Cardiopulmonary Flashcards
Tidal Volume
Amount of air we inhale and exhale in normal quiet breathing
TV=~500mL
Minute respiratory volume (MRV)
Amount of air inhaled and exhaled in 1 minute
MRV= TV x # of respirations per minute
Avg RR: 12 to 20 per minute
500mL x 12 breaths/min = 6000 mL
- Shallow breathing associated with smaller TV -> requires increased RR to achieve necessary MRV
Inspiratory reserve volume (IRV)
Volume that can be inhaled beyond TV
Normal IR: 2000-3000 mL
Expiratory reserve volume (ERV)
Volume that can be exhaled beyond TV
Normal ER: 1000-1500 mL
Residual volume (RV)
Amount of air left in lungs after max forceful exhalation
Avg range: 1000-1500 mL
- RV ensures there is some air in lungs at all times
- Maintains continuous exchange of gases
Inspiratory Capacity
Amount of air that can be inhaled beginning from tidal exhalation
TV+IRV=IC
Functional residual capacity (FRC)
Amount of air remaining in lungs following tidal exhalation
RV+ERV=FRC
Vital Capacity (VC)
Amount of air in lungs under volitional control
Avg VC: 3500-5000mL
TV+IRV+ERV=VC
Total lung capacity (TLC)
TV+IRV+ERV+RV=TLC
External Respiration
Exchange of gases between air in alveoli and blood in pulmonary capillaries (blood and lungs)
O2: alveoli -> pulmonary capillaries
CO2: pulmonary capillaries -> alveoli
- High concentration of O2 and low concentration in alveoli
- Pulmonary capillaries concentration of CO2 is high and low O2
Blood returned to the heart has HIGH concentration of O2 and LOW CO2
- loads oxygen into blood and removes carbon dioxide
Internal Respiration
Exchange of gases between blood in systemic capillaries and interstitial fluid (blood and tissues)
O2: systemic capillaries -> interstitial fluid (and then cells)
CO2: interstitial fluid -> systemic capillaries (CO2 being removed from tissues/interstitial space)
- Systemic capillaries have HIGH concentration of O2 and low CO2
- Tissue fluid/cells/interstitial fluid has HIGH concentration of CO2 and low O2
Blood of systemic veins returning to heart has low O2 and high CO2
- Delivers oxygen to cells and picks up waste CO2
Nervous System Regulation of Respiration (Medulla)
Steps controlled in MEDULLA
1. Inspiration center (dorsal respiratory group) automatically generates impulse in rhythmic spurts
2. Impulse travels to respiratory muscles to tell them to contract & lungs expand
3. Receptors detect lung expansion/stretching
4. Send impulses to MEDULLA to depress inspiration center
(Hearing-Bruer inflation reflex: prevents over inflation of lungs)
Expiration center (ventral respiratory group)
- stimulated by inspiration center when forceful exhalations are needed
- generates impulses to internal intercostals and abdominal muscles
Nervous System Regulation of Respiration (not medulla)
Pons
- Apneustic center prolongs inhalation
- Pneumotaxic center helps bring about exhalation
Hypothalamus
- influences changes in breathing in emotional situations
Reflex centers in medulla
- Coughing and sneezing occur to remove irritants from upper respiratory tract
Regulation of RR
- Increased CO2 in blood and CSF (ex: from working out)
- CENTRAL Chemoreceptors in MEDULLA detect INCREASED blood CO2 levels
- Stimulation of Inspiratory muscles (diaphragm)
- Increased RR (take deeper breaths)
- More CO2 is exhaled (because of all the breaths)
- CO2 levels DECREASE, pH INCREASE
- Reduced stimulation of chemoreceptors (stimulus is solved)
- Slowing/decreased RR and depth
- More CO2 retained (cycle starts again)
Regulation of RR (when desensitized to CO2)
Chronic hypercapnia (elevated CO2)
1. Medullary chemoreceptors become desensitized to elevated CO2 levels (no longer major regulator of normal respiration)
2. CO2 increases, O2 slightly decreases
3. NO increase in RR
4. Decrease in O2 levels (not getting enough oxygen)
5. Low O2 stimulates peripheral chemoreceptors in carotid and aortic bodies O2 becomes major regulator for respiration
6. Inspiratory muscles now stimulated
7. Increased RR
8. CO2 is removed and more O2 comes in
9. O2 levels increase and CO2 decreases
10. RR slows down (then starts again)
Nasopharynx
- Soft palate blocks nasopharynx during swallowing
only for air, NOT FOOD - Eustacian tubes from middle ears open into nasopharynx
Oropharynx
Passage for FOOD AND AIR
Palatine tonsils on lateral walls
Laryngopharynx
Passage for FOOD AND AIR
- opens anteriorly into larynx and posteriorly into esophagus
Larynx
Voice box and airway
Made of…
- Thyroid cartilage: largest and most anterior
- Epiglottis: uppermost cartilage, covers larynx during swallowing
-> vocal cords: lateral to epiglottis
Trachea
Extends from larynx to bronchi
- C shaped cartilage keep trachea open
-> Ciliated Epithelium with goblet cells: sweeps and traps up to pharynx
Nasal Mucosa
Ciliated epithelium with goblet cells
- warms and moistens incoming air
- Mucus traps dust and microorganisms
- Cilia sweep up to pharynx
