Neuronal Communication

Question 1

What are the different types of sensory receptor?

Answer 1

Photoreceptor- Change in light intensity, light to electrical energy

• Thermoreceptor- Temperature receptors, heat to electrical
• Baroreceptor- Pacinian corpuscles that detect pressure changes in the skin, movement to electrical energy
• Sound- Vibration receptors in the chochlea of the ear, movement to electrical
• Movement, hair cells in inner ear, movement to electrical
• Proprioceptor, detects changes in stretch of muscles, movement to electrical
• Chemoreceptors, detect changes in concentrations of chemicals, chemical to electrical

Question 2

How does a pacinian corpuscle work?

Answer 2

• The corpuscle is an oval shaped structure that consists of a series of concentric rings of connective tissue wrapped around the end of a sensory neuron

Question 3

How is a potential difference created across the membrane?

Answer 3

• The membranes of neurones contain sodium-potassium pumps
• These pump out 3Na+ ions for every 2K+ ions pumped in
• The membrane is more permeable to K+ than Na+ meaning that some K+ leaks out of the cell
• The potential difference in the across the membrane is -60mV as there are more positive ions on the outside of the cell than on the inside, this is known as resting potential