Respiratory system Flashcards
Function of respiratory system
- Ventilation movement in and out of the lungs
- External respiration exchange and transport of CO2 and O2 in the blood
Respiration definition
- Cellular metabolism provides O2 needed for cellular respiration - make ATP from glucose
- Removal of toxic CO2
Function of repiratory system
Regulation of blood pH
- Altering blood CO2 levels on the blood
Functions of respiration
Voice production
Air movement past the vocal cords
Functions of respiration
Olfaction
Airborne molecules are drawn into the nasal cavity
Functions of respiration
Innate immunity
- Protects against certain microorganisms and other pathogens - preventing them from entering the body and by removing them from respiratory surfaces
Structure of respiratory system
– Upper repiratory tract Nose and nasal cavity
* Air enters
* Pharynx
* Larynx
Lowere respiratory tract
- Trachea
-Bronchi - Lungs
The lungs
- 2 lungs seperated by mediastinum in which the heart is situated
How many lobes are in the lungs
- Left lung – 2 lobes
- Right lung – 3 lobes
Where is the heart situated with respect to the lungs
- Cardiac notch left lung slightly narrower
Lung structure detail
- Surrounded by
-a pleural cavity viceral pleural - Passage branch which decrease in size and Increase in number
Conduction of airways
- Stricly for ventilation purposes
- Trachea is a cartilage that is split into left and right of bronchi bifurcation
Bronchial tree
- Left and right bronchi division then secondary divion of bronchi in lobes of lung then to tertiary and finally terminal bronchi
- Top of tree is usually lots of cartilage with smooth muscle which allows air to flow into the lungs
Alveoli
- Air filled sacs
- Membrane v elastic that can expand and contract
- Surrounded by a capillary network to provide efficient gas exchange
- Contain repiratory membrane gas exchange between the air and blood takes place
- Very very thin
Type I alveolar cells
- Forms alveolar wall allowing gas exchange
Type II alveolar cells
– Secreate surfactant Type of mucus
- Defence
* Role in breathing and stabilises
alveoli
* Recoil of lungs
Alveolar macrophage
- Defence against foreign
particles/infectious
microorganisms that reach the
alveoli
Ventilation
- Inhalation and exhalation which is regulated by the thoratic volume by pressure changes
- the pressure difference between the atmosphere and inside the lungs
Air flow and
pressure changes Gas exchange
- Increase volume of a container increases, the pressure within the container decreases the respiratory muscles change volume of thorax
- Air flows from an area of higher pressure to an area of lower pressure the greater the pressure difference, the greater the rate of airflow
Respiratory muscles
- Diaphragm
- Intercostal muscles
- External and Internal
- Scalene muscles
- Sternocleidomastoid muscles
- Pectoral muscles
- Abdominal muscles
Diaphragm
- Dome shaped
- Contraction downwards and flattens increasing thorotic cavity
- Relaxing recoils upwards reducing the thorotic cavity
- Only muscle to work while sleeping
Intercostal muscle
- Between ribs
- Two planes of muscular and tendinous fibres occupying each intercostal space
External intercostal muscle
- Slope downwards and forward
- Contract the ribs upwards and outward
- Elevates ribs and sternum
Internal intercostal muscle
- Opposing directions contracting the lower ribs
Inspiration
- Diaphragm contracts
- External intercostals and contraction occours
-Forced breathing where contraction occours more forcefully such as scalene muscles, Sternocleidomastoid and Pectoral muscles
Active process of inspiration
- Signals from the respiratory centre in the medulla oblongata
- Contraction of the diaphragm and intercostal muscles leading to the diaphragm moving downward
- Transverse and vertical expansion of thorotic pressure
- Lung volume increases and the intra-alveolar pressure decreases
- Air is then sucked inwards
Expiration
- Passive process Elastic tissue
- Lung recoils
- Diaphragam relaxes dome decrease in vol
- External intercostal muscles relax downwards and inwards
- Internal intercostals contract
- Abdominal muscles contract
End of Expiration
- Intra pulmonary pressure =
atmospheric pressure - No air movement
Inspiration
- Increased thoracic volume
- Increased alveolar volume
- Decreased alveolar pressure
- Atmospheric pressure > alveolar
pressure - Air moves into lungs
End of inspiration
- Alveolar pressure = atmospheric
pressure - No air movement
Expiration pressure cycle
- Decreased thoracic volume
- Decreased alveolar volume
- Increased alveolar
- Alveolar pressure > atmospheric pressure
- Air moves out of lungs
Pleural Pressure
- Lower than alvear pressure
- Suction effect - fluid removal by the lymphatic system
What happens if there is a lower plural pressure compared to alveolar
- Pulls the pleura away from the outside of the alveoli
- Pressure on the alveoli is lower
- Expansion opposes lung tendancy to recoil
Pneumothorax
- Air introduced
- Pleural pressure is not low enough to overcome lung recoil
- Alveoli collapse
