Lecture 18: Pulmonary A&P Flashcards

1
Q

what forms the thoracic cavity and what is contained within

A

formed by ribs, thoracic vertebrae, sternum, and clavicles

contains R and L pulmonary cavities and mediastinum

provides skeletal framework for attachment of mm used for breathing

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2
Q

describe the sternum and its components

A

flat breastbone; sits directly over mediastinum

manubrium = thickest part; articulates with clavicles and ribs 1-2

body = articulates with ribs 3-7

diploid = most caudal potion of sternum; doesn’t ossify until teens

angle of Louis = marks level of tracheal bifurcation into R and L main stem bronchi

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3
Q

what are vertebrosternal ribs

A

“true ribs”

ribs 1-7 attach to the sternum via the costal cartilage

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4
Q

what are vertebrochondral ribs

A

“false ribs”

ribs 8-10 attach to rib above via their costal cartilage

ribs 11-12 end freely

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5
Q

what is the weakest point of the rib

A

the shaft where vertebral and sternal end connects

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6
Q

purpose of inspiratory mm

A

increase volume of the thoracic cavity by producing “bucket handle” and “pump handle” movements of the ribs and sternum

diaphragm is the primary inspiration mm (phrenic nn C3-5)

external intercostals also assist with inspiration

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7
Q

how does the diaphragm move with breathing

A

moves downward with contraction to increase thoracic volume

vacuum effect pulls air into lungs

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8
Q

what do the intercostals do with inspiration

A

elevate ribs and expand chest

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9
Q

name the accessory inspiratory muscles

A

SCM
scalenes
upper trap
pec major and minor
serrates anterior
rhomboids
latissimus dorsi
serrates posterior superior
thoracic erector spinae

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10
Q

what muscles are involved with expiration

A

expiration = more passive than inspiration via elastic recoil; less energy required

abdominal mm = increase intra abdominal pressure for expulsion of air

internal intercostals = depress ribs and decrease thoracic volume

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11
Q

describe different anatomical components of the lungs

A

consists of airways and blood vessels to perform gas exchange

apex = superior cone shaped potion underneath and superior to rib 1

base = inferior/diaphragmatic surface

root = endurance of bronchi, pulmonary arteries/veins, lymphatics, nn into each lung

hilum = mediastinal surface where structures of the root enter the lung

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12
Q

describe the R lung

A

larger

3 lobes (superior, middle, inferior)

2 fissures ( horizontal and oblique)

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13
Q

describe the L lung

A

smaller

2 lobes (superior and inferior)

1 fissure (oblique)

cardiac notch

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14
Q

what is the purpose of dividing lungs into segments

A

R and L lungs are broken down into segments that correspond with their air supply

used for naming location of infection, surgery, tumor, fluid accumulation, etc

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15
Q

describe the parietal pleura

A

on chest wall

highly innervated

capillaries receive blood from systemic circulation

higher capillary blood pressure

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16
Q

describe the visceral pleura

A

directly on lungs

no sensory innervation

capillaries receive blood from pulmonary circulation

lower capillary blood pressure

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17
Q

describe the difference in blood vessels that vascularize the parietal pleura vs the visceral pleura

A

parietal = vascularized by high pressure systemic blood vessels

visceral = vascularized by low pressure pulmonary blood vessels

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18
Q

how does the pressure gradient work to move fluid in and out of the pleural region

A

normal pressure gradient causes constant fluid movement out of the parietal capillaries into the pleural space and is then reabsorbed by visceral capillaries

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19
Q

how much fluid passes through the pleural space

A

5-10L fluid per day

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20
Q

what are the components of the upper respiratory tract and their function

A

nose = air filtration, humidification, temp control, and olfaction

pharynx = throat; connects nasal cavity to tracheoesophageal junction

larynx = voice box; sits directly on top of the trachea

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21
Q

what are the components of the lower respiratory tract and their function

A

trachea = large airway made of cartilage rings, elastic, and fibrous tissue; carina splits trachea into R and L mainstream bronchi

bronchi = airways that enter each lung
- R bronchi has steeper Ange
- bronchi become smaller as they turn into segmental and sub segmental bronchi

terminal units = brochioles, alveolar ducts, and alveoli

22
Q

what is the conducting zone

A

no gas exchange

air movement only

23
Q

what happens at the respiratory zone

A

gas exchange

24
Q

what are type 1 pneumocytes (AT1)

A

flat cells that perform gas exchange

25
Q

what are type 2 pneumocytes (AT2)

A

cuboid cells that produce surfactant

26
Q

describe the anatomy of the epithelial lining

A

cilia = tiny hair like structures lining the respiratory epithelial surfaces

natural movements of cilia help trap and propel substances and secretions upwards in the respiratory tract

expectorate = cough

27
Q

what is compliance property of lungs

A

distensibility of lung tissue

how well it can stretch with inhalation

28
Q

what is elasticity property of lungs

A

ability to return to its initial size after being distended

hig levels of elastin and collagen allow for recoil

29
Q

what is surface tension

A

maintained with surfactant to prevent airway collapse

ultimately allows lungs to get smaller during exhalation

30
Q

what is airway diameter and resistance

A

controlled by autonomic nervous system

upper airways are responsible for higher airway resistance

lower airways are too irregular to influence airway resistance

31
Q

what is ventilation

A

moving air in and out of lungs

relationship between mm. contractions and pressure fluctuations

  1. diaphragm and other mm of respiration contract
  2. decreased intrapulmonary pressure
  3. air moves into lungs
32
Q

medulla role in regulation of breathing

A

inspiration and forced exhalation

33
Q

pons role in regulation of breathing

A

pneumotaxic center
- rhythms of ventilation, timing of inhalation and exhalation, inhibits apneic breathing

apneustic center
- facilitates apneic or prolonged breathing patterns

34
Q

function of motor cortex of frontal lobe in regulation of breathing

A

voluntary and conscious breathing

35
Q

types of chemoreceptors and their function in regulation of breathing

A

central chemoreceptors
- located in medulla
- facilitates increasing respiratory depth and rate to restore normal blood gas levels

peripheral chemoreceptors
- located in carotid artery and aortic arch
- facilitates increased ventilation in response to high CO2 or low O2

36
Q

function of irritant receptors in regulation of breathing

A

initiates cough reflex

37
Q

function of stretch receptors in regulation of breathing

A

protects lung from excessive inflation

38
Q

how does intrapulmonary and atmospheric pressure play a role in inhalation and exhalation

A

inhalation = decrease in intrapulmonary pressure allows air to flow in

exhalation = increase in intrapulmonary pressure allows air to be expelled out

39
Q

what is intrapleural pressure

A

elastic tension of ling trying to collapse lungs

outward pull of thoracic wall trying to expand lungs

opposition creates negative pressure within pleural space

40
Q

what are transmural pressures

A

intrapleural pressure is less than intrapulmonary

allows changes in lung volumes

41
Q

describe the mechanics of breathing

A

intrapulmonary pressure inside lung decreases as lung volume increases during inspiration; pressure increases during expiration

intrapleural pressure in the pleural cavity becomes more negative as chest wall expands during inspiration; returns to initial value as chest wall recoils

volume of breath = during each breath the pressure gradients move 0.5 L of air into and out of the lungs

42
Q

what is respiration/oxygenation

A

process of gas exchange in the lungs facilitated by diffusion
- delivers O2 used for energy production
- removal of CO2 waste product

occurs at alveolar-capillary membrane
- gas exchange occurs due to differences in pressure gradients between different gas molecules

43
Q

what are partial pressures of gases and what are the values for atmospheric air

A

amount of pressure exerted by a gas within a mixture

nitrogen = 79.04%
oxygen = 20.93%
carbon dioxide = 0.03%

in liquid (i.e. blood) gases are dissolved in proportion to their partial pressures

44
Q

what is diffusion in regard to respiration

A

partial pressures of O2 and CO2 exist in both alveoli (air) and capillary (blood)

gases will diffuse from high to low concentration across alveolar membrane

45
Q

what is perfusion

A

amount of blood flow to the lungs

effects capacity for gas exchange

positional or regional

lungs have low resistance and low pressure vasculature

46
Q

what is ventilation perfusion (V/Q) matching

A

distribution of gas (V) and blood (Q) at the alveolar level of capillary interface must be matched

both ventilation and perfusion are greater in gravity dependent areas

if perfusion > ventilation = shunt
- blood but no air

if ventilation > perfusion = dead space
- air but no blood

47
Q

describe the cellular transport of O2 and CO2

A

O2 transported by binding with Hgb; delivery to tissue is dependent on blood flow and amount of O2 content

CO2 is transported by Hgb, bicarb, or plasma

acid base balance is maintained by lungs, kidneys, and liver

48
Q

SpO2 of 90% corresponds to what partial pressure of O2

A

60 mmHg

minimum O2 concentration to prevent ischemia

49
Q

L shift on oxyhemoglobin dissociation curve

A

Hgb hods onto O2 since tissues don’t need it

more O2 bound to Hgb

lower partial pressure O2

lower temp and mm work

higher blood pH

50
Q

R shift on oxyhemoglobin dissociation curve

A

releases O2 to tissues that need it more

less O2 bound to Hgb

naturally happens during exercise

higher temp and mm work

lower blood pH (more acidic)