Pack 26 - Receptors Flashcards
What is the receptors flow diagram?
Stimulus–>Generator Potential in Stimulus–>Action Potential in Stimulus–>Action Potential in Sensory Neurone
What does the Photoreceptor respond too?
Light
What does the Mechanoreceptor respond to?
Mechanical pressure (touch)
What does the Thermoreceptor respond to?
Temperature
What does the Chemoreceptor respond to?
Chemicals
What does the Baroreceptor respond to?
Blood pressure changes
What is a Pacinian Corpsucle?
Modified Neurones that have layers of lamellae surrounding the unmyelinated end of the sensory neurone containing stretch mediated Na+ channels
How do stretch mediated Na+ channels work?
Pressure deforms the membrane which then changes the shape of the stretch mediated Na+ channels
This allows Na+ to diffuse across the membrane
If a threshold is reached then an action potential will occur
Gel will then flow back into the membrane and the membrane will spring back to normal shape (pressure has been released)
The sudden removal of pressure causes more Na+ to diffuse across the membrane and therefore could release more action potentials could occur
What type of organ is the eye?
Sense organ
What type of receptors are found in the eye and what part of the eye are they found?
Photoreceptors are organised in the retina
What pigment do Rod Cells contain?
Rhodopsin
Why is Rhodopsin useful?
Very sensitive to light which allows for vision in the dark
What happens to Rod Cells in bright light?
When in bright light breakdown of rhodopsin occurs faster then rhodopsin can reform
This means rod cells can’t function and become photobleached
What pigment do Cone Cells contain?
Iodopsin
Why is Iodopsin important?
Sensitive to high light intensities of different optimal wavelengths
Can see colours
What are the different wavelengths for blue, green and red?
Blue –> 445nm
Green –> 535nm
Red –> 575nm
Easy way to remember is that they are in alphabetical order from smallest to largest
How does the brain interpret colour?
Based on the proportion of cone cells stimulated
What is the overall function of Rod Cells?
Provide vision in dim light
What is the is the overall function of Cone Cells?
Vision in bright light
Colour Vision
Greater Detail
What controls the rate of heart beat?
The Automatic Nervous System
How does the Automatic Nervous System control Heart rate?
Sympathetic Nerve - increases heart rate (more impulses means faster heart rate)
Parasympathetic Nerve - decreases heart rate (more impulses means slower heart rate)
What are the two receptors involved in control of heart rate?
Chemoreceptors
Baroreceptors
Summarise Sympathetic control
Fall in blood pressure detected by Baroreceptors
Impulses carried in sensory neurones to cardiac centre in medulla
More frequent impulses along sympathetic nerve to SAN
Noradrenaline released from sympathetic nerve to SAN
Summarise Parasympathetic control
Rise in blood pressure in aorta detected by baroreceptors
Impulses carried in sensory neurones to cardiac centre in medulla
More frequent impulses along parasympathetic nerve to SAN
Acetylcholine released from parasympathetic nerve to SAN
