W8- Lecture 41- Respiratory system Flashcards
describe the functions of the respiratory systems
Supplies the body with oxygen and removes carbon dioxide.
Filters inspired air.
Goblet cells and cilia of the trachea remove more foreign particles.
normal adult averages respiratory rate
12 breathes per minute
where in the brain can voluntary breathing come from ?
cerebral cortex.
where is the respiratory control centre?
brainstem, within the reticular formation through both the medulla oblongata and the pons
what respiratory group has the most important role in the control of respiration (inspiration/ exhalation).
inspiration- DRG dorsal respiratory group
exhalation- VRG ventral respiratory group
what is the Hering-Breuer (Inflation reflex) reflex ?
Hering-Breuer Reflexes prevent over inflation or excessive deflation of the lungs.
When the lungs are inflated to their maximum during inspiration, pulmonary stretch receptors send an action potential to the medulla and pons in the brain through the vagus nerve.
The PRG sends signals to inhibit the inspiratory area.
Signals are sent to the diaphragm to stop.
what is the Hering-Breuer (deflation reflex) reflex ?
As inspiration stops, expiration begins and lungs deflate.
As the lungs deflate the stretch receptors are deactivated and the compression proprioreceptors activated.
Inhibitory signals stop and inhalation can begin.
describe the role of Proprioceptors in muscles ?
Proprioceptors present in muscle detect movement of the body. These receptors input into the respiratory centres and they play a role in stimulating the increase in ventilation that occurs during exercise.
describe the role of baroreceptors in vessels
Baroreceptors detect changes in blood pressure. A sudden increase in blood pressure will lead to a decrease in respiration rate (and vice versa).
what components make up the upper respiratory tract
The upper respiratory tract – consisting of the nose and nasal cavity, and the pharynx.
what components make up the lower respiratory tract
The lower respiratory tract – consisting of the larynx, the trachea, the bronchi, and the lungs.
how are the airways divided ?(zones)
The airways are divided into two functional zones with the first 16 generations of branches comprising the conducting zone and functioning to conduct air to the deeper parts of the lungs.
The last seven generations participate in gas exchange and comprise the respiratory zone.
what is the purpose of the conducting zone in the respiratory tract
structures
carries air into and out of the site of gas exchange.
The conducting airways are lined with mucus-secreting and ciliated cells that function to remove inhaled particles.
Humidifies the inhaled air and removes particles
Structures: Nose Pharynx Larynx Trachea
where does the trachea begin/ length
splitting at what point ?
Trachea is 11cm long and begins at c6.
T4/5: Trachea bifurcation
Trachea consists of c-shaped hyaline cartilage rings
describe mucosa in the respiratory tract
A layer of pseudostratified ciliated columnar epithelial cells that secrete mucus.
Found in nose, sinuses, pharynx, larynx and trachea.
Mucus can trap contaminants.
Cilia move mucus up towards mouth.
describe the structure of the lower conducting zone
anatomical differences left v right
segments
clinical references
The position of the heart means that the left bronchus branches off at an angle so that inhaled foreign bodies tend to go down the right bronchus.
A broncho-pulmonary segment is a discrete anatomical and functional unit of the lung that can be removed without disturbing the function of the other segments.
The right lung has 10 segments. The left lung has 9-10.
Clinical relevance:
bronchitis, infection of the bronchi.
bronchiectasis can occur following infection, such as pneumonia, when the bronchi widen, and excess mucus gathers
what structures form the respiratory zone of the resp tract
Respiratory bronchioles
Alveolar sacs
describe the purpose of alveoli
number
structure to increase exchange
debris movements/ what by
diameter
Purpose: site of gaseous exchange between alveoli and capillary blood
Each lung has 200 million alveoli.
Gaseous exchange between alveolar gas and pulmonary capillary blood can occur efficiently as alveolar walls are thin with large surface area.
Contain alveolar macrophages to carry debris to upper airway.
Diameter of 200-500 μm.
how does age effects the number of alveoli / SA ?
birth
8y
adult
birth-low no- low SA
8y-high no- mid SA
adult-high no- high SA
lobes of lungs
right
left
how are the lobes separated ?
what are lobes divided into ?
right - 3 lobes superior, middle and inferior.
left - 2 lobes superior and inferior.
by connective tissue
lobes into lobules the right lung consists of 10 lobules whilst the left lung consists of 9 lobules.
each lung is contained in a separate cavity, what is this called ?
the pleural cavity
The pleural cavities
- formed from
- 2 membranes make
- pleural fluid + functions
The pleural cavities are formed from 2 pleural serous membranes. Known as the parietal pleura, which covers the inner thoracic wall, the diaphragm, and the mediastinum. And the visceral pleura, which covers the surface of the lung.
Between these 2 membranes exists the pleural fluid.
The pleural fluid has 2 functions:
1- To lubricate the movement during breathing of the pleural membranes past one another
2- Holds the pleural membranes together, which in turn insures they can slide easily over one another, whilst making them hard to separate.
what are the two lung pleura?
+ cavity between pleura
Parietal: lines the chest cavity and contains the lungs.
Visceral: lines the lung surface.
Cavity between the pleura is called the pleural space.
how are both the pleura innervated ?
+ location of pain
Parietal pleura- somatic fibers from intercostal nerves and phrenic nerves; somatic pain will be localised to the intercostal spaces and/or referred to the neck and shoulder areas.
Visceral pleura- innervated by fibers from the cervical and thoracic sympathetic chain and parasympathetic fibers from the vagus nerve; visceral pain is typically vague and poorly localised.
