28/29. Respiratory System Flashcards
What is the thoracic wall made of
Ribs covering the lateral aspect
Sternum on the anterior aspect
Vertebrae on the posterior aspect
Two apertures
Two apertures of the thoracic wall
Superior thoracic aperture
Inferior thoracic aperture that is covered completely by the diaphragm, which assists in inhalation
Contents of the thoracic cavity
Pleural cavity contains the lungs
Mediastinum contains the heart and surrounding pericardium
Functions of the respiratory system
Gas exchange, air conditioning, sound production, olfaction, and defense
Parts of the respiratory tract
Upper respiratory tract consisting of nasal cavity and pharynx
Lower respiratory tract consisting of larynx, trachea, bronchi, and lungs
Location and function of nasal vestibule:
Air enters nose through external nares (nostril)
Air then flows in the nasal vestibule (the hallway leading into the nasal cavity)
Vibrissae, sticky with mucus, collect foreign particles, antigens, pollen, etc
Epithelium found in nasal vestibule
Stratified squamous epithelium
What is the nasal septum made of
Articulation of the perpendicular plate of the ethmoid bone and the vomer bone
Where are nasal conchae found and how are they named
Named for position on lateral wall of nasal cavity (superior, middle, inferior)
Superior and middle conchae are part of ethmoid bone
Inferior conchae is a separate bone
Function of nasal conchae and meatuses
Nasal conchae protrude from lateral wall of the nasal cavity
Form spaces underneath called meatuses
Meatuses provide additional surface area through which air can flow
As air circulates through the conchae and meatuses it is warmed and humidified
4 Paranasal sinuses and their functions
Frontal, ethmoidal, sphenoidal, maxillary
Lighten skull, tone voice, protect vital structures in head, and produce mucus to maintain moisture in the nasal cavity
Location of Superior meatus
Opening of sphenoidal and ethmoid sinus
Location of Middle meatus
Ethmoid air cells projecting into middle meatus
Semilunar hiatus formed from by the ethmoid bulla
Opening of maxillary and frontal sinus within the SL hiatus
Location of inferior meatus
Opening of the nasolacrimal duct
Respiratory epithelium
Ciliated, pseudo-stratified columnar epithelium with goblet cells
Function is to help moisten and clean the airway
Goblet cells secrete mucus in which foreign debris gets caught
Movement of cilia directs mucus out of respiratory tract
Three structures that make up respiratory epithelium
Cilia, goblet cells, pseudostratified columnar cells
Layers and function of mucus membrane
Respiratory epithelium, characteristically thick basement membrane, and lamina popria containing seromucus glanda
Main function as protectant and secretant
Function and location of seromucus glands
Within the lamina propria of mucus membrane
Serous fluid contains lysozymes to destroy foreign particles
Olfactory epithelium
A specialized respiratory epithelium which lines the superior region of the nasal cavity
Olfactory epithelium contains olfactory receptor cells
Overall what are the specialized linings of the respiratory tract
Stratified squamous epithelium: thick layer of cells
Respiratory epithelium: cilia, goblet cells
Mucus membrane: thick layers, mucus production, lysosomes
Olfactory epithelium: olfactory receptor cells
How is the pharynx subdivided
Begins at the internal nares
Divided into three regions which are for their association with the nasal cavity, oral cavity and larynx:
Nasopharynx, oropharynx, and laryngopharynx
Characteristics of nasopharynx
Extends from internal nares to soft palate
Contains pharyngeal tonsil and uvula
Includes Pharyngotympanic (eustachian) tunes
Respiratory epithelium
Characteristics of oropharynx
Contains tonsils and most of the epiglottis
Lined with a stratified squamous epithelium
Characteristics of laryngopharynx
Contains opening into larynx
Stratified squamous epithelium
Includes Epiglottis
Contents of the larynx
Laryngeal cartilage
Vocal folds/cords
Cartilages of the larynx and their function
Thyroid, cricoid, arytenoid
Function in protection of larynx and as attachment sites for intrinsic laryngeal muscles
Functions of laryngeal components
Epiglottis: covers the larynx during swallowing
Hyoid bone: provides site for muscular attachment
Cricoid cartilage: covers the anterior and posterior side of the larynx
Arytenoid cartilage: articulate with cricoid cartilage and location of insertion for vocal ligaments
How are sounds produced when air passes through the vocal ligaments
Different skins produced depending on whether the ligaments are adducted or abducted
Muscles originate and insert onto the cartilages of the larynx that will adduct and abduct the vocal cords resulting in production of sound
Components of the trachea
Begins inferior to the cricoid cartilage
Bifurcates into the two primary bronchi
C-shaped cartilaginous rings support the trachea
Smooth muscle between the cartilaginous rings
Posterior side of trachea is covered by a muscle that will allow the esophagus to slightly bulge into the lumen of the trachea when swallowing
Emergency access to an airway
Cricothyroidotomy: through thyroid membrane
Tracheostomy: through 2nd and 3rd tracheal rings (temporary or permanent intubation)
Bifurcation of the trachea
Bifurcate into primary bronchi
Both the trachea and primary bronchi are supported by C shaped cartilaginous rings
Carina is the last line of defense against foreign matter in the airway
Bifurcates asymmetrically on left side around the heart
Where does a foreign object get lodged when aspirated
Right main bronchus
Because right main bronchus bifurcates of the trachea at a more obtuse angle than left main bronchus
How do bronchi continue
Branch into smaller segments called bronchioles
Bronchi supported by cartilage and bronchioles by smooth muscle
Respiratory bronchioles are where gas exchange will take place
Function of smooth muscle in airway
Allow for dilation and constriction of airway
Dilation allows more air to lungs
Constriction reduces amount of air into lungs
Function of sympathetic and parasympathetic innervation in airway
Sympathetic: increase in respiration, body requires more oxygen, leads to bronchodilation
Parasympathetic: decrease in respiration, body requires less oxygen, leads to bronchoconstriction
What happens in the respiratory zone
Alveolar sacs are line with alveoli off of bronchioles
Alveoli are made of a simple squamous epithelium that functions in gas exchange
Alveolus (plural alveoli)
Final termination of the airway and where gas exchange takes place
Lined mostly with simple squamous epithelium! Which is the location of gas exchange
Structure of the alveolus
Alveolus wall: one cell thick to facilitate gas exchange
Alveolus pore: communication and collateral ventilation
Alveoli surround the duct (one cell thick and sides of alveolus appear honeycombed)
Cell types of alveoli
Type 1 pneumocyte, dust cells, and type 2 pmeumocyte
Type 1 pneumocyte
Simple squamous cells
Dust cells
Macrophages
Free or migratory
Remove foreign cells
Type 2 pneumocyte
Produce surfactant
Function as stem cell
Blood brain barrier of respiratory zone
Barrier between capillary and alveoli which also promote gas exchange
Three layers: alveolar epithelium, fused basement membrane, capillary epithelium
Components of the lungs
Assymetrical
Right lung had horizontal and oblique fissure dividing superior, middle, and inferior lobes
Left lung has oblique fissure dividing superior and inferior lobes
What is a cardia impression
Formed during development of heart
More obvious on left lung but found on both
Two structures on left lung that make space for the heart
Cardiac notch is an indentation on the anterior border of the left lung’s superior lobe and is there to accompany the heart
The lingula extends from the cardiac notch and the oblique fissure and is the remnant of what would have been the middle lobe
How do pulmonary arteries and veins branch
Use same pattern as bronchi
Contents of the pleural cavity
Lungs, pleural linings, potential space
Development of the pleural cavity
Analogy to fluid filled balloon:
Balloon has a single layer surrounding fluid
As the hand is pressed into the balloon, the lining will wrap around the hand
Forms two layers from one single membrane
Layers are separated by fluid
Development of bronchi
At four weeks old, a lung bud develops as an outgrowth of the ventral wall
The bud will form the trachea and bronchial buds
Buds will develop into the right and left primary bronchi
Secondary buds, followed by tertiary buds, will develop
Development of the visceral and parietal pleurae
At same time as lung bud developing, it is growing into the fluid filled space of the intradaembryonic cavity
Cavity filled with serous fluid
Single layer of mesoderm covering the lung is the visceral pleura
Layer of mesodermal retained on the thoracic wall is the parietal pleura
Serous fluid maintains connection between two layers of pleura
Functions of serous fluid
Lubrication of the plural cavity
Creation of tension between the visceral and parietal layers that sticks the two layers of pleura together
Muscles of respiration
Skeletal muscles assist in inhalation and exhalation by increasing and decreasing the volume of the thoracic cavity
Diaphragm increases the vertical dimensions of the thorax
Intercostal muscles also help elevate ribs to increase the lateral dimensions of the thorax
Muscles of forced inhalation
Muscles superior to the thoracic cavity: Pectoralis minor and serratus posterior superior
Muscles lying in superior plane pull the sternum up and out and expand the rib cage laterally
Muscles of forced exhalation
Muscles inferior to the thoracic cavity: abdominals, serratus posterior inferior, and internal intercostal mm
What nerve innervates the diaphragm and what spinal cord segments
Phrenic nerve (cervical spinal cord segments 3, 4, and 5
Which nerves innervate the intercostal muscles
Intercostal nerves from T1-T11 run in the inferior border of each rib with the intercostal vein and artery
Intercostal nerves innervate the intercostal muscles
From which structure does the respiratory center gather information
Neural control comes from the medulla oblongata
Nuclei will set a baseline rate of ventilation = respiratory center
Respiratory center gathers information from stretch receptors in the lungs and chemoreceptors in the arteries
How do stretch receptors in lungs work?
Mechanoreceptors
In smooth muscle
Respond to excessive stretching in the lung
Stops inhalation and initiates exhalation
Function of aortic bodies and carotid bodies
Chemoreceptors
Sense changes in blood oxygen and carbon dioxide levels
Changes in pH
Trigger inhalation
Which cranial nerves sense and receive information from the carotid and aortic bodies?
Carotid bodies: glossopharyngeal nerve (CN IX)
Aortic bodies: vagus nerve (CN X)
Chemoreceptors sense change in blood O2 and CO2 levels
What determines rate of respiration
Total lung capacity tables determine baseline rates of respiration
Give how much air you pull into lungs and push out
Knowing these baseline rates are essential for diagnosis of disease and following the progress of a respiratory disease
