Cardio respiratory mechanics Flashcards
(50 cards)
Draw the graph for how the volume of air in the lungs change during inspiration and expiration

draw the graph for Palv and flow rate during inspiration and expiration
why do they look so similar
They look similar because air flows down pressure gradient. The greater the presure the greater the flow rate

draw the graph to show how the pressure in the pleura changes during inspiration and expiration.
Try to explain the significance

draw a flow volume loop and explain what each point and loop signify

what is the protocol in order to perform a pulmonary function test
- patient wears noseclip
- Patient wraps lips round mouthpiece
- Patient completes atleast one tidal breath
- Patient inhales steadily to total lung capacity
- Patient exhales as hard and fast as possible
- exhalation continues until Residual voulme is reached
- patient immediately inhales to total lung capacity
- visually inspect performacne and volume time curve and repeat if neccessary
after performing the pulmonary function test, what should you look out for?
- Inconsistencies with clinical picture
- Interrupted flow data
draw the flow volume curve for mild obstructive lung diseases
- displaced to the left
- indented exhalation curve

draw the flow volume loop for severe obstructive disease
- Shorter curve
- displaced to the left
- indented exhalation curve

draw the flow-volume loop for restrictive lung disease
- displaced to the right
- narrower curve

draw the flow volume loop for variable EXTRATHORACIC obstruction
- Blunted inspiratory curve
- Otherwise normal

draw the flow volume loop for INTRATHORACIC obstruction
- Blunted expiratory curve
- otherwise normal

draw the flow volume loop for FIXED AIRWAY obstruction
- Blunted inspiratory and expiratory curve
- otherwise normal

How is resistance to flow related to diameter
Inversely proportional to 4th power of radius
Why doesn’t the resistance continue to increase as airways get smaller
They branch out more and the increased surface area reduce the overall resistance of the system

How does resistance and conductance of airway change with increasing lung volume.
give reasons why
- Resistance decreases (1/x equation)
- conductance increases at a constant rate- airway dilates as lung volume increases

What is Poiseuille’s Law

What is the purpose of te extensive smooth muscles in arteries and arterioles
They help to regulate diameter and resistance to blood flow
What is the purpose of the highly compliant venules and veins?
Act as reservoir for blood volume; can easily expand and stretch to have mor blood.
Draw the graph for how total surface of vessels, Mean pressure and proportion of systemic blood volume varies across, arteries, veins and capillaries

Why does pressure fall across circulation? And what vessels present more resistance to flow?
Pressure falls due to viscous (frictional) pressure losses and the small arteries and arterioles present most resistance to flow
What is the relation between Mean arterial pressure and cardiac output ?
P= Qx TPR (Total peripheral resistance)
Q- cardiac output

What are the assumptions taken in order to derive the equation that relates mean arterial pressure and cardiac output?
- There’s steady flow
- the vessels are rigid
- right atrial pressure is negligible
Physiologically, how is regulation of flow of blood achieved
This is achieved by variation in resistance of the vessels, whilst blood pressure remain as relatively constant
What does resistance of a tube to flow depends on?
Poiseuille’s law
- fluid viscosity
- length of tube
- inner radius of tube
hence small changes in vascular tone can produce large changes to flow










