Lungs structure and function

Question 1

components of respiratory stystem

Answer 1

lungs, conducting airway, CNS, chest wall, muscle of respiration

Question 2

gross structure of lungs- right and left lobes

Answer 2

right is bigger, separated into 3 (upper, middle, lower) lobes and left is separated into 2 lobes (upper and lower)

Question 3

gross structure of lungs- horizontal lobe and oblique fissure

Answer 3

separates upper and middle on right

oblique fissure- separates upper and lower lobes on left side, middle and lower on right side

Question 4

gross structure of lungs- bronchopulomonary segments

Answer 4

right= 10, left= 8, both lungs have grooves for large vessels

Question 5

gross structure of lungs- pleura

Answer 5

surrounded by pleura (visceral- outer membrane and parietal- inner membrane)

Question 6

location of lungs

Answer 6

anatomical markings- 2.5cm above midpoint of the medial 1/3 clavicle, 6th costal cartilage 7cm from midline anteriorly, rib 8 laterally, T2-10 posteriorly

Question 7

functions of the lungs

Answer 7

gaseous exchange, surfactant production, reservoir of blood, filter (prevent infection by trapping bacteria with mucous), part of immune system (macrophages produce to attack pathogens), pH balance (by controlling how much we breath and how much co2 is in blood)

Question 8

surfactant production

Answer 8

type 2 immunocytes make and produce surfactant- keeps alveoli open

Question 9

the upper respiratory tract

Answer 9

nose, mouth, phalanx, larynx, function is to warm up air with breath, also involved with swallowing and voice

Question 10

lower respiratory tract

Answer 10

trachea, primary bronchi, secondary bronchi, tertiary bronchi, bronchioles, terminal bronchioles, respiratory bronchioles, alveolar ducts, alveolar sacs

Question 11

lower respiratory tract- trachea- position and potential pathology

Answer 11

begins immediately below larynx (C6), 2.5cm in diameter 11cm long, potential pathologies include floppy, i.e. no cartilage obstruction

Question 12

lower respiratory tract- trachea structure

Answer 12

15-20 c-shaped cartilaginous rings, divided to form 2 branches at the carina (T5), posteriorly faces the oesophagus and flexible for stalling

Question 13

lower respiratory tract- primary bronchi- right and left

Answer 13

separated by carina, C-shaped cartilaginous support (keeps them open), right has a larger diameter and depends at a steeper angle, accesses lungs via the hilum, potential pathology is obstruction

Question 14

lower respiratory tract- secondary bronchi

Answer 14

right has 3 serving the upper middle, and lower lobes, left has 2, have cartilaginous plates- keep airways open, example of a pathology is lobar pneumonia

Question 15

lower respiratory tract- tertiary bronchi

Answer 15

each tertiary bronchi supplies air to a singlee brocnhopulomonary segment, right has 10 and left has 8-9, have cartilaginous plates, increasing amount of smooth muscle, potential pathology- bronchitis

Question 16

tertiary bronchi- less cartilaginous support

Answer 16

with less cartilaginous support, the amount of tension in those smooth muscles has a greater effect on bronchial diameter and resistance to airflow

Question 17

lower respiratory tract- bronchioles

Answer 17

more smooth muscle, potential pathologies affecting this area include COPD and fibrosis alveolitis

Question 18

lower respiratory tract- terminal bronchioles

Answer 18

0.3-0.5mm diameter, made up of smooth muscle, autonomic system regulates- sympathetic stimulation= dilation, parasympathetic constriction, potential pathologies- asthma and fibrosis

Question 19

lower respiratory tract- respiratory bronchioles

Answer 19

each terminal bronchiole branches to several of these, thin and delicate with no cilia, deliver air to gas exchange surface of lung

Question 20

lower respiratory tract- alveolar ducts

Answer 20

connect respiratory bronchioles to alveoli, pathologies- CF or pneumonia

Question 21

lower respiratory tract- alveolar sacs

Answer 21

where gas exchange occurs, surfactant to stay open, pathologies- CF or pneumonia

Question 22

conducting zone

Answer 22

trachea to terminal bronchioles, no gas exchange, gas transport by convection, location of anatomical dead space

Question 23

respiratory zone

Answer 23

respiratory bronchioles to alveoli, gas exchange at alveolar/ capillary membrane, has transport by diffusion , large SA

Question 24

alveolar structure

Answer 24

2 types of cells within them, pneumocyte type 1- responsible for gas exchange across its membranes, pneumocyte type 2- produce surfactant, also make and replicate themselves into type 1 to replace damaged cells
they have a large capillary network for gas exchange- mesh like network

Question 25

alveoli- collateral ventilation

Answer 25

network of interconnections between respiratory bronchioles and alveoli

Question 26

collateral ventilation- intrabronchiolar channels of Martin

Answer 26

between 1 respiratory bronchiole to another

Question 27

collateral ventilation- bronchiolar alveolar channel of Lambert and pores of cone

Answer 27

BACL- from respiratory bronchiole to alveolar

pores of cone- connections between alveolar

Question 28

diaphragm

Answer 28

large dome shaped muscle, flattens on contraction and domes on relaxation, its movement will alter pressure in lungs, sometimes referred to as 2 sides- hemidiaphragms

Question 29

circulatory systems- pulmonary artery

Answer 29

pulmonary artery receive all of the output from the right heart

Question 30

circulatory systems- pulmonary system

Answer 30

low pressure system- gives opportunity for gas to exchange

Question 31

circulatory systems- bronchial circulation

Answer 31

supplies airways- provides blood supply to airways and is not involved in exchange- this is at a higher pressure but not a high pressure

Question 32

properties of respiratory system- compliance

Answer 32

compliance- expanded ability if the lungs, measured as change in volume/ change in pressure
boils law says that- when you increase the pressure the volume decreases, when you increase the volume the pressure decreases

Question 33

causes of reduced compliance

Answer 33

atelectasis, fibrosis, pneumothorax, obesity, pulmonary vascular engorgement, pleural effusion

Question 34

properties of respiratory system- resistance

Answer 34

this presents where air flows through a vessel. it is composed of airway and tissue resistance. 80% if airway resistance is produced by medium sized bronchi, 20% of AWR is produced by small airways with diameter <2mm

Question 35

factors determining airway resistance

Answer 35

lung volume, state of contraction of bronchial smooth muscle, airway obstruction, tissue resistance- ability to move chest wall during inspiration and expiration, type of airflow

Question 36

properties of respiratory system- airflow patterns

Answer 36

airflow occurs when there is difference between pressures of air flowing through a region normally from high pressure to low.

Question 37

3 patterns of airflow

Answer 37

laminar flow pattern- mainly seen in very small airways
tuberlant flow pattern- seen in trachea and large airways, especially with higher velocity (exercise)
transitional flow pattern- (combination of laminar and tuberulent) is seen in most medium sized airways especially at branch point s

Question 38

properties of respiratory system- elastic resistance

Answer 38

is a measure of the work that has to be exerted by the muscles of inspiration to expand the lungs. elastic recoil- the ability of the lungs to rebound having been stretched during inhalation

Question 39

properties of respiratory system- work of breathing

Answer 39

is the physical work that has to carried out by the muscles of respiration to overcome the elastic resistance and the non-elastic resistance of the airways. WOB increases as respiratory load increases

Question 40

why does WOB increases as respiratory load increases

Answer 40

poor compliance, increases resistance- intrinsic (airflow) and extrinsic (tissue), decrease in respiratory capacity, more elastic resistance

Question 41

opening and closing pressures of alveoli

Answer 41

high pressures are needed for opening collapsed alveoli, at a critical opening pressure, maintained inspiratory effort will inflate most of the lung tissue, on deflation, alveoli tend to remain open and empty lower pressures, stays open due to surfactant and collateral channels

Question 42

what is residual volume

Answer 42

air that remains in lungs after expiration

Question 43

surfactant

Answer 43

has a head (hydrophilic) and tail (hydrophobic) to it, head is attracted to water molecules in ways of alveoli- push against wall- keeping alveoli open, leave an internal dry area for gas exchange