Test Bank Solution Manual for biological measurements, fibre optics, and ultrasound Rated 100%
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Course
Fibre Optic
Institution
Fibre Optic
Test Bank Solution Manual for biological measurements, fibre optics, and ultrasound Rated 100%
What are nerve cells - Answers long fibres that can be up to a metre long but only a few micrometers in diameter
what do nerve cells do - Answers conduct electrical signals around the body
how do the...
Test Bank Solution Manual for biological measurements, fibre optics, and ultrasound Rated 100%
What are nerve cells - Answers long fibres that can be up to a metre long but only a few micrometers in
diameter
what do nerve cells do - Answers conduct electrical signals around the body
how do these nerve signals travel - Answers in the form of a changing pd which is generated by the
movement of ions across cell membranes
the imbalance of ions causes the change in pd
4 main stages of electrical signals - Answers resting cell polarised
depolarisation, initation of electrical signal
repolarisation
restoration of orginal ion concentration
resting cell and polarised
what is conc of K+ inside cell - Answers high
resting cell and polarised
conc of Na+ outside of the cell - Answers low
what does the conc gradient mean in context - Answers K+ wants to leave the cell by diffusion from a
high concentration to a low concentration
What happens when K+ leaves cell - Answers it continues to leave the cell until there is excess positive
charge outside the cell which is enough to stop them from leaving
voltage of inside cell compared to the outside - Answers -70mV
what happens at -70mV - Answers the concentration gradient and potential gradient are in equilibrium
at resting potential, cell is polarised
what happens when the electrical signal is initiated - Answers initiation of nerve impulse
the voltage gated channel increases permeability to Na+ for 1ms so Na+ moves into cell and cell
becomes positively charged
pd across cell increases to +35mV and Na+ channels close
cell is depolarised
, what happens when cell is repolarised - Answers at 35mV the K+ channels reopen
K+ leaves the cell
causes restoring potential of -70mV to be restored 'repolarisation'
in terms of original ion concentrations, what happens at repolarisation - Answers original ion
concentrations restored via sodium potassium pump
resting potential of -70mV restored
action potentials of nerve cell - Answers - pattern of changing potential
- at one nerve changing potential activates a new action potential in an adjacent site
propagation speed of action potential - Answers 100 m/s
what happens to propagation speed at muscles like the heart - Answers they travel much slower (4m/s)
which causes the muscles to contract
speed of action potentials in heart - Answers much slower and last a lot longer
do action potentials in the heart need external impulses - Answers no
what ion travelling across cell membrane - Answers Ca2+
depolarisation in heart - Answers lasts longer
0.25s in heart
5ms in skeletal muscle
what does the longer potential cycle allow the heart to do - Answers relax completely before the next
contraction
why is the left ventricle thicker - Answers needs a greater force to pump blood around the body
What does the sinoatrial node do? - Answers generates electrical signal that causes the atria to contract
that goes to the bundle of his, the perkinje fibres and then through the ventricle
what are ECGs used for - Answers monitoring the electrical activity of the heart
how do ECGs work - Answers electrical signals transfer from heart to surroundings and fluids that are
detected by silver electrodes that are coated with silver chloride that are taped to skin
how can we improve conduction of ECG - Answers removing dead skin cells and applying a conducting
gel
why are silver electrodes used - Answers they dont react to chemicals on the skin
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