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BIOL 1190 > Ch. 23 - The Respiratory System > Flashcards

Ch. 23 - The Respiratory System Flashcards

1
Q

What is respiration?

A

exchange of gasses between atmosphere, blood, and cells

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2
Q

What are the 3 steps that respiration requires?

A
  1. pulmonary ventilation (breathing; movement of gases in and out of lungs)
  2. pulmonary respiration (gas exchange between lung alveoli and blood)
  3. tissue respiration (bt blood and cells)
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3
Q

What does the upper respiratory system comprise of?

A

nose, pharynx, associated structures

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4
Q

What does the lower respiratory system comprise of?

A

larynx, trachea, bronchi, lungs

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5
Q

What are the functional divisions of the resp system?

A

conducting portion (~150 mL) and respiratory portion (~5-6 L)

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6
Q

What is the conducting portion and what does it comprise of?

A
  • filter and moisten air and conduct into lungs

- nose, pharynx, larynx, trachea, bronchi, bronchioles, terminal bronchioles

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7
Q

What is the respiratory portion and what does it comprise of?

A
  • tissue w/i lungs where gas exchange occurs

- resp bronchioles, alveolar ducts, alveolar sacs, alveoli

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8
Q

RECALL: how is the nasal cavity divided? What is this division composed of?

A

nasal septum: septal cavity, vomer, perpendicular plate of ethmoid bone

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9
Q

What is the anterior portion inside the nostrils called?

A

nasal vestibules

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10
Q

How does the nasal cavity communicate with the pharynx?

A

posteriorly through 2 openings called internal nares

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11
Q

Which ducts open into the internal nose?

A

paranasal sinuses and nasolacrimal ducts

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12
Q

What are the functions of the nose?

A
  • warm, moisten, filter air
  • olfaction
  • modify speech
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13
Q

How does air pass through the nostrils?

A

through vestibule lined with coarse hairs that filter dust particles

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14
Q

What is the function of the conchae?

A
  • subdivide each side of nasal cavity into series of passages –> sup, middle, inf meatuses
  • cause air to swirl for increased contact w mucous membrane that lines cavity and conchae
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15
Q

What is the pharynx composed of and where is it located? (throat)

A
  • tube of sk muscles lined w mucous membranes

- internal nares and extends to cricoid cartilage of larumx

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16
Q

What are the 3 regions of the pharynx and where are they each locate?

A
  1. nasopharynx: internal nares to soft palate
  2. oropharynx: soft palate to hyoid
  3. laryngopharynx: hyoid to esophagus
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17
Q

What is the function of the pharynx?

A
  • houses tonsils
  • passageway for air and food
  • resonating chamber for speech
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18
Q

What is the larynx composed of and where is it located? (voicebox) What does it connect?

A
  • extrinsic and intrinsic muscles & thyrohyoid membrane
  • anterior to esophagus (C4-C6)
  • connects laryngopharynx to trachea
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19
Q

What are the 3 main cartilage pieces in the larynx?

A
  • thyroid C (Adam’s apple)
  • cricoid C (ring at top of trachea)
  • epiglottis (elastic C; covers glottis during swallowing)
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20
Q

What are the 2 pairs of folds the mucous membrane of the larynx forms?

A
  1. vestibular folds (false vocal cords)

2. vocal folds (true vocal cords)

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21
Q

What is the function of vestibular folds?

A
  • holding breath against pressure in thoracic cavity

* do not produce sound

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22
Q

What are vocal folds attached to?

A

ligaments that are attached to muscles responsible for speech/sounds

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23
Q

How do vocal cords produce speech and sound?

A
  • muscles contract and stretch the vocal folds during speech

- folds vibrate when air is directed against them and produce sounds

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24
Q

What is the trachea composed of and where is it located?

A
  • smooth muscle and C-shaped rings of C (rings keep airway open!)
  • lined with pseudostratified ciliated columnar epithelium
  • extend from larynx to primary bronchi
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25
Q

What is the function of cilia in the trachea?

A

sweep mucus/debris away from lungs and back to throat to be swallowed

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26
Q

List the airway branchings in the conducting zone (from trachea)

A
  1. main bronchi (primary)
  2. lobar bronchi (secondary)
  3. segmental bronchi (tertiary)
  4. bronchioles
  5. terminal bronchioles
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27
Q

List the airway branching in the respiratory zone (from terminal bronchioles)

A
  1. respiratory bronchioles
  2. alveolar ducts
  3. alveolar sacs
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28
Q

Describe briefly the change in epithelium from the main bronchi to the alveolar sacs

A
  • pseudostratified ciliated columnar w/ goblet cells in main bronchi
  • simple non-ciliated cuboidal w/o goblet cells in terminal bronchioles
  • simple squamous epithelium line alveolar sacs
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29
Q

What separates each lung?

A

mediastinum

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30
Q

What encloses each lung?

A

pleural (serous) membrane

  • visceral pleura covers lung
  • parietal pleura lines wall of thoracic cavity
  • pleural cavity (between layers) contains pleural fluid
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31
Q

What is the function of the pleural cavity?

A
  • fluid lubricates to prevent friction

- provides surface tension to help breathing

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32
Q

What is pleuritis?

A

inflammation of pleura

- causes pain due to friction between membranes

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33
Q

What is pleural effusion?

A

when fluid accumulates in pleural cavity

- impairs breathing bc lungs cannot inflate properly

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34
Q

What are alveoli composed of? (small air sacs)

A
  1. type I alveolar cells

2. type II alveolar cells

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35
Q

How do the 2 types of alveolar cells differ?

A
  • type I form simple squamous epithelium
  • type II secrete alveolar fluid and contain surfactant (decreases surface tension and allows ease of alveolar inflation)
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36
Q

What covers each alveolus?

A

blood capillaries for gas exchange

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37
Q

What is the respiratory membrane composed of?

A
  1. alveolar wall (type I cells)
  2. epithelial basement membrane
  3. capillary basement membrane
  4. capillary endothelium
38
Q

Describe the blood supply to the lungs

A
  • de-O2 blood arrives through pulmonary arteries from R ventricle
  • bronchial arteries branch from aorta to supply O2 blood to lung tissue
39
Q

How do external (pulmonary) and internal (tissue) respiration differ?

A

E - pulmonary capillary picks up O2 and loses CO2

I - systemic capillary loses O2 and gains CO2

40
Q

How does air move in and out of the lungs?

A
  • moves IN when pressure inside lungs is less than atmospheric pressure
  • moves OUT when pressure inside lungs is greater than atmospheric pressure
41
Q

What is pulmonary ventilation controlled by?

A

contraction/relaxation of resp muscles

42
Q

What is Boyle’s law?

A
  • as size of closed container decreases (less space for molec to move), the pressure inside the container increases
43
Q

How is Boyle’s law related to pulmonary ventilation?

A
  • during breathing, size of lungs change
  • change in size causes pressure change inside lungs
  • pressure change causes air to move from area of high pressure to area of low pressure
44
Q

How do the contraction of resp muscles function in normal/quiet inhalation?

A
  • contraction of ext intercostals makes ribs move UPWARDS

- contraction of diaphragm flattens it downwards, allowing lungs to expand vertically

45
Q

What additional muscles are involved in forced/laboured inhalation?

A
  • accessory muscles of inspiration are recruited: sternocleidomastoid, scalenes, pectoralis minor
  • further elevate sternum and ribs allowing more space for lung inflation
46
Q

How do relaxation of resp muscles function in normal/quiet exhalation?

A
  • relaxation of diaphragm causes it to move up
  • relaxation of ext intercostals move ribs down and inward

**reduce intrathoracic cavity size

47
Q

What additional muscles are involved in forced exhalation?

A
  • contraction of abdominal muscles (move inf ribs downward and compress abdominal viscera) and internal intercostals (pull ribs inferiorly)
48
Q

What are 3 factors affecting pulmonary ventilation? (ease of breathing)

A
  1. surface tension of alveolar fluid
  2. compliance of lungs (ease of expanding)
  3. airway resistance (diameter of airways)
49
Q

How does surface tension of alveolar fluid affect breathing? What can it be reduced by?

A
  • water molecules attract to each other and cause alveoli to collapse (like a wet plastic bag)
  • surfactant (mixture of P-lipids and lipoproteins)
50
Q

What is respiratory distress syndrome in infants?

A

RDS is due to lack of surfactant

51
Q

How does compliance of lungs affect breathing?

A
  • results from high elasticity and low surface tension
  • decreased compliance can result from fluid in lungs, deficient surfactant production, physical impairment of lung expansions
52
Q

How does airway resistance affect breathing?

A
  • contraction of smooth muscles in airways causes constriction reducing airway size
53
Q

How does airway resistance relate to asthma?

A

absence of C in small airways contribute to airway constriction

54
Q

How do you calculate vital capacity (VC)?

A

TV + IRV + ERV = VC

55
Q

How do you calculate total lung capacity?

A

VC + RV = TLC

56
Q

What are some factors that affect the rate of diffusion?

A
  • partial pressure difference
  • SA available for gas exchange
  • diffusion distance
  • solubility of gases
57
Q

What would happen to the rate of diffusion at high altitudes?

A

difference in pressure

58
Q

What would happen to the rate of diffusion in a patient with emphysema (breakdown of alveoli)?

A

:)

59
Q

How much O2 is dissolved in the plasma? Where does the rest go to?

A
  • 1.5% dissolves in plasma

- 98.5% binds to heme complexes on Hb

60
Q

How many O2 molecules can each Hb molecule carry?

A

4

61
Q

What are the normal saturation levels of Hb?

A

95-100%; all heme groups bound to O2

**less than 90% is considered low

62
Q

How does the binding of O2 to Hb differ in pulmonary and systemic capillaries and why?

A

P - O2 must strongly bind to Hb to bee transported in the blood

S - O2 must loosely bind to/dissociate from Hb to diffuse into tissue cells

63
Q

What is affinity? (of Hb to O2)

A

how tightly Hb binds to O2

64
Q

What are 4 factors that affect binding and dissociation?

A
  1. partial pressure of O2
  2. acidity (pH)
  3. partial pressure of CO2
  4. temperature
65
Q

What are characteristics of metabolically active tissues? Would these increase or decrease affinity of Hb for O2?

A

increase since O2 is most needed by metabolically active tissues

66
Q

How does partial pressure affect affinity?

A

the greater the PO2, the more O2 will combine with Hb

  • higher Hb saturation = less O2 dissociation
  • lower Hb = more dissociation; can be used by tissues
67
Q

How do shifts of curve affect affinity?

A

shift to R - decreased affinity

shift to L - increased affinity

68
Q

How does pH affect affinity?

A

as acidity increases, affinity of Hb for O2 decreases
- H+ binds to Hb and alters shape; O2 dissociates more readily

  • metabolically active cells produce acid, which enhances O2 release at tissues
69
Q

How does partial pressure of CO2 affect affinity?

A

as PCO2 rises (with metabolic activity), O2 affinity for Hb decreases
- increased CO2 levels in blood make blood more acidic; decreases affinity

70
Q

How does temperature affect affinity?

A

as temperature increases, Hb affinity for O2 decreases (O2 is more readily released)

71
Q

At rest, why is temperature higher near tissue cells than in arteries?

A
  • metabolic activity; generates heat

- allows O2 to dissociate more easily

72
Q

Does fetal Hb or maternal Hb have a higher affinity for O2?

A

fetal because the baby needs the O2; different a.a (eventually diff proteins) determine affinity differences for maternal and fetal Hb

73
Q

What causes carbon monoxide poisoning? How can it be counteracted?

A

CO binds to Hb heme group more strongly than O2

  • administering pure O2; use pressure to cause more O2 to dissolve in blood (hyperbaric oxygen)
74
Q

How is CO2 transported in the blood?

A
  1. dissolving in plasma (7%)
  2. bound to globin part of Hb (23%)
  3. transported in plasma as part of bicarbonate ion (70%)
75
Q

What is the formula for the conversion of CO2 to HCO3

A

CO2 + H20 —- H2CO3 (carbonic acid) —– H+ _ HCO3

76
Q

In systemic capillaries, CO2 is converted into what? How does this affect blood?

A

excess CO2 is converted into H+ and HCO3 for transport, making blood more acidic

77
Q

In pulmonary capillaries, H+ and HCO3 are converted into what?

A

combined to reform CO2 so gas molecules can diffuse out of capillaries and be exhaled

78
Q

What are respiratory muscles controlled by?

A

neurons from the pons and medulla (under autonomic control)

79
Q

What is the function of the medullary rhythmicity area?

A
  • controls basic resp rhythm (quiet inhalation)

- specialized cells in dorsal resp group (DRG) and ventral resp group (VRG)

80
Q

What do the cells in DRG and VRG respectively do?

A

DRG - autorhythmic cells innervate diaphragm and ext intercostals for contraction (active 2 sec) and relaxation (inactive 3 sec)

VRG - neurons only active during forced ventilation; innervates accessory muscles

81
Q

What is the pontine respiratory group? (PRG)

A

located in pons, oversees signals to DRG

- transmits nerve impulses to DRG to modify respiratory rhythm when needed (e.g. when exercising, sleeping)

82
Q

How do signals from the cerebral cortex affect breathing patterns?

A
  • voluntarily alter patterns; allow conscious control of respiration for protection (e.g. holding breath, swimming)
83
Q

What is voluntarily breath holding limited by?

A

overriding stimuli of increased PCO2 and [H+]

- stimulates DRG, triggering inhalation

84
Q

What is the role of central chemoreceptors in chem regulation of respiration? (in medulla)

A

respond to changes in PCO2 or [H+] in cerebrospinal fluid

85
Q

What is the role of peripheral chemoreceptors in chem regulation of respiration? (in walls of aorta and carotid arteries)

A

respond to changes in PO2, PCO2, [H+]

86
Q

How does negative feedback function in regulation of breathing?

A
  • stimulus: increase in arterial PCO2
  • stimulate receptors
  • stimulates DRG
  • muscles of resp contract more frequently and forcefully
  • PCO2 decreases
87
Q

What is the inflation reflex?

A

detects over-expansion of lungs with stretch receptors in bronchioles

  • inhibit DRG; allow for exhalation to take place
  • after exhalation, stretch receptors no longer stimulated –> DRG no longer inhibited –> inhalation occurs

**protective mechanism; not part of normal breathing

88
Q

What other factors influence the respiratory rate?

A
  • anticipation of exercise, excitement, fear, anxiety all cause limbic system to excite DRG; increase resp rate
  • temperature: increase in temp increases rate
  • pain: sudden pain causes brief apnea; prolonged pain increases resp rate; visceral pain slows rate
89
Q

What does the irritation of respiratory mucosa do?

A

stops inspiration, triggers coughing or sneezing

90
Q

Why does breathing increase at the beginning of exercise?

A
  • proprioceptors of joints/muscles activate DRG

- axon collaterals sent to DRG from motor neurons in primary motor cortex area

91
Q

Why does breathing gradually increase as exercise progresses?

A
  • decreased PO2 due to increased use of O2 (hypoxia)
  • increased PCO2 due to increased CO2 production (hypercapnia)
  • increased metabolic activity leads to increased temp

BIOL 1190 (18 decks)

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