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Pathophysiology 1 > Lungs- Structure And Function > Flashcards

Lungs- Structure And Function Flashcards

1
Q

COMPONENTS OF RESPIRATORY SYSTEM

A 
LUNGS
CONDUCTING AIRWAYS 
CNS
CHEST WALL
MUSCLES OF INSPIRATION
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2
Q

GROSS STRUCTURE OF LUNGS

A

Left and right
Right lung larger as left lung makes room for heart
Right lung = upper, middle and lower lobes
Left lung= upper and lower lobes and lingula area. Lingula is projection of upper lobe of left lung.
Right lung broader and left lung longer

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3
Q

More gross structure of lungs

A

Left lung = lobes separated by oblique fissure
Right lung = upper and middle by horizontal fissure and middle and lower by oblique fissure

Each lung has bronchopulmonary segments- 10 right and 8 left

Pleura - visceral outer and parietal inner. Fluid 10-20ml to lubricate and smooth breathing.
Layers slide over each other as lungs expand and recoil during breathing.

Pleura has a negative pressure naturally and layers of pleura want to stick together as if they don’t, lungs collapse down

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4
Q

Grooves

A

Visceral and parietal layers stick together

Groove for large vessels in both lungs. Left lung has cardiac notch in lower lobe

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5
Q

ANATOMICAL MARKINGS FOR LUNGS

A

2.5cm above middle 1/3 clavicle
Anteriorly down to 6th costal cartilage , 7cm lateral to mid line
Laterally down to rib 8
Posterior from T2-T10

Lungs shorter at front and longer at back

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6
Q

Functions of lungs

A

GSRFPM

Gaseous exchange
Surfactant production - type 2 pneumocytes produce this and keeps alveoli open. Produce in development about week 32.
Reservoir for blood - rich blood supply
Filter - prevent getting infections as lungs trap particles and bacteria
Part of immune system - Large particles trapped in nose, nasopharynx and larynx and we cough them up.
Further in is mucociliary escalator to trap particles and carry debris to pharynx.
If particles get further, macrophages will fight off pathogens before they take hold
Maintains PH blood- maintains ph of blood for enzymes to work well. Lungs control breathing rate and thus, how much co2 exits or is retained inside you.
More Co2= more acidic

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7
Q

Upper respiratory tract, functions and symptoms

A

Made of : Nose , mouth, pharynx (throat) and larynx (voicebox)
Functions : moisten and warm air, filter particles, swallow and communication through talking

Infection: virus or bacteria, symptoms are cough, sneeze, sore throat and stuffy nose

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8
Q

LOWER RESPIRATORY TRACT COMPONENTS

A 
TRACHEA 
PRIMARY BRONCHUS 
SECONDARY BRONCHUS 
TERTIARY BRONCHUS 
BRONCHIOLES 
TERMINAL BRONCHIOLES 
RESPIRATORY BRONCHIOLES 
ALVEOLAR DUCTS 
ALVEOLAR SACS
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9
Q

TRACHEA

A 
Below C6 
11cm Long and 2.5cm diameter 
15-20 C cartilage rings 
Gap posterior for oesophagus so you do not swallow and hit cartilage 
Carina (T5) , bifurcation of trachea

Pathologies : choking, tracheal cancer and floppy trachea (no cartilage)

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10
Q

Primary bronchi

A

From carina into left and right
C shaped cartilage rings , so airways open
Right one is steeper and wider
So particles likely to enter right lung if it is inhaled
Primary bronchi enter the lungs via the hilum

Pathologies : choking / obstruction and cancer

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11
Q

Secondary bronchi

A

From primary bronchus
Serves lobes of lungs - right is three and left is two
Cartilaginous plates to keep airways open (not rings)

Pathology : lobar pneumonia

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12
Q

Tertiary bronchi

A

To bronchopulmonary segments
10 in right and 8/9 in left
Some cartilage plates and less as you go along
Introduction of smooth muscle
So a pathology can constrict airways, reducing air flow and increase resistance to airflow

Pathology : bronchitis (infection and inflammation)

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13
Q

Bronchioles

A

Come from tertiary bronchi
More smooth muscle than cartilage

Pathology : COPD and fibrosing alveolitis

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14
Q

Terminal bronchioles

A

From bronchioles
0.3mm - 0.5mm diameter
Smooth muscle and controlled by ANS - sympathetic is bronchodilation and parasympathetic is bronchoconstriction

Pathologies : asthma and fibrosis

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15
Q

Respiratory bronchioles

A

Each terminal bronchioles branches into many of these
Small, thin and delicate with no cilia
Pathogen will be removed but not able to expel (defence mechanisms rather than physical cough)
Deliver air to gas exchange surfaces of lungs

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16
Q

Alveolar ducts

A

Joins respiratory bronchioles to alveolar sacs

Affected by cystic fibrosis and pneumonia

17
Q

Alveolar sacs

A

Gas exchange site
300 million alveoli - 150 million per lung
Surfactant to keep them open - from type 2 pneumocytes , babies produce this at 32 weeks pregnancy.
If no surfactant, they collapse and gas exchange can’t occur

Pathology : cystic fibrosis or pneumonia

18
Q

What is bronchial tree divided into?

A

Conducting and respiratory zones

19
Q

CONDUCTING ZONE

A 
Trachea to the terminal bronchioles 
No gas exchange 
Gas transportation via convection 
Anatomical dead space - no gas exchange 
Alveolar dead space would be air in alveoli not used in gas exchange 
Up to generation 16
20
Q

Respiratory zone

A

From respiratory bronchioles to alveoli
Gas exchange in respiratory zone from alveolus to capillary
Gas transport via diffusion
300 million alveoli , large SA for gas exchange
17-23 generations

21
Q

ALVEOLI CELLS

A

Type 1 pneumocytes= gas exchange- allows gases to move over alveolar and capillary membranes

Type 2 pneumocytes - produce surfactant to keep alveoli open
Also can produce and divide themselves into type 1 pneumocytes if type 1 cells are damaged

Large capillary network for large SA

22
Q

Collateral ventilation - interconnections between respiratory bronchioles and the alveoli

A

PATHWAYS:

Interbronchiolar channels of Martin - between respiratory bronchioles

Bronchiole-alveolar channels of lambert - between respiratory bronchioles to alveoli

Interalveolar pores of Kohn = interconnections between 2 or more alveoli

Allows gas exchange from alveoli from different tracts. If something is blocked off close to the alveolus, we don’t lose the alveoli for gas exchange due to interconnections.

23
Q

DIAPHRAGM

A

Major muscle in respiration
Large dome shaped muscle
Contraction = moves down and flattens , ribs move up and out, air moves in down pressure gradient (positive pressure outside and negative alveolar pressure).

Relaxation= moves up and domes out, ribs move down and in , air moves out down pressure gradient (positive alveolar pressure and more negative external pressure)

Movements of diaphragm will alter pressure changes in lungs

Clinically, separated into hemi diaphragms

24
Q

PULMONARY AND BRONCHIAL CIRCULATORY SYSTEMS

A

Pulmonary system = involved in. Gas exchange. Takes in 02 and removes CO2. Low pressure system.

Blood flows slow through capillaries for gas exchange

Bronchial circulatory system = higher pressure than pulmonary system and supplies blood to airways themselves- not involved in gas exchange. A lot of blood evened out pressures though (so bronchial system never at too high a pressure).

25
Q

COMPLIANCE OF LUNGS

A

Ability of lungs to expand. Lungs are elastic.

Measured as change in volume / change in pressure

Boyle’s law = as pressure increase, volume decreases
As pressure decreases, volume increases

Problems with compliance may be:
Atelectasis- airways collapse down due to lung disease making lungs stiff
Fibrosis - lung tissue damaged and scarred and tissue thickened and stiff
Pneumothorax - collapsed lung / part of lung
Obesity - weight of chest impedes on lung expandability.
Pulmonary vascular engorgement
Pleural effusion- fluid built up between layers of pleura

26
Q

Resistance

A

Ease of air flowing through bronchial tree

Consists of = airway resistance and tissue resistance

80% airways resistance in medium size bronchi
20% airway resistance in small size less than 2mm airways

27
Q

Factors determine resistance

A

How much lung volume there
Any obstruction in airways like tumour or sputum
State of contraction of smooth muscles
Tissue resistance - ability to move chest wall in breathing. Fracture rib impedes chest wall movement.
Type of airflow

28
Q

What are the three types of airflow ??

A

1- Laminar airflow , small airways. Organised air flow where it flows in straight lines.

2- Turbulent airflow, at high velocities in large irregular airways. Disorganised airflow and can form swirling patterns eg, trachea and primary bronchi

3- Transitional airflow - combines laminar and turbulent. At medium sized airways at branch points

29
Q

ELASTIC RESISTANCE

A

Elastic resistance - measure of work exerted by resp muscles in inspiration to expand lungs

Elastic recoil= ability of lungs to return to normal shape after expansion in inhalation

Patients can lose elastic recoil of lungs so some air remains in lungs and they are hyper inflated.

30
Q

WOB - work of breathing

A

Physical work carried out by muscles in respiration, to overcome elastic resistance in lungs and non elastic resistance in airways.

WOB INCREASES WITH EXERCISE OR PATHOLOGY

Increased WOB is caused by:
Poor compliance of lungs
Increased resistance - intrinsic airflow and extrinsic tissue 
Decrease resp. Capacity 
More elastic resistance
31
Q

Pressures of alveoli

A

High pressure needed to open collapsed alveoli

Pathology deflates alveoli, to closing volume and they collapse

Prevent deflation : safety mechanisms like collateral ventilation and some is related to SA

CRITICAL OPENING PRESSURE- maintaining inspiratory effort will inflate most lung tissue

Alveoli tend to remain open and empty at low pressures

STAY Open due to surfactant and collateral channels

32
Q

SURFACTANT

A

Liquid with head and tails

Heads hydrophilic

Tails hydrophobic

Heads at alveolar wallls where water is and tails inside where gas exchange occurs

Pathophysiology 1 (22 decks)

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