Unit 4: Respiratory Flashcards
6 Main Functions of the Respiratory System
1) Provide O2 and CO2 exchange
2) Regulates pH in coordination with kidneys
3) Phonation
4) Removal and screening of incoming microbes
5) Can remove arterial chemical messengers
6) Traps and dissolves blood clots
Anatomy: Epiglottis: Name meaning
Over(epi) hole (glottis)
Anatomy: Cartilaginous C Rings
Surround the trachea with the open end at the back. Prevents collapse of the trachea while sucking air in.
Anatomy: Pharynx vs. Larynx
Pharynx = above the larynx, part of both the air and food tunnels. Larynx is only part of the wind tunnel
Describe the route of air from Trachea to alveolar sacs
Trachea>Bronchi>Bronchioles>Terminal bronchioles>Respiratory bronchioles>Alveolar ducts>Alveolar sacs
What are the names of the two zones in the air hierarchy?
Conducting Zone and the Respiratory Zone
How many square meters do the alveoli have in terms of surface area?
A tennis court, 70 sq meters
What do type I cells do in the alveoli?
Type I cells are the walls
What do type II cells do in the alveoli?
They provide surfactant, and also act as a defense (macrophages)
What are the three components of the pleura moving from the inside to the outside?
Visceral pleura, intrapleural fluid, then parietal pleura.
What is the purpose of the pleura?
Like a biological slide with water between it, it is very easy for the two sheets to slide relative to each other, but it is incredible hard to separate the slides. This analogy is for the lungs and the Thoracic wall
Define respiration from a chemical standpoint
Food and O2 makes CO2, Energy, Waste, and water
What is Boyle’s Law for the purposes of this class?
P1V1=P2V2
How does Boyle’s Law show what happens during inspiration?
During inspiration, the chest expands volume, lowering the pressure below atmospheric, therefore allowing air to flow down its pressure gradient into the lungs.
What is FRC?
Functional Residual Capacity: the volume of air in the lungs after an exhale when the respiratory muscles are relaxed
What pressures are balanced to provide FRC?
The alveolar and atmospheric pressure are at relative 0 atm, and the inter pleural pressure is negative 4.
What happens in pneumothorax?
Puncture in the chest causes the pleural cavity to no longer maintain negative pressure, which causes the lungs to collapse.
4 major muscles involved in inspiration:
1) Diaphragm: contracts to flatten the muscle, expanding the thoracic space
2) Ext. Intercostals: elevates the ribs to widen cavity
3) Scalenus: lifts the rib cage
4) Sternocleidomastoid: elevates the sternum
2 major muscles involved in expiration:
1) Int. Intercostals: Depresses the ribs
2) Abdominals: abs able to flatten the belly forces air out and pushes the diaphragm in
Steps that occur during inspiration:
Diaphragm and Inspiratory Intercostals contract, thorax expands, inter pleural pressure becomes negative, increased transpulmonary pressure, lungs expand, pressure in alveoli lowers below atmospheric, and air flows into the alveoli
Describe compliance
The greater the compliance, the greater increase in volume for a step in transpulmonary pressure.
2 major determinants of lung compliance:
Collagen/Elastin: more of these = less compliance
Surface Tension: increased surface tension = less compliant, more surfactant = more compliant
F = ? for lungs?
Ppi(r^4)/8Lnu
Emphysema
loss of elastic recoil causes airway collapse. Will not require more work via muscles for exhaling. Patients adopt a high FRC (barrel chest)
Dyspnea
gas transport lowered causes anxiety and depression
Minute Ventilation: General definition and equation
Total ventilation in mL/min = Frequency of breathing x Tidal volume
Alveolar Ventilation: General definition and equation
Total ventilation of useful air (not including the dead space) = frequency x (Tidal volume - dead space)
What is the normal minute ventilation?
12 breaths/min x 500 mL/breath = 6000 mL/min
What is the normal alveolar ventilation?
12 breaths/min x (500 mL/breath - 150 mL/breath) = 4200 mL/min
How much O2 is released in our breath?
A lot, about 3/4 of the initial amount