Exam 3 Study Guide Questions Flashcards
Why is the nose better than the mouth for breathing purposes? Which type of tissue is most responsible for making the nose better?
Filters/cleans air, pseudostratified ciliated columnar epithelium (also found in nasopharynx)
What are the three regions of the pharynx? Into which does the pharyngotympanic/auditory/eustachian tube drain? Which allow both food and air to pass through?
nasopharynx, oropharynx, laryngopharynx
nasopharynx (drain)
oropharynx (food and air passes)
Which two cartilage tissues make up the larynx? Which forms the epiglottis and why is that an important structure/function relationship?
Hyaline cartilage (rigid), elastic cartilage (epiglottis - flexible flap that can open and close)
Describe the mechanism by which you can vocalize and adjust volume and pitch.
Small space between true vocal folds (cords) allows air to be pushed through on exhalation creating vibration and resonance in the chamber emitted out of mouth. Force of exhalation generates stronger amplitude of sound waves (volume) and greater/lesser stretch of vocal cords creates frequency (more stretch, higher pitch).
What are the three tissue layers of the trachea? Which best transports mucous? What structure keeps the trachea from collapsing during negative pressure breathing?
Hyaline cartilage - keeps trachea from collapsing, smooth muscle, pseudostratified ciliated columnar
epithelium - transport mucous
What type of bronchi channels air to individual lobes?
Secondary or lobar bronchi
Which tissue is most responsible for constriction and dilation in bronchioles? What is the last type of bronchiole before entering an alveolar duct?
Smooth muscle
Respiratory bronchiole
What are the 3 general processes of respiration? In which would CO2 be exchanged between blood and the lungs?
Ventilation, internal and external respiration
External respiration
List in order from nose to alveoli the pathway for air entering the body.
Nares ➡️ nasal conchae and meatuses ➡️ nasopharynx ➡️ oropharynx ➡️ laryngopharynx ➡️ larynx ➡️ trachea ➡️ primary bronchi ➡️ secondary and tertiary bronchi ➡️ bronchioles ➡️ terminal bronchioles ➡️ respiratory bronchioles ➡️ alveolar ducts ➡️ alveolar sacs ➡️ alveoli
The simple squamous cells of these two structures create the gas/blood exchange surfaces in respiration.
Alveolus, pulmonary capillary
These cells secrete surfactant. What does the surfactant do to ease breathing?
Type Il pneumocytes, surfactant reduces surface tension (increases ability to inflate alveolus)
Contrast Atmospheric pressure (Patm), Alveolar pressure (Palv), and generally define Pleural pressure (Pip).
Patm = pressure of air outside the body
Palv = air pressure in alveolus (can be changed by inspiration/expiration)
Pip = pressure between inside rib cage and outside of lung
Total lung capacity
5800 mL
Inspiratory lung capacity
3500 mL
Vital capacity
4600 mL
Functional residual capacity
2300 mL
Residual volume
1200 mL
If your diaphragm contracts, why does air enter your lungs?
Diaphragm contracts “down” to increase volume of thoracic cavity and reduces Palv. So Patm > Palu, air moves down pressure gradient (outside air to alveolus).
If your diaphragm relaxes, why does air leave your lungs?
Diaphragm moves up in relaxation to decrease volume of thoracic cavity and increases Palv. So Palv> Patm, air moves down pressure gradient (alveolus to outside air).
If you forced expiration, which additional muscles would participate?
Internal intercostal muscles “squeezes” rib cage/thoracic cavity further increasing Pal
What is left after you have expired all of your respiratory reserve volume?
Residual volume - 1200 ml
What is a normal tidal volume? When might you increase it?
500 ml - resting breathing, exercise
Tidal volume
500 mL
Inspiratory reserve volume
3000 mL
Expiratory reserve volume
1100 mL
Why does O2 move from alveoli to pulmonary capillaries?
PO2 in air sac = 100 mmHg and PO2 in pulmonary capillaries returning to lungs from tissues is = 40 mmHg.
This creates partial pressure gradient and O2 diffuses through epithelial layers of air sac and capillary into bloodstream.
Why does CO2 move from the blood to lungs (or tissues to blood) just as well as O2 even though it has a much smaller partial pressure gradient?
CO2 is more soluble - travels/diffuses better than O2
Why does O2 always move from blood to tissues? How is 98% of O2 delivered in blood?
PO2 blood = 100 mmHg and PO2 tissues = 20-40 mmHg.
Partial pressure gradient from blood to tissues.
98% delivered by Hemoglobin (Hb)
Even though O2 content might be substantially different between sea level and 6,000 ft of elevation, O2 saturation of Hb for people in those two locations is very close. Why?
Hb has high affinity for O2 over wide range of PO2. Flat top of saturation curve.
What does lower pH do to the O2 saturation curve (Bohr effect)?
Lower pH, higher PCO2 and higher temp will each shift O2 saturation curve to right meaning at any given PO2 pressure, Hb will release more O2 at that pressure. Each condition changes the shape of Hb slightly so affinity is decreased. Think exercise and higher demand for O2.
How is most CO2 transported in blood? Which enzyme assists in its temporary conversion? Conversion to what?
CO2 + H20 with help of carbonic anhydrase ➡️ H2C03- (carbonic acid) ➡️ HCO3- and H+ (travels in this
form)
Which part of the medullary respiratory center stimulates the diaphragm?
Dorsal group
What does the pontine respiratory group do to breathing?
Controls switching between inspiration and expiration (rhythm).
Contrast limbic vs cortical respiratory control.
Limbic - primitive emotions (anger, fear, etc) can affect breathing as limbic includes hypothalamus which has “override” regulation of pons and medulla
Remember medulla, pons and limbic are all subconscious control.
Cortical (consciousness/voluntary) - you think/control respiration but there are limits (hold your breath).