjugation metabolise the drug?
Attaches glucuronic acid, glutathione, sulphate or acetate to the metabolite generated in phase 1
What does conjugated the drug achieve?
Increases water solubility, enhancing excretion
Usuall results in activation of the drug
What factors inhibit or induce drug metabolism?
Other drugs/substances Genetics Hepatic blood flow Liver disease Age Sex Ethnicity
How do other drugs and substances affect drug metabolism?
Many drug metabolising enzymes can be induced by other substances (alcohol and smoking), decreasing drug effect Other drugs (e.g. clairythromycin) inhibit enzymes through a number of mechanisms
How do genetics affect drug metabolism?
Drug metabolising enzymes are often expressed in different forms so differences in the individual’s gene expression can vary
Can cause absences or deficiencies of certain enzymes, leading to toxicity
How does age affect drug metabolism?
Metabolising enzymes often absent or reduced in foetuses or premature babies, renal disruption common
What are the advantages and disadvantages of using drugs in solution or suspension?
Absorbed rapidly
Can be given to young or elderly
Can be given to those with issues swallowing
May be given via nano-gastric or PEG tube
Absorption depends on gastric emptying
First pass metabolism
What are the advantages and disadvantages of using drugs in tablet or capsule form?
Convenient Accurate does Easy to reproduce Stability Ease of mass production Absorption depends at the rate the tablet breaks down First pass metabolism
What are the types of adverse drug reaction?
Augmented Bizarre Chronic Delayed End of treatment Failure of treatment
Describe what is meant by an augmented adverse drug reaction
Predictable, dose dependent reaction that resolves when the drug is stopped
Describe what is meant by a bizarre adverse drug reaction
Unpredictable, rare reaction that can cause serious illness or death
Describe what is meant by a chronic adverse drug reaction
Semi-predictable reaction related to the dose and length of treatment
Describe what is meant by a delayed adverse drug reaction
Occurs years after treatment in patient or children of patient
Describe what is meant by an end of treatment adverse drug reaction
Effects caused when drug treatment is stopped
Describe what is meant by a failure of treatment adverse drug reaction
Common reaction frequently caused by drug interactions
What are the common mechanisms of drug-drug interactions?
Pharmacodynamic Pharmacokinetic Distribution Metabolism Elimination
When do pharmacodynamic drug interactions happen?
When drugs act on the same or interrelated receptors, resulting in additive, synergistic or antagonistic effects
What are pharmacokinetic drug interactions?
Interactions affecting absorption, distribution, metabolism or excretion
When are pharmacokinetic drug interactions important?
When drug has a short half life or rapid results are needed
What are distribution drug interactions?
Interactions that cause an alteration in the distribution of the drug
What are metabolism drug interactions?
One drug influencing the metabolism of another
What are elimination drug interactions?
Interactions between drugs that cause alterations in their elimination from the system
What factors predispose a patient towards drug interactions?
Higher number of drugs Age Critical illness Undergoing surgery Chronic underlying conditions
What are the uses of a clinical study?
Provide evidence
Test efficacy
Test safety
What are the basic considerations involved in clinical trial design?
Time scale End point Choice of control drug Choice of patients Exclusion criteria Drug used
What are the types of clinical trial? 12
Double blind Single blind Randomised Placebo controlled Prospective Retrospective Cross over Sequential Parallel Factorial Large simple
What are single blind trials?
The patient doesn’t know what treatment they are receiving but the doctor does
What is a randomised trial?
Patients are assorted to groups randomly to prevent bias
What is a placebo controlled trial?
Half of patients are given a placebo and half given the treatment and comparisons made
What is a retrospective trial?
The data is collected from past records and does not follow patients
What is a prospective trial?
Participants differ with certain respects under study and differences in outcome monitored
What is a cross over trial?
Participants receive a sequence of different treatments
What is a sequential trial?
A trial where the sample size is not fixed in advance
What is a parallel study?
Two groups of participants are given two different drugs
What are factorial clinical trials?
More than one factor is evaluated
What is a large simple trial?
Deals with fewer aspects in a larger sample size
What is the structure of DNA?
2 chains of nucleotides bound in a double helix structure
What is the structure of a nucleotide?
Deoxyribose pentose sugar, phosphate and a base
Briefly describe the process by which DNA is replicated
DNA helices unzips double helix by breaking H bonds between bases
New nucleotides added in 5’ to 3’ direction using DNA polymerase
In lagging strand, short Okazaki fragments are made using a primer then linked together by DNA ligase
Why can DNA synthesis be described as semi-conservative?
One half of each new strand of DNA id ‘old’
Describe the process of transcription
The strand is unzipped by DNA helices and methionine acts as a start codon for the beginning of transcription
The sequence is read in codons and transcribed into mRNA until a stop codon is reached
Introns are then spliced out of the copy and a cap added to each end of the strand to protect it from being broken down by other enzymes
Describe the process of translation
tRNA attaches to the mRNA molecule and reads it a codon at a time
tRNA brings the correct amino acid correlating to that codon and begins the polypeptide chain
The rRNA moves along the mRNA coding of the amino acids until a stop codon is reached
What are the different kinds of DNA mutation?
Silent
Missense
Nonsense
Frameshift
What are silent mutations?
One base change that does not result in a change of amino acid
What are missense mutations?
The wrong amino acid is coded for
What are nonsense mutations?
A stop codon is coded for prematurely, resulting in a small protein
What are frameshift mutations?
Insertion or deletion mutations that result in the whole sequence being changed
What is the polymerase chain reaction used for?
Forensic medicine
Genetic identification
Detections of mutations
DNA cloning
What does gel electrophoresis do?
Separates DNA fragments by size using an electric field
What are the advantages of gel electrophoresis?
Quick
Easy to use
Robust
Sensitive
What is restriction fragment length polymorphism analysis?
Bacterial cells that cut DNA at known sites used to get required sections of DNA for gel electrophoresis
What is amplification refraction mutation system?
Normal and mutant primers used with strands of DNA to detect a mutation
Describe the basic structure of a chromosome
Centromere connecting the two sides
Telomere on the tips of arms
DNA is tightly packaged around positively charged histone proteins to form nucleosomes which coil into a chromosome
Describe the difference between heterochromatin and euchromatin
Euchromatin= open structure, being expressed Heterochromatin= dense, tightly bound structure not being used
Describe the structure of a nucleosome
146 negative base pairs wrapped around 8 positive histone proteins
What are the stages of mitosis?
Interphase Prophase Metaphase Anaphase Telophase Cytokenesis
Describe the steps of prophase
Chromosomes condense
Nuclear membrane disappears
Spindle fibres form from centrioles
Describe the steps of metaphase
Chromosomes align at the cell equator and attach to spindle fibres
Describe the steps of anaphase
Sister chromatids separate longitudinally at centromere
Move to opposite poles of the cell
Describe the steps of telophase
New nuclear membrane forms and each cell has 46 chromosomes
Describe the steps of cytokenesis
Cytoplasm separates and 2 new daughter cells form
How do the first and second divisions of meiosis differ?
In the second division, the chromosomes are not copies and haploid cells are created
What are the main differences between spermatogenesis and oogenesis?
Spermatogenesis= meiotic cycle takes roughly 60 days, undergoes many divisions (greater chance of mutation) Oogenesis= Each meiotic cycle produces 1 ovum and 3 polar bodies that develop into ova
What us meant by a trisomy abnormality?
There are 3 copies of a chromosome instead of 2
What condition occurs from trisomy 21 and give symptoms
Downs syndrome
Distinct facial characteristics and IQ less than 50
What condition occurs from trisomy 13 and give symptoms
Patau syndrome
Multiple dysmorphic features, few live beyond first year
What condition is caused by trisomy 18 and give life span
Edwards syndrome
1 month-1 year
What condition would have 46, X?
Turner syndrome
What condition would have 46, XXY?
Klinefelter syndrome
What is a Robertsonian translocation?
One chromosome has the two long arms while the other has the two short arms
What is a chromosomal deletion?
Sections of the chromosome ‘disappear’ from one or both of the arms
What is a chromosomal inversion?
A section of DNA is inverted
What are the 2 types of chromosomal inversion and what are they?
Paracentric= a section of DNA on the arm of the chromosome is inverted Pericentric= a section of DNA around the centromere is inverted
What are the three types of sex linked abnormalities?
X linked recessive
X linked dominant
Y linked
What is non-mendelian inheritance?
Inheritance that doesn’t follow Mendel’s laws
What are Mendel’s laws?
Law of segregation- Alleles from each gene segregate so gamete only carries one
Law of independent assortment- genes for different traits can segregate independently
Law of dominance- Some alleles are dominant while others are recessive
Give examples of non-mendelian inheritance
Anticipation- Huntington’s, Myotonic dystrophy, fragile X syndrome
Mitochondrial disease- maternal inheritance
What is the Hardy-Weinberg principle?
Allele and genotype frequencies will remain constant from generation to generation in the absence of mutation or selective pressures
What factors affect the Hardy-Weinberg principle?
Mutation Migration Population Mating Selective pressures
Where are the gene mutations in myotonic dystrophy and Duchenne muscular dystrophy?
Myotonic- autosomal genes
Duchenne- X chromosome
What are photo-oncogenes?
Genes that code for cell growth and regulation
Mutations can turn these into oncogenes
What are oncogenes?
Genes that accelerate cell growth, forming a tumour
What are tumour suppressor genes?
Genes that inhibit the cell cycle and/or promote apoptosis
How many mutations are needed to cause cancer in a photo-oncogene and tumour suppressor genes?
Proto-oncogenes= 1
Tumour suppressor= 2
What are benign and malignant tumours of the squamous epithelia called?
Benign= squamous papilloma Malignant= squamous carcinoma
What are benign and malignant tumours of the glandular epithelia called?
Benign= adenoma Malignant= adenocarcinoma
What are benign and malignant tumours of the bone called?
Benign= osteoma Malignant= osteosarcoma
What are benign and malignant tumours of theft called?
Benign= lipoma Malignant= liposarcoma
What are benign and malignant tumours of the fibrous tissue called?
Benign= fibroma Malignant= fibrosarcoma
What is cancer of the lymphoid tissue called?
Lymphoma
What are tumours of the gremlin cells called?
Teratomas
Ovary usually benign
Testes usually malignant
What are the differences between benign and malignant cells’ growth pattern?
Benign= non invasive Malignant= invasive
What are the differences between benign and malignant cells’ capsules?
Benign= usually encapsulated Malignant= no capsule, or capsule has been breached
What are the differences between benign and malignant cells’ cell shape?
Benign= cells similar to normal Malignant= cells abnormal
What are the differences between benign and malignant cells’ function?
Benign= function similar to normal tissue Malignant= loss of function
What are the differences between benign and malignant cells’ differentiation?
Benign= well differentiated Malignant= poorly differentiated
What are the properties of cancer cells?
Altered genetics
Altered cellular function
Abnormal structure
Cells capable of independent growth
What are the mechanisms of cancer spread?
Local spread
Lymphatic spread
Blood spread
Trans-coelomic spread
What is the mechanism of local spread of tumours?
Malignant tumour invades surrounding connective tissue and into the lymph/blood vessels
What is the mechanism of lymphatic spread of tumours?
Tumour cells adhere to lymph vessels, penetrate, then pass to the lymph nodes forming metastases
What is the mechanism of blood spread of tumours?
Tumour invades blood vessels and then out of the vessels into the tissues
What is the mechanism of trans-coelomic spread of tumours?
Tumour invades the peritoneal, pleural, pericardial or subarachnoid spaces and spreads
What are common sites of metastases?
Liver Lungs Brain Bone Adrenal gland
What are the local effects of benign tumours?
Pressure
Obstruction
What are the local effects of malignant tumours?
Pressure Obstruction Tissue destruction Bleeding Pain Effects of treatment
What are the systemic effects of malignant tumours?
Secretion of hormones- normal (produced by correct organ but abnormal control) or abnormal (produced by wrong organ)
Weight loss
Effects of treatment
What is dysplasia?
Pre-malignant change that indicates a tumour is becoming malignant
Features- disorganisation of cells but no invasion
What is an intra-epithelial neoplasia?
A tumour in the epithelium that is developing and will form a malignant tumour if left unchecked or untreated
What are the phases of the cell cycle?
M, G1, S, G2
What occurs during the G1 phase of the cell cycle?
Cell growth
Synthesis of components for DNA synthesis
What happens during the S phase of the cell cycle?
DNA synthesis
What happens during the G2 phase of the cell cycle?
Cell growth
Preparation for mitosis
What two pathways are most affected by carcinogenesis?
Cyclin pRb pathway
Protein p53 pathway
How is the pRb cycle disturbed by carcinogenesis?
pRb usually acts as the cell cycle brakes, and mutation prevents this, allowing for uncontrolled growth and proliferation
How is the protein p53 pathway disturbed by carcinogenesis?
p53 normally stops the cell cycle upon damage, allowing for repair, and mutation stops this function and the cell cycle continues with these mutations, leading to cancer
What are the major causes of cancer?
Inherited predispositions
Proto-oncogene to oncogene
Viruses
Chemicals
What is the scientific basis of an MRI?
Magnetic field makes all of the protons spin in the same direction. A radio frequency pulse then distorts the protons and takes pictures by displaying the protons going back to their original positions
Explain the process and use of using contrast agents in MRIs
Galdolinium DPTA causes changes in the magnetic field, altering the tissue signals
Allows vascular lesions and some tumours to be seen very clearly
What factors are involved in staging cancer?
Position of tumour Depth of penetration of tumour Relationship of adjacent structures Involvement of regional lymph nodes Presence of metastases
What are the classes of anti-tumour therapeutics?
Alkylating agents Antimetabolites Vinca alkaloids Texans Antimitotic antibiotics
How do alkylating agents fight cancer?
Alkyl groups attach to guanine and prevent the DNA strands from separating during replication, preventing it from taking place
How do antimetabolites fight cancer?
Antimetabolites integrate themselves into the nuclear membrane or irreversibly bind with vital enzymes to prevent mitosis
How do vinca alkaloids fight cancer?
Prevent metaphase by preventing spindle formation
How do takahes fight cancer?
Promote spindle formation and then freeze mitosis at this stage
How to anti mitotic antibiotics fight cancer?
Anthracyclins and non-arythracyclins intercalate to prevent DNA and RNA synthesis
