Pulmonary Part 1 Flashcards
What does the respiratory system refer to?
the entire system from openings on the surface of the body for gas inhalation/exhalation to the tissue and cellular utilization of O2 and removal CO2
Functions of Respiratory System
- Provide O2
- Eliminate CO2
- Regulate pH
- Speech
- Defend body against microbes
- Hormonal regulation of body
- Involved in thrombo-embolism
Upper Respiratory Tract Anatomy
Nasal and oral airway down to vocal cords
Functions of upper respiratory tract
- provide low resistance pathway
- defend against microbes, toxins, and foreign bodies
- warm and moisten air
- provide for vocalization
upper respiratory tract pathology
paralysis or loss of sensation in any part of the pharynx can result in dysphasia and/or aspiration (sets you up for pneumonia)
what does the lower respiratory tract connect?
vocal cords to alveoli
two parts of the lower respiratory tract
- conducting airway
- acinar or terminal respiratory units
What is the conducing airway?
Tracheobronchial tree
Conducting airway characteristics
- not involved in gas exchange
- 16 generations of branching from 1 inch in diameter in trachea to 1 mm in terminal bronchioles
- cartilaginous rings support upper part
- lower part is muscular
Acinar or terminal reparatory units
alveoli and alveolar ducts
parts of the conducting airways
trachea and bronchi
Trachea
- From cricoid to bifurcation
- Deviates to R before bifurcation
- 16 to 20 incomplete cartilaginous rings
- first is thicker & broader, last has carina
Bronchi
mainstem, secondary, tertiary, 4th, so on
Bronchi characteristics
- R mainstem is wider and shorter than L
- R leaves trachea at 25 degree angle
- L mainstem bronchus leaves at 40 degree angle (R often involved in aspiration or foreign body obstruction)
Parenchyma
functional tissue of the lung
Superior aspect of the lungs
extend 1 inch above level of the middle of the clavicle into the root of the neck
Base of the lungs:
concave, resting on convex surface of diaphragm
Cardiac impression
- the indentation for the heart
- more notable on the left secondary to apex
- lines up with 5th ICS and MCL
Hilus
- entrance/exit of vessels to lung
pulmonary ligament
extension of the hilus inferiority
can you hear the inferior lobe anteriorly?
- not really
- you can hear it posteriorly or laterally
Parietal Pleura
- Serous membranous lining of thoracic cavity
- costovertebral
- diaphragmatic
- cervical
- mediastinal (innervation & vascular supply via intercostal N and vessels)
Visceral Pleura
- thin serous tissue which is adherent and inseparable from the lung parenchyma
where does innervation and vascular supply to the visceral pleura come from?
phrenic nerve and bronchial blood supply
Pleural Space
- potential space between the layers
- fluid accumulates here in disease states
What do segmental bronchi ramify within a segment to form?
- bronchopulmonary segments
- surrounded by CT layer, continuous with visceral pleura
Division of the bronchopulmonary unit
– secondary lobule: smaller unit surrounded by CT
– served by lobular bronchiole
– pyramid shaped
– terminal bronchioles ramify forming respiratory
bronchioles
Review the bronchial tree on slide 14
bronchioles are to the respiratory system what…
arterioles are to the circulatory system
What does secondary lobule contain?
–Terminal bronchiole
–Reparatory bronchioles
–Primary lobules
-Alveolar ducts
-Alveolar sacs
what are alveoli/primary lobules
terminal respiratory unit containing alveolar ducts & sacs
– 50 primary lobules/secondary lobule
– 300 million alveoli/mature lung
– mean surface area of 143 m2 (large for gas exchange)
Type I alveolar cells
provide for gas exchange
Type II alveolar cells
- produce surfactant
- Dipalmitoyl lecithin: phospholipid detergent, decreases surface tension
Alveolar-capillary septum
- epithelium and endothelium
- very, very thin membranes –> RBC traveling through there, so the gas doesn’t have far to go to get through
review overview of steps of respiration slide 18
Specialized cells within the lung
- Type I alveolar epithelial cells (pneumocytes)
- Type II alveolar cells (granular)
- others: specialized paracrine cells, mucous
producing cells, inflammatory cells, WBC & support cells
Type I alveolar epithelial cells (pneumocytes)
walls & septa of sac, squamous, thin & broad
* Function in gas exchange
* cover 93% of alveolar surface
Type II alveolar cells (granular)
- produce surfactant
- occupy the corners of the terminal sac
4 periods of respiratory system development
- Pseudoglandular period: 5-17 weeks
- Canalicular period: 16-25
- Terminal Sac period: 24th week to birth
- Alveolar period: years after birth
Pseudoglandular Period
5-17 weeks
- secondary bronchi to level of pulmonary segments
Canalicular Period
Weeks 16-25
Most of the branching and framework of
respiratory tree occurs:
* pulmonary segments to respiratory bronchioles
* alveolar ducts and beginning of terminal sacs
Terminal Sac Period
24th week to birth
– pulmonary alveoli develop
– capillaries and lymphatics
– surfactant is produced at about 28 weeks
Alveolar Period
Late fetal period to 5-7 years after birth
– 1/6 to 1/8th of the adult number of pulmonary alveoli are present at birth
– over the next 5 - 7 years pulmonary alveoli mature and come “on line”
After Birth:
▪ About 1/3 of the fluid in the lungs of the neonate is squeezed from the lung in birth canal.
▪ During the next few breaths another 1/3 of the fluid is absorbed into the capillaries.
▪ Remaining fluid is drained by lymphatics
What two problems does the neonate have in breathing?
- viscosity of the remaining fluid.
- high surface tension
what occurs during birth?
During birth, placental gas exchange is disrupted,
resulting in fetal hypoxemia & hypercapnia
Neonatal breathing
▪ First breath requires almost 60 mmHg trans-
pleural pressure to open lung
▪ Each successive breath requires less trans-pleural pressure
structure of the airways:
- upper regions and conducting airways
- lower regions (terminal & respiratory bronchioles)
Upper regions and conducting airway:
– basal lamina sits on smooth muscle
– ability to constrict
Lower regions (terminal & respiratory
bronchioles)
– single layered, cuboidal and mostly non-ciliated
– basal lamina on which they sit has bands of
elastin
- provides elastic recoil during exhalation
Innervation of the Respiratory System
- Receives sympathetic & parasympathetic
fibers
– Parasympathetic innervation from Vagus Nerve
– Sympathetic from upper sympathetic ganglia
(cardiac plexus)
what do both SNS and PNS fibers form?
anterior and posterior plexi
Activation of PNS
bronchiolar constriction, dilation of arterioles,
increased glandular secretion
Activation of SNS
bronchiolar dilation, vasoconstriction,
decreased glandular secretion
what does gas transport include?
lungs, muscles of respiration, upper and lower respiratory tract
ventilation
the physical movement of respiratory
gases (CO2 and O2) in & out of the lungs
Diffusion
how gas gets across the membranes
Perfusion
- the interface between blood and gas
- mismatching of ventilation & perfusion
Respiration
all of the above plus the cellular utilization of oxygen
Maintenance of Lung Integrity
- Transpulmonary P keeps the lung from collapsing
- Difference in P from inside the alveoli to intrapleural space
- Elastic recoil is the tendency of a tissue to resist stretch & return to pre-stretched shape
Compliance
- change in volume/ change in pressure
- ability of a material to deform when subjected to a deforming surface
Wall tension or stress (T)
- the tension required to inflate a sphere
Law of LaPlace
P = 2T/r, P = pressure & r = radius
– smaller radius sphere requires greater wall tension to remain open
– Small alveoli prone to collapse!
Effect of Surfactant
- Surface tension is greater in a smaller alveolus compared to a larger one (Law of Laplace) - air will move into the larger alveoli.
- Surfactant prevents this by decreasing T in the smaller alveoli.
- Sighing/deep breathing stimulates type II cells to make more surfactant
Surfactant
– Dipalmitoylphospatidylcholine:
– non-polar end (tail)
– polar end (head) dissolves in the surface film of water while the non-polar ends bind the actual alveolar surface, reducing surface tension
What does constant-volume breathing allow?
surfactant to equilibrate between alveoli, diminishing effectiveness
Resistance to Gas Flow - Low rate of Flow
Laminar Flow: P = flow rate x c
Resistance to Gas Flow - High rate of flow
Turbulence: P = flow rate x c
Effect of volume
As lung V increases, the
radius of the smallest airways increases, decreasing resistance
Normal motion of chest wall:
he chest rises slightly (1-1/2 inches), the diaphragm descends and the stomach moves out in normal quiet breathing
Paradoxical breathing chest wall motion
paralysis of intercostals
* chest moves in secondary to loss of motor function and negative intrathoracic cavity pressure
normal breathing - inspiration
Active (work done by diaphragm and ICs
normal breathing - Expiration
*Passive at rest (work done by elastic recoil of lung
when does paradoxical breathing pattern occur
paraplegia
Rib movement in breathing:
- Upper ribs (3-6) move in “pump handle” motion
- Lower ribs (7-10) move with “bucket handle motion
any disease that restricts rib movement affects ….
ventilation (restrictive lung disease)
Kyphoscoliosis (severe kyphosis)
causes ribs to approximate each other decreasing excursion
*affects more males than females
scoliosis
ribs on convex side of bend diverge while ribs on concave side approximate each other
minute ventilation
- volume moved through the lung/min
- Vmin = Vt x RR
- for given Vmin, patients with decreased TV, must breathe at a faster rate
dead space (anatomic)
- the portion of gas in the lung not in contact with blood (that part that does not participate in gas exchange)
- Vd = about 150 ml in a normal healthy adult
- for a person breathing at a higher RR, dead air/min is increased (wasted effort and increased work of breathing)
primary muscles of respiration
Diaphragm
* External Intercostals: run diagonally inferior and
anterior –> probably inspiration
* Internal Intercostals: run diagonally inferior and
posterior –> Fx- probably inspiration
* Innermost Intercostals: same as internal
excursion of diaphragm in varying body positions:
– Supine: expiratory excursion is greatest
- Moves further into thoracic cavity
– Standing and side lying: intermediate excursion.
– Sitting: minimal excursion
quiet breathing
diaphragm moves 2/3 inch
maximal breathing
2.5-4 inches
Accessory Muscles of Respiration
- Sternocleidomastoid
- Scaleni
- Trapezius:(upper only)
- Pectoralis Major & Minor
- Serratus Anterior
- Latissimus Dorsi
- Serratus Posterior/ Superior
- Quadratus Lumborum
- Iliocostalis
Scaleni
– anterior: attaches to 1st rib
– middle: attaches to 1st rib
– posterior: attaches to 2-3 rib
Number of pulmonary arteries and veins
fixed at birth at level of terminal respiratory units
Number of arterioles and venules in respiratory units
increase with age, parallel with addition of new RUs
what is pulmonary artery pressure at birth?
- high
- declines over next 4 months
- if pressure remains high, artery wall changes
pulmonary capillaries
very fine network of branches capillaries
where are pulmonary capillaries located
in the septa and walls of alveoli
what do pulmonary veins serve as?
a reservoir for LV, negating the pulsatile flow of the RV and changes in flow with inspiration/expiration.
Pulm. A & Vs parallel branching of bronchi to the
level of the segments:
veins run between segments and multiple veins drain each segment
Bronchial circulation
- One R-bronchial artery, 2 L-bronchial arteries
- Accompany branching of the bronchi down to the level of the terminal bronchioles
- Bronchial arteries receive 1-2% of the CO
function of bronchial circulation
to maintain blood supply in the event of pulmonary embolism
Static Lung Volumes
- Tidal Volume (VT)
- Inspiratory Reserve Volume (IRV)
- Expiratory Reserve Volume (ERV)
- Residual Volume (RV)
- Inspiratory Capacity (IC)
- Functional Residual Capacity
- Vital Capacity (VC)
- Total Lung Capacity (TLC), ERV - RV
dynamic lung:
volumes/rates
PEF
peak expiratory flow
FVC
forced vital capacity
FEV1
forced expiratory volume in 1 second
FER
FEV1/FVC ratio
what is COPD
Class of diseases of respiratory tract caused by
obstruction of the airways
COPD signs and symptoms
cough, dyspnea on exertion, wheezing expectoration of mucus
diagnosis of COPD
- based on pulmonary function tests
– expiratory flow rate limited
– residual volume increased - Hyperinflated lung: exhalation affected
– Also: increased mucus production, inflammation of mucosal lining, mucosal thickening, bronchiolar
muscle spasm
COPD includes:
- bronchopulmonary dysplasia
- cystic fibrosis
- asthma
- bronchiectasis
- chronic bronchitis
- emphysema
bronchopulmonary dysplasia
fibrotic changes in lung of infant secondary to ventilation
cystic fibrosis
excessive mucus production
asthma
airway hyper-responsiveness to allergens/irritants
bronchiectasis
dilation/distortion of bronchi secondary to infection
chronic bronchitis
excessive production of mucus secondary to smoking
emphysema
enlargement of terminal sacs, destruction of alveolar walls & septa, loss of elastic tissue
look at the little pulmonary function testing on 25
type A COPD - chronic emphysema
– SOB
– Little sputum production
– Barrel shaped chest w flat diaphragm & horizontal ribs
– Hypertrophied accessory muscles of
respiration & use of posturing
– Rapid, shallow breathing
– Due to hypercapnia, patients with light complexion may appear paradoxically pinkish
type B COPD
- productive cough
- Over-weight
- cyanosis
- associated w/ heart failure and peripheral edema
restrictive lung disease
an abnormal reduction in pulmonary ventilation with diminished expansion of the lungs
causes of restrictive lung disease
trauma, radiation Rx, rib or spinal deformity or secondary to primary lung disease
compliance =
change in V/change in P
compliance in restrictive lung disease
- compliance of either or both chest wall and lungs are decreased
- This results in a stiffer lung which is more difficult to open at any given volume, but especially at high lung volumes when C is minimal already
lung volume in restrictive lung disease
Because the distensibility of the lung is
decreased, all lung volumes are affected:
– Inspiratory reserve volume: decreased
– VT -initially preserved, but in time decreases
– Expiratory reserve volume: decreased, but especially affected by RLD that is caused by a decrease in lung, not chest wall, compliance.
– Residual Volume: decreased
– TLC and vital capacity also decreased
clinical manifestations of restrictive lung disease
tachypnea, alveolar hyperventilation, ventilation perfusion mismatching, crackles, decreased diffusing capacity, cor pulmonary
RLD- tachypnea
increased rate secondary to decreased volume
RLD- hyperventilation
overcompensation
RLD- ventilation perfusion mismatching
hypoxemia
RLD- crackles
secondary to atelectatic alveoli opening
RLD- decreased diffusing capacity
widening of interstitial space due to scar tissue , stretching
RLD- cor pulmonary
- pulmonary arterial HTN secondary to hypoxemia, fibrosis, compression of pulm. capillaries
- may lead to R-side HF, decreased exercise tolerance
RDL symptoms
- Dyspnea/SOB (initially w/exercise, but later at rest)
- Irritating, dry and unproductive cough –> secondary to irritation from increased velocity of air movement across airways
- Muscle wasting/cachectic look –> secondary to the increased work of breathing
- Difficulty eating secondary to increased work of breathing –> decreased appetite
- Acute and chronic cyanosis –> Clubbing of nails (chronic cyanosis), Bluish discoloration of nail beds and mucosa
clubbing of the nails
- broadening of distal phalanges with down-ward angulation and rounding of the nail
- Common with restrictive lung disease, but may also happen with COPD
