Session 1.3 - Lecture 1 Flashcards
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3 - Development of the respiratory system
Development of the respiratory system
The respiratory system develops as a ‘diverticulum’ from the pharynx
{diverticulum: a blind tube leading from a cavity or passage.
Resp system (RS) started as a diverticulum from the GI tract (pharynx - digestive system; conducting zone of the respiratory system).
RS developed as an outpocketing (an outward growth or movement of part of a surface so as to form a pocket-like or sac-like cavity) of the anterior surface of primitive gut tube – endodermal in origin.
Implications
– interaction between resp & digestive system
– many recognised anomalies of dvlpmnt or lungs and airways
– what you need to be aware of is that this process of forming a diverticulum or outpocketing can go wrong - might not even develop any lungs (incompatible with life – baby not able to breathe) – whole load of anomalies where airways can communicate with GI tract – form fistulas {abnormal channel or passageway connecting one internal organ to another, or to the outside surface of the body} between airways and GI tract – can have important consequences bc food can get into airways – want food and air to go to right place but don’t want two to cross over}
4 - Nasal cavity
Nasal cavity
- Induce turbulent flow (nasal conchae)
- Warm and moisten inspired air
- Recover water from expired air
- Speech production (phonation)
- Olfaction
{V top of the RS – NC. NC has many functions: NC is much more than what you see on face – external nose is v small function.
NC – main thing to take away is it’s folded and presents a massive surface area of contact between air we breathe and vascular mucosa lining our nasal cavities. So therefore, your nose is able to warm the cold air you breathed in. In addition – the nasal mucosa is moist – adds water to the inhaled air. As you breathe in, moisten the inhaled air. Reason is quite obvious – gaseous exchange occurs best via water – so we need water to dissolve oxygen, therefore nasal cavity helpful to maintain lvl of humidity in lungs.
Survival advice: breathe through your nose and not your mouth (inhale & exhale) - recover some of the moisture that you would lose if you mouth breathe. Know that bc when you have a cold and you mouth breathe – end up with a really dry mouth bc lost so much water from mouth.
Obvs NC important for olfactory and sense of smell. Olfactory nerves sit right at the top – also important for speech production. Need normal sinuses to have speech – e.g. think cold, nose bunged up – voice sounds difference.
Crucial bit of anatomy is that the NC run horizontally. Important to know for when you’re passing nasogastric (NG) tubes or endoscopes into NC- need to know which way to pass that instrument or tube. Bc don’t want to shove it directly upwards – never going to back of throat – need to push it horizontally across- nasopharynx back here, down to the oesophagus – NC runs horizontally. [Think Derren Brown nail vid] all the way along the NC down to the end of the floor – tip of the nail ends nowhere near brain.}
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