Formatives Past Papers 3 Flashcards
What type of genetic mutation results in Turners Syndrome?
Turners Syndrome = A chromosomal disorder in which a female is born with only one X chromosome. Turner syndrome results from a missing or incomplete sex chromosome.
The genetic alterations of Turner syndrome may be one of the following:
- Monosomy = complete absence of an X chromosome - error in the gametes (eg. error in meiosis)
- Mosaicism = error occurs in cell division during early stages of fetal development - results in some cells in the body having two complete copies of the X chromosome while other cells have only one copy of the X chromosome.
- X chromosome abnormalities = Abnormal or missing parts of one of the X chromosomes can occur. Cells have one complete and one altered copy. This error can occur in the sperm or egg with all cells having one complete and one altered copy. Or the error can occur in cell division in early fetal development so that only some cells contain the abnormal or missing parts of one of the X chromosomes (mosaicism).
- Y chromosome material = In a small percentage of Turner syndrome cases, some cells have one copy of the X chromosome and other cells have one copy of the X chromosome and some Y chromosome material. These individuals develop biologically as female.
A football patient comes in with upper left shoulder pain and low bp / high heart rate.
List 3 reasons to establish IV access in the patient.
- Administration of intravenous fluids - fluid replacement for shock
- Administration of drugs - pain releif +prophylactic Abs if open fracture
- Measurement of blood gases etc.
The yearly average of Hepatitis C cases in a town is 4. Why is 4 cases in the month of May alone an epidemic?
Epidemic = a widespread occurrence of an infectious disease in a community at a particular time.
If yearly average = 4 then 4 in the month of May alone is alot for that particular time.
What are four ethical concerns with a doctor not using a translator to a non English/deaf patient?
Cannot consent if don’t understand the information
Dad is carrier of a CFTR mutation and mum isn’t. How would you explain the risk the child having CF?
The risk of the child having CF = 0
Risk of child being a carrier = 50%
CC x Cc = CC, Cc, CC, Cc
What are the major risk factors for breast cancer?
Major Risk Factors for Breast Cancer
-
Genetics/Family History
- mutation of tumour suppressor genes - eg. BRCA1/BRCA2
- Increase protooncogenes - eg. HER2
-
Demographics
- Increased age
- Gender - Female (99%) vs Male
- Prolonged Estrogen Exposure
X number of Skateboarders have accidents - why cant we do a relative risk for this group.
We don’t know the total number of skateboarders in NSW.
What area of the prostate grows in BPH?
Transition zone (TZ)- Anterior lobe/Isthmus
- Hyperplasia through impaired cell death caused by androgen-induced stromal cell proliferation
- BPH involves hyperplasia of both epithelial and stromal components of the prostate
- Increased stromal: epithelial ratio
- Dihydrotestosterone (DHT) a metabolite of testosterone mediates prostatic growth via producing GF
- DHT formed in prostate by conversion of testosterone by enzyme type 2 5 -reducase (produced by stromal cells)
- DTH binds to nuclear androgen receptor -> transcription of androgen-related genes
- Increased growth factors + growth factor receptors; most important = fibroblast growth factor, esp. FGF-7, produced by stromal cells
List 2 types of fluid replacement and 2 examples of each.
Patient has yellow sclera, malaise, anorexia and fatigue. What 6 symptoms you would need to ask about to come up with ddx.
Symptoms of Hepatitis
- Fever
- Fatigue
- Loss of appetite
- Nausea
- Vomiting
- Abdominal pain
- Dark urine
- Pale-colored stools
- Joint pain
- Jaundice
What are some symptoms of Type II Diabetes.
Symptoms of Type II Diabetes
- Increased thirst
- Frequent urination
- Increased hunger
- Unintended weight loss
- Fatigue
- Blurred vision
- Slow-healing sores
- Frequent infections
- Numbness or tingling in the hands or feet
- Areas of darkened skin, usually in the armpits and neck
A patient has a mass directly behind the stomach, and also enlargement of the c section of the duodenum. Where is the mass likely to have originated from.
Pancreas
What is the appearance of E. coli on a gram stain?
E. Coli
Gram negative bacilli (rod shaped) - stains pink
Why does E coli commonly cause UTIs?
E. Coli often gains entry into the urinary tract via stool. Women are particularly at risk for UTIs because their urethra sits close to the anus, where E. coli is present (commensal).
Inhibition of PEP Carboxykinase does what?
PEP carboxykinase = an enzyme used in the metabolic pathway of gluconeogenesis.
- It converts oxaloacetate into phosphoenolpyruvate (PEP) and carbon dioxide.
Inhibition of PEP Carboxykinase = oxaloacetate NOT converted into PEP + CO2 = won’t be able to form glucose (impaired gluconeogenesis)
Which types of hepatitis can be vaccinated against?
Hep A = YES
Hep B = YES
Hep C = NO
Hep D = YES - Hep B vaccine
Hep E = NO (but in development)
Inherited vs non-inherited Down syndrome
- Trisomy 21 = De novo
- Translocation
- Mosacism = Both de novo + genetic influences
What area of the antibody is changed during Isotype class switching?
Fc region
- An antibody class is determined by the heavy chain of the antibody.
- The constant heavy chain segment create the Fc region, which is vital for binding to Fc receptors on other cell types and mediating antibody function.
- Changes in this region by class switching will, therefore, alter the functional abilities of the antibody without altering the specificity of the paratope (antigen binding site).
Patient has taken a positive inotrope, assuming preload and afterload remain constant, what will happen?
Positive inotrope = an agent that will increase myocardial contractility by increasing the velocity and force of myocardial fiber shorterning.
End systolic volume will be decreased
Increases in inotropic state help to maintain SV at high HR and elevated MAP. Increased HR alone decreases SV because of reduced time for diastolic filling, which decreases end-diastolic volume.
When in the cardiac cycle is arterial pressure the greatest?
(isovolumetric contraction, isovolumetric relaxation, or ventricular ejection, etc.)
Phases of Cardiac Cycle
- (a) Ventricular filling and (b) Atrial Systole
- Isovolumetric contraction
- Ventricular ejection
- Isovolumetric relaxation
Draw a simple diagram of how insulin and glucagon maintain BSL
Insulin - reduces BSL by moving glucose into cells (GLUT2 - a transmembrane carrier protein that enables protein facilitated glucose movement across cell membranes.)
Glucagon - raises BSL
What are the effects of glucagon in the body?
Fasting State - Glucagon released from Alpha cells (pancreas) in response to low BSLs
- Brain = ↓ food intake, ↓appetite, ↑satiety
- Pancreas = ↑insulin secretion
- Liver = ↑Glucose production, ↓Glucose breakdown, ↑Lipid breakdown, ↓Lipid production, ↑ketone body production, ↑amino acid breakdown
- Brown adipose tissue = ↑resting energy expenditure
- Heart = ↑HR + ↑Contractility
What are the different classes of shock?
Define the physiological response of the heart to shock
-
Shock: occurs when the circulation of blood fails to deliver sufficient oxygen [and nutrients] to sustain aerobic metabolism.
- Consequence of insufficient tissue perfusion, resulting in inadequate cellular oxygenation and accumulation of metabolic wastes .
- Heart responds to ↓MAP by ↑HR, ↑myocardial contractility and ↑TPR (vasoconstriction)
- stimulation via the SNS on heart and vessels
What are the contents of the inguinal canal?
Inguinal Canal Contents
In males
- Spermatic cord and it’s contents
- Ilio inguinal nerve
In females
- Round ligament of uterus
- Ilio inguinal nerve
Name the borders of the inguinal canal (roof, bottom, anterior and posterior)
Inguinal Canal Borders
Inguinal canal = Tunnel extending from deep to superficial inguinal ring, paralleling inguinal ligament
- Roof = Arching muscle fibres of internal abdominal oblique and transversalis abdominal muscles
- Bottom/Floor = inguinal ligament (ASIS –> pubic tubercle)
- Anterior wall = Aponeuroses of external and internal abdominal oblique muscles
- Posterior wall = Transversalis fascia
A guy has a perianal abscess. What lymph nodes would be swollen if:
A) the abscess is ABOVE the pectinate line.
B) the abscess is BELOW the pectinate line
The pectinate line = a line which divides the upper two thirds and lower third of the anal canal. Developmentally, this line represents the hindgut-proctodeum junction.
ABOVE pectinate line = internal iliac lymph nodes
BELOW pectinate line = superficial inguinal lymph nodes
3 times where it’s acceptable to breach patient confidentiality/privacy
Exceptions to confidentiality
- When required to do so by law (summon, subpoena, legislation, court order)
- When patient has given consent to share the information
- If there is a serious and imminent threat to their life or the lives of others
- Patient is harming themself
- Patient is harming someone else
- Patient is being harmed by someone (mandatory reporting)
Why does St John’s wort reduce the effectiveness of the oral contraceptive pill?
St John’s wort = an inducer of cytochrome P450 (CYP) 3A enzymes
- The combined oral contraceptive pill contains ethinyloestradiol and levonorgestrel
- Ethinyloestradiol and levonorgestrel are metabolised by CYP3A4
- StJohn’s wort may induce (give rise to) CYP3A4
- ↑CYP3A4 = ↑metabolism = ↓blood levels
- St John’s wort may reduce ethinyloestradiol and levonorgestrel blood levels leading to breakthrough bleeding and reduced efficacy of the oral contraceptive
Leukemia symptoms and their pathophysiology - silly question - needs to specify which leukemia!
Leukaemia = cancer of blood-forming tissues, including bone marrow. Many types exist such as acute lymphoblastic leukaemia, acute myeloid leukaemia and chronic lymphocytic leukaemia.
Symptoms = Fatigue, weight loss, frequent infections and easy bleeding or bruising.
Omeprazole works via inhibiting what enzyme and what does this do physiologically?
Omeprazole = Proton Pump Inhibitor
- They bind to H+/K+ ATPase and inhibit the proton pump
- Produce a potent and long lasting suppression of basal and stimulated gastric acid secretion
- As they act distal to the receptors they can reduce gastric acid secretion irrespective of the stimulus (acetylcholine, histamine or gastrin)
In a patient suffering hypovolemic shock, why does the heart beat faster?
Hypovolemic shock = Reduction in blood volume for adequate tissue perfusion
- Blood loss could be due to:
- Loss to an extravascular cavity (hemorrhage).
- Shift of plasma into the tissues if substantial amount of interstitial fluid are lost (burns).
- Loss of blood = ↓ venous return = ↓EDV = ↓SV = ↓CO = ↓MAP.
- MAP = CO x TPR
- CO = HR x SV
- MAP = (HRxSV) x TPR
- ↓MAP = ↑HR
- SNS response on heart
Pneumonia occurs approx 15 times per 8000 in a town, and diabetes occurrence X times per 1000 - what is the chance a diabetic gets pneumonia.
Prevalence of pneumonia = 15/8000
Prevalence of pneumonia in diabetics = X/1000
X = 15 x 8 = 80 + 40 = 120
What are the common types of organisms that colonize a person with cf lungs.
- H. influenzae
- S. aureus
- P. aeruginosa
What phase of the cell cycle are cells most sensitive to radioactive treatment?
Cells in mitosis and G2 are the most radiosensitive
A person has large sized red blood cells. What type of deficiency are they experiencing?
Large RBCs = Macrocytosis - seen in:
- B12 deficiency = Because DNA synthesis requires B12 as a cofactor, a deficiency of the vitamin leads to decreased DNA synthesis in the erythrocyte, thus resulting in macrocytosis.
- Folate deficiency
A person has normal red blood cells but a reduced amount. What deficiency could they have?
Increased/premature erythrocyte destruction: Haemolytic Anaemias
- glucose-6-phosphate dehydrogenase deficiency: G6PD is the only source of NADP in RBC and so these cells have a reduced capacity to regenerate reduced glutathione and thus the RBC become more sensitive to oxidative destruction.
What are two physiological reasons for hyperbilirubenemia.
Hyperbilirubenemia = build up of bilirubin in the blood
- Prehepatic jaundice
- unconjugated hyperbilirubenemia
- excessive extrahepatic production of bilirubin
- Eg. haemolytic anaemia
- Hepatic jaundice
- Unconjugated hyperbilirubinaemia
- Reduced hepatocyte uptake (drug interference)
- Impaired conjugation (drug/viral induced hepatitis, cirrhosis)
- Conjugated hyperbilirubinaemia
- Decreased hepatocellular excretion (deficiency of canalicular transporters)
- Unconjugated hyperbilirubinaemia
- Post hepatic jaundice
- Conjugated hyperbilirubinaemia
- Impaired bile flow (gallstones)
What are the enzymes in enzymes in a liver function test?
Why do men have a greater chance of bph as they get older.
Less testosterone but Dihydrotestosterone (DHT) still being produced (10x more potent)
- DHT = a metabolite of testosterone mediates prostatic growth via producing GF
- DHT formed in prostate by conversion of testosterone by enzyme type 2 5alpha-reducase (produced by stromal cells)
- As men age, the enzymes aromatase and 5-alpha reductase increase in activity. These enzymes are responsible for converting androgen hormones into estrogen and dihydrotestosterone, respectively. This metabolism of androgen hormones leads to a decrease in testosterone but increased levels of DHT and estrogen.
A competitive antagonist possesses what qualities (efficacy and affinity)?
- Affinity = the ability of a natural substance, or a drug to form a drug-receptor complex
-
Efficacy = the maximum response a drug can produce
- When the formation of a drug-receptor complex activates the receptor, and an overt response occurs it is called efficacy or intrinsic activity
-
Key and lock analogy
- Key goes into the lock (affinity)
- Key is turned and door opens (efficacy/intrinsic activity)
-
Competitive Antagonist = reduces affinity but not efficacy –> will need a higher agonist concentration to outcompete and achieve the same efficacy
- A competitive antagonist shifts the agonist dose response curve to the right
What are two major differences between mitosis and meiosis
Meiosis
- Generation of 1-4 non-identical gametes
- Recombination/crossing over of chromosomes during prophase I
- DNA content = Haploid (half no. of chromosomes)
- No of cell divisions = One cell division (4 stages total)
Mitosis
- Generation of two identical daughter cells (somatic cells)
- No recombination/crossing over in prophase
- DNA content = Diploid
- No of cell divisions = Two cell divisions (8 stages total)
What compartment of the femoral sheath does the femoral artery reside in (medial, superficial etc).
The 3 compartments of the femoral sheath include:
-
The lateral compartment
- femoral artery
- femoral branch of genitofemoral nerve
-
The middle compartment
- femoral vein
-
The medial compartment
- femoral canal
- lymphatics
How does typhoid differ from general e.coli?
Cause of Typhoid = Salmonella Typhi (S. Typhi)
E.Coli = gram negative rod (bacillus)
List 6 clinical symptoms of acute leukemia.
Acute Leukemia - Clinical Symptoms
- Bleeding from the gums
- Bone pain
- Fever
- Frequent infections
- Frequent or severe nosebleeds
- Lumps caused by swollen lymph nodes in and around the neck, armpits, abdomen or groin
- Pale skin
- Shortness of breath
- Weakness, fatigue or a general decrease in energy
What is the term for the pressure the heart has to pump against?
Mean Arterial Pressure
Define Central tolerance and positive/negative selection
Central tolerance = the process of eliminating any developing T or B lymphocytes that are reactive to self. Through elimination of autoreactive lymphocytes, tolerance ensures that the immune system does not attack self peptides.
Positive Selection
- Occurs early on in T cell development
- T cells interact with MHC expressed on epithelial cells in the cortex
- TCR must weakly interact with MHC (positive signal) otherwise the T cell undergoes apoptosis
- Determines a T cell to become a CD4 or CD8 T cell
Negative Selection = To decrease chances of auto immunity B cells undergo negative selection.
- If TCR binds too strongly to self-MHC or to the complex of self- MHC and self-peptide, -> apoptosis
- Eliminates self-reactive T cells (that could cause autoimmunity)
- T cells that do not strongly recognise self- peptide + MHC are allowed to migrate to the periphery
