Unit 5&6 Flashcards
Conducting Zone
(no gas exchange) :
Send air to respiratory zone
Conducting Zone’s Structure
- Nasal & oral cavities
- Pharynx & larynx
- Trachea
- Bronchi
- Terminal bronchioles
Respiratory Zone
(gas exchange):
Receive air from conducting zone
Respiratory Zone’s Structure
- Respiratory bronchioles
- Alveolar ducts
- Alveolar sacs
- Alveoli
Def. of Ventilation
move air in & out of lungs
Def. of Transportation
oxygen & carbon dioxide between lungs & tissues
Def. of External respiration
gas exchange between lungs & blood
Def. of Internal respiration
gas exchange between blood & all body cells
Def. of Nasal Cavity
- Provides an airway for respiration
- Moisten, warm or cool, filter air
- Resonating chamber (speech)
- Olfactory receptors
What does Mucous contain and what it destroys?
lysozyme, bacteria
Function of Larynx
- Airway to the lungs
- Voice production
True vocal cords:
- Inferior to false vocal cords
- Vibrate (elastic) to produce sound as air rushes up from lungs
False vocal cords:
- Superior to true vocal cords
- No sound production
Sound is “shaped” into language by:
- Pharynx
- Tongue
- Soft palate
- Lips
Type I alveolar cells
Gas exchange
Type II alveolar cells
Secrete surfactant
Function of Alveolar pores
- Connect alveoli
- Equalize air pressure throughout lung
- Macrophages (dust cells) keep alveoli sterile
Sequence of Pulmonary Circulation
RV → Pulmonary trunk → pulmonary arteries → pulmonary capillaries (surrounding alveoli) → pulmonary veins → LA
Function of Parietal pleura:
Covers pleural cavity wall
Function of Visceral pleura:
Covers external lung surface
Inspiration (inhalation)
air enters lungs
Expiration (exhalation)
air exits lungs
Pulmonary Ventilation
- Depends on thoracic cavity volume changes
- Volume changes → pressure changes
- Pressure changes → gas flow
- Gases move along a pressure gradient (↑pressure → ↓pressure)
Boyle’s Law
-Describes an inverse relationship between pressure & volume of gases:
↑V → ↓P ↓V → ↑P
-P = gas pressure (mmHg)
-V = gas volume (mm3)
Inspiration according to Boyle’s Law
- ↑Thoracic cavity volume causes ↓pressure inside the lungs
- Air moves from atmosphere → lungs
Expiration according to Boyle’s Law
- ↓Thoracic cavity volume causes ↑pressure inside the lungs
- Air moves from lungs → atmosphere
Atmospheric pressure (Patm):
pressure exerted by air surrounding the body
Intrapulmonary pressure (Ppul):
pressure w/in alveoli
Intrapleural pressure (Pip):
- pressure w/in pleural cavity
- Intrapleural pressure is always <atmospheric pressure
Transpulmonary Pressure
- Transpulmonary pressure = intrapulmonary pressure – intrapleural pressure
- Keeps lung tissue expanded
- Prevents lung collapse
Def. of Friction:
major source of resistance to airflow
Relationship between flow (F) & resistance (R):
↑R → ↓F
↓R → ↑F
What is the normal transpulmonary pressure?
760 mmHg
What does severely constricted or obstructed bronchioles do?
Prevent normal ventilation
What does epinephrine do?
dilates bronchioles (↓resistance)
What does Ach (aceteylcholine) do?
Increase resistance, constrict bronchioles
Def. of surface tension
attraction of water molecules for one another
What does water in the alveolar surface coating do?
to ↓alveolar size (collapse)
Surfactant (phospholipid):
- Soap-like
- ↓Surface tension
- Prevents alveoli from collapsing
3 ways Thoracic Volume Increases During Inspiration
- Expansion → superior & inferior direction (top to bottom)
- Expansion → anterior & posterior direction (front to back)
- Expansion → lateral direction (sideways)
Muscles used during Inspiration
Diaphragm & external intercostal muscles contract
Inspiration
- Rib cage rises & expands
- Lung volume increases
- Intrapulmonary pressure decreases below atmospheric pressure
- Air flows into lungs (↑P → ↓P)
3 ways Thoracic Volume Decreases During Expiration
- Compression → superior & inferior direction (top to bottom)
- Compression → anterior & posterior direction (front to back)
- Compression → lateral direction (sideways)
Muscles used for NORMAL expiration
ALL muscles RELAX
Expiration
- Rib cage lowers
- Lung volume decreases
- Intrapulmonary pressure rises above atmospheric pressure
- Air flows out of lungs (↑P → ↓P)
Muscles used during FORCED inspiration
diaphragm, external intercostals, sternocleidomastoids scalenes, pectoralis minors contract
Muscles used during FORCED expiration
internal intercostals, abdominal muscles contract
Tidal Volume (TV)
air moving into & out of the lungs w/ each breath (500 mL)
Expiratory Reserve Volume (ERV):
air evacuated from the lungs below tidal volume (1200 mL)
Residual Volume (RV):
air remaining in lungs after forced expiration (1200 mL)
Vital Capacity (VC):
amount of exchangeable air during normal breathing (4800 mL)
VC = TV + IRV + ERV
Total Lung Capacity (TLC):
maximum amount of air that can be held in the lungs (6000 mL)
TLC = VC + RV
Respiratory Rate (RR):
total breaths per minute (BPM)
Respiratory Minute Volume (RMV):
normal air volume exchanged per minute (mL/ min)
RMV = RR x TV