Gas Exchange III - Mechanism of Ventilation 2

Descripción

Fichas sobre Gas Exchange III - Mechanism of Ventilation 2, creado por J yadonknow el 22/12/2017.
J yadonknow
Fichas por J yadonknow, actualizado hace más de 1 año
J yadonknow
Creado por J yadonknow hace casi 7 años
0
0

Resumen del Recurso

Pregunta Respuesta
How do air molecules move? (2) Bulk flow and diffusion
What happens when you move down the bronchiole tree? The trans cross-sectional area of the lungs increases
What airway generation do the alveoli occur? Gen. 17
How does the total trans-sectional area differ in the different zones of the respiratory tract? Total trans-sectional area in conducting zone is small so resistance is high Total trans-sectional area in respiratory zone is high so resistance is negligible
How does the movement of gas molecules occur in the conducting zone? Bulk flow due to high R
How does the movement of gas molecules occur in the respiratory zone? R negligible CO2 and O2 diffuse independently
Describe laminar flow (3) Slow flow rate parallel stream lines molecules near edges of tube travel slower than those in the middle due to friction
What is Poiseuille's Law? V=Pπr4/8ƞl p=pressure gradient r=radius of airway l=length of airway ƞ=viscosity of subtance
Re-arrange Poiseuille's law to show the effect of reducing the radius of the airway R=8ƞl/πr4 R∝1/r4 So if radius is halved, resistance increases by x16
Describe turbulent flow (3) High flow rate disorganised stream lines net movement is still forward, occurs with asthma/exercise
Describe transitional flow (3) Intermediate flow rate eddy currents at the branches, flow here is static. Diagram
Where does majority of airway resistance occur? conducting airways
What effect does ^ lung volume have on Raw? Raw decreases
What effect does radial traction have? Decreases resistance
How does radial traction occur? Lungs expand Connective tissue pulls on bronchiole.
Why does this decrease Raw? Diameter of bronchioles increase
Conditions leading to Dynamic Compression low lung volume OR intrathoracic pressure>alveolar pressure
When does Dynamic Compression occur? In forced expiration, large transient pressure gradients created to force air out of lungs.
Type of airflow through constricted airways Turbulent
If intrathoracic p > atmospheric p then: resistance increases enormously, airway may collapse under high pressure
What type of change in bronchial smooth muscle tone produces which effect on RAW? Bronchioconstriction - increases RAW Bronchiodilation - decreases RAW
What are the causes of bronchioconstriction? (4) 1. Vagal stimulation 2. Fall in PCO2 3. Irritants inducing reflex constriction 4. Asthma
What stimulates bronchiodilation? (2) 1. Circulating catecholamines - autonomic 2. Sympathetic agents (B2 agonists)
What is the effect of inflammation on RAW? Raw increases
How does inflammation cause this change in RAW? External walls stay the same diameter whilst internal get smaller.
Draw a diagram showing how increased airway resistance increases the work of breathing Expiration line passing through positive axis on the graph
Why does expiration have to be active? As accessory muscles must contract to force air out
What is elastic recoil determined by? Elastic properties of the lung tissues Surface tension of the alveoli
What sort of fibres are found in alveolar walls and around vessels and bronchi? Elastin and collagen fibres
What is the function of these fibres? Form network to allow distension under P Recovers geometry when P is released
How does the fluid lining alveoli facilitate gas exchange? Decreases surface tension of water so O2 can dissolve in fluid, increases rate of diffusion.
What is "pulmonary surfactant" A phospholipoprotein secreted from Type II alveolar cells
What are the mechanical functions of surface? (2) Compresses alveoli to its spherical shape Surface tension causes alveoli to recoil when pressure is released
What problems can arise because of this high attraction force? Transudation - drawing of ISF into alveoli
What are the roles of the pulmonary surfactant? Lowers surface tension in the liquid layer of alveoli Prevents alveolar collapse at low pressure, which is essential for maintaining the FRC
Where is pulmonary surfactant found? In all air-breathing animals and in the swim bladder of some fish.
Under what conditions is compliance reduced? (2) When elasticity is impaired When surface tension is increased (reducing production of surfactant.)
Mostrar resumen completo Ocultar resumen completo

Similar

Tabla Periódica de los Elementos
maya velasquez
3) Fish and Seafood
John Goalkeeper
Factorización
maya velasquez
TÉCNICAS DE CREATIVIDAD
mirnaedl
AMÉRICA: PAÍSES~CAPITALES...
Ulises Yo
MAPA CONSEPTUAL
velezm428
Admisión del Personal
1991mayra
irregular verbs
Rosalia Ruiz Jurado
MODELOS PEDAGÓGICOS
wfas197
LEY 1/2000 ENJUICIAMIENTO CIVIL: "De los procesos matrimoniales y de menores" (II)
Miguel Angel del Rio