BIO210Y5 Lecture Notes - Lecture 16: Stratified Squamous Epithelium, Simple Squamous Epithelium, Bronchiole

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18 Feb 2016
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Lecture 16B Notes – Respiratory Structures
Respiratory System Overview
The upper respiratory system is sometimes called the conducting system to get the air into your body
There are a lot of hollow spaces that connect in the upper respiratory system to allow the passage of air
The pharynx is shared with the digestive system – needs to be protected by epiglottis
There are layers of different types of cells that explain the function
oIn upper respiratory system, the function is to humidify and warm the air
Need a moisture environment to effectively take up the oxygen
oMucosa provides warmth and humidity
oAbove the cilia layer is the mucus the cilia move the mucus through and trap unwanted particles
oIf you collect too many particles you don’t need you collect mucus and cough it up (you’re sick!)
oNicotine makes the cilia very stiff so when smokers wake up in the morning they have a throat full of
mucus
Eventually smokers lose the cilia completely causing abnormal cells which when divide is
causing cancer
You want the pharynx to be protected stratified squamous epithelium
In the larynx you have respiratory mucosa with mucus layer
The rest of the lower respiratory system (different parts of your lungs) are there to conduct the respiration of
the body
Bronchioles and alveoli function for gas exchange so they have cuboidal or simple squamous epithelium
because gases need to diffuse across these cells so they have to be very thin
oThin boundary between respiratory system and the blood vessels
With the mucus layer you can block some of the passages below the larynx which causes cystic fibrosis
oBlocks bronchioles and bronchi
oThe thick mucus layer should be only in the larynx and should be coughed out
Upper Respiratory System
The windpipe is protected by a cartilaginous cover
When you swallow, your larynx goes up to cover the trachea so that nothing goes down the windpipe
Your palette is soft in the very back
The glottis is an opening that allows pressure and air to make sounds
oWhen you plug your nose your voice sounds different because the flow of air becomes different
The tongue has to do with how much air passes through the glottis so it is also important for the sounds
produced
The vestibular folds open or close and the cords are what vibrate when air passes through
The thyroid cartilage is like a shield the thickening of this shield is where the Adam’s apple is
The cricoid (ring) cartilage is a complete full circle (only one!)
The tracheal cartilage doesn’t go all the way around because the back has to be flexible because the
esophagus is there so you need the food to be able to go down
Cartilage is necessary to keep the trachea rigid against the pressure of getting air into and out of the lungs
oYou don’t want the trachea to collapse when you are breathing!
Lower Respiratory Surfaces
From the trachea you see branching into the bronchi
You increase the network so you increase the SA available for gas exchange
Terminal bronchioles come really close to the alveolar sacs
Pulmonary bronchi lead to the pulmonary lobules where the alveolar sacs are that are surrounding by
capillaries
Lung tissue is more elastic in its properties and this very hard network goes right through it
The middle lobe doesn’t really appear on the left lobe which has the cardiac notch to accommodate for the
heart
External and Internal Respiration
External respiration includes ventilation and what happens in the tiny alveoli structures
Internal respiration is how does tissue take up oxygen once it is in the blood and how does the need for oxygen
change
Low oxygen levels is hypoxic and almost no oxygen is anoxic
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