Respiratory System Flashcards
Pulmonary ventilation is when…
There is an exchange of air between the atmosphere and alveoli
Boyle’s Law is…
Air moves from high to low pressure
INHALATION:
Atmospheric pressure is _______than alveolar pressure. Air goes towards the _______ concentration
Higher; lower
Muscles used for inhalation:
Diaphragm, External intercostals, sternocleidomastoid, scalenes
The _________ controls the diaphragm
phrenic nerve
EXHALATION:
Atmospheric pressure is _______than alveolar pressure. Air goes towards the _______ concentration
lower; lower
Exhalation starts when ________ and results from ________ of the chest walls and lungs
inspiratory muscles relax; elastic recoil
there are ____ inwardly directed forces that contribute to elastic recoil. They are:
2 ; the recoil of elastic fibers that were stretched during inhalation and the inward pull of surface tension due to the film of alveolar tissue
Inhalation is an ______ process
active
Exhalation only becomes active with _______ ; the following muscles are used….
Forceful breathing; Internal intercostals, external obliques, internal obliques, transversus abdominis, rectus abdominis
Other factors that affect pulmonary ventilation:
1) Surface tension
2) Compliance of the lungs
3) airway resistance
Surface tension:
A thin layer of alveolar fluid that coats the luminal surface of alveoli an
If surface tension is not overcome the alveoli will burst. What fluid reduces surface tension?
Surfactant
HIGH compliance vs LOW compliance
High = lungs will easily expand Low = lungs will resist expansion
In the lungs compliance is related to two principal factors: ____________ and ____________
Elasticity; surface tension
the three different breathing patterns are:
1) Eupnea - normal quiet breathing
2) Costal - shallow chest breathing
3) Diaphragmic - deep breathing using the abdomen
The average healthy adult has _____ Breaths per minute, _____ ml per breath and a minute ventilation of ______
12bpm ; 500ml ; 6L/min
___% of tidal volume reaches the respiratory zone while the other ____% goes into the conducting zone/anatomical dead space
70% ; 30%
Inspiratory Reserve
The extra air that is inhaled
Expiratory Reserve
The extra air that is forcefully exhaled
Residual Volume
Left over air in the lungs even after the expiratory volume is expelled
Minimal Volume
The left over air that is only expelled when the thoracic cavity is opened
Inspiratory Capacity
tidal volume + inspiratory reserve volume
Tidal Volume
air expelled during normal breathing - 500ml per breath
Functional Residual Capacity
residual volume + expiratory reserve volume
Vital Capacity
inspiratory reserve volume + tidal volume + expiratory reserve volume
Total Lung Capacity
vital capacity +residual volume
Dalton’s Law
Each gas in mixture exerts its own pressure called partial pressure. Gas will move from high partial pressure to low partial pressure.
Henry’s Law
Quantity of gas dissolved in liquid depends on partial pressure and solubility
The atmospheric pressure we breath contains…
Nitrogen, Oxygen and Carbon Dioxide
The rate of Pulmonary and systemic gas exchange depends on…
1) Partial pressure differences of gases - Alveolar PO2 must be higher than blood PO2 for oxygen to diffuse from alveolar air into blood
2) surface area - alveoli have a huge surface area to allow for 900ml of blood to participate in gas exchange
3) diffusion difference - This respiratory membrane allows for fast diffusion of gases.
4) molecular weight and solubility of gas - CO2 diffuses 20X faster than O2
_____% of O2 is dissolved in blood plasma; ____% of O2 is bound o Hemoglobin in red blood cells
1.5%; 98.5%
What is the Oxygen-Hemoglobin Dissociation Curve?
The relationship between the percent saturation of hemoglobin and the partial pressure of O2
the ______ the partial pressure of oxygen the ______ the hemoglobin is saturated with oxygen
Higher; Higher
Full Hemoglobin Saturation….
When all four binding sites in the hem. are saturated with O2. When PO2 is high, saturation is almost 100%
Partial Hemoglobin Saturation …
When only some of the binding sites are saturated. If 2 of the binding sites are saturated with O2 then the hem. is 50% saturated.
Oxygen Partial Pressure = ?
How much O2 binds to Hemoglobin
What factors affect the affinity of hemoglobin for oxygen?
1) Acidity
2) Partial pressure of CO2
3) Temperature
4) BPG
High acidity = _____ oxy-hemoglobin affinity
LOW
High PCO2 = _____
oxy-hemoglobin affinity
LOW
High Temperature = _____ oxy-hemoglobin affinity
LOW
High BPG = _____ oxy-hemoglobin affinity
LOW
How is Carbon Dioxide transported?
1) Dissolved CO2 (7%)
2) Carbamino compounds (23%)
3) Bicarbonate ions (70%)
What does the Pontine respiratory centre do?
Sends impulses to the medullary respiratory Centre, plays a role in inhalation/exhalation, located in the Pons,
What is the Pontine Respiratory Centre?
a collection of neuron in the pons.
What is the Medullary respiratory centre made out of?
1) Dorsal Respiratory Group
2) Ventral Respiratory Group
What does the Dorsal Respiratory Group do?
known as the inspiratory centre. the neurons of the DRG generate impulses to the diaphragm via the phrenic nerves, and impulses to the extrnal intercostals via the intercostal nerves.
What does that Ventral Respiratory Group do?
1) Expiratory centre - forceful breathing, impulses to accessory muscles, used in exercise
2) Pre-Botzinger Complex - Composed of pacemaker cells, controls rhythm of breathing.
What is the Ventral Respiratory Group made out of?
The Botzinger complex.
Chemoreceptor regulation of the respiratory system is…
Chemoreceptors in the MEDULLA OBLONGATA and in the AORTIC ARCH and CAROTID BODIES monitor levels of CO2 and provide input to the respiratory system .
What are chemo receptors in the Medulla Oblongata called and what do they do?
Central Receptors; Respond to changes in H+ and Pco2 in cerebrospinal fluid
What are chemo receptors in the Aortic Arch and Carotid bodies called and what do they do?
Peripheral receptors; Respond to changes in H+, Pco2 and Po2 in arterial blood
Explain the positive feedback cycle of an increased level of Co2
an increase in Co2 is referred to as Hypercapnia. This change is detected by Peripheral receptors in the Aortic arch and carotid body. the receptors send impulses to the Dorsal Respiratory group. In severe cases of Hypercapnia, activity of the Dorsal Respiratory Group is depressed. This leads to fewer breaths and thus less oxygen. This feedback loop can be fatal.
Cortical Regulation of the Respiratory System
Voluntarily holding breath, overridden by respiratory centre
Proprioceptor stimulation
Feedback from joint/muscle movement, impulses to the DRG
Inflation reflex…
Stretch receptors (baroreceptors) in bronchi/ bronchioles inhibit DRG, causing exhalation
Other factors that regulate the respiratory system are…
1 ) Limbic system stimulation 2) Temperature Pain 3) Stretching the anal sphincter 4) Irritation of airways 5) Blood pressure
What happens to breathing during exercise?
Increase of Pulmonary Perfusion and increase in O2 diffusion capacity . Also Increase in sympathetic nervous impulses to the lungs and increase in air movement into the lungs.
