PAPER 2- TOPIC 2 BIOPSYCHOLOGY ✅ Flashcards
define the nervous system
- specialised network of cells in body, that is our primary internal communication system
- based on electrical and chemical signals
role of nervous system
- collect, process and respond to information in the environment
- communicates with and co-ordinates the different organs and cells
two sections of the nervous system
central nervous system
peripheral nervous system
Describe what makes up the Central Nervous System
•brain
- centre of conscious awareness (makes all decisions)
- controls every process (e.g. thoughts, emotion hunger)
- cerebral cortex wraps around whole brain
•spinal cord - passes messages to and from brain - connects nerves from brain to the peripheral nervous system - responsible for reflex arc (effectively an extension of the brain)
role of central nervous system
controls all complex demands and decisions
define the peripheral nervous system
- connects CNS to organs, limbs and sensory receptors
- transmit messages from the outside world to the CNS
- transmit messages from the CNS to the effector cells
describe the two sections of the peripheral nervous systems
•somatic nervous system -transfers info from receptors to CNS ----> and CNS to effectors ......????? -controls voluntary muscle movement
•autonomic nervous system
- important in homeostasis (vital involuntary processes)
- transmits info from CNS to organs (and from organs to CNS) automatically
- –> allows automatic responses and vital functions to occur
- splits into parasympathetic and sympathetic
describe the two sections of the autonomic nervous system
and examples of what occurs
•sympathetic
- prepares the body for a fight or flight response during stressful events
e. g. ——increases heart and breathing rate
•parasympathetic
- restores body to normal resting state after stressful event
- works as an antagonist to the sympathetic nervous system (opposite)
e. g. ——-slows heart rate, resumes digestion
way to remember sympathetic and parasympathetic
S sympathetic = S cared
P arasympathetic = P revent
define a neuron
an specialised nerve cell that carries neural information around the body through electrical and chemical impulses
describe the route that each neurone takes
sensory- info from stimuli in receptor cells in PNS to the CNS
relay- connect sensory and motor neurons, or between other relay neurons, form part of reflex arc (mostly in brain and spinal cord)
motor- from the CNS to effector cells (muscles and glands)
outline the role of the different structures in a neuron
nucleus- control centre for activity and contains genetic material
cell body- contains information being carried, contains nucleus
axon- carry impulse away from cell body across the neuron
dendrite- carries message from other neurones towards cell body
axon terminal (terminal buttons)- where axons communicate with other neurons across a synapse - releases neurotransmitters into synaptic cleft
myelin sheath- insulates and protects axon, to speed up transmission
nodes of ranvier- small gaps in the myelin sheath that speed up transmission (as impulse must “jump”)
describe the structure of a sensory, relay and motor neuron
sensory: long dendrites . cell body . short axons
relay : short dendrites . cell body (majority of neuron) . short axons . (no myelin sheath)
motor: short dendrites . cell body . long axons
define neurotransmitters
2 features
chemicals which diffuse across synapses to relay impulses to the next neuron
—-> electrical impulses trigger their release from synaptic vesicles
- every NT has its own specific structure and so fits into specific receptor sites like a lock and key
- either have an excitatory effect or inhibitory effect on neighbouring neurons
define a synapse
extremely small gap between neurons that allow them to communicate through chemical impulses
define synaptic transmission
how neurons communicate with other neurons (& rest of body) by sending chemical impulses across a synapse
describe the process of synaptic transmission of neurons
- electrical impulse is converted to a chemical impulse (neurotransmitters)
- neurotransmitters are released from synaptic vesicles in the pre- synaptic terminal , diffuse into the synaptic cleft
- they are absorbed by the specific post synaptic receptor sites in the dendrites of the next neurone
- and converted back to electrical impulse
describe the stages of electrical transmission of neurons
- when a neuron is at a resting state, the cell body is negatively charged
- when the neuron is activated by a stimulus, the cell body becomes positively charged for a split second
- causes action potential
- which causes an electrical impulse to travels down axon towards end of neuron (neuron is fired)
describe the idea of summation
• decides whether post-synaptic neurone fires or not
- post synaptic neurons can receive both excitatory and inhibitory neurotransmitters simultaneously
- these influences are summed and the net effect is what charge the post synaptic neuron will have
• if reaches positive threshold, the action potential is triggered, the cell body is momentarily positively charged, causing an electrical impulse to travel down the neuron’s dendrites
describe the excitatory effect a neurotransmitter can have on a neuron
example
- increases the neuron’s positive charge and makes it more likely to fire
- e.g adrenaline makes the neuron and more positively charged and more likely to fire
describe the inhibitory effect a neurotransmitter can have on a neuron
example
- increases the neuron’s negative charge and makes it less likely to fire
- e.g serotonin makes the more neuron negatively charged and less likely to fire
