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 Inflammation is a stereotypic, non specific response to infection. Its functions are to: ·          Deliver components of the immune system to the site of infection ·          Eliminate pathogen (if present) ·          Repair the damage ·          Return to homeostasis Ideally the inflammatory response should be rapid (acute), destructive, but also localised and self limiting. This essay will describe the events that occur during the acute inflammatory response and discuss its importance with respect to controlling infections. Inititaition/trigger The initiation and/or trigger for the acute response is the afferent arm of the immune system. Its function is to detect dangerous stimuli (which include PAMPs but also ‘self PAMPs’) and subsequently trigger the acute inflammatory response. This serves to eith...

To answer this question first must understand what they are. These are both trypanomastid , protozoan parasites with kinetoplasts. This is an extracellular DNA that consists of maxi and mini circles of DNA which contain enzymes for mitochondria. They both have indirect life cycles where they require 2 hosts. Draw below: Trypanasome: Metacyclic -> long slender -> short stumpy -> procyclic -> epimastigote -> metacyclic Leishmania: Promastigote (infectious) -> Amastigote (back to sand fly) Here it is clear to see that vectors play a part in their transmission. Nature of sandfly vs Tsetse Tsetse is definitive host, takes up parasite on tenerial feed. Within the fly it matures and becomes infective. The actual tsetse fly is not that common as it lays pupae, not eggs. Also it prefers feeding on livestock or game rather than humans. Sandfly is much more common as each fly lays around 100 eggs. They lay them into organic matter such as soil. What is the r...

In order for a pathogenic bacterium to exploit a new host it needs to adapt to the new environment. It needs to acquire the ability to: ·          Invade the host ·          Attatch to and colonise the host tissue ·          Survive within the host avoiding both the hosts innate and adaptive immune system ·          Acquire nutritients within the host ·          Disseminate from the host and allow transmission. Often it is these attributes of the bacteria that cause its virulence (although evolution would favour the bacteria that can complete the above tasks without causing virulence as this would allow for greater transmission) The central dogma of biology states that the characteristics of an organism are determined by the DNA in the following way: DNA->RNA-> Protei...

The role of the spermatozoa is to successfully deliver the paternal DNA to the oocyte to allow for sexual reproduction to occur. In order for this to happen, several events must occur and they which will be outlined in the overview fig 1: 1)     Movement into the epididymus 2)     Spermatozoa maturation 3)     Spermatozoa release during intercourse into female vagina 4)     Overcoming the cervix 5)     Capacitation in the uterus 6)     Activation of the sperm 7)     Binding to the oocyte 8)     Fusion with the oocyte 9)     Syngamy (not discussed) This process is a very difficult task and it serves as a selection process so that only the best sperm will be able to fertilise the egg. We begin with spermatozoa in the seminiferous tubules. In this state the sperm are immature . They do not have proper movement and cannot actually swim...

Define neural crest as the ectodermal cells from the lateral neural plate. They go on to form various parts of the body such as: Skull + teeth, PNS, calcitonin producing cells, parathyroid glands, carotid bodies, spiral septum, adrenal chromaffin cells. They start from the neural tube but during development they migrate . Subsequently the study of these have given greater insight into cell migration mechanisms. Furthermore these neural crest cells are plastic and have allowed for improved understanding into how regulative development occurs. Finally labelling experiments have allowed us to trace the lineage of differentiated cells to form fate maps . This has enabled us to understand the origins of many types of cells are actually neural crest and subsequenty help us to understand why conditions such as DiGeorge’s which causes craniofacial deformities can also cause      thyroid gland agenesis and persistent truncus arteriosus. Neural crest fate mappi...

Segmentation is a key process in animal development defined as the serial repetition of tissue pattern along the axis of the body and allows differentiation of the developing organism. This differentiation in particular is mediated through Hox Genes. This essay will discuss their role and possible mechanisms for how they work. What are the hox genes? The hox genes are a set of genes that determine a segments identity. In the human there are 4 sets of 13 genes. These contain a homeobox domain which allows them to trigger the expression of various genes throughout the tissue. The exact nature of their expression is unknown however their role in patterning can be shown throughout various experiments. Experiments in flies The hox genes were originally discovered in the drosophila by Edward B lewis when he noticed that in some mutant drosphila some segments took the identity of segments above them. For example the drosophila expressed a pair of wings where it should have expressed ...