week 8- respiratory Flashcards
In exhalation, describe pressure and volume
High pressure
Low volume
What do lower airways include
Trachea
Bronchi
Bronchioles
Alveoli
What helps filter large particles
Nasal hairs
Turbinates
Mucus
What is the main muscle of the respiratory system
Diaphragm
What muscles are required when greater effort is required
External intercostals
Abdominal muscles
What muscles are required when maximal effort is required
Scalenes (accessory muscles)
What is the serous membrane
A double membrane that surrounds the lungs and fluid around them
What are conducting airways lined with
Epithelial cells
CILIA are present until bronchioles
What do conducting airways do
Move air to areas that gas exchange
Function of goblet cells
Secrete mucus which collect foreign particles from the air.
What is mucus made up of
GEL layer
PERCILARY layers
What is the function of the end of the cilia
Move the gel layers towards the mouth
Once the cilia move gel layer toward the mouth what occur
What is this known as?
Cilia detach and move backwards through PERCILIARY LAYER before reattaching and starting the process again
MUCOCILLARY ESCALATOR
What is each alveolar duct surrounded by?
Connective tissue septa (interlobular)
Rich blood supply
What is alveoli surrounded by
Elastin (elastic tissue)
Name the 3 types of pressure
Blood pressure
Intrapulmonary pressure
Atmospheric pressure
Define pressure
Force applied to a unit area of surface
What is the function of the nasal turbinates (conchae)
Produce warm turbulent air
What is the function of the mucus gel layer
Capture pathogens and humidify incoming air
Identify the muscles used in inspiration
Diaphragm
External intercostals
Pectoral muscles
What is the function of type 2 alveolar cells
Secrete surfactant
What does ventilation not include
The exchange of gases between the lungs and blood
What does changing the volume of gas affect
The pressure
What will a low volume create
High pressure
All the air molecules are being squeezed and means there is more FORCE against the sides
What will a high volume create
Low pressure
All the air molecules are spread out and this means there is less FORCE against the surface
What occurs in inspiration
Ribs elevate and Sternum flares as external intercostals contract
Diaphragm moves inferiority during contraction
What occurs in expiration
Ribs and sternum depress as external intercostals relax
Diaphragms moves superiority as it relaxes
The rib cage has a ‘pump handle’ action. What does this mean?
A superior and outwards/anterior movement. volume increases
What Is compliance
The change in lung volume at a given pressure
What is force required to overcome?
Recoil forces
-elastic properties
-surface tension in 300million alveoli
Function of elastic fibres
-store energy for recoil
-help to open airways in inspiration
-support airways n expiration (prevent collapsing)
What is the extra cellular matrix made of
Loose mesh of collagen fibres
Elastic fibres- elastin
Ground stance (proteogylcans-decor in)
What’s surface tension lowered by
Surfactant
What is surfactant
Phospholipid that floats on the surface no reduces surface tension
What is surfactant secreted by
Alveolar type 2 cell
What is surface tension
Uneven H bonding of water molecules causing the inward pull at its surface
What would happen if lung tissue was replaced by scar tissue
Lung compliance would decrease
Work of breathing would increase
What is the resistance changed by when the radius of a tube is reduced by 1/2
16 times
Explain compliance in easy terms
How easy it is to comply,breathe ect
With a low lung compliance,how would this effect breathing
Increase frequency of breaths
Function of nasal turbinates
Generate turbulent air which spins large particles/ bacteria into the oropharynx walls, where they sticks to mucus. They also have a very good blood supply and act as a heat exchanger, warming incoming air and cooling out going air. This adds moisture to incoming air and removes it when leaving
Describe the location of parietal pleura
Outer layer of lung attached to rib cage, diaphragm etc
Describe the pleural cavity
Fluid filled cavity between parietal and visceral pleura
What is the function of the pleural membrane
Fluid filled cavity allowing friction free movement of the lungs with its surrounding tissue. As the parietal and visceral layers are attached to different structures the pull in opposite directions, it means the pressure within the cavity is low. Important for maintain inflation of the lung
Epithelial cells of upper airways contain cilia, what are cilia and what are their function in the respiratory tract.
Cilia are small extensions of epithelial membrane. They are made up of microtubules as well as motor proteins that promote movement. The move in Mexican wave and in doing so help to move mucus up the respiratory tract towards the mouth
What cell type produces mucus in respiratory tract
Goblet cells
Describe structural make up of mucus
Mucus gel layer made up of mucin (glycoprotein)
Pericellular layer made up of water
Describe how air is warmed and cleaned in upper airways
-turbinates turbulent air which spins large particles/ bacteria into naso and oropharynx walls where they stick to mucus
-mucus continues to pick up smaller particles and bacteria up until bronchioles.
-mucus continuously moves along mucocillary escalator meaning it is hard for the bacteria to colonise
Describe elastin fibres and their role within lung tissue
Fibres within ct
Stores elastic energy during lung tissue expansion
Used to recoil forces during experiation (passive at rest)
Describe the blood supply to alveoli structures
From pulmonary arteries
Blood moves into bronchial arteries
Into capillary beds which wrap around alveoli
Describe how respiratory membrane in alveoli has changed from upper airways. Explain why this is necessary
Loss of cartilage, goblet cells, smooth muscle (and ct where alveolus walls meet capillary walls)
expansion reduces the diffusion distance for gas exchange
What is the role of type 2 alveolar cell
Release surfactant
Surfactant is phospholipid that reduces surface tension
Without it the recoil forces of the water lined alveoli (300 million) would be too great to inflate
What is pressure inversely proportional to
Volume
Describe the process of inhalation
Diaphragm contracts and moves inferiority increasing thoracic volume and decreasing pressure
Air moves down its pressure gradient from high to low
External intercostals move the rib cage upwards and outwards although this tends to be used more during strenuous activity in patients with respiratory conditions
Describe the process of exhalation
Diaphragm and intercostal muscles relax and recoil the diaphragms superiorly and the fall of the rib cage under gravity, increases pressure in the thorax and air moves from its high pressure in the lungs to a low pressure In the atmosphere
Internal intercostal muscles may also be contracted which pulls the rib cage downwards and inwards although this tends to be used during stresnuous activity or in patients with respiratory conditions
Define ventilation
Movement of air into and out of the lungs.
It does not describe movement of gas into and out of the body
Consider a patient with increased fibrosis collagen deposits in the ct of their lung. How will this effect lung compliance?
collagen will mean compliance is reduced and they will have a reduced volume change for a given pressure change
this means that to maintain even a normal tidal volume will require much more energy
describe airway resistance
air passing through airways generate frictional forces
these forces need to be overcome to allow movement of air into and out of the lungs
how would a smaller tube effect airway effect resistance
1/2 radius is 16x resistance
increasing respiratory effort ad lowering dynamic compliance
define turbulent air flow
chaotic, air molecules hit the sides of airways
define laminar air flow
linear, only air molecules at the sides making contact with airways walls
how does turbulent air change resistance
increase frictional forces
increase airway resistance
x2 energy required
