Lecture 18: Pulmonary A&P

Question 1

what forms the thoracic cavity and what is contained within

Answer 1

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

Question 2

describe the sternum and its components

Answer 2

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

Question 3

what are vertebrosternal ribs

Answer 3

“true ribs”

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

Question 4

what are vertebrochondral ribs

Answer 4

“false ribs”

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

ribs 11-12 end freely

Question 5

what is the weakest point of the rib

Answer 5

the shaft where vertebral and sternal end connects

Question 6

purpose of inspiratory mm

Answer 6

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

Question 7

how does the diaphragm move with breathing

Answer 7

moves downward with contraction to increase thoracic volume

vacuum effect pulls air into lungs

Question 8

what do the intercostals do with inspiration

Answer 8

elevate ribs and expand chest

Question 9

name the accessory inspiratory muscles

Answer 9

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

Question 10

what muscles are involved with expiration

Answer 10

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

Question 11

describe different anatomical components of the lungs

Answer 11

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

Question 12

describe the R lung

Answer 12

larger

3 lobes (superior, middle, inferior)

2 fissures ( horizontal and oblique)

Question 13

describe the L lung

Answer 13

smaller

2 lobes (superior and inferior)

1 fissure (oblique)

cardiac notch

Question 14

what is the purpose of dividing lungs into segments

Answer 14

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

Question 15

describe the parietal pleura

Answer 15

on chest wall

highly innervated

capillaries receive blood from systemic circulation

higher capillary blood pressure

Question 16

describe the visceral pleura

Answer 16

directly on lungs

no sensory innervation

capillaries receive blood from pulmonary circulation

lower capillary blood pressure

Question 17

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

Answer 17

parietal = vascularized by high pressure systemic blood vessels

visceral = vascularized by low pressure pulmonary blood vessels

Question 18

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

Answer 18

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

Question 19

how much fluid passes through the pleural space

Answer 19

5-10L fluid per day

Question 20

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

Answer 20

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

Question 21

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

Answer 21

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

Question 22

what is the conducting zone

Answer 22

no gas exchange

air movement only

Question 23

what happens at the respiratory zone

Answer 23

gas exchange

Question 24

what are type 1 pneumocytes (AT1)

Answer 24

flat cells that perform gas exchange

Question 25

what are type 2 pneumocytes (AT2)

Answer 25

cuboid cells that produce surfactant

Question 26

describe the anatomy of the epithelial lining

Answer 26

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

Question 27

what is compliance property of lungs

Answer 27

distensibility of lung tissue how well it can stretch with inhalation

Question 28

what is elasticity property of lungs

Answer 28

ability to return to its initial size after being distended hig levels of elastin and collagen allow for recoil

Question 29

what is surface tension

Answer 29

maintained with surfactant to prevent airway collapse ultimately allows lungs to get smaller during exhalation

Question 30

what is airway diameter and resistance

Answer 30

controlled by autonomic nervous system upper airways are responsible for higher airway resistance lower airways are too irregular to influence airway resistance

Question 31

what is ventilation

Answer 31

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

Question 32

medulla role in regulation of breathing

Answer 32

inspiration and forced exhalation

Question 33

pons role in regulation of breathing

Answer 33

pneumotaxic center - rhythms of ventilation, timing of inhalation and exhalation, inhibits apneic breathing apneustic center - facilitates apneic or prolonged breathing patterns

Question 34

function of motor cortex of frontal lobe in regulation of breathing

Answer 34

voluntary and conscious breathing

Question 35

types of chemoreceptors and their function in regulation of breathing

Answer 35

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

Question 36

function of irritant receptors in regulation of breathing

Answer 36

initiates cough reflex

Question 37

function of stretch receptors in regulation of breathing

Answer 37

protects lung from excessive inflation

Question 38

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

Answer 38

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

Question 39

what is intrapleural pressure

Answer 39

elastic tension of ling trying to collapse lungs outward pull of thoracic wall trying to expand lungs opposition creates negative pressure within pleural space

Question 40

what are transmural pressures

Answer 40

Difference in pressure inside va outside lungs intrapleural pressure is less than intrapulmonary allows changes in lung volumes

Question 41

describe the mechanics of breathing

Answer 41

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

Question 42

what is respiration/oxygenation

Answer 42

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

Question 43

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

Answer 43

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

Question 44

what is diffusion in regard to respiration

Answer 44

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

Question 45

what is perfusion

Answer 45

amount of blood flow to the lungs effects capacity for gas exchange positional or regional lungs have low resistance and low pressure vasculature

Question 46

what is ventilation perfusion (V/Q) matching

Answer 46

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

Question 47

describe the cellular transport of O2 and CO2

Answer 47

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

Question 48

SpO2 of 90% corresponds to what partial pressure of O2

Answer 48

60 mmHg minimum O2 concentration to prevent ischemia

Question 49

L shift on oxyhemoglobin dissociation curve

Answer 49

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

Question 50

R shift on oxyhemoglobin dissociation curve

Answer 50

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)