respiration and lung mechanics Flashcards
what is in the conducting zone
larynx, trachea, lungs, bronchi, bronchioles
what is boyle’s law
that the pressure (P) of a gas is inversely proportional to its volume (V)
* Thus – can change alveolar pressure by changing its volume
what is the function of ciliated cells
propel the mucus up the glottis to be swallowed or expelled
what is the function of the respiratory zone
Exchange of gases between air and blood by diffusion
what are pores of Kohn
permit airflow between adjacent alveoli (collateral ventilation)
describe the respiratory muscles during inspiration
contraction of external intercostal muscles causes elevation of ribs (increases side to side dimension)
diaphragm contracts and lowers (increases verticla dimension)
elevation of ribs causes sternum to move up and out (increasing front to back dimension)
how do you calculate ventilation
Difference between Pressure alv and Pressure atm
what are Type I alveolar cells
- Make up wall of alveoli, single layer epithelial cells
- They form the alveolar-capillary barrier, facilitating efficient gas exchange
- Their thin structure minimizes the diffusion distance for gases, improving oxygen uptake into the blood.
describe alveolvar pressure during expiration
At the end of inspiration, alveolar pressure is equal to atmospheric pressure
The reducing thoracic volume (muscles relax), decreases lung volume, causing the alveolar pressure to increase above atmospheric pressure
Because of this pressure gradient (higher pressure in the alveoli than outside), air flows out of the lungs.
As air leaves, alveolar pressure returns to 0 cm H₂O, equalizing with atmospheric pressure.
what are the 4 steps of external respiration
- gas exchange between atmosphere and air sacs in lungs
- exchange of O2 and CO2 between air in alveoli and the blood in the pulmonary capillaries
- Oxygen is transported from the lungs to the tissues through the bloodstream, Carbon dioxide is transported from the tissues back to the lungs in the blood
- oxygen is released from hemoglobin in the blood and diffuses into the tissues, while carbon dioxide from the tissues enters the blood to be transported back to the lungs for removal.
what muscles are invovloved in inspiration
external intercostal
interchondral part of internal intercostal
diaphragm
sternocleidomastoid
scalenes
describe alveolar pressure during inspiration
muscles contracting increases the volume of the thoracic cavity
the lungs also expand. This increase in lung volume causes the air inside the lungs to spread out, reducing the pressure in the alveoli.
The decrease in alveolar pressure makes it lower than atmospheric pressure, creating a pressure gradient. This difference allows air to flow into the lungs from the outside
the alveolar pressure equalizes with atmospheric pressure at the end of the inspiration phase
what muscles are involved in expiration
internal intercostal exceot interchondral part
abdominal muscles
rectus abdominis
external/internal oblique
transversus abdominis
what is external respiration
Exchange of oxygen and carbon dioxide between atmosphere and body tissues
name secondary functions of the respiratory system
- Short term regulation of pH
- Help in defense against pathogens in the airways
- Eliminates heat and water
- Enabling speech, singing, and other vocalizations
what are Three different pressure considerations important in ventilation
- Atmospheric (barometric) pressure
- Intra-alveolar pressure (intrapulmonary pressure)
- Intrapleural pressure (intrathoracic pressure)
what are the 3 alveoli types
Type I alveolar cells
Type II alveolar cells
Alveolar macrophages
what is the function of goblet cells
secret mucus and traps foreign particles
what is internal respiration
metabolic processes carried out within the mitochondria, which use O2 and produce CO2, while deriving energy from nutrient molecules
oxidative phosphorylation
what is in the epithelium of the conducting zone
Goblet cells and Ciliated cells
what is functional residual capacity
volume of air
in lungs between breaths
(defined as rest)
Palv = Patm (2.2L)
describe intra-alveolar pressure
During inspiration = negative
(less than atmospheric)
During expiration = positive
(more than atmospheric)
whta is the transmural pressure gradient across thoracic wall
atmospheric pressure minus intrapleural pressure
what is atmospheric pressure
760 mm Hg at sea level
what are Type II alveolar cells
They produce and secrete pulmonary surfactant, a lipoprotein-rich fluid that reduces surface tension in the alveoli, preventing their collapse during exhalation
They also serve as progenitor (stem) cells that can differentiate into Type I cells to repair damaged alveoli.
what is in the epithelium of the respiratory zone
- Epithelial cells of alveoli
– Endothelial cells of capillary
what is in the respirtory zone
alveolar ducts, respiratory bronchioles, alveolar sac and alveoli
what is intrapleural pressure at rest
756 (or -4) mm Hg
Always less than alveolar pressure
why is intrapleural pressure negative
– Lungs recoil inward
– Chest wall recoils outward
– Opposing pulls on intrapleural space creating a negative pressure within the pleural cavity
Quiet breathing requires _% of total energy expenditure
3
what is the formula for the force of air flow
flow = atmospheric pressure - alveolar pressure divided by resistance to air flow (Resistance related to radius of airways and mucus)
describe the respiratory muscles during expiration
contraction of interal intercostal muscles, flattens ribs and sternum (reducing side to side and front to back dimension)
contraction of abdominal muscles causes diaphragm to move upward (reducing vertical dimension)
what is the transmural pressure gradient across the lung wall
intra-alveolar pressure minus intrapleural pressure
what factors affect pulmonary ventilation
lung compliance and airway resistance
what factors determine intra-alveolar pressure
- Quantity of air in alveoli
- Volume of alveoli
what are the function sof the conducting zone
Air passageway
Increase air temperature to body temperature
Humidify air
what are Alveolar macrophages
These are immune cells that patrol the alveolar surface, playing a crucial role in defense.
They engulf and digest inhaled pathogens, dust particles, and cellular debris via phagocytosis, keeping the lungs sterile.
They help clear excess surfactant and secrete inflammatory mediators when needed
what are barriers for diffusion
Alveoli: Type 1 cells + basement membrane
Capillaries: Endothelial cells + basement membrane
what is lung compliance affected by
elasticity (elastic recoil) and surface tension of lungs (alveoli) (type II cells produce
surfactant to decrease surface tension)
what is airway resistance affected by
passive forces, contractile activity of smooth muscle and mucus secretion
what are the two main types of pulmonary disease
Asthma and Emphysema
List the different respiratory volumes and the capacities and give average values for a 70Kg male.
Tidal volume= 500ml
Inspiratory reserve volume = 3000ml
Expiratory reserve volume = 1000 ml
Residual volume = 1200ml
Inspiratory capacity = 3500ml
Vital capacity = 4500ml
Functional lung capacity = 2200ml
Total lung capacity= 5700ml
Explain the significance of the Bohr Effect.
The Bohr Effect is based on the fact that as oxygen binds to Haemoglobin, some amino acids in Haemoglobin release hydrogen ions
Increased H⁺ lowers blood pH, causing hemoglobin to release oxygen.
This effect is reversible: in the lungs, as CO₂ is exhaled, pH rises, increasing hemoglobin’s oxygen affinity.
what is Emphysema
Emphysema is long term disease of the lungs that primarily cause shortness in breath. In people with
emphysema the tissues necessary to support the physical shape and functions of the lungs is destroyed. because the destruction of lung tissue around smaller sacs, called alveoli, makes these air sacs unable to hold their functional shapes upon exhalation.
what is the cause of emphysema
Emphysema is most often caused by smoking tobacco and long term exposure to air pollution.
how to treat emphysema
but can be slowed down by quitting smoking and avoiding air pollution. It can also be
treated by giving the patient a source of oxygen and steroid medication or anticholinergic’s (inhaler)
what is asthma
a chronic disease where the walls of bronchial become inflamed and oversensitive to things like smoke, air pollution, mould, and many chemical sprays.
They also can be irritated by allergens like dust mites and by respiratory infections like a cold. When the airways overreact they get narrower. This limits the flow of air into and out of the lungs and causes trouble breathing.
how to treat asthma
Asthma is treated by opening the lung airways. Inhalers are used to dilate the airways for ease of air passage. Asthma is also treated by avoiding asthma triggers such as allergens and irritants and by inhaling corticosteroids.
