PBL
Main mineral found in bones?
Calcium Hydroxyapatite
(Calcium phosphate complex)
Which of the following is released when there is an increase in plasma calcium?
PTH
Calcitriol
Calcitonin
Cholecalciferol
Calcitonin
Define patient autonomy
The right of competent patient to make informed decisions about their own medical care
Which vitamin/mineral supplementation has greatest evidence for reducing birth defects?
Folic Acid
What kind of organism is Giardia lamblia?
Flagellated protozoan
How does a fractured neck of femur present?
Shortened and externally rotated lower limb
Bone development and growth is best represented by which one of the following processes?
Diaphyseal plate chondrocyte hyperplasia
Endochondral ossification
Intermembranous ossification
Osteoclast activity after parathormone stimulation
Periosteal outer lining cells hypertrophy
Endochondral ossification
Outline 2 ethical issues related to the use of artificial reproductive technologies.
Family relationships - The use of donor sperm, donor eggs and surrogacy can create issues around who is the legal as opposed to biological parent of the child. Issues around the need to ‘adopt’ the child in some cases.
Informed consent - The need for full disclosure and fair representation of all the potential medical, social and emotional outcomes and risks.
Embryo status - the ethical and legal status of the human embryo
Baby's head is in the fundus. What presentation is this?
Breech presentation
Outline the function of LDL and HLD, and impact on the risk of developing atherosclerosis
Low Density Lipoproteins -> Carry cholesterol from liver to tissues. Increase risk of atherosclerosis
High Density Lipoproteins -> Remove excess cholesterol from circulation and arterial walls and return it back to the liver. In liver, they can be excreted into bile or resynthesises into VLDLs. Decrease risk of atherosclerosis
Indicate the most important actions of the 3 hormones directly responsible for calcium homeostasis
PTH stimulates bone resorption, increasing plasma Ca
Calcitonin inhibits bone resorption
1,25(OH)2D3 stimulates uptake of Ca from the gut
Describe the effect of elevated parathyroid hormone on bone density
Parathyroid hormone (PTH) induces the maturation of osteoclasts which dissolve bone to release calcium and phosphate into the circulation to maintain plasma levels. An ongoingly elevated PTH level will cause decreased bone density leading to potential osteopenia or osteoporosis in the patient
What are some examples of primary prevention of cardiovascular disease?
Attempts to reduce CV disease morbidity/mortality through risk factor modification in people without evidence of established CV disease:
For example:
Smoking cessation advice and programs
Healthy diet advice
Exercise programs
Treatment for hypertension or hypercholesterolemia
What 4 bones fuse at the pterion? What artery runs under this area? What type of haemorrhage would occur?
Parietal, frontal, temporal and sphenoid (greater wing)
Middle meningeal artery runs in greater wing of sphenoid bone. It is vulnerable to rupture and epidural haemorrhage
Dilation stage - cervical shortening and dilation
Expulsion stage - expulsion of foetus
Placental stage - delivery of placenta
Name the 2 different types of bone and describe how they differ from each other
Cortical bone is found principally in the shafts (diaphyses) of long bones and consist of a number of irregularly-spaced, overlapping cylindrical units known as Haversian systems
Trabecular bone is found principally at the ends of long bones and in vertebral bodies. It comprises a network of trabeculae within which are intercommunicating spaces. Trabecular bone is metabolically more active than cortical bone
Describe the role of the kidney in calcium homeostasis
The kidney excretes calcium and phosphate. Parathyroid hormone acts on the kidney to induce wasting of PO4 and retention of Ca in response to hypocalcemia. The renal enzyme 1a-hydroxylase converts 25-OH-Vitamin D into 1,25 – dihydroxyvitamin D (1,25(OH)2D), the most active form of Vitamin D. 1,25(OH)2D enhances the intestinal absorption of calcium and phosphate, and impacts on bone mineralisation to maintain plasma calcium and phosphate levels
List four persons, organisations or agencies that, depending on the situation, could provide consent to medical treatment of a person under the age of 18
The patient themselves
Parent
Legal guardian
Court
Guardianship board
Name the ECG leads and surface anatomy for placement (landmarks)
V1 - 4th intercostal space at the right sternal border
V2 - 4th ICS at the left sternal border
V3 - Midway between V2 and V4
V4 - 5th ICS at the left midclavicular line
V5 - At the horizontal level of V4 at the left anterior axillary line
V6 - At the horizontal level of V4 and V5 at the left midaxillary line
RA LA
RL LL
What are four features of adaptive immunity that differentiate it from innate immunity?
Adaptive immune system is antigen specific, where as innate is not
Adaptive immune system has an improved second response, innate does not
Adaptive immune system has a memory, innate does not
Adaptive immune system achieves maximal response in days, innate immune system achieves it in minutes to hours
Describe the normal bone remodelling sequence
Bone remodelling is initiated by the recruitment of osteoclasts, which act on matrix exposed by proteinases derived from bone-lining cells.
A resorptive pit is created by the osteoclasts
This resorptive phase is followed by a bone formation phase in which osteoblasts fill the lacuna with osteoid
Osteoid is subsequently mineralised to form new bone matrix
Explain 3 different sites of PTH and function?
Bone - increases RANKL/OPG ratio which increases osteoclast differentiation and activity which increases serum calcium and phosphate
Kidney - increases calcium reabsorption in the DCT and decreases phosphate reabsorption in the PCT
GIT - PTH stimulates inactive vitamin D3 to its active state (calcitriol) in the kidneys which then increases the number of calcium binding proteins in intestinal epithelial cells which increases calcium absorption
List five common criteria that governments use to determine how funds are distributed for health care
Population characteristics
Population need
Existence of fee for service
Historic levels of funding
Cost effectiveness
Lobbying groups
Political processes (elections)
Explain the mechanism of ketoacidosis and ketonuria in an anorexic patient
In starvation, increase glucagon leads to increase FFA mobilisation. FFAs undergo b-oxidation forming acetyl-CoA and enter TCA cycle, then onto ketogenesis resulting in an accumulation of acidic ketones and ketoacids. When the production of ketones exceeds that of the bodies compensatory limits, it will attempt to excrete them leading to ketonuria. When the production is above its excretion capacity, the accumulation causes metabolic acidosis.
Explain the mechanism of inherited Down Syndrome and trisomy 21 and how they differ
Inherited - Robertsonian translocation is the result of a reciprocal translocation of chromosome 21 onto another chromosome. When a parent is a balanced carrier, they will not be impacted. However, should they hand down the translocated chromatid to their offspring, it will lead to the zygote receiving effectively 3x the genetic material for chromosome 21.
Trisomy 21 is the most common genetic aberration that causes Down Syndrome. It arises due to an error called non-disjunction during meiosis, where the sister chromatids or homologous chromosomes fail to separate properly. This leads to one gamete receiving an extra copy of chromosome 21. It is not inheritable, however, there is an increase in risk of Trisomy 21 with maternal age, with mothers >45 having a 1/25 risk