RACDS primary exam notes

So I'm halfway through the orientation course. So far the first few topics Cell biology and pathology have been fairly dry but fear not, it does improve! They're boring but I suppose that's because I had covered such topics in university albeit a long time ago. The particular lecturers do have a droning voice and a tendency to read off the slides but I found the topics interesting anyway. It's quite remarkable how the inner workings of the body don't breakdown more often. I do remember thinking that same thing as I learned this stuff the first time around. I thought Mark Schifter's lectures were fantastic and he's a very knowledgeable and interesting speaker. He did deserve more time to go through his content though. Microbiology was pretty much the same stuff that I encountered in university but delivered much more enthusiastically and more in depth by Laurie Walsh than he did at university. I am looking forward to further lectures on Micro, Histo and A

The seven broad topics of the RACDS are: Anatomy, Cell biology and biochemistry, Histology, Microbiology, Pathology, Pharmacology, Physiology. To consider how to study through these I reckon it is best to start small and work bigger. More macro topics such as anatomy and physiology require knowledge of building blocks such as cell biology and microbiology. In my opinion, work through the topics as follows: 1. Cell biology and biochemistry 2. Microbiology 3. Histology 4. Physiology 5. Pathology 6. Pharmacology 7. Anatomy Once you have gone through the initial set of notes, revise your way through at your leisure. Will keep you updated if my thoughts change.

An axon is responsible for the conduction of action potentials along its length to communicate between the central nervous system and the periphery. Afferent nerve fibres transmit signals from receptors in the periphery towards the nerve cell body. Nerve fibres are classified into Groups of A, B and C fibres. A and B type fibres are myelinated and C fibres are unmyelinated. Alternatively, a classification exists of sensory fibres only of Type I, II, III, IV (Figure 1). Conduction speed relates to the degree of myelination and axon diameter. Figure 1 AAlpha fibres include type Ia and b fibres and refer to afferent fibres from skeletal muscle i.e golgi tendon organs and muscle spindles ABeta and Agamma fibres are Type II fibres and are afferent fibres from stretch receptors ADelta fibres are Type III fibres and are nociception fibres relating to acute pain, cold and pressure B fibres are less myelinated than A fibres and are usually general visceral afferent fibres and pregangl

Sensation is the perception of the brain in response to the processing of signals from the periphery. Peripheral receptors transduce stimulus energy into action potentials which travel up axons for neural processing. There are two basic types of receptors (Figure 1): A) Separate receptor cell with specialised membrane activated by the stimulus. On stimulation, the receptor cell releases a chemical messenger which crosses the extracellular cleft and binds to the afferent nerve ending opening specific chemical gated channels. B) specialised nerve endings of afferent peripheral nerves. Stimulus directly opens voltage gated channels in the membrane which can be ionotropic (ligand gated ion channels) or metabotropic (acts through a second messenger) Figure 1 Some types of receptors: Skin mechanoreceptors (Figure 2): Rapidly adapting (phasic) receptors has a quickly diminishing response and then stops e.g pacinian corpuscle.It does not provide information on the duration of the st

Most body organs are efficient at a stable, defined temperature. Severe deviations from this temperature can be a sign of extreme conditions or pathology and can lead to tissue damage.  To maintain homeostasis heat input and output should be carefully regulated. The external environment has a large variety of temperatures. for a balanced, steady state body temperature, input is equal to output (Figure 1). Figure 1 Heat loss balancing heat inpupt from internal production and gain from the external environment can occur through different methods (Figure 2). Figure 2 The hypothalamus is the central regulator of thermoregulation (Figure 3). It adjusts heat production and loss to regulate temperature though negative feedback. Peripheral thermoreceptors in the skin detect changes in skin temperature from the external environment.and central thermoreceptors detect core temperatures. These communicate with the hypothalamic centres for thermoregulation to cause behavioural changes,