Flashcards in Respiratory System Deck (113):
At a constant temperature, the amount of a gas that dissolves in a liquid is directly proportional to the partial pressure of the gas above the liquid
How much of a gas will dissolve in a liquid at a given partial pressure also depends on what?
Solubility of the gas
How many more times is CO2 more soluble than O2?
As compared to atmospheric gas, alveolar gas contains what amounts of O2?CO2?H20?
less, more, and more
Gas exchange across respiratory membrane
What factors influence external respiration?
thickness and SA of respiratory membrane, Partial pressure gradients and gas solubilities
What is the average thickness of the respiratory membrane in healthy lungs?
0.5-1 m thick
Gas exchange between systemic capillaries and tissue cells
What occurs during internal respiration?
O2 moves from blood into tissue and CO2 moves from tissues into blood
Which 2 ways is O2 transported in the blood?
1. Bound to Hb
2. Dissolved in plasma
Reduced Hb (deoxyHb)
HB that has released O2
Define. Hb saturation
extent to which Hb is combined with O2
How many O2 are bound to heme to be considered to be fully saturated?
How manyO2 are bound to heme to be considered partially saturated?
What describes the relationship between the local Po2 and Hb saturation?
oxygen-Hb dissociation curve
In blood leaving lungs when the P02 is at 100 mmHg how saturated is Hb?
At resting tissues, what are the values for partial pressure of O2 and Hb saturation?
Po2= 40 mmHg
Hb saturation: 75%
Which 4 factors affect Hb at a given Po2?
temperature, pH, 2-3,BPG, and Pco2
What are the effects of the increase of temperature, H+, Pco2, or BPG?
Hb unloads O2 more easily
Curve shifts to the right
%Hb saturation ill be lower
What are the functions of the respiratory system?
to obtain O2 for use by body cells and to eliminate CO2 that cells produce
What are the 4 processes in respiration?
1. Pulmonary ventilation
2. External Respiration
3. Transport of gases
4. Internal Respiration
What are the major organs of the respiratory system?
nose, nasal cavity, paranasal sinuses, pharynx, larynx, trachea, bronchi, lungs and alveoli
Site of gas exchange
All other respiratory passageways that cleanse, and humidify and warm air
Which organs are a part of the respiratory zones?
respiratory bronchioles, alveolar ducts and alveoli
Provides airway for respiration, filters inspired air, moisten and warms inspired air, houses olfactory receptors
Opens to exterior via nostrils
Continuous with pharynx via posterior nasal apertures
Bony structure in the nasal cavity
Muscular structure in the nasal cavity
Lines upper respiratory tract and moistens, warms, and filters incoming air
Increase mucosal surface area and enhance air turbulence
Warm and moisten air and lighten skull
Paranasal sinuses (frontal, ethmoid, and maxillary)
Connects nasal cavity and mouth to larynx and esophagus
Openings of auditory tubes. Epithelium?
nasopharynx. Pseudostratified columnar
Where is the pharyngeal tonsil located?
Passageway for air and food. epithelium?
oropharynx. Stratified squamous
Where are the palatine and lingual tonsils located?
Provides a patent airway, routes air and food into proper channels and voice production.
Composed of nine cartilages
Vibrate as air rushes up from lungs
vocal folds (true vocal cords)
Help close glottis during swallowing
vestibular folds (false vocal cords)
What type of epithelium is the trachea composed?
pseudostratified columnar epithelium
What connects the trachea?
Air passages undergo 23 order of branching
What is the sequence of the conducting zone?
trachea -> right and left main bronchi -> lobar bronchi -> segmental bronchi
If a bronchiole is >0.5mm
As airways become progressively smaller what are 3 things that change?
1. support structures change
2. epithelium type changes
3. amount of smooth muscle increases
What define a respiratory zone?
the presence of alveoli
What is the pathway of the respiratory zone?
terminal bronchioles -> respiratory bronchioles-> alveolar ducts -> aveolar sacs
Alveolar walls are primarily what type of cells? epithelium?
type 1 alveolar cells. simple squamous epithelium
Type II alveolar cells consist of what type of epithelium?
What is the function of alveolar macrophages?
keep surface sterile
What are the 3 components of the respiratory membrane?
pulmonary capillary walls, alveolar walls, and their fused basement membrane
How many lobes are in each lung?
L: 2 superior and inferior
R: 3 superior, middle, and inferior
From the heart to the body back to the heart list the order of events in pulomonary circulation.
heart -> pulmonary trunk -> pulmonary arteries -> pulmonary capillaries -> pulmonary veins -> heart
In pulmonary circulation where is oxygenated and deoxygenated blood located?
Deoxygenated blood is in the pulmonary trunk and arteries. Oxygenated blood is located in the pulmonary veins
Covers external lung surface
Covers thoracic wall, superior surface of diaphragm, and lateral walls of mediastinum
Allow lungs to glide over thoracic wall and surface tension separation of pleurae
period when air flows into the lungs
period when air flows out of the lungs
Pressure around 760 mmHg at sea level exerted by air surrounding body
Pressure in alveoli that rises and falls with breathing, but always equalizes with Patm
Pressure in pleural cavity that rises ad falls with breathing, but always negative relative to atmospheric and intrapulmonary
By how mmHg is Pip less than Patm and Ppul
What are the 2 forces that act to pull lungs away from thorax wall and cause lungs to collapse?
lungs natural tendency to recoil and surface tension of alveolar fluid
What opposes lung collapsing forces?
elastic recoil of chest wall
What type of pressure prevents the lungs from collapsing? Difference between Ppul and Pip
air in pleural cavity
At constant temperature, pressure of a gas varies inversely with its volume
What are the muscles involved in inspiration?
diaphragm and external intercostals
During inspiration, what is the action of the diaphragm?
When contracting, moves inferiorly and flattens
During expiration, what is the action of the diaphragm?
dome shaped and superior
During inspiration, what is the action of the external intercostals?
contraction lifts rib cage and pulls sternum superiorly and ribs swing outward
Is inspiration a passive or active process?
When the inspiratory muscles contract, what happens to the volume in the thoracic cavity?
Is expiration a passive or active process?
When the inspiratory muscles relax what happens to the volume in the thoracic cavity?q
During expiration, what muscles help depress the rib cage?
internal intercostal muscles
What secretes surfactant?
type 11 alveolar cells
Reduces surface tension of alveolar fluid and prevents collapse of alveoli between breaths
Condition of insufficient surfactant in premature infants
infant respiratory distress syndrome
Amount of air moved into and out of lungs with each breath
Amount of air that can be forcefully inhaled beyond tidal volume
inspiratory reserve volume
Amount of air that can be forcefully exhaled beyond tidal volume
expiratory reserve volume
Air remaining in lungs after a forced expiration
What is the value associated with residual volume?
What is the value associated with inspiratory reserve volume?
What is the value associated with tidal volume?
What is the value associated with expiratory reserve volume?
How to calculate total lung capacity?
How to calculate vital capacity?
What are the partial pressures of 02 & CO2 when blood is entering pulmonary capillaries?
O2: 40 mmHg
CO2: 45 mmHg
What are the partial pressures of 02 & CO2 when blood is leaving i pulmonary capillaries?
CO2: 40 mmHg
In order what are the 3 ways CO2 is transported in blood?
1. As bicarbonate ions
2,. Combined with Hb
3. Dissolved in plasma
At the tissue level, bicarbonate ions diffuse out what into plasma?
In the lungs COs diffuses out of what? and into what?
out of RBCs and into alveoli
What are the 2 medullary respiratory centers?
ventral and dorsal respiratory group
Sets normal respiratory rate
Stimulate neurons that innervate inspiratory muscles?
Inhibit inspiratory neurons
What is normal respiratory rate called?
Integrates input from sensory receptors and sends indo to VRG
Transmit impulses to VRG to modify and fine-tune breathing rhythms and smooth out transitions from inspiration to expiration
pontine respiratory centers
Which factors influence respiratory rate and depth?Detected by?
Arterial blood CO2, O2, and pH
Central and peripheral chemoreceptors
Located in the brain stem and responds to H+ in brain ECF?
Located in aortic arch and carotid arteries that respond to CO2, O2, & H+ in arterial blood
What depresses respiratory centers?
What stimulates respiratory centers ti increase ventilation?
What is the most powerful stimulus for respiration?
rising CO2 levels