Lecture 9 Flashcards
Exam 2 content
What are the accessory muscles used for and where are they?
The scalene muscles counteract the diaphragm, these anchor into the top of the neck C3-C7. They prevent the thorax from being pulled down when the diaphragm contracts.
What nerves innervate the diaphragm?
The phrenic nerve from C3, C4, C5 keeps the diaphragm alive!
What structure do you have to watch out for when doing cervical and brachial plexus regional blocks?
the phrenic nerve (Only need one phrenic nerve to stay alive)
What is the diameter of the trachea in a normal, healthy adult?
1.8 cm
What is the diameter of the bronchi in a normal, healthy adult?
1.22 cm each
What is a conducting zone? What structures can be found in this zone?
where air movement occurs but no gas exchange. The trachea, two main bronchi and bronchioles.
What is a respiratory zone? What structures can be found in this zone?
Where gas exchange occurs. Respiratory bronchioles, alveolar ducts and alveolar sacs.
What type of tissue can be found in the structures in the conducting zone?
cartilage
What is orthopnea?
A change in breathing related to a change in body position
What is cyanosis?
Deoxyhemoglobin > 5g/dL
What is a normal tidal volume (Vt)?
a normal breath… 0.5L
What is total lung capacity (TLC)?
6.0 L. The maximum amount of air we can get into our lungs (3L each lung). TLC is the sum total of all the lung volumes (IRV, Vt, ERV, RV)
What is function residual capacity (FRC)?
3.0L. The amount of air that is already in the lungs in between breathes (a reservoir of oxygen in the lungs)
What are two uses for the functional residual capacity (FRC)?
Hold airways open and prevent atelectasis. Also, to keep blood gas stable between breaths.
The FRC is the combination of which two volumes?
- Expiratory reserve volume
- Residual volume
What is the expiratory reserve volume (ERV)?
The amount of air we could push out of our lungs if we tried. 1.5L.
What is the residual volume (RV)?
The air we cannot push out of our lungs. 1.5L.
What is the inspiratory reserve volume (IRV)?
The amount of air a healthy person can inspire in addition to a normal tidal volume. 2.5L.
What is the vital capacity (VC)?
4.5 L. The largest breath we can inspire/expire on one maximal effort. Includes the IRV, Vt, and ERV
What is the inspiratory capacity (IC)?
3.0L The amount of air we can take in from FRC to TLC. A combo of IRV and Vt.
At the end of inspiration, our thoracic pressure will drop to what? What does this draw in?
Intrathoracic pressure drops from -5 cmH2O to -7.5 cmH2O and this draws in our tidal volume of 0.5L.
Peak inspiration is highest when our alveolar pressure is____________.
lowest
How much blood flow does Zone 2 of the lung receive? What determines this?
There is intermittent blood flow to this area of the lung. When Pa > PA > Pv
Why does the bottom part of the lung receive the most blood flow?
Blood is heavy which increases intravascular pressure in the lower part of the lung. This stretches out the compliant blood vessels. Less resistance of these vessels translates to more blood flow.
How much blood flow does Zone 3 of the lung receive? What determines this?
This blood flow is “always on,” so this perfusion zone gets the most blood flow. Pa > Pv > PA
How much blood flow does Zone 1 have in a healthy person? What determines blood flow to this portion of the lung?
In a healthy person–> no blood flow “always off.” In an unhealthy person where PA > Pa > Pv there will be a little perfusion.
What is significant about Zone 4 of the lungs? Where is this area?
The bottommost portion of the lung comprises zone 4. This part of the lung is seated on top of the diaphragm where some of these blood vessels are compressed by the diaphragm. Here blood flow is slightly less than in zone 3.
