Neuronal Communication Module 5.1.3 Flashcards
What is a description and function of dendrons and dendrites?
-Dendrons split into smaller dendrites
-They carry nerve impulses towards the cell body
What is a description and function of the axon?
-Elongated nerve fibres which can be short or long depending on the type of neuron
-Carry nerve impulses away from the cell body
What is a transducer?
-A cell that can convert one form of energy into another
What is the structure and function of a sensory neuron?
-They have short dendrites and one long dendron carries action potential from receptor cells to the cell body
-One short axon then carries the action potential to the CNS
-Specialized cells and transducers
-Each sensory receptor only responds to one type of stimulus
What is the structure and function of motor neurones?
-Short dendrites carry action potential from CNS to a cell body
-One long axon then carries cell body to effector cells
What are the structural differences between a motor and sensory neuron?
-Sensory neuron has short dendrites and long dendrons whereas motor neuron only has short dendrites
-Sensory neuron has a short axon whereas motor neuron has a long axon
What is the structure and function of Relay neurones?
-Short dendrites that carry action potential away from sensory neurones to cell body
-One axon carries action potential to motor neurones
What are the four main types of sensory receptors, their stimulus and an example of an organ they belong to?
- Mechanoreceptor- Pressure and movement- Skin
- Chemoreceptor- Chemical- Nose
3.Thermoreceptor- Heat- Tongue
4.Photoreceptor- Light- eye
What is the membrane of a sensory receptor-like when not being stimulated?
-There is a difference of charge between the inside and outside of the cell, the inside is negatively charged relative to the outside
What is a generator potential?
-When a stimulus is detected the receptor cell changes permeability ions move into and out of the cell via pumps and channels
-Ions carry a charge so there is a change in potential difference, this change due to a stimulus is a generator potential
What will happen if a stimulus is too small?
-A smaller stimulus will produce a smaller movement of ions across the membrane
-This causes a smaller change in potential difference across the membrane and the threshold level isn’t reached so there is no action potential
When is an action potential triggered and what is it?
- If the generator potential is big enough
-An action potential is a nerve impulse that travels along a neuron
What is the Pacinian Receptor?
-Sensory receptor, found in the skin
-Contains Mechanoreceptors that detect mechanical pressure and vibration
What happens when pressure is applied to the Pacinian Corpuscle?
-Stretch mediated sodium channels in the membrane of the neurone change shape and sodium ions diffuse across the membrane into the neurone.
-This creates a generator potential and if it reaches the threshold potential an action potential is triggered
