Unit 14: Respiratory System Flashcards
(17 cards)
Overview of the respiratory system
Main functions:
- ventilation - air movement into and out of lungs
- exchange of gases (O2 and CO2) btw. lungs and blood
Two subdivisions:
1) Upper respiratory system = nose, nasal cavity, pharynx
2) Lower respiratory system = larynx, trachea, bronchial tree, lungs
Mucosa of most of respiratory tract is ciliated pseudostratified epithelium w goblet cells sitting on the lamina propria (exceptions are indicated in the notes below)
- CT layer of ALL mucosa = lamina propria, and tissue subtype = loose areolar
- goblet cells secrete mucous
- cilia sweep mucous to esophagus where swallowed
What are the respiratory system organs?
Nose, nasal cavity, paranasal sinuses, pharynx (throat), larynx (voice-box), trachea, lungs, bronchial tree, and respiratory membrane.
Info on nose
- supported by bone and hyaline cartilage
- nostrils are called nares
Info on nasal cavity
Functions:
a) airway passage (warms, moistens, and filters air)
b) olfaction (sense of smell)
c) speech (resonance chamber)
Divided by nasal septum:
a) anterior part = hyaline cartilage
b) posterior part = vomer, ethmoid, maxillae, palatine bones
3 areas (next card)
What are the 3 areas of the nasal cavity?
a) vestibule (entrance area)
- anterior region
- no mucosa; lined by thin skin w/ hair that filters particles (e.g. dust, pollen)
b) respiratory area
- posterior region
- CHONCHAE protrude medially from the lateral walls of nasal cavity
- superior (projection of ethmoid)
- middle (projection of the ethmoid)
- inferior (separate bones referred to as the inferior nasal
chonchae)
- air passes through nasal meatuses (channels) that are btw. the nasal chonchae
- chonchae and meatuses cause air turbulence that helps to humidify air and trap dust/pollen on the ciliated epithelium
- NASOLACRIMAL DUCT connect the medial region of eye to the inferior nasal meatus, allowing lacrimal fluid (which includes tears) to drain into nasal cavity
c) olfactory area
- found in roof of nasal cavity
- mucosa contains olfactory neurons that are sensory receptors for the sense of smell
Info on paranasal sinuses
= 8 air-filled spaces in skull
a) paired L and R spaces in: frontal, sphenoid, ethmoid, maxillae
- open directly into nasal cavity
- function = warm, moisten air
- sinusitis = when the mucous membrane becomes inflamed due to infection
Info on pharynx (throat)
Wall are formed of skeletal muscle lined by mucous membrane. Divided into 3 interconnected regions (from superior to inferior):
a) nasopharynx
- located posterior to nasal cavity
- passageway for air only
- contains:
- pharyngeal tonsil located on posterior wall
- openings:
- 2 posterior nasal apertures - connect nasal cavity to
nasopharynx
- 2 pharyngotympanic (auditory) tubes - connect middle
ear to nasopharynx
b) oropharynx
- posterior to oral cavity
- epithelium of mucosa is a stratified squamous epithelium
- passageway for both air and food from soft palate to top of epiglottis
- contains:
- palatine tonsils
- lingual tonsil
c) laryngopharynx
- posterior to the larynx - from the epiglottis to the opening of the larynx
- epithelium of mucosa is a stratified squamous epithelium
Info about larynx (voice-box) “la la la - LArynx”/voice box)
- anterior to laryngopharynx
- air passageway that connects the pharynx to the trachea
- composed of 8 hyaline cartilages and 1 elastic cartilage (epiglottis):
- epiglottis = flexible, covers the glottis during swallowing to prevent food from entering the larynx
- vocal cords (ligaments) are 2 sets of paired folds under the laryngeal mucosa in the mid-larynx
a) vestibular folds = superior, called the false vocal cords,
helps close the glottis
b) vocal folds = inferior, called the true vocal cords,
produce sound by vibration - glottis
a) includes the vocal folds (true vocal cords) and the
opening btw. them
b) closes to prevent food and liquid from entering trachea - laryngitis = inflammation of larynx due to infection or irritation
Info about trachea
- anterior to esophagus
- connects larynx to main bronchi (the 2 main bronchi are branches off trachea leading to each lung)
- passageway for air only
- consists of 20 C-shaped pieces of hyaline cartilage
- open part of C faces esophagus - permits expansion of
esophagus
- open part of C faces esophagus - permits expansion of
Info about the lungs
- R and L lungs are separated by mediastinum
- R lung = 3 lobes (superior, middle, inferior)
- L lung = 2 lobes (superior, inferior), and has cardia notch (where heart lies)
- pleura = serous membrane
a) visceral - on surface of lung
b) parietal - on inner thoracic wall, superior diaphragm and
mediastinum - pleural cavity = filled w/ serous fluid
a) prevents friction when lungs move
b) holds lungs to thoracic cavity wall
Info about the bronchial tree
- connects trachea to alveoli of lungs
- extends from L and R main bronchi to alveolar ducts
- air passageway that repeatedly branches into smaller and smaller passageways
What does the bronchial tree consist of?
a) conducting zone structures
i. 2 Main (primary/1st level) bronchi (L and R)
ii. 5 Lobar (secondary/2nd level) bronchi - 3 on R, 2 on L
iii. Segmental bronchi (multiple levels of branching)
iv. Terminal bronchioles (multiple levels of branching)
- epithelium of mucosa transitions from ciliated pseudostratified epithelium in larger bronchi to ciliated simple cuboidal epithelium in the terminal bronchioles
b) respiratory zone structures
- site of gas exchange (oxygen enters blood and carbon dioxide exits blood in these structures)
- consists of:
i. Respiratory bronchioles (multiple levels of branching)
ii. Alveolar ducts (tips of bronchial tree)
iii. Alveoli (millions - NOT PART OF BRONCHIAL TREE) = honeycomb-like chambers, main site of gas exchange, form part of respiratory membrane
- epithelium of mucosa transitions from ciliated simple cuboidal epithelium in respiratory bronchioles to simple squamous in the alveolar ducts
Info about respiratory membrane
3 layers = 2 epithelia and their fused basement membrane:
a) wall of alveolus = simple epithelium; made of 2 cell types:
i. Type I alveolar cells = simple squamous, allow gas
diffusion
ii. Type II alveolar cells = simple cuboidal, secrete
surfactant = molecule that covers inner surface of
alveoli; reduces attractive forces btw. water molecules
making it easier for alveoli to expand during inhalation
- ALVEOLAR PORES (openings) allow air mvmt. btw. adjacent
alveoli
- macrophages - freely move btw. blood and alveoli; remove
dust, cellular debris, and pathogens
b) basement membranes of alveolus and capillary
c) wall of capillary = simple squamous epithelium (=
endothelium)
What are the two routes for blood supply to the lung?
1) Pulmonary circulation
2) Bronchial circulation
*see notes for flow charts
Outline of pulmonary circulation = blood TO BE oxygenated
RV
to
pulmonary trunk
to
pulmonary arteries
to
capillaries in respiratory potion of lungs (become oxygenated)
to
pulmonary veins
to
LA
Info about bronchial circulation
- = subdivision of systemic
- blood TO NOURISH lung tissue
- bronchial arteries
- arise from aorta (systemic)
- carry oxy. blood to lung tissues (e.g. bronchi) except respiratory portion
- returning to heart blood drains into:
- bronchial vein (little blood) (to RA - systemic)
- OR pulmonary veins (most blood) (to LA - pulmonary)
What is pulmonary edema, pulmonary embolism, inspiration, and expiration
1) pulmonary edema = accumulation of fluid in the lungs - btw. cells and w/in alveoli
2) pulmonary embolism = blockage of pulmonary vasculature; results from blood clots, arteriosclerosis, air bubbles in vessels, etc.
- inspiration = intake of air (diaphragm and external intercostals contract)
- expiration = air moves TO atmosphere from lungs (diaphragm and external intercostals RELAX - exhale = passive)
