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Upper
- everything i the neck and head
- structures: nose, pharynx, larynx, trachea
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Two functioins of the nose
- 1. Filter incoming air
- Warm air
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Structure of the nose`
- a. Tunica mucosa of the nose is pseudostratified ciliated columnar because the respiratory system opens to the outside and thus has mucous membranes
- i. Cilia and mucus help trap particles
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At entrance of nasal cavity
Lining
- a. At the entrance of the nasal cavity are course hairs called virissae, which help to trap airborne particles
- i. Function: filter
- b. Lot of blood vessels in the lining of the nose that help warm the air
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Pharynx
- a. Small, muscular tube used by both the digestive and respiratory system
- b. Communicates with the oral, larynx, and the nasal cavity
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Divisions of the pharynx
- i. Due to this, it has three functional divisions with different linings
- 1. Nasopharynx: back of nose
- a. Pseudostratified ciliated columnar
- 2. Oropharynx: mouth
- a. Moist stratified squamous
- 3. Laryngopharynx: upper part of the larynx
- a. Moist stratified squamous
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Function of pharynx
transport of food and air
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Larynx (voice box) composition
- a. Made up of nine cartilages, 3 are paired (6), and 3 singled
- i. Singled ones form the structure of the larynx
- ii. The doubled are tiny and work in sound production
- b. Stratified squamous moist
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Epiglottis
- a. Epiglottis is a single cartilage
- i. Leaf-shaped cartilage
- ii. When you eat food, the epiglottis closes over the opening of the larynx and diverts food posteriorly into the esophagus
- iii. Serves as a cover to the entrance of the larynx (glottis)
- 1. Closes over when you’re eating
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Larynx function
voice production
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Trachea (windpipe)
- a. Function: transport of air only
- b. To prevent collapse, you have cartilage rings all along the length of the trachea
- i. In humans, those rings are not complete rings, but are C-shaped cartilage connected by muscle in the back
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Function of C-shaped cartilage
- 1. Function: keep trachea open to prevent collapse
- 2. Anteriorly is the ring; behind is an empty space
- b. Mucosa is pseudostratified ciliated columnar
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Parts of the lower respiratory tract
- respiratory tree;
- everything in the thorax
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Respiratory tree
a. Begin branching into branches of a treeà secondary bronchi until you eventually get terminal bronchioles, which are the smallest and lead into alveolar sacs, which are composed of alveoli
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Alveoli
- i. Alveoli are in lungs
- 1. Lungs are air-filled sacs
- 2. Alveoli are where gas exchange takes place between the circulatory system and your lungs
- 3. Highly vascularized because gas exchange occurs here
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Wall of alveolus
1. Because diffusion is taking place there, the wall of the alveolus is simple squamous epithelium
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Other cells of the alveoli
- septal cells
- alveolar macrophages
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Septal cells
- i. Produce surfactant
- 1. A phosopholipid that reduces surface tension in the alveoli and prevents their collapse
- 2. Must be kept open because gas exchange takes place there
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Alveolar macrophages
- i. Dust busters
- ii. Anything that got passed the pseudostratified and vibrissae will be phagocytosed by these particles
- iii. Phagocytic cells to get rid of material that ended up in alveoli
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Lungs
- a. Covered by a pleural membrane because the lungs have a serous membrane
- b. Like all serous membranes, there is the parietal and the visceral layer
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Explain the two layers of the lungs
- i. Parietal: attaches to wall of thorax
- ii. Space between is a potential space because, if you want to keep the lungs inflated, you want the pleura to remain together
- 1. Potential because it’s a very tiny space, but, generally, the two membranes are together
- 2. Reason why there is a potential space is to keep the lungs inflated
- iii. Visceral: outside of the lungs
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