Receptor And Stimuli Flashcards
What is a receptor
- cell adapted to detect change in the environment
- specific to a single type of stimuli
- produce a generator potential by acting as a transducer
How can receptors be classified
According to the type of stimulation they respond to
Chemoreceptors
Stimulated by chemicals eg smell and taste
Mechanoreceptors
Sensitive to touch or pressure
Photoreceptors
Simulated by light
Thermoreceptors
Stimulated by temperature
Why are receptors also transducers
They change from one form or energy to another
For example receptors change stimulus energy into electrical energy
What type of receptor pacinian corpuscle
Mechanoreceptor
Where is pacinian corpuscle fund and what is their function
Deep in skin, fingers, soles of feet = respond to pressure
Joints, ligaments, tendons = enable organism to know which joints are changing directions
How does a receptor cell work
- generator region must develop a generator potential in the neurone ending
- this is caused by depolarisation of the membrane surrounding the neurone ending
Why are neurone membranes said to be polarised at rest
- Inside of the cell is much more negative relative to the outside of the cell
- Due to sodium potassium pump actively transports 3 sodium ions out f the cell in exchange for 2 potassium ions
- membrane selectively permeable for different ions
How are the membranes selectrivly parable for ion s
Channel proteins specific to particular ions
What sodium ion channels are found in the membrane of the sensory neurone in pc
Stretch mediated sodium channels
What are stretch mediate sodium channels
Permeable to sodium ion change when they are deformed eg stretch
Describe depolarisation
A temporary reversal of charges over the membrane of neurone/receptor