BIOL 131 - FINAL EXAM

-from the nares to choanae
- hard palate: floor of nasal cavity
- Nasal Septum-partition dividing cavity into left and right
- Sinuses: cavities in nearby bone
Functions:
-cleans, humidifies, warms air
-olfaction
- along with paranasal sinuses= resonating chambers for speech

Common opening for digestive and repiratory systems
Nasopharynx- pseudostratified columnar epithelium with goblet cells. Mucus and debris is swallowed. opening of auditory tubes
- floor is soft palate (uvula is posterior extention)
- oropharynx:lined with moist stratified squamous epithelium
Laryngopharynx- epiglottis to the opening of the esophagus. lined with moist stratified squamous epithelium

Unpaired cartilages:
thyroid- largest (adams apple)
Cricoid:base of larynx
Epiglottis: attached to thyroid with a flap near base of tongue
Ligaments:
-vestibular folds or false vocal folds
-true vocal cords or vocal folds: sound production. opening between is glottis

- maintains open (patent) airway: thyroid and cricoid cartilages
- epiglottis and vestibular folds prevent swallowed material from moving into larynx
- vocal folds are primary source of sound production
-the pseudostartified siliated columnar epithelium traps debris, preventing its entery into the lower respiratory tract.
- dont forget the goblet cells which also live there

Tube of dense regular CT and smooth muscle; supported by 15-20 hyaline cartilage C-shaped rings open posteriorly. posterior surface is elastic tissue with smooth muscle
- lumen lining: pseudostratified ciliated columnar epithelium with goblet cells
- branches into left and right primary bronchi
- carina

Cartilage at bifurcation. epithelium of carina especially sensitive to irriation and inhaled objects initiate the cough reflex.

The trachea divides into two primary bronchi
- secondary bronchi : 1/lobe
-tertiary bronchi
-bronchopulmonary segments: defined by tertiary bronchi
-tertiary bronchi further subdivide into smaller and smaller bronchi, then bronchioles ( less than 1 mm in diameter), then finally into terminal bronchioles- these end in repiratory bronchioles
- cartilage: holds tube system open; smooth muslce controls tube diameter.

Site for gas exchnage
- respiratory bronchioles give rise to alveolar ducts which end as alveolar sacs- 2 or 3 alveoli at their terminus
- no cilia, but debris removed by macrophages. macrophages then move into nearby lymphatics or into terminal bronchioles

Type I pneumocytes- thin squamous epithelial cells ( 90% of surface). gas exchange
Type II pneumocytes- produce surfactant
"Dust cells"- macrophages

Two lungs: they are the principal organs of respiration
-Base sits on diaphragm
-Apex at the "top"
-Hilus on medial surface where bronchi and blood vessels enter the lung. (all the structures in hilus called root of the lungs
Right lung-3 lobes seperated by fissures
Left Lung- 2 lobes, and an indenation called the cardiac notch

Lobes- supplied by secondary bronchi
Bronchopulmonary segments- supplied by tertiary bronchi and separated from one another by connective tissue partitions).
- right lung: superior, middle, inferior
-left lung: superior, inferior
Lobules- supplied by bronchioles and separaed by incomplete partitions.

Pleural surrounds each lung, formed by pleura, filled with pleural fluid
-visceral pleura : adherent to lung
-simple serous squamous epithelium
-partietal pleura:adherent to internal thoracic wall
-- pleural fluid: acts as a lubricant and helps hold the two membranes close together (adhesion)
mediastinum: central region, contains contents of thoracic cavity except for lungs,

Two sources of blood to lungs:
- pulmonary artery brings deoxygenated blood to alveoli. This blood returns to the heart via the pulmonary veins
-- oxygenated blood travels to the tissues of the bronchi via bronchial arteries and exits through the bronchial veins (a little deoxygenated blood is mixed with the oxygenated blood)

Lymphatic vessels exit from hilus- THERES NO LYMPHATICS to drain alveoli

- air moves from area of higher pressure to area of lower pressure
Boyle's Law: P=k/V
P- gas pressure
V-volume
k- constant at a given temperature
- if barametric pressure is greater than alveolar pressure, then air flows into the alveoli
-if diaphragm contracts, then size of alveoli increases. Remember P is inversly proportional to V; so as V gets larger ( when diaphragm contracts), then pressure in alveoli gets smaller

elastic recoil:elastic fibers in the alveolar walls
suraface tension: film of fluid lines the alveoli. where water interfaces with air, polar water molecules have great attraction for each other with net pull in toward other water molecules . tends to make alveoli collapse
---surfactant: reduces tendency of lungs to collaspe by reducing surface tension. ( produced by type II pneumocytes)
---respiratory distress syndrome (hyaline membrane disease). common in infants with gestation age of less than 7 months. nots enough surfactant produced.