Exam 2 - Pulmonary Intro Flashcards
Which lung is larger?
Why?
- Right lung
- Heart is in the left side of the chest, taking up more space
What is the name for the top of the lungs?
How far do they extend?
- Apex
- Up to first rib or even past the clavicles
This connective tissue surrounds the lungs?
Visceral pleura
This connective tissue attaches to the chest wall in the thorax?
Parietal pleura
Where is the diaphragm anchored?
Lumbar spine
Label 1 and 2
- Right dome of diaphragm
- Left dome of diaphragm
What is 1?
Caval aperture - opening for IVC
What is 2?
What is interesting about it and what is its function?
- Central tendon
- Its called a tendon even though it is not connected to a bone
- The heart sits on top of it
What is 3?
Esophageal aperture
What is 4?
Aortic aperture
How is the diaphragm innervated?
Phrenic nerve, once on each side of the muscle
Where are the scalene muscles connected?
What is their purpose?
- Base of the skull/ top of the neck
- Can pull rib cage up to assist with breathing or contract to prevent the rib cage from being pulled down by the diaphragm
What is a consequence of regional blocks in the brachial/cervical plexuses?
- Potential for local anesthetic to leak out and affect the phrenic nerve, paralyzing one side of the diaphragm
How many generations of branches are there in the lungs?
24
What makes up the conducting zone?
What happens here?
How many generations are in the conducting zone?
- Trachea, bronchi, and bronchioles
- No gas exchange, just passageways for air to move through
- 16
What makes up the transitional and respiratory zones?
What occurs here?
Transitional zone: Respiratory bronchioles
Respiratory zone: Alveolar ducts and sacs
Gas exchange
What is the diameter of a normal trachea?
How does airway size change as you move further from the trachea?
- ~ 2 cm
- Continously get smaller in size
How are bronchioles and alveoli different structurally?
Bronchi contain cartiledge to support their shape
Alveoli have no cartiledge and only soft tissue
What is eupnea?
Normal breathing
What is stridor?
What can cause it?
- “Funny sounds” coming from the lungs
- Lung tumor or asthma
What is hyperpnea?
Fast/over breathing
What is hyper/hypoventilation
Breathing in excess (hyper) or below (hypo) the bodies metabolic demands
Define cyanosis
Having > 5 g/dL of deoxyhemoglobin
Makes tissues turn blue
Differentiate hypoxia and hypoxemia
Hypoxia: decreased O2 at the tissue level (localized)
Hypoxemia: decreased O2 in the arteries (systemic)
What is the conversion factor between mmHg and cmH2O?
1 mmHg = 1.36 cmH2O
Why do we use cmH2O in the lungs and mmHg in the vasculature?
Water is much less dense than mercury and allows for better resolution at low pressures
Essentially stretches out the scale we are using
What does content mean?
Content of oxygen in the blood (attached to Hgb and dissolved in blood)
What abbreviation is used for arterial and alveolar?
Arterial: a
Alveolar: A
What does v and V abbreviate for?
v = venous
V = ventilation
What is VE and VI?
VE: Expired ventilation
VI: Inspired ventilation
What does a V with a dot over it mean?
Volume per minute
VO2 = volume of oxygen consumed per minute
What is the inverse of compliance in the lungs?
Elastance
What is normal tidal volume (VT)?
What does that describe?
- 0.5 L
- Normal volume of inspiration and expiration of a normal breath
What is total lung capacity (TLC)?
What is normal?
What contributes to this capacity?
- The maximum amount of air that be contained in the lungs
- 6.0 L (3.0 L per lung)
- Comprised of the summation of IRV, VT, ERV, and RV
What is functional residual capacity (FRC)?
What is normal?
What contributes to this capacity?
- The volume of air in the lungs at the end of a normal expiration
- 3.0 L
- ERV and RV
What are the 2 important things that FRC does?
- Stabilizes blood gases: Allows for continous oxygen exchange between breaths - basically a reservoir for O2
- Holds airways open: Airways that have no cartiledge would collapse if there was not an internal pressure to keep them open - this is why at low lung volumes alveoli collapse causing atelectasis
What is expiratory reserve volume?
What is normal?
- Volume that could be expired after a normal expiration
- 1.5 L
What is residual volume?
What is normal?
- The volume that cannot be expired from the lungs
- This is because if more of the volume could be expired, the airways would collapse
- 1.5 L
What is inspiratory reserve volume?
What is normal?
- The volume that could be inspired with a maximal effort, above the tidal volume
- 2.5 L
What is vital capacity?
What is normal?
- The maximum volume of air that could be inspired and expired
- 4.5 L
- Consists of IRV + VT + ERV
What is inspiratory capacity?
What is normal?
- Consists of IRV + VT
- 3.0 L
What can decrease ERV?
Supine positioning
What is a normal respiratory cycle time?
5 seconds
Inspire for 2s, expire for 2s, Nothing for 1s
What is a normal RR for this class?
12 bpm
1 cycle every 5 seconds → 60 ➗ 5 = 12
What is intrapleural pressure in between breaths and at the end of inspiration?
What does this change in pressure do?
Between breaths: -5 cmH2O
End of inspiration: -7.5 cmH2O
- Allows for the VT to be sucked in
How does airflow change throughout inspiration and expiration?
What and when is fastest airflow during inspiration and expiration?
- Starts off slow and reaches peak airflow at 1s for both inspiration and expiration
- Peak airflow is -0.5 L/s for inspiration and +0.5 L/s for expiration
In what manner does intrapleural pressure change over the course of a respiratory cycle?
Linearly; decreases for 2s and increases for 2s
When is alveolar pressure at its lowest?
What is it?
- At peak inspiratory airflow: 1s
- -1 cmH2O
When is alveolar pressue at its highest?
What is it?
- During maximal expiratory airflow (1s)
- +1 cmH2O
What is alveolar pressure in between breaths?
0 cmH2O
Explain why alveolar pressure reaches 0 cmH2O at the end of inspiration?
During inspiration, alveolar pressures decrease drawing air in. At the end of inspiration, alveolar pressure has now equilibrated with the atmosphere and is once again 0 cmH2O.
Also, Ptp and Pip have the same magnitude making PA 0
(PA = Ptp + Pip)
Explain how expiration occurs at the alveolar level?
At the end of inspiration the alveoli have stretched out and become taut. When the diaphragm relaxes, this passive elastic recoil is used to push the air back out.
What happens to expiration in diseased lungs?
Expiration time increases because of the loss of elastic recoil
What is PIP or Pl?
Intrapleural pressure
What is transpulmonary pressure PTP?
Whats another name for this?
- Compares pressure difference between the pleura and alveoli - this is the pressure that allows for inspiration and expiration
- Transmural pressure
What is blood flow through the lung dependent on?
What areas have more flow?
- Gravity
- Areas closer to the ground have higher flow d/t increased pressure = wider vessels = lower resistance = increased flow
What is perfusion zone 2 of the lungs?
What is the zone 2 formula?
- Intermittent blood flow, dependent on arterial pressures (when pressures are high = flow, when pressures are low = no flow)
- Pa > PA > Pv
What is perfusion zone 3 of the lungs?
What is the formula?
- “Always on” blood flow because of the increased effects of gravity - stretches out the vessels and increases flow
- Pa > Pv > PA
What is perfusion zone 1?
What is the formula?
When does this occur?
- “Always off” blood flow - highest risk at the apex of the lung where vacular pressures are lowest
- PA > Pa > Pv
- Occurs in unhealthy patients or during PPV (PEEP compresses highly compressible vessels blocking flow)
Explain the curve below?
What is happening at the beginning of the curve?
- Vessels closer to the base have more flow due to increased pressure from gravity
- The exception is the very base of the lung - its has lower flow because it is sitting on top of the diaphragm, compressing the vessels - this is called zone 4
