Intro to Respiratory System Flashcards

1
Q

what is respiration?

A

the interchange of gases (oxygen and carbon dioxide) between air and blood in the lungs

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2
Q

what is ventilation?

A

the inhalation and exhalation of air into and out of the lungs through the respiratory tract

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3
Q

how can you talk about the respiratory tract in functional terms?

A

-conducting portion - tubes that lead from mouth and nose to lungs
-respiratory portion - minute components in lungs where gas exchange occurs (alveoli)

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4
Q

how can you talk about the respiratory tract in clinical terms?

A

-the upper respiratory tract (URT) comprises the tubes as far down as the larynx and
-the tubes below the larynx and in the lungs constitute the lower respiratory tract (LRT)

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5
Q

describe the conducting portion of the respiratory tract

A

-pressure changes occur in tubes due to movement of air
-bone/cartilage reinforces tubes to prevent them from collapsing due to pressure change
-lined w respiratory mucosa

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6
Q

describe the respiratory mucosa

A

-comprises one layer of columnar cells with cilia on their luminal surface
-Secretory (goblet) cells are interspersed and secrete mucus onto the surface

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7
Q

describe the purpose of mucus in respiratory bronchioles

A

Mucus lines respiratory tract from the nose to respiratory bronchioles

It is there to trap inhaled particles and the cilia beat to move the material up or backwards into the pharynx - it can then be swallowed or expectorated (spat out)

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8
Q

what are the structures contained in the conducting portion/upper respiratory tract?

A

-nose
-pharynx
-larynx
-trachea
-bronchial tree

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9
Q

discuss the nose

A

-cleans using cilia
-warms with vascular mucosa
-humidifies air as it is breathed in w mucus
-paranasal air sinus extend nasal cavity into surrounding bone to provide a reservoir of mucus out of direct airflow

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10
Q

what is the pharynx?

A

-muscular tube share by respiratory and gastrointestinal tracts
-food and drink exit into oesophagus and air exit into larynx

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11
Q

what is the larynx?

A

-tube reinforced w cartilage that can move relative to each other
-contains vocal folds

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12
Q

what do vocal folds do?

A

-protect airway from food ingestion during swallowing
-generate sound for speech

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13
Q

how do airways trap pathogens?

A

-turbulence - air twists as it enters
-strikes walls so pathogens are trapped
-warms w vascular mucosa
-cleans w cilia
-mucus is sticky so traps pathogens
-humidifies w mucus

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14
Q

describe the lungs

A

-consist of paired air-filled sacs made of millions of tiny alveolar sacs where gaseous exchange takes place
-right lung has 3 lobes
-left lung has 2 lobes

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15
Q

what does the Lower Respiratory Tract consist of?

A

-trachea
-bronchi
-bronchioles

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16
Q

what are the bronchi split into?

A

-main bronchi
-lobar bronchi
-segmental bronchi

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17
Q

what are bronchioles

A

small tubes without cartilage, smooth muscle regulates air flow into the respiratory portion of the lungs (alveoli)

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18
Q

describe the mucus in the respiratory tract

A

-2 layers - gel layer and periciliary layer
-periciliary layer is thicker and protects cell from damage
-periciliary layer is immobile so the ciliated cells propel the gel layer

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19
Q

what releases mucins?

A

goblet cells

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20
Q

what do mucins do?

A

-travel into gel layer
-attach to membranes in periciliary layer
-attach to sugar on cilia so cilia are attached to each other - helps them beat together

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21
Q

what is the gel on brush model?

A

-mucus layer on top of periciliary layer
-mucins link cilia by attaching to sugars

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22
Q

what do charged polymers in mucus do?

A

-act as lubricants in aqueous environments - this enables low friction beating of cilia

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23
Q

compare the density of mucins in the gel and periciliary laye

A

-the density increases from gel layer to epithelium so more mucins in periciliary layer
-this minimises contact bw epithelial cells and infectious microbes w diameter larger than 40μm
-high density in periciliary layer means there is constant amount of liquid

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24
Q

what happens if there is an increase in liquid volume in the lungs?

A

periciliary layer cannot absorb any more liquid so causes swelling of gel layer - this is well tolerated in CF patients

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25
what happens if there is a decrease in liquid volume in the lungs?
-periciliary layer takes liquid from the gel layer -when gel layer is too dehydrated for more liquid transfer, mucus clearance will fall due to compression of cilia
26
what can cause decreased hydration in the lungs?
-cystic fibrosis (CF) -chronic obstructive pulmonary disorder (COPD) -airway infections
27
describe ciliated cells
-columnar cells - 300 cilia per cell -cilia beat in one direction towards oropharynx propelling mucus and particulates to be removed (spit it out or swallow it) -loss of cilia activity can cause respiratory infections -microvilli present at apex of cells
28
describe mucous goblet cell
-secrete mucus that traps particulate matter -sparse microvilli
29
describe brush cells
-columnar with short, blunt microvilli on apical surface -sensory receptor cells
30
describe basal cells
-base of epithelium and do not reach lumen -stem cell function
31
describe small granule cells
-contain granules at base of cell (bronchial Kulchitsky cells) -neuroendocrine function - similar to enteroendocrine cell of gut
32
describe the distal elements of conducting portion (club cells)
-secrete lipoprotein that is a surface active agent -progenitor cells -xenobiotic metabolism (metabolises foreign agents)
33
describe type I cells (pneumocytes)
-squamous epithelia -organelles are near nucleus so extranuclear region quite thin -covers 95% of gas exchange surface
34
describe type I cells (pneumocytes)
-squamous epithelia -organelles are near nucleus so extranuclear region quite thin -covers 95% of gas exchange surface
35
describe type II cells
simple cuboidal cells found at alveolar wall junctions -covers 5% of gas exchange surface -lamellar bodies contain pulmonary surfactants which reduce surface tension between alveolar wall and air -progenitor cell -xenobiotic metabolism
36
bronchioles and alveolar sacs: histology
37
Describe alveoli and adaptations
-millions of alveolar sacs hanging from bronchioles so v large SA -alveolar walls v thin so quick diffusion -formed by pneumocytes and capillaries -can break down due to smoking so less SA for gas exchange
38
What damage happens to alveoli in respiratory system from smoking
The alveoli break down so the surface area for gaseous exchange is drastically reduced
39
Name these structures
40
Name these structures
41
Describe cystic fibrosis
-lungs blocked w mucus so air cannot pass down tubes -CFTR channel is responsible for movement of salts in and out of epithelial cells and controls how thick mucus will be -protein in membrane can be structurally faulty or non-functioning CFTR is made -lungs are blocked so air cannot pass through -1 in every 3000 neonates diagnose w CF - have to inherit 2 defective genes
42
describe the structure of lungs
-lots of elastic tissue so they can recoil after inflation -separated from thoracic wall by pleura -made up of millions of alveoli
43
what is the pleura?
two thin membranes lining thorax and enveloping lungs
44
Name the 2 pleura
Parietal pleura line the thoracic cavity Visceral pleura cover the lungs
45
what is the space between the two pleura called?
The pleural cavity
46
what does the pleura do?
-allows lungs to slide over thoracic wall as they inflate and deflate -allow lungs to stay inflated by surface adhesion by a thin layer of pleural fluid
47
What does the thoracic wall consist of?
-sternum -ribs -internal and external intercostal muscles -diaphragm -accessory muscles
48
What are the two layers of intercoastal muscles in the thoracic wall?
internal and external intercostal muscles
49
what is the diaphragm?
-thin muscular sheet which separates thorax from abdomen -attached to lower ribs, tip of sternum and vertebral column
50
what are accessory muscles?
muscles that are normally used for one function but may be recruited to aid in another function
51
what are the accessory muscles of respiration?
-scalenes - ribs to neck -pectorals - ribs to arms -abdominals - ribs to pelvis
52
what are the accessory muscles of respiration?
-scalenes - ribs to neck -pectorals - ribs to arms -abdominals - ribs to pelvis
53
describe the mechanism of ventilation
-ventilation increases volume of thorax to decrease pressure so air is drawn in -as thoracic cage moves, parietal pleura will follow -as the visceral pleura and lungs adhere to the parietal pleura, they follow the movement of the chest wall
54
what is quiet ventilation?
-aka eupnea breathing that occurs at rest and does not require conscious thought
55
what is forced ventilation?
-hyperpnea forced breathing which required muscle contraction for both inspiration and expiration
56
what happens during quiet ventilation?
-during inspiration, external intercostal muscles contract which raises ribcage and diaphragm contracts so thoracic vol increases -expiration occurs by passive elastic recoil -diff in pressure can be small but gases will still move
57
when will quiet ventilation be overridden?
Ventilation is automatic but can be overridden -when the body requires more oxygen or need to expel excess CO2 (e.g. after exercise) = forced ventilation -when we need to modify the ventilatory cycle for speech -by emotional responses (e.g. fear)
58
what happens during forced ventilation?
-during inspiration, intercostal muscles, diaphragm and accessory muscles are used to their max -total lung vol is used during expiration, intercostal muscles bring down ribcage and accessory muscles (abs) help push diaphragm up
59
What is the vital capacity of lungs
4 – 6 L depending on age, sex, fitness
60
how does ventilation change for speech?
Speech breathing requires non-rhythmic ventilation -short deep inspirations to match length of utterance counteraction of passive elastic recoil to match length of the utterance
61
How many litres does different speech take?
Conversational speech uses c 1.5 L Voice projection (e.g. lecturing) uses c 2.5 L Shouting uses most of vital capacity