week 7 Flashcards
describe the upper respiratory tract
the upper respiratory tract is composed of the airways from the nasal cavity to the larynx
describe the lower respiratory tract
the lower respiratory tract is composed of the airways from the trachea to the lungs which are composed of the bronchi which leads to the bronchioles which lead to the alveoli
where are the lungs found?
the lungs are found in the thoracic cavity and are enclosed within the rib cage and diaphragm
describe the nasal cavity
the nasal cavity is found within the nose. it contains hairs and a mucosa to filter air and trap particles. it is connected to paranasal sinuses by small passageways
describe the 3 sections of the pharynx (throat)
nasopharynx: important for warming, humidifying, and filtering inspired air.
oropharynx: passageway for both air and food
laryngopharynx: also a common passageway for both air and food
- anterior portion opens into the larynx and posterior portion opens into the esophagus
describe the larynx
also known as the voice box, the larynx contains the vocal cords and is an important passageway for keeping food and liquids out of the respiratory tract
describe what happens to the larynx during swallowing
the larynx is lifted up by the surrounding muscles and the glottis is closed by the epiglottis - this blocks off the entryway into the larynx
glottis is the opening to the larynx
describe the trachea
- the anterior and lateral surfaces of the trachea are covered in rings of hyaline cartilage. the posterior opening allows the esophagus to expand during swallowing.
the lumen of the trachea is lined with a mucosa - pseudostratified ciliated columnar epithelial cells and goblet cells
lowest part branches into the right and left primary bronchi.
describe the bronchial tree
the primary bronchi are very similar in appearance to the trachea
as the bronchi become smaller:
- cartilage rings become incomplete and more space is found between each ring
- smooth muscle lining - the small bronchi can change diameter to control air flow into specific bronchioles and alveoli
describe the bronchioles
the bronchioles are the smallest airways. they have an inner lining composed of simple cuboidal epithelium and are enclosed within a thick ring of smooth muscle.
bronchioles have no hyaline cartilage and are lined w/ elastic fibers
airflow is modulated by bronchoconstriction and bronchodilation
respiratory bronchioles have some alveoli budding directly off the walls and each respiratory bronchiole branches into two more alveolar ducts.
describe the alveoli
the alveolar ducts end in alveolar sacs. alveoli are the final destination for inspired air within the respiratory tract - alveoli are also lined with elastic fibers
describe type I alveolar cells
- innermost layer of the resp membrane
- simple squamous cells
- account for 90% of cells in the alveoli
- gases diffuse across these cells (O2 and CO2)
describe type II alveolar cells
- small cuboidal cells
- account for 10% of alveolar wall
- responsible for making and secreting surfactant
describe alveolar macrophages
immune cells that eat up and digest debris that get into the alveolus
what does surfactant do
surfactant interrupts the H bonds that create surface tension in the inner lining of the alveoli in order to reduce this tension within the alveoli
what are the left and right lungs separated by?
they are separated by the heart and the mediastinum
the left lung only has 2 lobes (superior and inferior) and a cardiac notch (groove to make space for the heart)
right lung has 3 lobes (superior, middle, and inferior)
inferior base of the lungs rest on the diaphragm
each lung is found within a pleural cavity
describe the 2 serous membranes that each lung is encased in within the pleural cavity
parietal pleura: the outer layer, fused to the rib cage and the diaphragm - turns over itself and turns into the visceral pleura
visceral pleura: the inner layer, continuous with the surface of the lungs. divides into fissures to form the lobes
what do the pleural membranes secrete in to the pleural cavity and why
they secrete a fluid in order to lubricate the lungs as they expand and recoil during ventilation