Chapter 6 - Respiratory System Flashcards
What passes through the pharynx?where is it located?
Located behind the nasal cavity, at the back of the mouth.
Pathway for air that is going to the lungs, and for food that is going to the esophagus.
Where is the larynx?
What are some features of the larynx? (Parts of it)
Below the pharynx - air only
The GLOTTIS is the opening to the larynx, and the EPIGLOTTIS functions to keep food out by covering the glottis during swallowing.
Contains TWO VOCAL CORDS
What are vocal cords made of?
Skeletal muscle
Cartilage
Pathway of air from mouth to lungs:
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Nares Nasal cavity Pharynx Larynx Trachea Bronchi Bronchiole Alveoli
What substance are the alveoli covered with?
Surfactant - a detergent
It lowers surface tension
Prevents the alveolus from collapsing on itself.
What are the differences between right and left lung?
LEFT LUNG
Has a small indentation (it’s smaller)
2 lobes (upper/lower)
RIGHT LUNG
Is bigger
3 lobes (upper/middle/lower)
What are vibrissae?
Nasal hairs
What parts of the respiratory system are lined with ciliated epithelial cells?
Bronchi and Trachea
Visceral pleura versus parietal pleura
Space between them
Visceral pleural: covers the lung
Parietal pleural: outer membrane
The space between is called the intrapleural space, and contains pleural fluid to lubricate the membranes.
*pressure differential between both membranes is what drives breathing
What does the diaphragm do? What is it controlled by?
Thin muscle that separates the thoracic cavity from the abdominal cavity.
Under SOMATIC control even though breathing itself is under AUTONOMIC control.
What muscles are involved in filling the lungs with air?
Filling of the lungs is ACTIVE - requires skeletal muscle to generate the negative pressure for expansion.
Intercostal muscles
Diaphragm
Muscles of the chest wall, abdomen, and neck also play a role, especially during labored/pathogenic breathing.
What is Boyle’s law?
How does it relate to breathing?
The pressure and volume of gases are inversely related.
“Negative-pressure breathing”
As the chest wall expands (and volume increases) the pressure in the lungs drops, and air is drawn in.
*the driving force is the lower pressure in the intrapleural space compared to the lungs.
What muscles CAN play a role in exhalation?
(Exhalation happens naturally via the relaxation of the EXTERNAL intercostal muscles)
Internal intercostal muscles
Abdominal muscles
What is emphysema?
Disease characterized by destruction of the alveolar walls.
Results in less recoil of the lungs, making EXHALATION very difficult.
(Usually caused by cigarette smoking)
What is a spirometer?
What can it NOT measure?
Instrument that measures lung capacities and volumes.
CANNOT measure the amount of air that remains in the lungs (residual volume)
What is total lung capacity (TLC)?
Max volume of air in the lungs when we inhale fully
About 6-7 liters
What is residual volume (RV)?
The minimum amount if air in the lungs when we exhale fully
What is vital capacity (VC)?
The difference between min and max volume of air in the lungs (TLC - RV)
What is tidal volume (TV)?
The volume of air inhaled or exhaled in a normal breath
Expiratory reserve volume (ERV)?
The volume of ADDITIONAL air that can be forcibly exhaled after a normal exhalation
Inspiratory Reserve volume (IRV)?
The volume of ADDITIONAL air that can be forcibly inhaled after a normal inhalation
What is the MEDULLA OBLONGATA?
Continuation of the spinal cord that forms the lowest portion of he brain stem.
Controls the heart and the lungs.
What is the ventilation centre?
A collection of neurons in the medulla oblongata.
Fire rhythmically to cause regular contractions of respiratory muscles.
These neurons have chemoreceptors that are sensitive to CO2 concentrations.
High CO2 levels (hypercarbia / hypercapnia) cause increase in resp rate to exhale more CO2 and decrease levels.
*also receptive to changes in O2 but only relevant during hypoxia (low O2 conc in blood)
What other part of the brain can control breathing?
The cerebrum.
We can choose to breathe more rapidly or more slowly, but if we hypoventilate and increase CO2 levels, medulla oblongata takes over.
