Respiratory Passages Flashcards
- soft, spongy, elastic organs, 0.5 kg each
- essential organs of respiration
- situated on either side of the heart and the mediastinal structures
Lungs
Features of Right Lung
1. Three lobes
* superior, middle and inferior
2. Two fissures
* horizontal and oblique
3. Shorted, wider and heavier as compared to left
4. Deeper diaphragmatic surface due to presence of liver
Features of the Left Lung
1. Two lobes – superior and inferior
2. One fissure (oblique); Cardiac notch; Lingula
3. Anterior border with cardiac notch
4. Lingula is present
* (tongue-like portion of the upper lobe
between cardiac notch and oblique
fissure)
read
- a serous membrane covering the lungs and made up of parietal and visceral layers.
- between visceral and parietal layer is the pleural cavity which contains a small amount of serous fluid to prevent friction of the 2 membranes as the lung will be expanding and collapsing.
o Parietal layer
Cover the mediastinal wall
o Visceral layer
Adherent to the lungs
the 2 layers are continuous at the root
of the lungs
Pleura
Phases of breathing
1. Inspiration/ Inhalation
* Air is flowing into the lungs (active phase)
During end of inspiration:
* Abdominal muscles relaxing
* The ribs moving up
* Diaphragm moving down
* Labored breathing: additional muscles contract, causing additional expansion of the thorax.
* Quite breathing: the external intercostal muscles contract, elevating the ribs and moving the sternum.
* Muscles of inspiration: sternocleidomastoid, scalene, pectoralis minor, external intercostal and diaphragm
- Expiration/ Exhalation
* Air is flowing out of the lung (passive phase)
During end of expiration
* Diaphragm moving up
* Muscles of expiration: internal intercostal and Abdominal muscles
read the Mechanism of Breathing
- Gases travel from area of high pressure to area of lower pressure
1. Intrapulmonary pressure
* pressure inside the alveoli
2. Intrapleural/ Intra thoracic pressure
* pressure in the pleural cavity
Equal pressure – no air movement
Low pressure within the lungs – there will be movement of gas
- when you have higher pressure outside from the atmosphere and there’s a low pressure inside – The air tends to move inside the lungs to have an equal pressure from the atmospheric pressure and alveolar pressure.
- Air will be moving inside when there is low pressure inside your alveolar sacs
- When there is already an increase pressure inside then the tendency of air will be to move out.
read the Pressure relationship in the Thoracic Cavity
- Friction in the air passageways
* resistance - Lung compliance
* Elasticity and flexibility - Surface tension of the alveolar fluid
* Surfactant – decreases surface tension
read the Physical Factors Influencing Pulmonary Ventilation
- Regular expiration and inspiration
Tidal volume (500ml)
- Maximum inspiration
Inspiration reserve volume (3000ml)
- Maximum expiration
Expiration reserve Volume (1100ml)
- Air remaining in the lungs
- You cannot totally remove the air within the lungs
Residual volume (1200ml)
- Residual volume and expiration reserve volume
Functional residual capacity (2300ml)
- Tidal and inspiratory reserve volume
inspiratory capacity (3500ml)
- Expiratory reserve, tidal and inspiratory reserve volume
Vital capacity (4600ml)
- Total of the air that will be present within the lungs
- All are included
Total lung capacity (5800ml)
A. Oxygen
1.Oxyhemoglobin – O2 and Hemoglobin -
97%
2.Dissolved in plasma - 3%
B. Carbon dioxide
1.Dissolved in plasma - 7-10%
2.Carbaminohemoglobin - 20-30%
3.Bicarbonate (HCO3) - 60-70%
Carbonic anhydrase CO2 + H2O\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_HCO3 + H H2CO3 ~ carbonic anhydrase ~ HCO3 + H
- When you have an increase level of CO2, more will be binding on water and with carbonic anhydrase. It will be broken down into bicarbonate and hydrogen
- Increase CO2 = increase hydrogen ion
- Increase hydrogen ion = decrease ph (respiratory acidosis; proton donors)
read the Gas transport
- External respiration: Pulmonary gas exchange
1.Partial pressure gradient and gas solubility
o CO2 and O2
2.Thickness of the respiratory membranes
3.Surface area
o alveoli increase the surface area 140
meters
4.Ventilation
o perfusion coupling
read the Gas exchange in the Body
- responsible for rhythm of breathing.
- Impulses travel to phrenic and intercostal nerve to diaphragm
Dorsal inspiratory group/ inspiratory centers
- contains both inspiratory and expiratory neurons
- during forceful breathing
medullary respiratory center
pontine respiratory group
dorsal respiratory group – will stimulate your diaphragm to contract
ventral respiratory group – will be stimulating the expiratory group of the
Ventral respiratory group/ expiratory center
- continuously sends inhibitory impulses to the inspiratory center of the medulla
- sets duration of inspiration
Pneumotaxic center
- provides inspiratory drive
- sends signals for inspiration for long & deep breaths
- controls intensity of breathing
- inhibited by stretch receptors or by pneumotaxic center
- increases tidal volume
Apneustic center
- Stretch receptors in the visceral pleura that transmit inhibitory signals to medullary inspiratory center
- When the lungs have reach maximum level of stretching, this herring-Breuer reflex will send an impulse to your medullary inspiratory center and tell to stop stimulating inspiration.
Herring-Breuer Reflex
- located in the medulla oblongata
- sensitive to changes in blood CO2 and Ph
- increase CO2 or hypercapnia – respiratory stimulant
- when you have more CO2, you need to move them out. So, respiration should be stimulated, so that you will dispose your CO2
Central chemoreceptors
- carotid bodies
- sensitive to changes in blood O2 levels
- if there’s a decrease in O2 level, you will be stimulated to breath, so that you increase the level of O2
Peripheral chemoreceptors
- Increase of ventilation
- Changes of blood pH, CO2 and O2
Effects of Exercise
