Biopsychology - Neurons Flashcards
Function of neurons
Transmit signals electrically/chemically to provide the nervous system with its primary means of communication
Types of neurons
Sensory neuron
Relay (interconnecting) neuron
Motor neuron
Sensory neuron
Carries messages from the (PNS) sensory receptors to the CNS (brain and spinal cord)
Long dendrites and short axons
Relay (interconnecting) neuron
carry signals from the central nervous system to the motor neuron
Short dendrites and short or long axons
Motor neuron
Carries messages from the CNS to effectors such as muscles and glands
Short dendrites and long axons
Electric transmission - the firing of a neuron (activating a potential)
A neuron that is in a resting state inside the cell is negatively charged compared to the outside
When the neuron is activated by a stimulus, the inside of the cell becomes positively charged for a split second causing an action potential to occurs
The action potential creates an electrical impulse that travels down the axon towards the end of the neuron
What is synaptic transmission?
Synaptic transmission is the process in which a nerve impulse (action potential) passes across the synapse from the presynaptic neuron to the post-synaptic neuron.
process of synaptic transmission?
1) An electrical impulse (action potentials) reach the presynaptic terminal and triggers the release of neurotransmitters e.g serotonin
2) These neurotransmitters diffuse across the synaptic cleft from a high to low concentration to the postsynaptic terminal
3) At the postsynaptic terminal the neurotransmitters combine with receptors on the postsynaptic membrane
4) This stimulation of postsynaptic receptors by neurotransmitters result in either excitation or inhibition of the postsynaptic membrane.
excitation
depolarisation - make it more likely the next neuron will fire
inhibition
hyperpolarization - make it less likely the next neuron will fire
The knee-jerk reflex
1) A stimulus (hammer) is detected by sensory receptors in the Perpheral nervous system (PNS)
2) The PNS then conveys a message along a sensory neuron to the central nervous system (CNS)
3) The CNS connects to a relay neuron that transfers the message to a motor neuron
4) The motor neuron carries the message to an effector (such as muscle causing it to contract and hence moving the knee)
PNS-Sensory-CNS-Relay-Motor-Effector
Process of a reflex
PNS-Sensory-CNS-Relay-Motor-Effector
Role of axons
carry electrical impulse down the length on a neuron - covered in a fatty latyer called a myelin sheath
