Receptors Flashcards
Explain how the fovea increases detail of an image
High visual acuity
Each cone is connected to a single bipolar neurone
Each cone sends a separate impulse to the brain
Explain how the connection of several rods to a single bipolar cell influences visual acuity
Summation means cannot distinguish between stimuli from different rod cells linked to same bipolar cell
Decreases acuity
Explain how the connection of several rods to a single bipolar cell influences sensitivity
Summation of Sub threshold stimuli produces threshold stimulation
Increases sensitivity
People with red green colour blindness are unable to distinguish between red and green and also between other colours.
Explain why
Cones are nonfunctional
Three different types of cones
Other colours can be seen due to stimulation of more than one cone
Explain how pressure on the pacinian corpuscle produces the changes in the membrane potential
Pressure deforms membrane which opens sodium channel
Sodium ions enter
Causing depolarisation
Increased pressure opens more channels
Size of generator potential determines frequency of action potentials
Exercise can cause an increase in heart rate.
Describe the role of receptors and of the nervous system in this process
Baroreceptors detect a rise in blood pressure
Send impulses to cardiac centre/ medulla
More impulses sent to sinoatrial node
By parasympathetic nervous system
The rate of atp consumption of a demyleinated neurone is greater than that of a myelinated neurone when conducting impulses at the same frequency
Explain why
Greater entry of sodium ions
In demyelinated neurone
By active transport
Explain how nervous control in a human can cause an increase in cardiac output during exercise
Coordination via medulla/ cardiac centre
Increased impulses along sympathetic nerve
To sing atrial node
Release of noradrenaline
More impulses sent from SAN across Arita
Increased heart rate
Explain why increased cardiac output is an advantage during exercise
Higher cardiac output increasing o2 supply to muscles
Increase glucose supply to muscles
More ATP produced by oxidative phosphorylation
Increased co2 removal
Increases heat removal
Delays formation of lactate
Describe how the pacinian corpuscle propagates an action potential
Pressure causes membrane to deform
Sodium ion channels in membrane open and sodium ion move in
Depolarisation leading to generator potential
Greater pressure more channels open
Describe what is meant by the term threshold
When threshold is reached
It triggers the all of nothing principal
Pacinian corpuscles
6m
Pressure on skin deforms the stretch mediated sodium Chennai proteins withing the membrane
Causes stretch mediated sodium channel proteins to open
Sodium ions diffuse in down a concentration gradient
More positive ions on the inside of the membrane causing depolarisation
