The Respiratory System Flashcards
(197 cards)
1
Q
Functions of the respiratory system
A
- Extensive SA for gas exchange
- Moving air
- Protecting surfaces
- Producing sounds
- Detecting odours
2
Q
Upper respiratory system
A
Nose, nasal cavity, paranasal sinuses, pharynx
3
Q
Lower respiratory system
A
Larynx, trachea, bronchi, bronchioles and alveoli
4
Q
Respiratory tract
A
The passageways that carry air to and from the lung exchange surfaces
5
Q
Conducting portion
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Begins at the entrance to the nasal cavity and extends through the pharynx, larynx, trachea, bronchi and larger bronchioles
6
Q
Respiratory portion
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Smallest, thinnest bronchioles and alveoli
7
Q
Respiratory mucosa
A
Lines the conducting portion of the respiratory system
8
Q
Mucosa
A
Mucous membrane
9
Q
Function of respiratory mucosa
A
To provide a series of filtration mechanisms that make up the respiratory defence system
10
Q
What does the respiratory defence system protect surfaces from?
A
Debris or pathogens inhaled in air that could damage the surfaces
11
Q
Structure of respiratory mucosa
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Epithelium and underlying areolar layer lamina propria
12
Q
Which upper respiratory components contain mucous glands in the lamina propria?
A
Trachea and bronchi
13
Q
Respiratory mucosa of the trachea
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Mucosa
Submucosa
Hyaline cartilage
Adventitial layer
14
Q
What is in the lamina propria of the conducting portions of the lower respiratory system?
A
Bundles of smooth muscle cells
15
Q
What do the smooth muscles do in the bronchioles?
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Form thick bands that encircle the lumen
16
Q
Cells lining nasal cavity and superior portion of pharynx
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Pseudostratified ciliated columnar epithelium
17
Q
Cells lining inferior portion of the pharynx and oral cavity
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Stratified squamous epithelium
18
Q
Why are the cells lining inferior portion of the pharynx stratified squamous epithelium?
A
This portion conducts air to the larynx and carries food to oesophagus so it needs protection from abrasion and chemicals
19
Q
Superior portion of the lower respiratory system and nasal cavity
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Pseudostratified ciliated columnar epithelium
20
Q
Smaller bronchioles
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Cuboidal epithelium with scattered cilia
21
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Exchange surface of the alveoli
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Simple squamous epithelium
22
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Alveolar epithelium
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The alveolar simple squamous epithelium and specialised cells scattered among the squamous cells
23
Q
What do mucous glands produce?
A
Sticky mucus that bathes exposed surfaced
24
Q
Mucociliary escalator
A
In the nasal cavity, cilia sweep mucus toward the pharynx where it is swallowed and exposed to stomach acids and enzymes
In the lower respiratory system, the cilia beat toward the pharynx, moving a carpet of mucus in that direction and cleaning the respiratory surfaces
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Tuberculosis (TB)
Results from an infection of the lungs by a bacteria which may colonise respiratory passageways, interstitial spaces, the alveoli or a combination
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Cystic fibrosis (CF)
Respiratory mucosa produces dense, viscous mucus that can't be transported by the respiratory defence system
Mucociliary escalator stops working - frequent infections
Mucus blocks smaller respiratory passageways so breathing is difficult
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Nasal vestibule
The space contained within the flexible tissues of the nose
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Nasal septum
Formed by the fusion of the perpendicular plate of the ethmoid and vomer
Anterior portion is formed of hyaline cartilage
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Dorsum of nose
Bridge
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Apex of nose
Tip
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Lateral and superior walls of the nasal cavity
Maxillae, nasal bone, frontal bone, ethmoid and sphenoid
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Paranasal sinuses
Sinuses of the frontal bone, sphenoid, ethmoid, and paired maxillae and palatine bones
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Olfactory region
Superior portion of the nasal cavity
1. Interior surface of the cribiform plate
2. Superior portion of nasal septum
3. Superior nasal conchae
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What gives us our sense of smell?
Receptors in olfactory epithelium
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Choanae
Openings of the nasal cavity
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Superior, middle and inferior nasal conchae
Air flows between adjacent conchae to pass from vestibule to the choanae
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Superior, middle and inferior nasal meatuses
Narrow grooves between chonchae
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Purposes of nasal turbulence
- Small airborne particles are likely to come into contact with mucus
- Extra time for warming and humidifying air
- Creates circular air currents that bring olfactory stimuli to olfactory receptors
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Hard palate (bony)
Made up of portions of the paired maxillae and palatine bones
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What separates nasal cavity from oral cavity?
Hard palate
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Soft palate (fleshy)
Marks the boundary between superior nasopharynx and the rest of the pharynx
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Where does the nasal cavity open into the nasopharynx?
At the choanae
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Functions of the nasal mucosa
1. Traps particles
2. Warms and humidifies incoming air
3. Dehumidifies and absorbs heat of outgoing air
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Why do patients breathing on a respirator need to receive air that has been externally filtered and humidified?
Since they are not breathing through their nasal cavity and thus they do not receive warmed and humidified air (dangerous)
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Epistaxis
Nose bleed
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Where does the pharynx extend?
Between the choanae and entrances to the larynx and oesophagus
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Wall of the pharynx
Superior and posterior: closely bound to axial skeleton
| Lateral walls: flexible and muscular
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3 parts of the pharynx
1. Nasopharynx
2. Oropharynx
3. Laryngopharynx
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Nasopharynx
- Superior portion
- Ciliated columnar epithelium
- Pharyngeal tonsil on posterior wall
- Pharyngeal opening of auditory tube on each side of pharyngeal tonsil
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Oropharynx
- Between soft palate and base of the tongue
- Continuous with the oral cavity
- Stratified squamous epithelium
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Laryngopharynx
- Inferior portion
- Between the hyoid bone and entrance to the larynx and oesophagus
- Stratified squamous epithelium
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Glottis
Slit like opening between the vocal cords
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Larynx
- Cartilaginous tube that surrounds and protects the glottis
| - C4 or 5 to C6
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3 unpaired cartilages of larynx
1. Thyroid cartilage
2. Cricoid cartilage
3. Epiglottis
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Thyroid cartilage
- Hyaline cartilage
- Largest
- U shaped
- Adam's apple
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Cricoid cartilage
- Hyaline cartilage
- Most inferior
- Expanded to provide support where there's no thyroid cartilage
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Functions of thyroid and cricoid cartilages
- Protect the glottis and entrance to trachea
| - Broad surfaces provide sites for attachment for ligament and muscles
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Epiglottis
- Elastic cartilage
- Forms a lid over glottis
- Prevents liquids and solids from entering respiratory tract
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3 pairs of smaller hyaline cartilages of larynx
1. Arytenoid
2. Corniculate
3. Cuneiform
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What binds the laryngeal cartilages?
Ligaments
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What surrounds the glottis?
Vestibular folds
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What makes up the glottis?
Vocal folds = vocal cords
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Space between vocal folds
Rima glottidis
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Function of vestibular folds
Help prevent foreign objects from entering the open glottis and protect more inferior, delicate vocal folds of glottis
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Muscles of the larynx
1. Muscles of the neck and pharynx - stabilise larynx
| 2. Smaller intrinsic muscles - control tension in glottal vocal folds
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Bolus
Pasty mass of food before swallowed
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Phonation
Sound production at the larynx
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Articulation
Modification of those sounds by voluntary movements of structures like tongue teeth and lips to form words
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How do we produce sounds?
Air passing through our open glottis vibrates its vocal folds and produces sound waves
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What controls the pitch of the sound?
Diameter, length and tension in the vocal cords
| Tension is controlled by voluntary muscles
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Laryngitis
Infection or inflammation of larynx
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Epiglottitis
Swelling caused by bacterial or viral infections
| Dangerous - could cause suffocation
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Where does the trachea extend?
Begins anterior to vetebra c6
| Ends mediastinum, vetebra t5
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What is the epithelium of the trachea continuous with?
The epithelium of the larynx
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Submucosa
A thick layer of connective tissue surrounds the mucosa
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Tracheal glands
- Contained within submucosa
| - Secretes mucous that reach tracheal lumen through short ducts
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Functions of tracheal cartilages
- Stiffen tracheal walls
- Protect the airway
- Prevent it from collapsing or over-expanding
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Tracheal cartilages
- C shaped
| - Discontinuous with tracheal wall so can easily distort when swallowing, allowing large masses to pass through
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Annular ligament and trachealis
Connect the ends of each tracheal cartilage
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Trachealis
Band of smooth muscle
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What reduces the diameter of the trachea?
Trachealis
| Controlled by sympathetic nervous system
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Bronchial tree
Left and right main bronchus > lobar bronchi
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Carina of trachea
Ridge that separates the openings of the right and left main bronchi
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Which main bronchus is larger in diameter?
The right
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Which lung is slightly larger?
The right
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Lobes of lungs
Right: Superior, middle and inferior (3 lobar bronchi)
Left: Superior and inferior (2 lobar bronchi)
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Segmental bronchi
- Branch from lobar bronchi
| - Supply air to bronchopulmonary segment
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Bronchopulmonary segment
Specific region of one lung
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Number of bronchopulmonary segment
Right: 10
Left: 10 during development and then 8 or 9
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Cartilage and smooth muscle in bronchi
Main, lobar and segmental bronchi contain progressively less cartilage
As cartilage decreases, smooth muscle increases
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Bronchitis
During an infection, bronchi and bronchioles become inflamed and constricted
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Bronchioles
Form from segmental bronchus
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Bronchiole walls
Lack cartilage
| Dominated by smooth muscle tissue
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How does the ANS control the luminal diameter of the bronchioles?
By regulating smooth muscle layer
Sympathetic: bronchodilation
Parasympathetic: bronchoconstriction
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Asthma
Excessive stimulation of smooth muscles in bronchioles cause mucosa to form a series of folds
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Pulmonary lobule
Each terminal bronchiole delivers air to a single pulmonary lobule
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Respiratory bronchiole
Deliver air to gas exchange surfaces of the lungs
Within the lobule, the terminal bronchiole branches to form several respiratory bronchiole
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What lines the terminal bronchioles and respiratory bronchioles?
Cuboidal epithelium
Only scattered cilia and no mucous cells or underlying mucous glands
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Alveolar ducts
Connect respiratory bronchioles and individual alveoli
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Alveolar sacs
Alveolar ducts end at alveolar sacs
Common chambers connected to individual alveoli
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What surrounds capillaries associated with alveoli?
Elastic fibres which help maintain relative positions of the alveoli and respiratory bronchioles
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What reduces the size of the alveoli during exhalation?
Elastic fibres surrounding capillaries
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Alveolar cell layer
Simple squamous epithelial cells called pneumocytes type I
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Alveolar macrophages
Patrol the epithelial surfaces and engulf any particles that have eluded other defences
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Pneumocytes type II
Scattered among the squamous cells
| Produce surfactant
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Surfactant
Oily secretion containing phospholipids and proteins
| Helps keep alveoli open by reducing surface tension in thin layer of water coating alveolar surface
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Respiratory distress syndrome
When pneumocytes type II don't produce enough surfactant and the alveoli collapse after each exhalation, making it difficult to breathe
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Blood air barrier
Where gas exchange occurs
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3 layers of blood air barrier
1. The alveolar cell layer
2. The capillary endothelial layer
3. The fused basement membrane between them
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Why can gas exchange take place quickly at the blood air barrier?
1. Only a very short distance separates alveolar air from blood
2. Oxygen and CO2 are small lipid-soluble molecules
3. SA of the blood air barrier is large
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Pneumonia
Develops from an infection or inflammation-causing particle
Inflammation occurs, fluid leaks into alveoli, respiratory bronchioles swell, narrowing passageways
Breathing is difficult
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What makes pneumonia more likely?
- Epithelial damage from smoking
| - Breakdown of immune system in AIDS
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Lobes and fissuresof the lungs
Right: superior, middle and inferior (separated by horizontal and oblique fissures)
Left: superior and inferior (separated by oblique fissure)
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Why is the right lung broader than the left?
Because most of the heart and great vessels project into the left thoracic cavity
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Which lung is longer?
Left
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Cardiac notch
Indents the medial margin of the left lung
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Hilum
Groove on the mediastinal surface of each lung where each main bronchus travels along
Also provides entry to pulmonary vessels, nerves and lymphatics
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Root of the lung
Complex of dense connective tissue
| Attaches to the mediastinum and fixes the position of the major nerves, blood vessels and lymphatic vessels
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Parenchyma
Functional cells
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Trabeculae
Connective tissues of the root of each lung
| Branch to form small partitions
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Interlobular septa
Divide the lung into pulmonary lobules
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What is the is the interlobular septa continuous with?
Visceral pleura, serous membrane covering the lungs
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Where do the respiratory exchange surfaces receive blood from?
Arteries of the pulmonary circuit
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Where does the conducting portion of the the respiratory tract receive blood from?
Bronchial arteries
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Venous blood from bronchial capillaries
Dilutes oxygenated alveolar blood within the pulmonary veins
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Pulmonary embolism
When a branch of a pulmonary artery stops blood flow to a group of lobules or alveoli
After a few hours the alveoli will collapse
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What separates the two pleural cavities?
Mediastinum
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Pleura
Serous membrane lining pleural cavity
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Layers of the pleura
Visceral and parietal
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Pleural fluid
Moist, slippery coating the lubricates the pleurae
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Thoracentesis
Sampling procedure where a long needle obtains pleural fluid to check for bacteria, blood cells, etc.
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Pleurisy
Condition when pleural fluid doesn't prevent friction between pleural surfaces
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External respiration
All processes involved in the exchange of oxygen and carbon dioxide between the body's interstitial fluids and external environment
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Function of external respiration
To meet respiratory demands of cells
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Internal respiration
Absorption of oxygen and the release of carbon dioxide by those cells
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Integrated steps of external respiration
1. Pulmonary ventilation - physical breathing
2. Gas diffusion - across blood air barrier
3. Transport of oxygen and carbon dioxide - between alveolar capillaries and capillary beds in other tissues
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Hypoxia
Low tissue oxygen level
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Anoxia
Oxygen supply cut off completely
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Pulmonary ventilation
Physical movement of air into and out of the respiratory tract
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Alveolar ventilation
Movement of air into and out of the alveoli
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Function of pulmonary ventilation
Maintain adequate alveolar ventilation
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Function of alveolar ventilation
Prevents the buildup of carbon dioxide in the alveoli
| Ensures a continuous supply of oxygen that keeps pace with absorption by the blood stream
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Boyle's law
Inverse relationship whereby decreasing volume of gas increases its pressure. Increasing volume of gas decreases its pressure
P = 1/V
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What holds the two pleural membranes together?
A fluid film
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Diaphragm contracts
It tenses and moves inferiorly, increasing the volume of the thoracic cavity, decreasing the pressure within it
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Diaphragm relaxes
It returns to its original position and the volume of the thoracic cavity decreases
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What are the pressures inside and outside of the thoracic cavity just prior to inhalation?
Identical
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What happens when the thoracic cavity enlarges?
Lungs expand to fill the additional space
Increase in volume decreases the pressure inside the lungs
Air then enters the respiratory passageways because P inside is lower than P outside
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What happens when the thoracic cavity decreases in volume?
Pressures increase inside the lungs, forcing air out of the respiratory tract
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Primary respiratory muscles
Diaphragm and external intercostals
| Active during normal breathing at rest
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Accessory respiratory muscles
Active when the depth and frequency and breathing must be greatly increased
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Muscles used in inhalation
- Contraction of diaphragm
- Contraction of external intercostal muscles raises ribs
- Contraction of accessory muscles help raise ribs
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Muscles used in exhalation
- Internal intercostal muscle and transverus thoracis depress the ribs
- Abdominal muscles can assist by compressing abdomen, forcing the diaphragm upward
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Quiet breathing, eupnea
Inhalation involves muscular contractions but exhalation is a passive process
Elastic rebound
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Diaphragmatic breathing, deep breathing
Contraction of the diaphragm provides necessary change in thoracic volume
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Costal breathing, shallow breathing
Thoracic volume changes because rib cage alters shape
| External intercostal muscles raise ribs
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Forced breathing, hyperpnea
Active inspiratory and expiratory movements
Accessory muscles assist with inhalation
Exhalation involves contraction of internal intercostal muscles
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What happens in absolute maximum levels of forced breathing?
Abdominal muscles take part in exhalation by compressing the abdominal contents and pushing them up against the diaphragm, reducing the volume of the thoracic cavity
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Intrapulmonary pressure
Pressure inside respiratory tract, at the alveoli
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What happens to pressure gradient when you breathe heavily?
It increases
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Intrapleural pressure
Pressure in the pleural cavity between the parietal and visceral pleura
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Respiratory pump
Cyclical changes in intrapleural pressure that assist venous return to the heart
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Pneumothorax
When air enters the pleural cavity and breaks the fluid bond between the pleurae and allows the elastic fibres to recoil resulting in a collapsed lung
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Atelectasis
collapsed lung
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Compliance
Measure of their expandability, or how easily the lungs expand in response to applied pressure
Lower the compliance, the greater force required to fill the lungs
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Respiratory rate
Number of breaths you take each minute
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Tidal volume
Amount of air moved into or out of the lungs during a single respiratory cycle
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Respiratory minute volume
Amount of air moved each minute
| Respiratory rate X tidal volume
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Alveolar ventilation
Amount of air reaching the alveoli each minute
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Anatomic dead space
Lagging volume of air in the conducting passages
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Expiratory reserve volume (ERV)
Amount of air that you can voluntarily expel after you have completed a normal, quiet respiratory cycle
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Residual volume
Amount of air that you can draw into your lungs after you have completed a quiet respiratory cycle
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Functional residual capacity (FRC)
Amount of air remaining in your lungs after you have completed a quiet respiratory cycle
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Vital capacity
Maximum amount of air that you can move into or out of your lungs in a single respiratory cycle
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Total lung capacity
Total volume of your lungs
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Dalton's law
In a mixture of gases, the individual gases exert a pressure proportional to their abundance in the mixture
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Partial pressure
Pressure contributed by a single gas
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Henry's law
The amount of gas in solution is directly proportional to the partial pressure of that gas
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Hemoglobin saturation
Percentage of heme units containing bound oxygen at any given moment
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Oxygen-hemoglobin saturation curve
Graph that relates the hemoglobin saturation to the partial pressure of oxygen
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Bohr effect
Effect of pH on the hemoglobin saturation curve
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Carbonic anhydrase
An enzyme catalyses the reaction of Co2 with water molecules
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2,3-biphosphoglycerate (BPG)
Compound that has a direct effect on oxygen binding and release
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Fetal hemoglobin
Contained in the RBCs of a developing fetus
| Much higher affinity for oxygen than mature RBCs which allows it to transfer oxygen across the placenta
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Chloride shift
Mass movement of chloride ions into the RBCs
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Carbaminohemoglobin
Compound whose formation decreases oxygen affinity to hemoglobin
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Ventilation-to-perfusion ratio (V/Q ratio)
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Lung perfusion (blood flow to alveoli)
Alveolar ventilation (airflow)
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Respiratory rhythmicity centers
Located in the medulla oblongata
| Plays a key role in establishing the respiratory rate and rhythm
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Subdivisions of the respiratory rhythmicity centres
Dorsal respiratory group (DRG) - inspiration
| Ventral respiratory group (VRG) - expiration
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When does the VRG function?
Only during forced breathing
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Apneustic centres and pneumotaxic centres of the pons
Regulate the depth and rate of respiration in response to sensory stimuli or input from other centres in the brain
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Higher centres
Alter the activity of the pneumotaxic centres
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Hypercapnia
An increase in the PCO2 of arterial blood
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Inflation reflex
Prevents over expansion of the lungs during forced breathing
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Deflation reflex
Stimulates inhalation when lungs are collapsing
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Emphysema
Destruction of alveolar surfaces and inadequate surface area for oxygen and carbon dioxide exchange
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Apnea
A period in which respiration is suspended
