Chapter 22: Respiratory System Flashcards
respiratory system
organ system that takes in air and expels it from the body
respiration refers to
ventilation of the lungs (breathing)
functions of the respiratory system
- gas exchange
- communication (speech)
- olfaction
- acid base balance
- blood pressure regulation
- blood and lymph flow
- platelet production
- expulsion of abdominal contents
blood pressure regulation
assists with synthesis of angiotensin II, a hormone that regulates blood pressure
blood and lymph flow
breathing creates pressure gradients between thorax and abdomen that promote flow of lymph and blood
platelet production
more than half of platelets are made by megakaryocytes in lungs (not in bone marrow)
expulsion of abdominal contents
breath-holding assists in urination, defecation, and childbirth
principal organs of respiratory system
nose, pharynx, larynx, trachea, bronchi, and lungs
conducting zone
-passages that serve only for airflow (no gas exchange)
-Nostrils through major bronchioles
upper respiratory tract
airway from nose through larynx
lower respiratory tract
regions from trachea through alveoli
respiratory zone
-regions that participate in gas exchange
-Alveoli and nearby structures
nose
-warms, cleanses, and humidifies inhaled air; detects odors; and serves as a resonating chamber that amplifies voice
-Extends from nostrils (nares) to posterior nasal apertures (choanae)—posterior openings
-Facial part is shaped by bone and hyaline cartilage
superior half of nose
nasal bones and maxillae
inferior half of nose
lateral and alar cartilages
ala nasi
flared portion at lower end of nose shaped by alar cartilages and dense connective tissue
what divides nasal cavity into right and left nasal fossae?
nasal septum
structure of nasal septum
-Vomer forms inferior part
-perpendicular plate of ethmoid forms superior part
-septal cartilage forms anterior part
-Paranasal sinuses and nasolacrimal duct drain into nasal cavity
Superior, middle, and inferior nasal conchae (turbinates) project from
lateral walls toward septum
nose epithelium
-Ciliated pseudostratified columnar epithelium
-Olfactory epithelium is involved in the sense of smell
goblet cells (ciliated cells)
have motile cilia that propel the mucus posteriorly toward pharynx to be swallowed
epithelia of pharynx
-Nasopharynx passes only air and is lined by pseudostratified columnar epithelium
-Oropharynx and laryngopharynx pass air, food, and drink and are lined by stratified squamous epithelium
muscles of the pharynx assist in
swallowing and speech
larynx
-Cartilaginous chamber about 4 cm (1.5 in.) long
-Primary function is to keep food and drink out of airway
-involved in production of sound, so commonly called the “voice box”
epiglottis
flap of tissue that guards superior opening of larynx
3 big solitary cartilages
-Epiglottic cartilage
-Thyroid cartilage
-Cricoid cartilage
3 smaller paired cartilages
-Arytenoid cartilages
-Corniculate cartilages
-Cuneiform cartilages
vocal cords (vocal folds)
-produce sound when air passes between them
-Contain vocal ligaments covered with stratified squamous epithelium, suited to endure vibration and contact
glottis
the vocal cords and the opening between them
trachea
-Lined by ciliated pseudostratified columnar epithelium
-Contains mucus-secreting cells, ciliated cells, and stem cells
mucocillary escalator
-mechanism for debris removal
-Mucus traps inhaled particles, upward beating cilia moves mucus to pharynx to be swallowed
trachealis
muscle spans opening in rings; contracts or relaxes to adjust airflow *internal median ridge—the carina
tracheotomy
-to make a temporary opening in the trachea and insert a tube to allow airflow
-Prevents asphyxiation due to upper airway obstruction
intubation
-when a patient is on a ventilator, air is introduced directly into trachea
-Air must be filtered and humidified
base
broad concave portion resting on diaphragm
apex
tip that projects just above the clavicle
costal surface
pressed against the ribcage
mediastinal surface
faces medially toward the heart
hilum
-slit through which the lung receives the main bronchus, blood vessels, lymphatics, and nerves
-Structures near hilum constitute root of lung
right lung
-Has three lobes—superior, middle, and inferior lobes
-Horizontal fissure separates superior and middle lobes, and oblique fissure separates middle and inferior lobes
left lung
-Has indentation to accommodate heart—cardiac impression
-Has two lobes—superior and inferior lobes, separated by a single oblique fissure
bronchial tree
-a branching system of air tubes in each lung
-Extends from main bronchus to 65,000 terminal bronchioles
main (primary) bronchi
-divide into lobar (secondary) bronchi
-A Lobar bronchi branch into segmental (tertiary) bronchi
bronchioles
continuations of airway that lack supportive cartilage and are 1 mm or less in diameter
pulmonary lobule
-portion of lung ventilated by one bronchiole
-terminal bronchioles
-respiratory bronchioles
-alveolar ducts
-End in alveolar sacs—clusters of alveoli around a central space (atrium)
alveoli
-microscopic air pouches in the lungs
-for gas exchange
cells of the alveoli
-Squamous (type 1) alveolar cells
-Great (type 2) alveolar cells
-Alveolar macrophages (dust cells)
Squamous (type 1) alveolar cells
-Thin cells allow rapid gas diffusion between air and blood
-Cover 95% of alveolus surface area
Great (type 2) alveolar cells
-Repair the alveolar epithelium when the squamous (type 1) cells are damaged
-Secrete pulmonary surfactant
pulmonary surfactant
mixture of phospholipids and proteins that coats the alveoli and prevents them from collapsing during exhalation
respiratory membrane
-thin barrier between the alveolar air and blood
-Gases exchanged across respiratory membrane, which consists of three layers:
Squamous alveolar cells
Endothelial cells of blood capillary
Their shared basement membrane
pleura
serous membrane that lines thoracic wall and forms surface of lung
visceral pleura
forms surface of lung
parietal pleura
Adheres to mediastinum, inner surface of the rib cage, and superior surface of the diaphragm
pleural cavity
potential space between pleurae-Fluid layer
pleural effusion
pathological seepage of fluid into the pleural cavity
functions of pleurae and plural fluid
-reduction of friction (allow lungs to move with minimal friction)
-creation of a pressure gradient (assist with lung inflation)
-compartmentalizatin (prevents spread of infection)
Boyles law
-governs air flow into and out of the lungs:
-At a constant temperature, the pressure of a given quantity of gas is inversely proportional to its volume
if lung volume decreases then intrapulmonary pressure
rises
if the pressure rises above atmospheric pressure then air
moves out of the lungs
if the pressure falls below atmospheric pressure then air
moves into the lungs
atmospheric (barometric) pressure
-the weight of the air above us
-lower at higher elevations