CNS and neurotransmitters Flashcards
What is the central nervous system made of ?
Brain and spinal cord
What is the nervous system responsible for ?
Monitors and coordinates internal organ function and responds to change in external environment
What is the spinal cord and what is it responsible for ?
Tube like extension of the brain, responds to reflex actions
What is the brain responsible for ?
Source of our conscious awareness divided into two near symmetrical hemispheres
What does the left and right hemisphere of the brain control ?
Left = right side of body
Right = left side of body
What are the 3 steps between nerves and neurons ?
- Nerves send info via spinal cord to the brain = carries nerve that control all movements
- Brain processes info & sends messages through body through spinal cord = to react and send our appropriate instructions
- Neurons in brain pass messages along through electrical impulses
What are neurons and what are they responsible for ?
Nerve cells in the brain that receive and transmit messages in the brain in response to info received from the rest of our body
What is a synapse ?
Where signals are passed to next neuron in the chain at special sites, a gap between neurons
What is the role of the cell body ?
Hold genetic material
What is the role of the mitochondria ?
Provide energy
What is the role of a dendrite ?
Receive messages from other neurons in order to trigger action potential
What is the role of an axon ?
Extension of the cell body that passes electrical impulse towards axon terminals
What is the role of an axon hillock ?
Where the nerve impulse is triggered from
What is the role of the myelin sheath ?
Fatty deposit that insulates the axon to speed up the rate of message transmission
What is the node of ranvier ?
Breaks between cells along the myelin sheath
What is the role of the axon terminal ?
Pass nerve impulses from cell body to parts of the body they control or activate & contain vesicles that store neurotransmitters ready for the next stage of neural transmission
What is the action potential ?
Nerve impulses pass down the axon to stimulate the release of neurotransmitters to create an electrical impulse that is triggered by a change in the electrical potential of the neuron
What is the resting membrane potential of a neuron ?
-70mV
What is depolarisation ?
Negative to positive charge switch rapidly
What is the 7 steps of synaptic transmission ?
- Electrical impluse generated at axon hillock
- Turn into chemical message at axon terminal
- Reach action potential at axon terminal & flood terminal button
- Vesicles with NS released a& travel down outer membrane of terminal button
- Casing of vesicle fuse with membrane
- Neuron pass message over synaptic gap
- Bind to receptor sites
What is the 2 step process of reuptake ?
- Any NS not absorbed by receptors are destroyed by enzymes/reabsorbed in pre synaptic neuron
- Reabsorbed destroyed by enzymes in neuron to ‘turn it off’ to prepare for future action potential
What is the pre synaptic neuron ?
Neuron sending the message
What is the post synaptic neuron ?
Neuron receiving the message
What is the synaptic gap ?
Space between two adjacent neurons
What is an excitatory neurotransmitter with example ?
Increases action potential (positive charge) = dopamine
What are inhibitory neurotransmitter with example ?
Prevents action potential (negative charge) = serotonin
What is supporting research ?
Jovanovic (2008) = looked at serotonin system in women (low serotonin link to depression more in women than men) with pre menstrual dysphoric disorder. Used scanning before & after ovulation. = PMDD did have differences in synaptic receptors, synaptic transmission relates to mood
What is opposing research ?
Allen & Stevens (1994) = synaptic transmission with hippocampus neurons is unreliable, less than half NS in pre synaptic neuron picked up by post synaptic neuron = neurotransmission not always steady, many factors in synaptic transmission
How good is research in neurotransmitters for reliability ?
Many use animal research, human brain scanning more used = scientific credibility & realibiliity
How good is research in neurotransmitters for generalisability ?
Animal research difficult to generalise, emotional functioning & consciousness different & low ecological validity if lab conditions
What are any compliments of neurotransmitters ?
Animal research allows control over EVs = high internal validity
What is the sensory neuron ?
Carry messages from sensory receptors along nerves in PNS to CNS = long dendrites, short axons
What is the motor neuron ?
Carry messages from CNS along nerve to PNS to effectors in body = short dendrites, large axons
What is relay neuron ?
Connect sensory & motor neurons together, connect to other relay neurons = short dendrites, short axons
