Review posters 11/05/2016 Flashcards
Pulmonary ventilation
Volume of air breathed in and out per minute
= TV x RR
Anatomical dead space
Not all the air inhaled reaches the alveoli for gas exchange. This air is unusable and is therefore known as anatomical dead space.
Alveolar ventilation
Volume of air exchanged between the alveoli and the atmosphere per minute
= (TV-anatomical dead space) x RR
Describe the ventilation and perfusion of the lung
Lung is less ventilated and perfused at the top.
Better ventilated and perfused at the bottom.
Alveolar dead space.
When an alveolus is well ventilated but not well perfused.
How would you go about increasing pulmonary ventilation?
Increasing TV or RR. Increasing depth of breathing (TV) is the most advantageous due to anatomical dead space.
What four factors influence the rate of gas exchange in the alveoli?
The thickness of the alveoli
The surface area of the alveoli
The diffusion co-efficient of oxygen and carbon dioxide
Partial pressure gradient
What is the diffusion co-efficient ?
The ability of a gas to dissolve in the membrane. Carbon dioxide has a much higher one that oxygen (20x)
Daltons law
The total pressure exerted by a gas is the sum of the partial pressures of each individual gas.
What is partial pressure of a gas?
The pressure that one gas in a mixture of gases would exert if it were the only gas present occupying the same volume
The equation to work out the partial pressure of oxygen in the alveoli is:
PaO2= PiO2- [PaCO2/0.8]
PaO2= the alveoli partial pressure of oxygen PiO2= the partial pressure of inspired oxygen PaCO2= the partial pressure of CO2 in the arteries 0.8= the respiratory exchange ratio
Ficks law
The amount of gas that moves across a sheet is proportional to the area but inversely proportional to its thickness.
What is the purpose of the membrane?
To form a boundary
Selectively permeable
Maintains difference in ion concentration
Controls entry of nutrients and exit of waste
Name the sorts of proteins you would find in the lipid bilayer?
Integral proteins (span the bilayer). These could be ion channels or carrier proteins Peripheral proteins (sit on the outside of the membrane) Glycoproteins- sugar attached to proteins on the outside of the membrane
Docking mannose receptors
Allow exocytosis
Describe the lipid bilayer
Fluid membrane made up of phospholipid molecules.
Each phospholipid molecule has a hydrophillic head and hydrophobic tail.
Cholesterol is present in the membrane and offers stability and fluidity.
What types of junctions can you get between cells?
Desmosomes
Gap junctions
Tight junctions
Describe the types of junctions you can get between cells
Desmosomes- adhering junctions. Anchor cells together in tissues prone to stretch e.g. skin, cardiac
Tight junctions- lateral borders of epithelial cells joined together.
Gap junctions- communicating junctions that allow movement of charged ions
Purpose of membrane carbohydrates
Self identity markers- different cells have different markers.
What are the factors important for a particle to be able to diffuse across a membrane
Lipid solubility Size of the particle Magnitude of the concentration gradient Surface area Diffusion distance
Diffusion
Movement of particles from a high concentration to a low concentration (passive process)
Osmosis
Net diffusion of water from a high concentration to a low concentration (passive process)
Name the two active processes that can transport particles across a membrane
Active transport
Facilitated diffusion
Facilitated diffusion
Movement of particles via a carrier/channel protein down their concentration gradient.
