module 2 - respiratory system Flashcards
what is external respiration?
The movement of gases between the environment and the cells of the body.
what is ventilation (V)
The exchange of the air between the atmosphere and the lungs.
what is internal respiration?
The movement of the gases from the lungs, through the bloodstream, and to the cells.
what are the divisions of the RS and what do they include?
The upper respiratory system consists of the nose, pharynx, and associated structures
The lower respiratory system consists of the larynx, trachea, bronchi, and lungs
structure and functions of the nasal cavity
- nasal conchae (superior, middle, and interior) - warm, humidify, filter, olfaction
- nasal meatuses (superior, middle, and interior) - direct airflow, olfaction, drain mucous and tears, resonance speech
- nasal vestibule - hair and sebaceous gland for protection and filtering, warming and humidifying, sensing touch and temperature
- tubal tonsil - immune and lymphatic drainage
- uvula - stops food moving into the nasal cavity, speech, and articulation, salivary glands, immune
- soft and hard palate - close off the nasal passages during swallowing and speech, help make m and n sounds
- olfactory epithelium and nerves - Olfactory receptor neurons: responsible for detecting odours and transmitting the sense of smell to the brain.
structure and functions of the pharynx
Nasopharynx
- pharyngeal tonsil (Also known as adenoid)
- tubal tonsil
oropharynx
- palatine tonsil
- isthmus of the fauces - The passage that connects the oral cavity to the oropharynx.
laryngopharynx
- Food and air passage, protective sensory receptors
lingual tonsil
external structures of the upper RS
body of hyoid bone - anchor point for muscles needed for swallowing and speech
jugular notch - used mechanically to assess venous pressure, inserting central venous catheter, observing the thyroid gland, radiological measurements
structure and functions of the larynx
epiglottis
- Prevents food and liquids
from entering the airway
structure and functions of the trachea
Flexible, slightly rigid tube in mediastinum
* Runs from end of larynx (C6) to T4/T5, where it bifurcates into the primary bronchi * Function: filter, warm, humidify air * Contains 15-20 U-shaped hyaline cartilages & trachealis muscle posteriorly
* Annular ligaments connect cartilage rings
mucosa
- pseudostratified ciliated columnar epithelium
- lamina propria (connective tissue)
submucosa
- seromucous gland in submucosa
hyaline cartilage
adventitia
what are cilia
microscopic, hair-like, made of specialized protein structures and can move rhythmically – known as the “ciliary escalator.”
name the 3 pleura membranes and their functions
Visceral Pleura: Covers the surface of the lungs
* Protects from friction
* Helps maintain shape
* Prevent lung collapse
* Synchronising movement with the chest wall
Parietal Pleura: Lines the thoracic cavity
* Covers not only the lungs but heart and major blood vessels
* Protects from friction
* Integrity of pleural cavity
Pleural Cavity: Contains Pleural Fluid (25mL): * creates a moist, slippery surface – easy sliding and ↓ friction * holds the lungs tight against the thoracic wall.
describe bronchial circulation
Component of the systemic circulation. It consists of tiny bronchial arteries and veins that supply the bronchi and bronchioles of the lung
* Bronchial arteries branch from the anterior wall of the descending thoracic aorta and supply structures in the bronchial tree
* Larger bronchial veins
* collect venous blood and drain into the azygos and hemiazygous systems of veins
lung structure
left main (primary) bronchus
lobar (secondary) bronchus
segmental (tertiary) bronchus
There is a blockage in the Right Lobar Bronchus. What is the consequence of this?
less oxygen would move inalveol= less CO2 leaving, less oxygen in blood overall = tired, cold, dizzy
bronchioles
- Hyaline cartilage is replaced by smooth muscle (keep them open)
- Terminal bronchioles branch
into respiratory bronchioles - Respiratory bronchioles branch
into alveolar ducts & alveoli
alveolus function and pneumocyte types
Perfusion (Q): delivering blood to tissues and organs in the body
pneumocytes
Type 1
* Simple squamous epithelial cells.
* Form the walls of the respiratory membrane
Type 2
* Simple Cuboidal epithelial cells
* Produce surfactant
Alveolar Macrophages
* Resident immune cells
* Phagocytose pathogens
respiratory muscles of inhalation
sternocleidomastoid, scalenes, external intercostals, diaphram
respiratory muscles of exhalation
internal intercostals, external oblique, internal oblique, transversus abdominis, rectus abdominis
what is Eupnea
Quiet breathing at rest. It can be diaphragmatic or costal
what is diaphragmatic breathing
deep breathing - Diaphragmatic contraction expands the thoracic cavity
Exhalation is passive. The diaphragm relaxes
what is Costal breathing
shallow breathing - Ext. Intercostal muscles contract, elevate the ribs and enlarge the thoracic cavity
Exhalation is passive. The muscles relax
what is Hypereupnea
Fast-forced breathing
describe Inspiration
Accessory muscles assist external intercostal muscles to elevate the ribs and enlarge the thorax
* Scalene muscles (elevate 1stand 2ndribs)
* Serratus anterior and posterior
* Pectoralis minor and major
* Sternocleidomastoid
describe exhalation
Internal intercostal muscles depress the ribs
At very rigorous breathing: Exhalation Abdominal muscles compress abdominal contents & reduce the volume of the thoracic cavity
* External and internal obliques
* Transversus abdominis
* Rectus abdominis
explain Boyle’s Law
the volume of a gas and pressure are inversely proportional at a given temperature (e.g., body
temperature).
- gases move from a higher pressure to a lower pressure
- decrease V = increased P
what are the 3 types of pressure? and explain them
Intrapulmonary pressure
* the pressure in the alveoli (also known as alveolar pressure)
* Inspiration -> increase lung volume -> decrease pressure -> less than the atmosphere -> air in
* Expiration -> ↓ lung volume -> increase pressure -> air out
Intrapleural pressure:
* Generally lower than the intrapulmonary and atmospheric pressures.
* Keep the lungs inflated and allow them to adhere to the chest wall, enabling efficient breathing.
* ↑ lung volume -> smaller intrapleural space -> increase pressure
* ↓ lung volume -> larger intrapleural space -> decrease pressure
Transpulmonary (transmural) pressure: the difference between these
* Always positive because the pressure inside the lungs is normally higher than the pressure
how do changes in transpulmonary pressure lead to changes in lung size
How much the lung and chest wall can stretch (distensibility).
Thin elastic band = Easily stretched (compliance)
Thick elastic band = Not easily stretched (low compliance)
High compliance: lungs and chest wall expand easily with each breath in, so it takes less effort to breathe.
Low compliance: they’re stiffer and it takes more effort to fill them with air.
what is airway resistance and what is it related to?
The resistance (opposition/ hindrance) to the flow of air through the respiratory tract during the process of breathing.
It’s a measure of how much effort is required to move air in and out of the lungs.
Related to
* Length
* Radius
* Cross-sectional area of the airways
* Bronchodilation
* Bronchoconstriction
* Density, viscosity (does not really change too much)
* Velocity of the gas
explain the role of pressure gradient & airway resistance
Airflow (F) is the volume of air flowing through the lungs at any point in time, It is directly proportional to the pressure gradient between the external atmosphere & alveoli, & inversely proportional to the resistance of airway passages:
F ∝ ΔP / R
- The volume of air that moves into or out of the lungs at any given point in time. ΔP= pressure gradient
- The difference in air pressure between two points e.g., external atmosphere and the alveoli R= resistance
- the opposition or difficulty that the air encounters as it moves through the airway passage
what is elastic recoil?
After we take a breath in, the lungs want to return to their normal state.
The chest wall also has elastic recoil, but outwards, counteracting the inward elastic recoil of the lungs.
This is the opposite of compliance.
Thin elastic band Easily stretched (compliance) BUT not great recoil!
Thick elastic band Not easily stretched (low compliance) BUT
good recoil!