Formative Flashcards
1
Q
List the categories of microorganism that cause disease
A
Bacteria Viruses Fungi Parasites Prions
2
Q
What is the role of microscopy in the diagnosis of bacterial infection?
A
Allows for staining and quick detection (but not identification) of bacteria in samples
3
Q
What is the role of culture in the diagnosis of bacterial infection?
A
Strains can be identified by colonial appearance and growth patterns
4
Q
What is the difference between sterile and non-sterile sites?
A
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
5
Q
What are some sterile sites? 4
A
Blood
CSF
Bladder
Lungs
6
Q
What are some non-sterile sites? 4
A
Skin
Nasopharynx
Urethra
Gut
7
Q
How are viruses detected?
A
Cell line must be innoculated, and electron microscopes used
Antigen election and nucleic acid amplificated used
8
Q
What is the function of bacterial ribosomes?
A
Protein synthesis
9
Q
What is the function of the plasma membrane in bacterial cells?
A
Allows diffusion
10
Q
What is the function of the bacterial cell wall?
A
Cell structure and support
11
Q
What is the function of the bacterial capsule?
A
Defence mechanism
12
Q
What is the function of the flagellum?
A
Motility
13
Q
What is the function of the fimbriae?
A
Allows adherence
14
Q
What are the main structures of a bacterial cell surface? 4
A
Plasma membrane
Penicillin binding proteins
Peptidoglycans
Lipopolysaccharides (only in gram negative)
15
Q
What is the function of penicillin binding proteins in the bacterial cell surface?
A
Synthesizes peptidoglycans
16
Q
What is the function of peptidoglycan in the bacterial cell surface?
A
Give the cell strength and shape
17
Q
What is the structure of peptidoglycan?
A
Carbohydrate polymers cross linked with amino acids
18
Q
What are the two shapes bacteria can be in?
A
Cocci= spherical Bacilli= bacilli
19
Q
Wha is the difference in structure between staph and strep?
A
Staph= clusters Strep= chains
20
Q
What can virus families be classified according to?
A
Virion shape/symmetry
Presence/ absence of envelope
Genome structure
Mode of replication
21
Q
How are viruses cultured?
A
In living cells (cell lines, tissues or intact animals)
Cell lines are grown in a nutrient containing medium with 5% CO2
22
Q
What respiratory infections are of major importance? 3
A
Influenza A
Rhinovirus
Respiratory syncytial virus
23
Q
What gastrointestinal virus is of major importance?
A
Rotavirus
24
Q
What neurological viruses are of major importance? 2
A
Enterovirus
Herpes simplex
25
What are the 3 classifications of fungi?
Basidomycetes
Ascomycetes
Zygomycetes
26
What are basidiomycetes?
Mainly mould and mushrooms, a few yeasts
27
What are ascomycetes?
Moulds and yeasts, some mushrooms
28
What are zygomycetes?
Moulds
29
What are dermatophytes?
Fungi that use keratin as a nutrient source and attack the skin and mucous membranes
30
What are systemic fungi?
Yeasts responsible for oral, skin, nail, and many other forms of infections
31
What are the main types of parasites? 3
Protozoa
Helminths
Ectoparasites
32
What is a protozoa?
A single celled organism that can only multiply in the host
33
What are helminths?
Worm parasites e.g. roundworm, tapeworm
34
What are ectoparasites?
Parasites that live on, as opposed to in, the host e.g. lice
35
What is active immunisation?
Production of antibodies in the immune system in response to the presence of an antigen, creating immunological memory
36
What is used to immunise in active immunisation?
```
Attenuated organism
Dead organism
Toxoid
Recombinant
Conjugate
```
37
What is passive immunisation?
Patient is immunised with antibodies specific to the pathogen, providing immediate protecting but no immunological memory
38
What are the advantages of using passive immunisation?
Easily stored and transported
| Safer- can be used on even immunocompromised
39
What are the gram positive coagulase positive bacteria?
Staphylococcus aureus
40
What are the gram positive coagulase negative bacteria?
Staphylococcus epidermis
| Staphylococcus saprophyticus
41
What are the gram positive aerobic non spore forming bacteria?
Listeria monocytogenes
| Corynebacterium diptheriae
42
What are the gram positive aerobic spore forming bacteria?
Bacillus species
43
What are the gram positive anaerobic spore forming bacteria?
Clostridium species
44
What are the gram positive partially haemolytic bacteria?
Streptococcus pneumonia
| Viridans streptococci
45
What are the gram positive completely haemolytic bacteria?
Streptococcus pyogenes
| Streptococcus agalactiae
46
What are the gram positive non haemolytic bacteria?
Enterococci
47
What are the gram negative cocci?
Moraxella catarrhalis
Neisseria gonorrhoeae
Neisseria meningitidus
48
What are the gram negative bacilli lactose fermenters that show growth on MacConkey's?
Escherchia coli
| Klebsiella species
49
What are the gram negative bacilli lactose non-fermenters that show growth on MacConkey's?
Proteus species
Salmonella species
Shigella species
Pseudomonas species
50
What are the gram negative anaerobic bacilli bacteria?
Bacteriodes species
Prevotilla species
Porphyromonas species
51
What are the gram negative curved bacilli?
Campylobacter species
Vibrio species
Helicobacter species
52
What are the gram negative cocci-bacilli?
Haemophilus influenzae
53
What is virulence?
A quantitive measure of the likelihood of a pathogen to cause disease
54
What are some of the virulence factors of bacteria?
Colonisation
Immunoevasion
Immunosuppression
Bacterial toxins
55
What is pathogenesis?
The process by which a pathogen causes a disease in the host
56
What is minimal inhibitory concentration?
Minimum concentration of antimicrobial required to inhibit visible growth of an organism
57
What is the minimal bactericidal concentration?
The minimum concentration of the antimicrobial needed to kill the arganism
58
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
59
What is a resistant organism?
An organism that is not killed or inhibited by the concentration of antimicrobial at the site of infection
60
What is a bactericidal?
An antimicrobial that kills bacteria
61
What is a bacteriostatic?
An antimicrobial that inhibits the growth of a bacteria
62
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
63
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
64
What are the 3 methods by which antibacterials act?
Inhibition of cell wall synthesis
Inhibition of protein synthesis
Inhibition of nucleic acid synthesis
65
What antibacterials act by inhibiting cell wall synthesis?
Penicillin and cephalosporins
| Glycopeptides
66
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
67
How to glycopeptides act as antibacterials?
Inhibit cell wall synthesis by inhibiting production of the peptidoglycan precursor in gram positive bacteria
68
Give examples of glycopeptide antibacterials
Vancomycin and teicoplanin
69
What types of antibacterials act by inhibiting protein synthesis?
Aminoglycosides
Macrolides and tetracycline
Oxazolidiones
70
What type of bacteria do aminoglycosides act on and give an example of one
Gram negative
| Gentamicin
71
What type of bacteria do macrolides and tetracycline act on and give examples
Gram positive
| Erythromycin and clairithromycin
72
What infection are oxazolidiones used to treat and give an example
MRSA
| Linezolid
73
What types of antibacterials act by inhibiting nucleic acid synthesis?
Trimethoprim and sulphamethoxazole
| Fluoroquinones
74
How do trimethoprim and sulphamethoxazole work?
Inhibit nucleic acid synthesis by inhibiting different steps in purine synthesis
75
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
76
What type of bacteria are fluoroquinolones effective against?
Gram negative
77
Give an example of a fluoroquinolone and explain why it cannot be used to treat children
Ciprofixacin
| Interferes with cartilage growth
78
What types of antifungal are there?
Polyenes
Azoles
Allylamines
Echnocandins
79
How do polyenes act as an anti fungal?
Bind to ergosterol and make the cell wall more permeable
80
Name two polyene antifungals and what they are used to treat
Amphotericin B- serious fungal and yeast infections
| Nyastatin- candida infections of the skin
81
How do azoles act as an antifungal?
Inhibit ergosterol synthesis
82
Name two azoles and what they are used to treat
Fluconazole- yeast infection
| Voriconazole and itraconazole- aspergillosis
83
How do allylamines work as antifungals?
Suppress ergosterol synthesis
84
What allylamine is in use and what is it used to treat?
Terbinafine
| Dermatophytes
85
How do echnocandins act as antifungals?
inhibit production of glucan polysaccharide
86
What organisms combat B-lactam activity and how do they do this?
Staph aureus
| Produces B-lactamas enzymes to break down penicillins and cephalosporins
87
What are the causes of acute inflammation?
```
Microorganisms
Mechanical trauma
Chemical changes
Extreme physical conditions
Dead tissue
Hypersensitivity
```
88
What are the cardinal signs of inflammation?
Dolor- pain
Calor- heat
Rubour- redness
Tumour- swelling
89
What are the benefits of acute inflammation?
Rapid response
Protects site
Neutrophils deal with damage
Plasma proteina localise process
90
Describe the change in blood vessel radius during acute inflammation
Transient arteriolar constriction followed by local arteriolar dilation (flush and flare)
91
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
92
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
93
List the systemic effects of acute inflammation
Pyrexia
General malaise
Neutrophilia
Septic shock
94
How can acute inflammation be detrimental to the patient?
Spread t the bloodstream causing sepsis
Bacteraemia
Septicaemia
Toxaemia
95
What cell types are involved in chronic inflammation?
Lymphocytes
Macrophages
Plasma cells
Fibroblasts
96
What are the major causes of chronic inflammation?
Arising from acute inflammation
| Arising as primary lesion
97
How can chronic inflammation arise from acute inflammation?
Large volume of damage
Inability to remove debris
Fails to resolve
98
How can chronic inflammation arise as a primary lesion?
Autoimmune disorder
Material resistant to cellular digestion
Exogenous substances
Endogenous substances
99
What are the effects of chronic inflammation?
Scarring and fibrosis
| Granuloma formation
100
What factors promote healing and repair?
```
Cleanliness
Apposition of edges
Sound nutrition
Metabolic stability and normality
Normal inflammatory and coagulation mechanisms
```
101
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
```
102
What kind of reaction is type I sensitivity?
Allergic reaction
103
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
104
What is a type II hyper sensitivity reaction?
The antibodies bind to antigens on the patient's own cell surface
105
What immunoglobulins are involved in type II hypersensitivity?
IgG and IgM
106
When do type III hypersensitivity reactions occur?
When there is an accumulation of immune complexes that cannot be cleared from the circulation
107
How long do type IV hypersensitivity reactions take to develop?
2-3 days
108
How are type IV hypersensitivity reactions mediated?
Through CD4 helper T cells
109
What is the process of a type IV hypersensitivity reaction?
CD4 cells recognise the antigen and produce cytokines, leading to an inflammatory response
110
What is an early phase response?
A response occurring within minutes performed by mast cell mediators
111
What is a late phase response?
Takes longer to respond with newly synthesised mediators
112
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
113
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
114
What factors are involved in the aetiology of the immune system?
Genetic factors
Immune regulatory factors
Hormonal factors
Environmental factors
115
What pathogenic mechanisms are involved in autoimmune disease?
```
Cell mediated
Antibody mediated
Antibody+ complement
Immune complex mediated
Recruitment of innate compounds
```
116
What are the 2 types of autoimmune disease?
Organ specific
| Non-organ specific
117
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
118
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
119
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
120
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
121
What factors affect the absorption of a drug from the GI tract?
Gut motility
Food
Illness
122
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
123
What is first pass metabolism?
Metabolism of the drug prior to it reaching the site of absorption
124
Where does first pass metabolism mainly occur?
```
Gut lumen (acid enzymes)
Gut wall (metabolic enzymes)
Liver (hepatic enzymes)
```
125
How can first pass metabolism be avoided?
Using different delivery methods
126
What are the benefits of administering drugs IV?
100% bioavailability
| Avoids first pass metabolism
127
What are the benefits of administering drugs topically?
Controlled, sustained doses of drug
| Avoids first pass metabolism
128
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
```
129
What is the bioavailability of a drug?
Amount of drug which reaches the circulation and is available for action
130
What factors affect bioavailability?
Formulation
Drug's ability to pass physiological carriers
Gastrointestinal effects
First pass metabolism
131
What affects a drug's ability to pass physiological barriers?
Particle size
Lipid solubility
pH and ionisation
132
What factors affect drug distribution?
```
Tissue perfusion
Membrane characteristics
Transport mechanisms
Disease/other drugs
Elimination
```
133
What membrane characteristics affect drug distribution?
Blood brain barrier
| Blood testes/ovaries barrier
134
What factors does renal filtration depend on?
Glomerular filtration
Passive tubular reabsorption
Active tubular reabsorption
135
What is glomerular filtration?
All unbound drugs are filtered at the glomerulus provided their size or charge doesn't prevent this
136
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
137
What is active tubular reabsorption?
Some drugs are actively secreted into the proximal tubules of the kidneys for excretion
138
What is drug metabolism?
Biochemical modification of pharmaceutical substances by living organisms usually through specialised enzymatic activity
139
What 3 reactions can be involved in phase 1 metabolism?
Oxidation
Reduction
Hydrolysis
140
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
141
What enzymes carry out phase 1 metabolism?
Cytochroms P450
142
What reaction is involved in phase 2 metabolism?
Conjugation
143
How does conjugation metabolise the drug?
Attaches glucuronic acid, glutathione, sulphate or acetate to the metabolite generated in phase 1
144
What does conjugated the drug achieve?
Increases water solubility, enhancing excretion
| Usuall results in activation of the drug
145
What factors inhibit or induce drug metabolism?
```
Other drugs/substances
Genetics
Hepatic blood flow
Liver disease
Age
Sex
Ethnicity
```
146
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
```
147
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
148
How does age affect drug metabolism?
Metabolising enzymes often absent or reduced in foetuses or premature babies, renal disruption common
149
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
150
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
```
151
What are the types of adverse drug reaction?
```
Augmented
Bizarre
Chronic
Delayed
End of treatment
Failure of treatment
```
152
Describe what is meant by an augmented adverse drug reaction
Predictable, dose dependent reaction that resolves when the drug is stopped
153
Describe what is meant by a bizarre adverse drug reaction
Unpredictable, rare reaction that can cause serious illness or death
154
Describe what is meant by a chronic adverse drug reaction
Semi-predictable reaction related to the dose and length of treatment
155
Describe what is meant by a delayed adverse drug reaction
Occurs years after treatment in patient or children of patient
156
Describe what is meant by an end of treatment adverse drug reaction
Effects caused when drug treatment is stopped
157
Describe what is meant by a failure of treatment adverse drug reaction
Common reaction frequently caused by drug interactions
158
What are the common mechanisms of drug-drug interactions?
```
Pharmacodynamic
Pharmacokinetic
Distribution
Metabolism
Elimination
```
159
When do pharmacodynamic drug interactions happen?
When drugs act on the same or interrelated receptors, resulting in additive, synergistic or antagonistic effects
160
What are pharmacokinetic drug interactions?
Interactions affecting absorption, distribution, metabolism or excretion
161
When are pharmacokinetic drug interactions important?
When drug has a short half life or rapid results are needed
162
What are distribution drug interactions?
Interactions that cause an alteration in the distribution of the drug
163
What are metabolism drug interactions?
One drug influencing the metabolism of another
164
What are elimination drug interactions?
Interactions between drugs that cause alterations in their elimination from the system
165
What factors predispose a patient towards drug interactions?
```
Higher number of drugs
Age
Critical illness
Undergoing surgery
Chronic underlying conditions
```
166
What are the uses of a clinical study?
Provide evidence
Test efficacy
Test safety
167
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
```
168
What are the types of clinical trial? 12
```
Double blind
Single blind
Randomised
Placebo controlled
Prospective
Retrospective
Cross over
Sequential
Parallel
Factorial
Large simple
```
169
What are single blind trials?
The patient doesn't know what treatment they are receiving but the doctor does
170
What is a randomised trial?
Patients are assorted to groups randomly to prevent bias
171
What is a placebo controlled trial?
Half of patients are given a placebo and half given the treatment and comparisons made
172
What is a retrospective trial?
The data is collected from past records and does not follow patients
173
What is a prospective trial?
Participants differ with certain respects under study and differences in outcome monitored
174
What is a cross over trial?
Participants receive a sequence of different treatments
175
What is a sequential trial?
A trial where the sample size is not fixed in advance
176
What is a parallel study?
Two groups of participants are given two different drugs
177
What are factorial clinical trials?
More than one factor is evaluated
178
What is a large simple trial?
Deals with fewer aspects in a larger sample size
179
What is the structure of DNA?
2 chains of nucleotides bound in a double helix structure
180
What is the structure of a nucleotide?
Deoxyribose pentose sugar, phosphate and a base
181
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
182
Why can DNA synthesis be described as semi-conservative?
One half of each new strand of DNA id 'old'
183
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
184
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
185
What are the different kinds of DNA mutation?
Silent
Missense
Nonsense
Frameshift
186
What are silent mutations?
One base change that does not result in a change of amino acid
187
What are missense mutations?
The wrong amino acid is coded for
188
What are nonsense mutations?
A stop codon is coded for prematurely, resulting in a small protein
189
What are frameshift mutations?
Insertion or deletion mutations that result in the whole sequence being changed
190
What is the polymerase chain reaction used for?
Forensic medicine
Genetic identification
Detections of mutations
DNA cloning
191
What does gel electrophoresis do?
Separates DNA fragments by size using an electric field
192
What are the advantages of gel electrophoresis?
Quick
Easy to use
Robust
Sensitive
193
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
194
What is amplification refraction mutation system?
Normal and mutant primers used with strands of DNA to detect a mutation
195
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
196
Describe the difference between heterochromatin and euchromatin
```
Euchromatin= open structure, being expressed
Heterochromatin= dense, tightly bound structure not being used
```
197
Describe the structure of a nucleosome
146 negative base pairs wrapped around 8 positive histone proteins
198
What are the stages of mitosis?
```
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokenesis
```
199
Describe the steps of prophase
Chromosomes condense
Nuclear membrane disappears
Spindle fibres form from centrioles
200
Describe the steps of metaphase
Chromosomes align at the cell equator and attach to spindle fibres
201
Describe the steps of anaphase
Sister chromatids separate longitudinally at centromere
| Move to opposite poles of the cell
202
Describe the steps of telophase
New nuclear membrane forms and each cell has 46 chromosomes
203
Describe the steps of cytokenesis
Cytoplasm separates and 2 new daughter cells form
204
How do the first and second divisions of meiosis differ?
In the second division, the chromosomes are not copies and haploid cells are created
205
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
```
206
What us meant by a trisomy abnormality?
There are 3 copies of a chromosome instead of 2
207
What condition occurs from trisomy 21 and give symptoms
Downs syndrome
| Distinct facial characteristics and IQ less than 50
208
What condition occurs from trisomy 13 and give symptoms
Patau syndrome
| Multiple dysmorphic features, few live beyond first year
209
What condition is caused by trisomy 18 and give life span
Edwards syndrome
| 1 month-1 year
210
What condition would have 46, X?
Turner syndrome
211
What condition would have 46, XXY?
Klinefelter syndrome
212
What is a Robertsonian translocation?
One chromosome has the two long arms while the other has the two short arms
213
What is a chromosomal deletion?
Sections of the chromosome 'disappear' from one or both of the arms
214
What is a chromosomal inversion?
A section of DNA is inverted
215
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
```
216
What are the three types of sex linked abnormalities?
X linked recessive
X linked dominant
Y linked
217
What is non-mendelian inheritance?
Inheritance that doesn't follow Mendel's laws
218
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
219
Give examples of non-mendelian inheritance
Anticipation- Huntington's, Myotonic dystrophy, fragile X syndrome
Mitochondrial disease- maternal inheritance
220
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
221
What factors affect the Hardy-Weinberg principle?
```
Mutation
Migration
Population
Mating
Selective pressures
```
222
Where are the gene mutations in myotonic dystrophy and Duchenne muscular dystrophy?
Myotonic- autosomal genes
| Duchenne- X chromosome
223
What are photo-oncogenes?
Genes that code for cell growth and regulation
| Mutations can turn these into oncogenes
224
What are oncogenes?
Genes that accelerate cell growth, forming a tumour
225
What are tumour suppressor genes?
Genes that inhibit the cell cycle and/or promote apoptosis
226
How many mutations are needed to cause cancer in a photo-oncogene and tumour suppressor genes?
Proto-oncogenes= 1
| Tumour suppressor= 2
227
What are benign and malignant tumours of the squamous epithelia called?
```
Benign= squamous papilloma
Malignant= squamous carcinoma
```
228
What are benign and malignant tumours of the glandular epithelia called?
```
Benign= adenoma
Malignant= adenocarcinoma
```
229
What are benign and malignant tumours of the bone called?
```
Benign= osteoma
Malignant= osteosarcoma
```
230
What are benign and malignant tumours of theft called?
```
Benign= lipoma
Malignant= liposarcoma
```
231
What are benign and malignant tumours of the fibrous tissue called?
```
Benign= fibroma
Malignant= fibrosarcoma
```
232
What is cancer of the lymphoid tissue called?
Lymphoma
233
What are tumours of the gremlin cells called?
Teratomas
Ovary usually benign
Testes usually malignant
234
What are the differences between benign and malignant cells' growth pattern?
```
Benign= non invasive
Malignant= invasive
```
235
What are the differences between benign and malignant cells' capsules?
```
Benign= usually encapsulated
Malignant= no capsule, or capsule has been breached
```
236
What are the differences between benign and malignant cells' cell shape?
```
Benign= cells similar to normal
Malignant= cells abnormal
```
237
What are the differences between benign and malignant cells' function?
```
Benign= function similar to normal tissue
Malignant= loss of function
```
238
What are the differences between benign and malignant cells' differentiation?
```
Benign= well differentiated
Malignant= poorly differentiated
```
239
What are the properties of cancer cells?
Altered genetics
Altered cellular function
Abnormal structure
Cells capable of independent growth
240
What are the mechanisms of cancer spread?
Local spread
Lymphatic spread
Blood spread
Trans-coelomic spread
241
What is the mechanism of local spread of tumours?
Malignant tumour invades surrounding connective tissue and into the lymph/blood vessels
242
What is the mechanism of lymphatic spread of tumours?
Tumour cells adhere to lymph vessels, penetrate, then pass to the lymph nodes forming metastases
243
What is the mechanism of blood spread of tumours?
Tumour invades blood vessels and then out of the vessels into the tissues
244
What is the mechanism of trans-coelomic spread of tumours?
Tumour invades the peritoneal, pleural, pericardial or subarachnoid spaces and spreads
245
What are common sites of metastases?
```
Liver
Lungs
Brain
Bone
Adrenal gland
```
246
What are the local effects of benign tumours?
Pressure
| Obstruction
247
What are the local effects of malignant tumours?
```
Pressure
Obstruction
Tissue destruction
Bleeding
Pain
Effects of treatment
```
248
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
249
What is dysplasia?
Pre-malignant change that indicates a tumour is becoming malignant
Features- disorganisation of cells but no invasion
250
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
251
What are the phases of the cell cycle?
M, G1, S, G2
252
What occurs during the G1 phase of the cell cycle?
Cell growth
| Synthesis of components for DNA synthesis
253
What happens during the S phase of the cell cycle?
DNA synthesis
254
What happens during the G2 phase of the cell cycle?
Cell growth
| Preparation for mitosis
255
What two pathways are most affected by carcinogenesis?
Cyclin pRb pathway
| Protein p53 pathway
256
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
257
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
258
What are the major causes of cancer?
Inherited predispositions
Proto-oncogene to oncogene
Viruses
Chemicals
259
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
260
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
261
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
```
262
What are the classes of anti-tumour therapeutics?
```
Alkylating agents
Antimetabolites
Vinca alkaloids
Texans
Antimitotic antibiotics
```
263
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
264
How do antimetabolites fight cancer?
Antimetabolites integrate themselves into the nuclear membrane or irreversibly bind with vital enzymes to prevent mitosis
265
How do vinca alkaloids fight cancer?
Prevent metaphase by preventing spindle formation
266
How do takahes fight cancer?
Promote spindle formation and then freeze mitosis at this stage
267
How to anti mitotic antibiotics fight cancer?
Anthracyclins and non-arythracyclins intercalate to prevent DNA and RNA synthesis
