Unit 5 - Neuronal Communication Flashcards
Main functions of nervous system
Send, recieve and interpret info
Two parts of the nervous system
CNS
PNS
What is a neuron
Conductive, excitable cells of the nervous system that are specialized to transmit electrical nerve impulses
Nerves vs neurons
Neurons are the cells and nerves are the elongated congregation of tissues
Rods and cones
Receptors in eyes
Detect changes in light
Taste buds
Receptors on tongue
Detect change in chemical potential
Pacinian corpuscles
Receptors on skin
Detect changes in movement and pressure
Meissners corpuscles do the same
Ruffinis endings
Receptors on skin
Detect changes in heat
Proprioreceptors
Receptors on muscles
Detect mechanical displacement
Involved in placement of limbs/ body awareness
What do the hair cells in semi-circular canals do
Detect movement
Involved in balance
What do the hair cells in the cochlea do
Detect sound
Transducers
Detect a spp type of energy and convert it into another e.g electrical energy
Where is action potential summed
At axon hillock which is then propagated down the axon
Resting membrane potential
Potential diff across the membrane of a neuron
Na^+/K^+ pump
Pump binds 3 Na^+ and 1 ATP
Hydrolysis of ATP provides energy to undergo a conformational change
Na is released to outside of the membrane and the shape changes to allow 2 K^+ to bind
Release of the phosphate allows the channel to revert to its original form, releasing the K^+ on the inside of the membrane
How do sensory receptors change the resting potential of the axon membrane
By taking the energy its detecting and using it to change the membrane permeability to Na^+ ions to start an action potential
Need for refractory period
Prevents overlap of action potential
Prevents action potential from moving backward (unidirectional)
Receptor potentials
Localised changes in membrane potential
Graded and arent self-propagated
Mechanoreceptor
Pressure/ stretch opens a VG ion channel
Thermoreceptors
Temp affects enzymes controlling an ion channel
Chemoreceptors
Chemical binds to a receptor, initiating a signal cascade to control an ion channel
Photoreceptors
Light alters a membrane protein initiating a signal that controls an ion channel
Motor neurons
Transmit impulses from a sensory/relay neuron to an effector. Have a long axon and short dendrites
Found in CNS
Myelin sheaths
Made of many layers of a plasma membrane produced by Schwann cells. Acts as insulating layer and allows impulses to be conducted much faster