Tricky topics Flashcards
chronic stage of respiratory damage caused by smoking
- proliferation of Type II pneumocytes - goblet cells and basal cells proliferate - club cells die - fibroblasts lay down scar tissue
club cells
role in detoxifaction via P450
cell renewal rate of trachea
1-2 month
cell renewal rate of alveoli
9 days
cell renewal rate club cells
NEVER
basal cells
stem cells of the lung
acute bronchitis
3 weeks
chronic bronchitis
is a daily productive cough that lasts for 3 months of the year and for at least 2 years in a row
COPD includes
emphesma and chronic bronchitis
gland definition
is an epithelial cell or aggregate of epithelial cells that are specialised for secretion of a substance
glycosylation
the covalent attachment of sugars by enzymes to proteins and lipids to form glycoproteins and glycolipids
how is the resting potential set up
chemical diffusion and electrical gradient
chemical diffusion
potassium moves out of the cell down conc gradient
electrical gradient
causes K+ to flow back in due to the negativity created by K+ initially leaving down conc gradient (also intracellular anions)
when is there no ent movement of potassium
when chemical diffusion and electrical gradient are equal and opposite
Nerst equation
membrane potential
the electrical charge that exists across a membrane
acute hyperkalemia
cells become less excitable- brining resting potnetial closer to the threshold–> intially more excitable
NaV and feedback mechanisms
when threshold is reached the sodium channels will all open. Initial opening of NaV will give positive feedback to other NaV causing them to open
then they will be inactivated- unable to open
potassium channels will then open
types of refractory period
absolute refractory period
relative refractory period
NaV channel structure
only one alpha unit made up of 4 repititve subunits
subunit I- pore
subunit II- voltage sensor
a Kv channel comprises
4 individual alpha subunits
classes of perpheral axon
Aalpha
Abeta
A gaba
Adelta
B
C
what increases conduction velocity
1) high resistance
2) low capacitance
3) larger diamater- less cytoplasmic resistance
capacitance
ability to store charge
devics disease
myelination of optic and spinal cord neveres
examples of anaesthetics
procain and lidocaine –> work by blocking sodium channels prveenting AP
when can procaine and lidocaine pass the membrane
in the unprotonated form
local anaesthetics block conduction in nerve fibres in the following order
- small myelianted axons
- non-myelinated axon
- large myelinated axon
CaV structure
similar to NaV
- slower
what can be used to diagnose myasthenia gravis
1) autoimmune antibody test
2) endrophonium test
outline endrophonium test
- pt does facila exercies
- pt given endrophonium chloride
- short acting acetylcholinesterase inhibitor–> increases conc of ACh at synapse
- face should relax
how do organophsophates cause poisoning
form a stable irreversible covalent bodn to ACh esterase
- recovery takes weeks waiting for ne ACh synthsis
