Respiratory Physiology Part 1 Flashcards
The whole purpose of the respiratory system is to ?
Three exmples?
support cellular respiration
- Delivery of oxygen to the cells
- Removal of CO2
- Without oxygen all tissues are affected
Four processes that supply the body with O2 and dispose of CO2
- Pulmonary ventilation (air in and out)
- External respiration (exchange of gas at lungs)
- Transport in the systemic circulation
- Internal respiration (exchange of gas at the tissues)
Major Organs of theh respiratory system?
6
Funcitonal anatomy can be divided into 3 categories. What are they?
- Nose, nasal cavity, and paranasal sinuses
- Pharynx
- Larynx
- Trachea
- Bronchi and their branches
- Lungs and alveoli
conducting zone
respiartory zone
respiarotyr muscles
What is the conducting zone and what does it include?
Conducting zone: conduits to gas exchange sites
Includes all respiratory structures that do not participate in gas exchange
(just the highway!)
What is the respiratory zone?
What are the microscopic structures involved? 3
Respiratory zone: site of gas exchange
Microscopic structures:
- respiratory bronchioles,
- alveolar ducts, and
- alveoli
What are the muscles involved (1)?
Respiratory muscles:
diaphragm and other muscles that promote ventilation
What are the three layers of the trachael wall?
mucosa
submucosa
hylaine cartilage
What is the mucosa made of?
2
1. Pseudostratified ciliated columnar epithelium 2. Lamina propria (connective tissue)
What is found in the submuscosa?
Seromucous gland
in submucosa
Conducting zone structures of the upper airway 5
Whats it important for?
Nose and sinuses Pharynx Nasopharyx Oropharynx Laryngopharynx
heating and mositening the air
Funtion of the nose and sinuses? 2
Location of the nasal musocsa?
Produce mucus,
warm, humidify and filter the air
Nasal mucosa
Continuous with the mucosa of the lower respiratory tract and extends into the nasolacrimal ducts
What is contained in the nasopharynx? 1
Oropharyx? 3
Layngopharynx? 1
Nasopharynx -adenoids Oropharynx -Palatine tonsils, -lingual tonsil -Epiglottis Laryngopharynx -Vocal cords
compare the right and left main stem bronchi
Each main bronchus separates how?
entrance, braching pattern
Right main bronchus is wider, shorter, and more vertical than the left
Enters hilum of one lung
Each main bronchus branches into lobar (secondary) bronchi (three right, two left)
Each lobar bronchus supplies one lobe
Air passages undergo how many orders of branching?
Branching pattern is called the what?
Air passages undergo 23 orders of branching
bronchial (respiratory) tree
What does each lobar bronchus branch into?
How big are bronchioles?
Which are the smallest?
- Segmental (tertiary) bronchi
Segmental bronchi divide repeatedly
Bronchioles are less than 1 mm in diameter
Terminal bronchioles are the smallest, less than 0.5 mm diameter
The smooth muslces does what during when?
What medicine works on this?
What structures helps with the flexibility with air moving in and out?
constricts during bronchoconstriction
bronchodilators
elastic fibers (connective tissues disorder pts develop restrictive disorders with this)
From bronchi through bronchioles, structural changes occur. Name these.
4
- Cartilage rings give way to plates; cartilage is absent from bronchioles
- Epithelium changes from pseudostratified columnar to cuboidal;
- cilia and goblet cells become sparse
- Relative amount of smooth muscle increases
Whats the main site for gas exchage?
What kind of cells are they (alveolar wall) made of?
alveolar sacs
type 1 alveolar cells basement membrane
1 cell layer thick
What are type 2 cells and what do they produce?
Type II (surfactant- secreting) cell
HOw thick is the air blood barrier?
~0.5-μm
What is the respiratory membrane made of?
Alveolar and capillary walls and their fused basement membranes
Scattered type II cuboidal cells secrete what? 2
surfactant and antimicrobial proteins
What are alveoli surrounded by?
They contain open pores that do what? 2
What do alveoli house and what are the purpose of these?
Surrounded by fine elastic fibers
Contain open pores that
- Connect adjacent alveoli
- Allow air pressure throughout the lung to be equalized
House alveolar macrophages that keep alveolar surfaces sterile
In COPD what would the alveoli look like?
grapes are popped to make one big one. really large alveoli. disrupting the funtion of the alveolar wall
Lungs occupy all of the thoracic cavity except for what?
mediastinum
What is the root of the lungs?
What is the costal surface made of? 3
site of vascular and bronchial attachments
anterior, lateral, and posterior surfaces
Compare the left and right lung?
Number of Bronchopulmonary segments on each?
Left lung is smaller, separated into two lobes by an oblique fissure
Right lung has three lobes separated by oblique and horizontal fissures
Bronchopulmonary segments (10 right, 8–9 left)
What are the smallest subdivisions and what are they served by?
How many segments does each lobe of the lungs have:
Right superior lobe?
Right middle lobe?
Right inferior lobe?
Left superior lobe?
Left inferior lobe?
Lobules are the smallest subdivisions; served by bronchioles and their branches
Right
superior
lobe (3
segments)
Right
middle
lobe (2
segments)
Right inferior lobe (5 segments)
Left superior
lobe
(4 segments)
Left inferior
lobe (5 segments)
Gotta cut like broccoli or cauliflower. and then tie up the vessels to that area (for surgery)
- Describe the pressure and volume of pulmonary circulation?
- Pulmonary arteries deliver what kind of blood?
- where do they feed into?
- pulmonary veins carry what kind of blood and from where?
- low pressure, high volume
- Pulmonary arteries deliver systemic venous blood
- Branch profusely, along with bronchi and feed into the pulmonary capillary networks
- Pulmonary veins carry oxygenated blood from respiratory zones to the heart
Describe the pressure and volume of systmeic circulation?
Bronchial arteries provide what kind of blood and to where?
Where do they arise from?
They supply all lung tissue exacept what?
Bronchial veins anastomose with what?
Pulmonary veins carry what kind of blood and where?
Systemic circulation (high pressure, low volume)
Bronchial arteries provide oxygenated blood to lung tissue
Arise from aorta and enter the lungs at the hilum
Supply all lung tissue except the alveoli
Bronchial veins anastomose with pulmonary veins
Pulmonary veins carry most venous blood back to the heart
Describe the pleura?
What are the two kinds?
What is in between and how does it function?
Thin, double-layered serosa
Parietal pleura on thoracic wall and superior face of diaphragm
Visceral pleura on external lung surface
Pleural fluid fills the slitlike pleural cavity
Provides lubrication and surface tension
What nerve systems are responsibe for constriction of the bronchioles and dilation?
2
Parasympathetic stimulation
= constriction of the bronchioles
Sympathetic stimulation
= dilation of the bronchioles
Pulmonary ventilation consists of two phases. Describe them
Inspiration: gases flow into the lungs
Expiration: gases exit the lungs
The mechanics of breathing is reliant on the following principles:
2
Pressure relationships in the thoracic cavity
Pulmonary ventilation
Pressure relationships in the thoracic cavity can be described as? 2
Pulmonary ventilation depends on what? 4
Intrapulmonary vs. intrapleural pressures
Boyle’s law
Airway resistance
Alveolar surface tension
Lung compliance
What is transpulmonary pressure?
Transpulmonary pressure is the difference between the alveolar pressure (intrapulmonary) and the intrapleural pressure in the lungs.
43
43
43
43
What is atmospheric pressure?
2
Respratory pressures are descirbed realtive to what?
Negative respiratory pressure is less than what?
Positive respiratory pressure is greater than what?
Pressure exerted by the air surrounding the body
760 mm Hg at sea level
Respiratory pressures are described relative to Patm
Negative respiratory pressure is less than Patm
Positive respiratory pressure is greater than Patm
Zero respiratory pressure = Patm
Intrapulmonary (intra-alveolar) pressure (Ppul) is what?
When does it flucuate?
What does it always equalize with?
Pressure in the alveoli
Fluctuates with breathing
Always eventually equalizes with Patm
What is intrapleural pressure? (Pip)
When does it flucuate?
Is it positive or negative?
Pressure in the pleural cavity
Fluctuates with breathing
Always a negative pressure (
Intrapleural pressure is always negative (Pip). This is caused by opposing forces. Describe this.
Two inward forces promote lung collapse
One outward force tends to enlarge the lungs
Which two forces promote lung collapse?
Which force tends to enlarge the lungs?
- Elastic recoil of lungs decreases lung size
- Surface tension of alveolar fluid reduces alveolar size
- Elasticity of the chest wall pulls the thorax outward
- The transpulmonary pressure does what?
- The greater the transpulmonary pressure equals what?
- How do we lose transpulmonary pressure?
- keeps the lungs open
- the larger the lungs
- A hole! collapse lungs
Pip = Ppul
0 transpulmonary pressure
If loss of integrity of the pleura what results?
What is the transpulmonary pressure here?
Results in the equalization of the intrapleural pressure
Lung collapse
0
What is lung collapse called?
Can be due to what two causes?
Atelectasis
- Lack of air delivery
Plugged bronchioles → collapse of alveoli - Lack of integrity of the pleura
Wound that allows air entry into pleural cavity (pneumothorax)
Name some conditions that cause atelectasis?
Break it down into 2 categories
Pleural problems
Ventilation problems
Pulmonary Ventilation
is what?
2
- Inspiration and expiration
2. Mechanical processes that depend on volume changes in the thoracic cavity
Volume changes cause what?
Pressure changes cause what?
Volume changes → pressure changes
Pressure changes → gases flow to equalize pressure
Describe boyles law?
The relationship between the pressure and volume of a gas
Pressure (P) varies inversely with volume (V):
P1V1 = P2V2
- Inspration can be described as what kind of process?
- Inspiratory muscles ______?
- Thoracic volume ______?
- Lungs are _____ and intrapulmonary volume ______?
- Intrapulmonary pressure ____ (to ____mm Hg)
- Air flows into the lungs, down its pressure gradient, _____=_____?
- An active process
- contract
- increases
- stretched
increases - drops
−1 - until Ppul = Patm
Expiration can be described as what kind of process?
active or passive
- Quiet expiration is a passive process
- Forced expiration is an active process using abdominal and internal intercostal muscles
During expiration:
- Inspiratory muscles ____?
- Thoracic cavity volume _____?
- Elastic lungs _____and intrapulmonary volume ______?
- Ppul _____ (to___mm Hg)
- (______ then Atm P)
- Air flows out of the lungs _____ its pressure gradient until 7. Ppul = ___.
- relax
- decreases
- recoil
decreases - rises
+1 - greater
- down
- 0
Intrapulmonary pressure: Pressure inside lung \_\_\_\_\_\_ as lung volume increases during inspiration; pressure \_\_\_\_\_\_\_ during expiration.
decreases
increases
Intrapleural pressure: Pleural cavity pressure becomes more \_\_\_\_\_\_\_ as chest wall expands during inspiration. Returns to \_\_\_\_\_ \_\_\_\_\_.
negative
initial value
Volume of breath: During each breath, the pressure gradients move how much air into and out of the lungs?
0.5 liter
57
57
58
58
59
59
Inspiratory muscles overcome three factors that hinder air passage and pulmonary ventilation
Airway resistance
Alveolar surface tension
Lung compliance
Friction is the major nonelastic source of what?
resistance to gas flow
What is the realtionship between flow pressure and resistance?
Flow=ΔP/R
bigger change in pressure = bigger change in flow
What is ΔP?
How are gas flow and resistance related?
- the pressure gradient between the atmosphere and the alveoli (2 mm Hg or less during normal quiet breathing)
- Gas flow changes inversely with resistance
Resistance is usually insignificant because of what factors?
2
- Large airway diameters in the first part of the conducting zone
- Progressive branching of airways as they get smaller, increasing the total cross-sectional area
Where does resistance disappear at?
Resistance disappears at the terminal bronchioles where diffusion drives gas movement
Where is the greatest resistance to flow seen?
2
- medium sized bronchi
- also in the conducting zone
(almost no resistance in the terminal bronchiole and respiratory zone. Branching goes way up, surface area goes way up, no resistance)
When airway resistance rises how does this affect breathing movements?
they become more strenuous
What can Severe constriction or obstruction of bronchioles? 2
How can we treat this? (and how does it work 2)
- Can cause respiratory failure
- Can occur during acute asthma attacks and stop ventilation
Epinephrine (sympathetic nervous system)
- dilates bronchioles and
- reduces air resistance
Forces at work that increase airway resistance
3
- Bronchospasm
- secretions
- muscosal edema
Why do COPD patients have to generate active expiration?
Lungs with COPD showed 72-89% reduction in number of terminal bronchioles per lung
They have to compensate for this
Conditions with increased airways resistance
- COPD
- Emphysema
- Chronic bronchitis
- Asthma
- Cystic Fibrosis
- Sleep apnea (upper airway resistance)
Alveolar surface tension attracts what?
resists what?
Attracts liquid molecules to one another at a gas-liquid interface
Resists any force that tends to increase the surface area of the liquid
What is surfactant and what is it produced by?
What does it prevent?
What will an insufficeient quantity in premature infants cause?
Detergent-like lipid and protein complex produced by type II alveolar cells
Discourages alveolar collapse
infant respiratory distress syndrome
What is lung compliance?
A measure of the change in lung volume that occurs with a given change in transpulmonary pressure
What three things are lung compliance normally due to?
- Distensibility of healthy lung tissue
- Ability of the thoracic cage to expand during inspiration under normal circumstances
- Reduction of alveolar surface tension secondary to surfactant
High compliance relates to lung expantion how?
much easier to expand
Conditions that decrease lung compliance?
6
- Nonelastic scar tissue
- Reduced production of surfactant
- Decreased flexibility of the thoracic cag
- Deformities of thorax
- Ossification of the costal cartilage
- Paralysis of intercostal muscles
