Question | Answer |
External Respiration | -in lungs -O2 in -CO2 out -exchange with blood to pulmonary ciruit |
Internal Respiration | -gases exchanged between blood & tissue |
Cellular Respiration | -breakdown material -gain energy |
Pulmonary ventilation | -breathing -bulk air moving in/out of lungs
-pump=diaphragm, ribcage & muscles |
conducting airways | -air between nose & deep Win lungs -thick walled -warms, humidifies & cleans air [nasal cavaties, trachea, pharynx larynx, bronchi/oles] |
Respiratory airways | -gases exchanged -tiny thin walled
- [bronchioles, alveoli] |
Nasal cavity + (4 parts) | -mucous membrane -tall narrow -filters, warms & humidifies
(1)medial surface
(2)paranasal sinus
(3)roof cavity
(4)axons |
(1)medial surface [nasal cavity] | -flat, lateral
-3 sloping conchae
-incr. SA of mucous membrane |
(2)paranasal sinus | -lighten face -add resonance to voice
-air-filled |
(3)roof cavity | -carries olfactory epithelium -sniffing carries air up |
(4)Axon | -of olfactory receptor cells -lead to brain |
Pharynx | -Naso(air) -oro(food&air) -Laryngo(food&air) -1*gastrointestinal |
pattern of branching of airways | *trachea->term. broichioles=conducting
*term.bronchioles->alveolar sacs=respiratory |
Trachea | -C-shaped cartilage -trachealis muscle connects
-ciliated epithelium psuedostratified columnar |
wall of bronchus | -psuedostratified ciliated columnar epithelium
-goblet cells & mucus glands
-SM -cartilage plates
-alveoli |
Wall of bronchioles | -ciliated columnar epithelium -clara cells
-SM
-no cartilage,goblet or mucous cells |
Goblet cells | -thick |
Mucous cells | -thick & watery
-serous mucous |
Clara cells | -watery substance -prevents walls sticking together |
Alveoli | network of capillaries rapped around single alveolus |
alveolar sac | -several bunched alveoli |
alveolar duct | -corridor of alveoli & alveoli ducts |
diffusion barrier | ~0.1micrometre |
Cartilage | -supports airways
-not past small bronchi (along with mucous glands) |
thickness of epithelium proportional to... | ....diameter -epi incr.=diameter incr. |
smooth muscle in relation to size of airways | -smaller airways have more SM proportional to size
-no SM past bronchioles |
Lobes of lung | -R=3 -L=2 |
segments of lung | -3* bronchi supply -have own air & blood supply |
segments [clinical significance] | -surgeons know boundaries
-prevent excessive leakage of air & blood |
Pleurae | -SM covers each lung & lines thoracic cavity -2 layers continuous to roof (hilium) of lung -fluid prevents friction of layers |
Ventilation movement of ribs [expiration] | -internal intercostal muscles contract -active during forceful exhalation
-drags ribs down |
Ventilation movement of ribs [inspiration] | -external intercostal muscles contract -lifts ribs -incr. vol thoracic |
Ventilation movement of diaphragm | -diaphragmatic muscle contraction= inspiration
-relaxation=passive expiration
-~75% bulkflow air |
tidal breathing | same pipes for in & out |
Functional residual capacity=? | -amount of air in lungs after normal experation |
Residual volume | -minimum voluntary volume |
tidal volume | ranges from residual volume to total lung capacity |
mechanics of breathing | -lung devoid of muscles
-Pressure grad for movement
-alveoli<atms |
exhalation | alveoli Pressure exceeds atmospheric pressure |
inhalation | alveolar Pressure is less than atmospheric |
lungs | -highly elastic
-collapse to 0vol. |
balance of forces (lungs) | -between collapsing lung & recoiling ribcage
-at functional residual capacity |
ribcage experiences forcre | -causes it to spring outward
-F from stretched tissue in sterno-costo vetebral joint |
pneumothorax | -air in interplueral space
-breaks cohesiveness
-lungs collapse
-chest recoils outwards |
factor effecting exchange of air | (1)compliance
(2)resistance
(3)dead space (4)diffusion |
(1)compliance | -change-in Vol/change-in P
-distensibility of lungs & chest wall
-inverse to stiffness |
(2)resistance | -change-in P/change-in flow
-how hard to push |
P-V relationship of lungs
[low vol.] | -V compliant
-lots P to overcome surface tension |
P-V relationship of lungs
[open alveoli] | -distend relatively easily
-till near inflation |
Air resistance | -flow depends of diff in P & R through airways
-mouth & nose contribute alot
-R greatest at medium 3* bronchi
-R decr. as tot-xsect. A incr. |
Dead space | -no exchange of gases in vol.
-dilutes tidal inspiration |
Fick's law | Vol. of gas exchange proportional to area |
Respiratory distress syndrome | -surface tension in alveoli by air-water interface
-pulm. surfactant reduces tension
-absent in babies |
emphysema | -alveolar & peri bronchi tissue damage
-bronchioles collapse
-FRC incr=barrel chest |
asthma | -bronchiole constriction
-incr. muscular effort
-labour breathing |
pulmonary edema | -water in alveolar space
-incr diffusion distance
-slower rate of gas exchange |
universal gas law | P=nRT/V
-P proportional 1/V |
partial pressure | -P required to keep plunger still
-keep gas from escaping out of solution |
Daltons law | P tot= sum of PP on individual constituents |
Henry's law | conc = sol. x pressure |
CO poisoning | -binding of O2 to Hb blocked
-decr. HbO2 sat |
Anemia | -haemoglobin reduced
-derc. tot O2 bound
-even though Hb 98% sat |
CO2 transport | -high sol. in simple solution |
Alveolar ventilation | -replenished supply of O2
-reg. to maintain constant PP of O2 & CO2
-changes due to metabolism |
Hyper-ventilation
[consequences] | -accum. O2 in alveoli
-incr. P O2
-decr. CO2 & P
-incr. blood pH |
alkalotic coma | -due to blood pH becoming basic
-incr. pH
-hyper-ventilation |
Hypo-ventilation | -decr. O2 in alveoli P
-accum. CO2
-incr. P CO2
-decr. pH
-acidosis |
Acidotic coma | -arterial blood acidic
-pH decreases
-Hypo-ventilation |
Response to altered inspiratory Pi O2/CO2 | -O2=low (flat region)
-CO2 & pH=greater |
Respiratory centres in CNS | -nueral input=brainstem
-motor nuerons
-in medulla oblongata |
Medulla oblongata | -Dorsal resp. grp= inspiration
-Ventral resp. grp= varies |
Slowly adapting stretch receptors | -on bronchi/oles
-activated lung inflation
-myelinated fibres in vagus
-term. lung inhal. |
irritant sensors | -mech&chem stimuli
-hyperinflation
-response to allergies
-cause:coughing, incr mucous secretion |
Feedback from chemoreceptors | -carotid & aortic bodies
-detect changes in P(CO2&O2)
-informs resp. control centre
-maintain blood gases |
Carotid | -bifurcation of common carotid arteries
-highly vascularised blood flow
-respond(P): decr.O2, Incr.CO2 |
aortic bodies | -aortic arch & subclavian arteries
-afferents in vagus nerve |
Central chemo receptors | -ventral surface of medulla
-sensitive to pH changes in cerebral fluid |
Intrinsic sensitivity to Pa O2 + CO2 | -measuring vent. reponse to changing each while others constant
-V sens. PO2 |
Involuntary [conflicting requirements] | -ventilation
-coughing
-sneezing
-sighing
-spitting |
voluntary [conflicting requirements] | -ventilation
-singing, whistling,speech
-urination |