Respiration Flashcards
What is the diaphragm necessary for?
Inspiration- composed of skeletal muscle and under somatic control
Define surfactant
A detergent that coats each alveolus that lowers surface tension and prevents the alveolus from collapsing on itself
What are the main muscles of inhalation?
Diaphragm and external intercostal muscles
Describe the process of inhalation.
The thoracic cavity enlarges with use of the diaphragm flattening and the external intercostal muscles expanding the chest wall. Intrapleural volume increases, which means pressure decreases. The pressure in the lungs, however, increases, allowing the lungs to expand into the intrapleural space.
Describe exhalation
Not an active process (inhalation is). Diaphragm and external intercostal a relax, chest cavity decreases in volume, intrapleural volume decreases and pressure increases, so air will be pushed out of the lungs. Internal intercostals speed up the process in more active situations.
What part of the brain controls respiration, and how?
The medulla oblongata-fire neurons (with chemoreceptors that sense changes in blood pH) that are sensitive to CO2 increases. As ppCO2 increases, respiratory rate will also increase to counter it.
Define hyper/hypo ventilation
Hyperventilation: breathing too frequently and blowing off too much CO2.
Hypoventilation: breathing too little, leading to increased CO2.
These 2 processes can be controlled by the cerebrum, but are ultimately overridden by the medulla
What is a normal respiration rate?
12 breaths/min
How does respiration change as we increase altitude (and decrease pressure)?
The higher the altitude, the less O2, and ventilation increases. (Ie: on top of Mount Everest, there is 1/3 as much O2 as at sea level, and ventilation increases to 80-90 breaths/min.
- Increased respiration
- Increase erythropoietin (make more RBCs to carry more O2)
- Increased vascularization (more blood vessels)
- Increased tidal volume
What is total lung capacity (TLC) in a healthy human?
Represents the total amount of air we an breathe in our lungs. About 6-7 liters.
Define vital capacity (VC) in a healthy human.
The amount of air we can vitally use-I we breathe out until we can’t breathe out anymore, it is the total amount of air forced out.
Define residual volume (RV).
The amount of air left over after breathing out the vital capacity. THERE WILL ALWAYS BE AIR LEFT OVER BECAUSE OTHERWISE, OUR LUNGS WOULD COLLAPSE.
TLC=?
TLC= VC + RV
Define tidal volume (TV)
The amount of air that naturally comes out with each exhalation (not forced out). ~1 liter/breath
Define expiratory and inspiration reserve volume (ERV & IRV).
ERV=the amount of extra air forced out after a tidal exhalation
IRV=the amount of extra air taken in after a tidal breath.
