m11 + 12 lecture - respiratory system Flashcards

1
Q

what is the respiratory system responsible for?

A
  • the exchange and maintenance of blood gases and pH
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2
Q

what are the steps in the exchange and maintenance of blood gases and pH?

A

1) ventilation- airflow through the lungs
2) respiration - at the aveoli/capillaries
3) transport of gases through blood
4) respiration at the capillaries/ tissue cells

  • all help to establish cellular respiration/ATP
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3
Q

what are the mechanics of ventilation (necessary components)?

A

1) air pressure changes -
vent. increases = pressure decrease
vent. decrease = pressure increase
2) intrapleural pressure - enables ventilation
3) compliance - elasticity
4) surfactant - decrease water tension, allows the aveoli to collapse/expand easily

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4
Q

what are some factors affecting ventilation?

A
  • airway resistance
  • loss of lung compliance
  • loss of airway surface tension
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5
Q

what two actions does ventilation require?

A
  • inspiration
  • expiration
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6
Q

what is inspiration?

A
  • it is an active process - contracting muscles which lower the pressure in the lungs to allow air to flow inward to the aveoli
  • expansion of the lungs by expanding the rib cage
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7
Q

what are the inspiratory muscles?

A

1) diaphragm
2) external intercostals

  • when contraction occurs - intrapleural pressure is created
    —-> a neg. pressure
    —-> a suction - lungs stick to the ribs
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8
Q

what is expiration?

A
  • passage of air out of the lungs
    — this is a passive process unless there is airway resistance
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9
Q

what is expiration directly initiated by?

A
  • elastic recoil
  • forced expiration
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10
Q

what is elastic recoil?

A
  • tendency of the ribcage and lungs to contract to equal atmospheric pressure
  • muscle relaxation
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11
Q

what is forced expiration?

A
  • only seen when there is an issue
    —> done thru muscular contractions of the - rectus abdominus, obliques, + internal intercostals
    —> overcomes airway resistance (blockages)
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12
Q

how does airway resistance affect breathing? (factors affecting ventilation)

A
  • directly effected by the size of the passage way
  • bronchioles are the greatest contributor of airway resistance
    —> smooth muscle in the bronchioles – dilate, constrict to affect airflow (ex. asthma, bronchitis)
    —> irritants (allergens)
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13
Q

what is the reason for loss of airway surface tension? (factors affecting ventilation)

A
  • surfactant decreases surface tension and prevents the tissue from sticking shut
    ex.) IRDS - Infant Respiratory Distress Syndrome is a serious breathing problem that occurs in premature babies whose lungs are not fully developed
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14
Q

what is the reason for loss of lung compliance? (factors affecting ventilation)

A
  • the ability of the lung to stretch and recoil
  • decreased by anything which would decrease the elasticity of the lungs
    ex.)
    1) scarring, disease - emphysema, COVID
    2) blockage of the bronchioles such as fluid - pneumonia
    3) decreased flexibility of the rib cage
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15
Q

what are the different types of breathing?

A

eupnea - normal breathing rhythm (12-20 breaths)
dyspnea - difficulty (labored) breathing
hypernea - rhythm during exercise

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16
Q

what must there be for gas exchange to occur?

A
  • a pressure gradient
    —> exchange is driven by simple diffusion (high to low concentrations)
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17
Q

what is dalton’s law?

A
  • partial pressures of gas
  • (ATM) air pressure is 760mmHg
    —-> this pressure’s made from the combined pressure of each gas in the atmosphere (1. nitrogen, 2. oxygen, H2O, + CO2)
  • air pressure is a constant measurement, but the partial pressures will change within each environment
    —> if one increases, the others must decrease to maintain air pressure
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18
Q

is the external air the same concentration than the air in our lungs and blood gases?

A

no, air is much more humid in the lungs to prevent dehydration and drying in the mucus membrane

  • % of O2 = 13% = pressure of 104mmHg
  • deoxygenated blood = PO2 = 40 mmHg
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19
Q

what is henry’s law?

A
  • gas disassociation into a liquid
    —> gas will pressurize into a liquid according to the pressure in the air that it is in contact with (depends of the gas solubility and temperature)
    ex.) soda, diving - hyperbaric chamber - bendz

Hg overcomes oxygens insolubility
male = 13-18g/100mL
female = 12-16g/100mL

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20
Q

what two things are needed for external respiration?

A

ventilation - air flow through the alveoli
perfusion - blood flow in the pulmonary capillaries

  • at rest, we use 9-16% of our lungs (bottom)

alveolar air
- decreased ventilation = increased CO2 in the usual alveoli as CO2 increases, BF decreases = vasoconstriction

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21
Q

how is gas exchange maintained?

A

by the reflex actions of the arterioles
- arterioles dilate or contrict due to the % of CO2 in the alveolar air + blood
—> as air flow increases, this causes the BF to increase
—> as the body’s needs change, the air flow through a region of the lungs will also change

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22
Q

what does an O2 sat count?

A

the percentage of Hb with O2 attached
- 100% saturation is 100% of the Hb with O2

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23
Q

what is the gas exchange amount in the alveoli? (O2 and CO2)

A

percentage of O2 in the lungs = 13.7% or 104mmHg
percentage of CO2 in the lungs = 5.2% or 40mmHg

  • these are the pressures that drive the gas exchange in the alveoli
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24
Q

what is the gas pressure in the capillaries? (O2 and CO2)

A

40mmHg of O2
45mmHg of CO2

25
Q

what is the bicarbonate equation?

A

CO2 + H2O ⇌ H2CO3 ⇌ HCO3- + H+

26
Q

what is the gas pressure in the blood during internal respiration?

A

O2 = 100mmHg due to limited area on the HB
CO2 = 40mmHg

-O2 will unload and CO2 will be loaded into the blood

27
Q

what is the gas pressure in the tissues during internal respiration?

A

O2 - 40mmHg
CO2 - 45mmHg

28
Q

what is the Bohr effect?

A
  • as CO2 rises and effects the pH, the affinity of Hb for O2 decreases
29
Q

what ways are O2 and CO2 carried to maintain equilibrium?

A
  • 98.5% of all O2 is carried in hemoglobin
  • 1.5% of all CO2 is carried in the plasma
30
Q

what happens the O2 sat when blood is carried thru the lungs?

A
  • the O2 sat will increase to about 100%
    —> most O2 unloading at the tissues, takes place between 70-100% HB saturation in the blood
    —> venous blood traveling to the lungs carries around 40mmHg O2 = 70-75% saturation
31
Q

what are some influences on hemoglobin saturation?

A
  • temperature - increase will decrease saturation levels
  • H+ and CO2 levels are also inversely related to O2 sat (Bohr effect)
  • RBC health/ HB #
32
Q

what quickens O2 saturation of hemoglobin?

A
  • decreased temp.
  • increased PO2
  • hyperventilation
33
Q

what slows the O2 saturation of hemoglobin?

A
  • lung Dz
  • hypoventilation
  • increased temp.
  • RBC health
34
Q

what are the types of hypoxia?

A

cyanosis is caused by (bluing, increased vitals:
- ischemic —> decreased BF, CHF, arteriole sclerosis
- histotoxic (tissue poisoning) —> cyanide - kills mitochondria
- anemic —> iron deficiency, bleeding
- hypoxemic —> blocking O2, by using CO2 it used up all the HB causing decreased vitals, fatigue, nausea, redness

35
Q

what is hypoxia?

A

decreased levels of O2 in the tissues

36
Q

how is CO2 transported?

A
  • some in plasma - 10%
  • some in hemoglobin - 20% (carbaminohemoglobin - blueish COHb)
  • 70% of CO2 is changed into bicarbonate

—> the conversion of CO2 into HCO3- is done by an enzyme called carbonic anhydrase in the RBC (helps act as a buffer to the plasma

37
Q

what is the chloride shift?

A
  • as bicarbonate moves out of the RBC, chloride moves inwards
38
Q

what is the haldane effect?

A
  • as CO2 changes to HCO3- in the RBC, Hb combines with H+ ions
  • this helps to remove excess H+ from the blood
  • in the lungs, CO2 is released and H+ combines with leftover HO to form H2O
39
Q

what happens if CO2 builds up in the blood?

A
  • it will force the blood to become more acidic, dropping the pH
  • lowers hemoglobin’s affinity for O2
40
Q

what does carbonic acid do?

A
  • helps to control the pH of the blood
  • can be effected rapidly by changes in breathing

—> shallow breaths will shift the equation to the right, making the blood more acidic
—> rapid breaths can shift the equation to the left, making the blood more alkalotic

41
Q

what is the arterial pH closely related to?

A

to CO2 levels in the blood
- respiratory acidosis –> increased CO2 (hypoventilation)
- respiratory alkalosis –> decreased CO2 (hyperventilation)

42
Q

how is pH regulation done?

A
  • by the regulation of CO2
  • respiratory acidosis
  • respiratory alkalosis
43
Q

what is respiratory acidosis?

A
  • caused by elevated CO2 levels (hypercapnea)
  • initiates the release of H+ ions into the plasma —> decreases O2 saturation rates

causes: lung Dz, hypoventilation

43
Q

what is respiratory alkalosis?

A
  • caused by decreased CO2 levels (hypocapnea)
  • hyperventilation depletes CO2 levels pulling H+ ions out of circulation
44
Q

what does the pons do in the respiratory system?

A

pons
- supervises the regulation and adjustment of breathing
- chemoreceptors and proprioceptors feed (excite) into this area
—-> greatly excited by CO2

45
Q

what does the the pneumotaxic (pontine) center do?

A

upper part of the pons
- sends directions into the medulla through the DRG (dorsal respiratory group)

46
Q

where are the chemoreceptors used by the pons located? (for regulation and adjustment of breathing)

A
  • the carotid sinus
  • aortic arch
  • brainstem centers
47
Q

what does the DRG (dorsal respiratory group) do?

A

group of neurons located in the medulla oblongata that primarily controls the initiation of inspiration (breathing in) by stimulating the diaphragm and intercostal muscles

48
Q

what causes sleep apnea/SIDS and what does it affect?

A
  • pontine (apneustic) center malfunctions
  • influences the rate and rhythm of breathing
49
Q

what is the hering-breuer reflex?

A
  • stretch receptors in the pleura will inhibit the VRG causing exhalation to prevent over inflation of the lungs
  • causes exhalation
50
Q

respiration is controlled by what in the brain?

A
  • pons
  • medullary respiratory center (VRG - inhale and DRG - exhale)
51
Q

what happens in the VRG (ventral respiratory group)?

A

inhale
- excitatory to the phrenic and intercostal nerves (diaphragm)
- cyclic pattern of around 12-20 breaths = 500mL/breath
- can be slowed or shut down but alcohol, morphine, sleeping pills, and anesthesia

52
Q

what happens in the DRG (dorsal respiratory group)?

A

exhale (relaxes the diaphragm)
- regulated by the pons
- inhibits the VRG
- establishes rhythm or the depth of each breath

53
Q

what is hypoxic drive?

A
  • in chronic lung disease (ex. smoking)m CO2 receptors become desensitized and the person acclimates to a high level of CO2
  • if CO2 is elevated, then O2 decreases
    —> O2 sats are low = 80s
54
Q

what are some types of chronic obstructive pulmonary diseases (COPD)?

A
  • emphysema (m/c)
  • chronic bronchitis
  • asthma
55
Q

what are common characteristics of COPDs?

A
  • usually patient history of smoking
  • sx of dyspnea
  • coughing and frequent lung infections
  • usually deaths occurs from respiratory failure
56
Q

what are common characteristics of emphysema?

A
  • long history of smoking
  • causes the deterioration of the respiratory membrane and widespread scarring
  • scarring causes loss of the elastic recoil
  • loss of elasticity results in the enlarging of the airway and the destruction of the alveolus
  • the alveoli open up and the patient has large open cavities in the lungs
  • when this happens the patient can’t exhale and develops a barrel chest (“pink puffer”)
  • causes the enlarging of the right ventricle
  • causing pulmonary hypertension
57
Q

what are common characteristics of chronic bronchitis?

A
  • inhaled irritants lead to an excess of mucus in the bronchioles
  • this blocks the airways and leads to hypoxia (blue bloaters)

causes: smoke and pollution
treatment: inhalers and bronchodilators

58
Q

what are common characteristics of asthma?

A

ARDS - acute respiratory distress syndrome
symptoms: chest tightness, coughing, wheezing, dyspnea
causes: allergic reaction to certain pulmonary irritants
—> resulting in severe inflammation (histamine release) of the airways and bronchiole constriction
treatment: antihistamine inhalants