Respiratory System Flashcards
what are the functions of the respiratory system (respiration)?
- ventilation
- external respiration: exchange of oxygen and co2 between the air in the lungs and the blood
- transports oxygen and co2 in the blood
- internal respiration: exchange of o2 and co2 between the blood and tissues
what are the functions of the respiratory system (not respiration)?
regulation of blood pH
voice production
olfaction
innate immunity
voice production?
air movement past the vocal cords
olfaction?
airborne molecules are drawn into the nasal cavity
innate immunity?
protects against certain micrroganisms and other pathogens- preventing them from enetering the body and by removing them from respiratory surfaces
what are the structures in the upper respiratory tract?
nose and nasal cavity
pharynx (throat)
larynx
what are the structures of the lower respiratory tract?
trachea
bronchi
lungs
what are the characteristics of the lungs?
Within the thoracic cavity
2 lungs
* separated by the mediastinum in which the
heart is situated
Each lung is divided into lobes
* Left lung – 2 lobes (upper and lower)
* Right lung – 3 lobes (upper, middle and lower)
Heart sits within the ‘cardiac notch’
* so the left lung slightly narrower
Each lung: Surrounded by
a pleural cavity
* formed by 2 pleural
membranes
* the visceral and parietal
pleurae
Passages branch
* Decrease in size
* Increase in number
what is the seperation of the bronchial tree?
- Left and right bronchi (one bronchus) or primary bronchi divide
- Secondary bronchi (in lobes of lung) - divide
- Tertiary bronchi - divide
- Bronchioles – divide (several times)
- Terminal bronchioles
what are the characteristics of the bronchial tree?
Top of tree
* Lots of cartilage some smooth muscle
* Keep airways open
Bottom of tree
* Lots of smooth muscle less cartilage
* Change diameter of airways
where is the respiratory zone?
alveoli
* Air filled sacs
* Membrane v elastic* Expand / contract
* Surrounded by a capillary network to provide efficient gas exchange
* The respiratory membrane
* where gas exchange between the air and
blood takes place
* Very very thin
what are the roles of type 1 alveolar cells?
Type I alveolar cells (95%) form
the alveolar wall,
* permit gas exchange
what are the roles of type 2 alveolar cells?
Type II alveolar cells secrete
surfactant
* Defence
* Role in breathing and stabilises
alveoli (surface tension)
* Recoil of lungs
what are the roles of alveolar macrophages?
defence against foreign particles/infectious
microorganisms that reach the alveoli
what are the two phases of ventillation?
- Inhalation (inspiration)
- Exhalation (expiration)
how is ventillation regulated?
- Changes in thoracic volume (drives)
- pressure changes
- Air flow is driven by
- the pressure difference between
- the atmosphere (barometric pressure)
- inside the lungs (intrapulmonary pressure)
what way does ai flow?
from an area of high pressure to low pressure
what are the respiratory muscles?
- Diaphragm
- Intercostal muscles
- External
- Internal
- Scalene muscles
- Sternocleidomastoid muscles
- Pectoral muscles
- Abdominal muscles
what are the characteristics of the diaphragm?
- 70 % ventilation
- Dome shaped
- Contracts
- Downwards and flattens
- (increasing thoracis cavity)
- Relaxes
- Recoils upwards
- (reducing thoracic cavity)
- Only respiratory muscle working when lying flat and sleeping
what are the charcateritics of intercoastal muscles?
- Between ribs
- Two planes of muscular and tendinous fibres occupying each intercostal space
* Internal beneath external - The external intercostal muscles
* slope downwards and forward
* Contract: ribs upwards and outward
* Elevates ribs and sternum - The internal intercostal muscles
* Opposite direction
* Contract: lower ribs - Stability
what is happening to the muscles while inspiration is happening?
- Quiet breathing
- Diaphragm contracts
- External intercostals
* Contract
- Forced breathing
- Contract more forcefully
- Others contract
- Scalene muscles
- Sternocleidomastoid
- Pectoral muscles
what is the active process of inspiration?
signals from the respuratory cavity in the medulla oblongta (brain stem) –>
contraction of the diaphram and intercostal muscles leading to the diaphram moving downward –>
transverse expansion of thoracic cavity+ vertical expansion of thiracic cavity –>
lung volume increases and the intra-alveolar pressure decreases –> air-sucked in
what is happening to the muscles while expirating?
- Quiet breathing
- Relatively passive
- Elastic tissue (lungs thorax)
- Lung recoils
- When…..
- Diaphragm relaxes
- Domes (decreases volume)
- External intercostals relax
- Downwards and inwards (decreases
volume)
- Downwards and inwards (decreases
- Relatively passive
- Laboured exhalation
- Internal intercostals contract
*Abdominal muscles contract
- Internal intercostals contract
what are the air flow and pressure changes in inspiration?
- Increased thoracic volume
- Increased alveolar volume
- Decreased alveolar pressure
- Atmospheric pressure > alveolar pressure
- Air moves into lungs
what are the air flow and pressure changes in expiration?
- Decreased thoracic volume
- Decreased alveolar volume
- Increased alveolar / intrapulmonary pressure
- Alveolar pressure > atmospheric pressure
- Air moves out of lungs
what is pleural pressure?
the pressure in the pleural pressure
-normally lower than alveolar pressure
-suction effect- fluid removal by the lymphatic system
why is exhalation a pasive process?
- A passive event due to elastic recoil of the
lungs - Relaxation of diaphragm and external
intercostal muscles - During forced expiration, ONLY there is
contraction of abdominal, internal
intercostal (accessory muscles)