RespirationRespirationGroup 5
PuentispinaPusing
RazalanRecio
3OTB
RESPIRATORY SYSTEM FUNCTIONSRESPIRATORY SYSTEM FUNCTIONS
• responsible for gaseous exchange between the blood and external environment.
• provides oxygen for metabolism in the tissues and removes carbon dioxide (the waste product of metabolism).
• facilitates sense of smell• can also produce speech• Can maintain acid-base balance, body water
levels and heat balance.
RespirationRespirationis the act of breathing
Processes/LevelsProcesses/Levels
External Respiration◦Absorption of O2 and removal of CO2 from the
bodyInternal Respiration
◦Utilization of O2 and production of CO2 by cells and the gaseous exchanges between the cells and their fluid medium
PASSAGEWAY of AIRPASSAGEWAY of AIR
Passageway of AirPassageway of Air
UPPER AIRWAYS
Nasal cavity pharynxlarynx
LOWER AIRWAYS
TracheaPrimary BronchiBronchial treeBronchiolesAlveoli
RESPIRATORY SYSTEM RESPIRATORY SYSTEM
Gas exchanging organ◦Lungs
Pump that ventilates the lungs◦Chest wall◦Respiratory muscles◦Areas in the brain
that control the muscles
◦Tracts◦nerves
THE LUNGSTHE LUNGS
the site of gas exchange and it occupies most of the thoracic cavity
divided into lobes: left lung (2 lobes); right lung (3 lobes)
has 2 pleural membranes
Between trachea and alveolar sacs -> airways divide 23 times◦1st 16 generation: conducting zone of the airways that transports gas from and to the exteriorBronchi, bronchioles, terminal bronchioles
◦Remaining 7 generations -> transitional and respiratory zones where gas exchange occursRespiratory bronchioles, alveolar ducts, alveoli
Pulmonary CirculationPulmonary Circulation
Blood-> pulmonary artery -> pulmonary capillary bed (oxygenated and returned to left atrium via pulmonary veins)
Bronchial arteries- small, separated, come from systemic arteries
Capillaries- drain into bronchial veins ; anastomose with pulmonary capillaries/veins
Bronchial veins- drain into azygos veins
Bronchial circulation nourishes bronchi & pleura
Pulmonary CirculationPulmonary Circulation
Pressure◦Pulmonary Circulation: 7mm Hg
Systemic Circulation- 90mm HgVolume
◦Pulmonary vessels at any one time =1LFlow
◦mean velocity at the root of pulmonary artery= about 40cm/s 0.75 secs- red cells traverse the pulmonary
capillaries at rest 0.3 s or less during exercise
What is Breathing?What is Breathing?
Breathing is the movement of air into and out of the lungs.
12-18 respirations/ min (adults)30-50 respirations/ min (infants)
*Patient Care skills by Pierson and Fairchild
12-15 respirations/ min (Ganong)
Control of BreathingControl of Breathing
Levels of ControlLevels of Control
Local ControlCentral Control
Local ControlLocal Control
Location: Alveoli, alveolar capillaries and bronchioles in localised areas of the lung
Role: To ensure blood and gas go to the appropriate parts of the lung for efficient gas exchange.
Local ControlLocal Control
When: There are localized changes in Co2 and O2
Mechanism: Local adjustments to blood flow (lung perfusion) and oxygen delivery (alveolar ventilation) to alveoli
Local ControlLocal Control
Independent of brain’s activity
2 components > Lung perfusion > Alveolar ventilation
Lung PerfusionLung Perfusion
Ensures that arteriolar blood flow is diverted to where it is needed in the lung.
Vasoconstriction of arterioles supplying lung areas low in O2
Lung PerfusionLung Perfusion
Alveolar VentilationAlveolar Ventilation
Ensures optimum conditions for gas exchange.
Adjusts the size of the bronchioles in response to alveolar PCO2.
Alveolar VentilationAlveolar Ventilation
Local Control – V/Q RatioLocal Control – V/Q Ratio
Ventilation (V)-Perfusion(Q) ratio Ratio between the amount of air entering the
alveoli and the amount of blood draining into the lung.
Allows an assessment of the efficiency of gas exchange.
Local control aims at maintaining an optimal V/Q.
Central ControlCentral Control
Location: The respiratory centres (pairs of nuclei located in the medulla oblongata and the pons) modified by sensory neurons(peripheral and in the brain’s cerebrospinal fluid) and higher centres (cerebral cortex).
Role: Adjust the depth and rate of ventilation
Central ControlCentral Control
When: During both normal breathing and also when there is a larger respiratory demand or conscious control is needed (e.g. during talking).
Mechanism: Both involuntary (respiratory reflexes involving sensory feedback) and voluntary (higher centres of the brain) control via the respiratory centres.
Central ControlCentral Control
Directs respiration via the respiratory centres of the brain.
Affect the rate and depth of breathing in response to various sensory and higher inputs.
2 Components:Voluntary Involuntary
Voluntary ControlVoluntary Control
Influenced indirectly by the cerebral cortex and affects the output of the respiratory centres in the medulla oblongata.
Influential factors include emotion, anticipation of exertion and activities requiring alteration to normal breathing (e.g. playing trumpet)
Involuntary ControlInvoluntary Control
Directs the depth and rate of breathing via outputs from the respiratory centres.
Ensure appropriate levels of ventilation.
Involuntary ControlInvoluntary Control
Normal Rhythmical Breathing – Respiratory Centers (Brain)
Rhythmicity Center – Medulla OblangataDorsal Respiratory groupVentral Respiratory group - output :
apneustic and pneumotaxic centres (pons)
Involuntary Control – Normal Involuntary Control – Normal BreathingBreathing
Controlling CentersMedullaPonsRespiratory Neurons I Neurons – inspirationE Neurons - expiration
I neurons send out streamsof impulses which travel down
to the ANTERIOR HORN CELLSof the SPINAL CORD on the opposite
site and are relayed fromCERVICAL SEGMENTS
by the PHRENIC NERVESto the DIAPHRAGM and from
THORACIC SEGMENTS
by the INTERCOSTAL NERVESto the INTERCOSTAL MUSCLES
These nerve impulses cause the muscle of inspiration to contract
In the nucleus retroambiguus (NRA) E neurons in the upper end Inhibit
the I neurons during expiration
PNEUMOTAXIC CENTER (PTC)(nucleus parabrachialis)
Normal function unknown but may have a role in switching
between inspiration and expiration
MEDULLARY GROUPSThe dorsal group in the nucleus of the
tractus solitarius (NTS) contain I neuron.The ventral group in the nucleus NRA
contain both E and I neurons.Afferent impulses in the vagus from lung
stretch receptors inhibit I neuron discharge.
Inspiratory neurons inhibited
The muscles of inspiration relax
Expiration follows passively in quiet respiration
Expiratory (E) neurons are excited in force expiration
Respiratory CenterRespiratory Center
Normal Breathing CycleNormal Breathing Cycle
Inhalation occurs in first 2 seconds followed by 3 seconds of exhalation
Inhalation: Within the first stage, the DRG (stimulated by the apneustic centres), enhance the activities of the inspiratory muscles
Exhalation: In the next 3 seconds, the pneumotaxic centres inhibit the apneustic centres resulting in unstimulated DRG. These no longer stimulate inhalation anymore, causing passive exhalation
Forced Breathing CycleForced Breathing Cycle
Inhalation: both the DRG and inspiratory centres of the VRG stimulate the contraction of inspiratory muscles and inhibition of the expiratory centres of the VRG. This leads to relaxation of expiratory muscles, resulting in inhalation
Forced Breathing CycleForced Breathing Cycle
Exhalation: The DRG and inspiratory centres of the VRG are inhibited. Meanwhile, expiratory centres of VRG bring about the contraction of expiratory muscles, causing forced expiration
Respiratory CenterRespiratory Center
Involuntary control: Involuntary control: Respiratory ReflexesRespiratory Reflexes
Normal pattern of breathing is modified via sensory reflexes in order to accommodate physiological changes and maintain homeostasis.
Receptors detect changes inside the body and send information to the central controllers.
Involuntary Control : Involuntary Control : Respiratory ReflexesRespiratory Reflexes
Output of the controllers is then modified changing the efferent signal to the effectors
StimulationChemicalMechanicalChanges in Blood Pressure
Chemoreceptor ReflexesChemoreceptor Reflexes
Detect changes in the chemical composition of the blood and cerebrospinal fluid.
Central ChemoreceptorsPeripheral Chemoreceptors
Hering-Breuer ReflexesHering-Breuer Reflexes
Function in controlling the inflation and deflation of the lungs during forced breathing.
Controls volume and stretch of lungs to avoid over expansion and over deflation.
Slowly adapting receptors (SARs)Inflation reflexDeflation reflex
Rapidly adapting receptors and Rapidly adapting receptors and protective reflexesprotective reflexes
Rapidly adapting receptorsCoughingSneezingBronchoconstrictionTachypneaAspiration
J receptors: Inflammation and J receptors: Inflammation and EdemaEdema
Stimulated by pulmonary edema and products of inflammation in the interstitium of the lungs.
Contributes to particular responses such as rapid shallow breathing,decreased tidal volume, increased respiratory rate, mucus secretion and cough.
Head’s Paradoxical ReflexHead’s Paradoxical Reflex
Presence of cold block on vagus nerve.Inflation is not inhibited in the lungs.Contributes to particular responses such
as rapid shallow breathing,decreased tidal volume, increased respiratory rate, mucus secretion and cough.
Muscle spindle reflexesMuscle spindle reflexes
Muscle spindles are sensory receptors that are widely located in the intercostal muscleswithin the ribcage and are involved in a reflex arc not involving the medulla (sensory neurons synapse directly with motor neurons).
Baroreceptor ReflexesBaroreceptor Reflexes
Affect respiratory frequency and tidal volume.
By decreased intrasinus pressure
Chemical ControlChemical Control of Respiration of Respiration
Chemosensitive Chemosensitive AreaArea
Additional neuronal area
Highly sensitive to changes in either blood PCO2 or hydrogen ion concentration -> excites portion of the respiratory center
Sensor neurons > Specially excited by hydrogen ion
Effect of CO2Effect of CO2
Indirect effect
React with water to form carbonic acid -> hydrogen and carbonate ion.
Easily passes through the blood-cerebrospinal fluid barrier.
Increae in CO2 -> increase in H ion in chemosensitive area
Explain the dominant role of CO2 in determining to Explain the dominant role of CO2 in determining to breathebreathe
An increased concentration of CO2 within the human body stimulates the respiratory system in order to restore the balance between O2 and CO2 concentrations. Therefore, breathing is initiated once the level of CO2 increases beyond the normal.
Experiment 5Experiment 5ResultsResults
After Normal Expiration After Over breathing After Half-Squat
Group 5 23.42 secs 43.19 secs 9.66 seconds
This Graph shows that the one with shortest time before breakout is during half squat followed by normal expiration and the one with longest time before breakout is during over breathing.
This graph shows the comparison between groups in the class. We can see that This graph shows the comparison between groups in the class. We can see that all (100%) groups agreed that their shortest time before breakout happens all (100%) groups agreed that their shortest time before breakout happens during half squats, 5 groups (except group 3, about 83.33% of class) has the during half squats, 5 groups (except group 3, about 83.33% of class) has the same result that their longest time before breakout happens after over same result that their longest time before breakout happens after over breathing and the second longest time is after normal expirationbreathing and the second longest time is after normal expiration
RATIONALERATIONALE
The shortest time before breakout is after doing half squats. During half squats, the oxygen and carbon consumption and carbon dioxide formation increases than normal and so there is an increase in ventilation. Ventilation begins immediately during the initiation of half squats before any blood chemicals have had time to change. The increase in respiration is due to direct transmission of neurogenic signals to the brain stem respiratory center causing the body to react (begin breathing/ begin the cycle-inspiration and expiration once again). Contrary to this is the reason why the longest time before breakout is during over breathing. The subject continuously breathes deeply for a short interval and then abruptly holds his breath. During over breathing, the person blows off too much carbon dioxide from the pulmonary blood while at the same time increasing blood oxygen. In this condition, it takes several seconds before the changed pulmonary blood can be transported to the brain ergo, inhibits excess ventilation. Once it is transmitted in the brain respiratory center, the center becomes depressed to an excessive amount and therefore the brain will respond and the breathing cycle begins once again.
Peripheral ChemoreceptorPeripheral Chemoreceptor
Detects changes in O2 in the blood
Located:Carotid bodies
(bifurcation of the common carotid > Hering Nerve > glossopharyngeal N. > dorsal respiratory area)
Peripheral ChemoreceptorPeripheral Chemoreceptor
Located:Aortic bodies(arch of
the aorta > Vagus Nerve > Dorsal respiratory area)
Peripheral ChemoreceptorPeripheral Chemoreceptor
Depletion of oxygen in arterial blood causes the stimulation of chemoreceptor area.
Glomus cells – synapse directly or indirectly to the nerve ending.
When does O2 becomes the primary stimulus When does O2 becomes the primary stimulus for breathing?for breathing?
When arterial carbon dioxide and hydrogen ion concentration remains normal despite increase respiration
Oxygen level is less than 60 mm Hg.
Which is the more important in respiration, Which is the more important in respiration, PO2 or PCO2?PO2 or PCO2?
The more important drive for respiration is the change in one's PCO₂, or the effect of carbon dioxide on the central chemoreceptors. This is because of the ready penetration of CO₂ to membranes, most especially at the blood-brain barrier.
Which is the more important in respiration, Which is the more important in respiration, PO2 or PCO2?PO2 or PCO2?
Proper delivery of oxygen can occur despite changes in lung ventilation on the other hand CO2 changes almost exactly inversely with the rate of ventilation
Breaking Point Breaking Point
Point at which breathing can no longer be voluntarily inhibited.
Breaking Point DelayBreaking Point Delay
Breathing 100% Hyperventilation
Raises alveolar PO2 initially thus breaking point is delayed.
CO2 is blown off ad arterial CO2 is lowered from the start thus breaking point is delayed