ch. 21 Flashcards
Role of Respiratory system
-provide O2 and remove CO2 which are produced during cellular respiration (the burning or oxidation of glucose to produce ATP).
Conducting zone vs. respiratory zone
Respiratory- actual site of gas exchange
- composed of the respiratory bronchioles, alveolar ducts, and alveoli (all microscopic structures)
Conducting- includes all other respiratory passageways, which provide fairly rigid conduits for all air to reach gas exchange sites.
-organs cleanse, humidify, and warm incoming air(so air reaching lungs has fewer irritants)
Nose and nasal cavity
-nose consists of external nose and nasal cavity which is internal;
-floor of the cavity is the hard and soft palate. -Hairs in nasal vestibule, presence of mucous and serous glands, secretion of lysozyme and mucus, cleanse and humidify the air.
-Role of cilia.
Presence of an abundant blood supply: warming the air.
-Posterior nasal apertures open to the pharynx.
Pharynx
description, function?
- passageway connecting nasal cavity to larynx and oral cavity to esophagus.
- passageway for air and food
3 subdivisions of Pharynx and their locations
- Nasopharynx(region posterior to the nasal cavity,from internal choanae to soft palate)
- oropharynx (region posterior to root of tongue)
- laryngopharynx ( region posterior to behind larynx, from epiglottis to cricoid cartilage)
nasopharynx
air only in this region, soft palate and uvula closing off the nasopharynx when swallowing, floor is hard palate and part of soft palate, adenoids (pharyngeal tonsil)
oropharynx
palatine and lingual tonsils, air /food possible
laryngopharynx
air/food possible..
Larynx “voice box” (Description)
- made of 9 cartilages
- 3 main ones to know- thyroid, cricoid, epiglottis
functions of epiglottis when swallowing
- larynz is pulled to superiorly and the epiglottis tips to cover laryngeal inlet (this keeps food out of lower respiratory passages)
- “guardian of the airways”
voice..
-Voice production by the lower set of (true) vocal cords (vocal folds). Exhaled air passes through the glottis and causes the vocal cords to vibrate. Tense, thin, shorter cords vibrate faster and produce higher sounds
Anatomy/functions of Trachea “windpipe”
-tracheal cartilage
- pseudostratified ciliated epithelium
- C shaped cartilage rings with trachealis muscle at the posterior where the esophagus is(allows it to bulge into the trachea during swallowing.)
- Contraction of trachealis muscle increases pressure of a cough.
- Carina, sensitive area.
Bronchial tree
Right and left main (primary) bronchi, lobar (secondary) bronchi, segmental (tertiary) bronchi→bronchioles, terminal bronchioles (last conducting zone passageway). Cartilage replaced by smooth muscle.
start of respiratory zone:
respiratory bronchioles → alveolar ducts→ alveoli. Alveolar sac =bunch of “grapes,” each alveolus is a “grape.”
respiratory membrane
simple squamous epithelium of alveolus (type I cell) + fused basement membranes + simple squamous epithelium of capillary.
Type II cells and surfactant (Role?)
-role in reducing surface tension so alveoli can expand easier
Infant respiratory distress syndrome
-breathing disorder more common in premature babies
-develops within first 24 hours of birth
-cause is lack of surfactant in the lungs. (Surfactant is a liquid that coats the inside of the lungs.)
-The substance coats the insides of the air sacs in the lungs. This helps keep the lungs open so breathing can occur after birth.
Without enough surfactant, the lungs will likely collapse when the infant exhales (breathes out).
Alveolar macrophages (dust cells)
- they are a significant feature of the alveoli
- Crawl freely along the internal alveolar surfaces
Lungs and pleural coverings
- Root
- apex
- base
- lobes: 3 and 2, each lobe getting a lobar bronchus
- bronchopulmonary segments, usually 10 and 8, each getting a segmental bronchus.
- Parietal pleura on the thoracic wall and diaphragm
- visceral pleura on the lung surface.
pleural fluid in pleural cavity?
-results in the lungs clinging to the thorax walls.
Mechanics of breathing
**Gases move along pressure gradients
Inspiration
To get air in the lungs, decrease the pressure in the lungs
Boyle’s Law: pressure of a gas varies inversely with volume. To decrease the pressure, increase the volume.
p1v1=p2v2 where p is pressure of gas and V is its volume
role of the diaphragm and the external intercostals in quiet inspiration
- diaphragm descends about 1 cm
- they both contract
