unit 3 aos 1 - key knowledge Flashcards
Role of central nervous system
Receives sensory information from peripheral nervous system
Sends motor information to peripheral nervous system
Role of brain
Command centre of central nervous system responsible for receiving panel processing information and generating responses to it
Role of spinal cord
Connects peripheral nervous system to brain
Controls reflex arc (spinal reflex)
Communicates neural information in two ways:
- carries sensory messages along ascending tracts from peripheral nervous system to brain for processing
- motor messages are sent along descending tracts from brain to muscles via peripheral nervous system
Roles of peripheral nervous system
Sends sensory messages to central nervous system
Receives and carries out instructions sent from CNS
Made up of both somatic nervous system and autonomic nervous system
Role of somatic nervous system
Controls muscles attached to skeleton, involved in voluntary movement
Two major functions:
- transmits sensory information from receptors in sensory organs to central nervous system => sensory (afferent) neurons transmit neural messages about bodily sensations from PNS to CNS
- control voluntary skeletal muscle movement via messages sent from CNS => motor (efferent) neurona transmit neural messages about motor movement from CNS to PNS
- Interneurons => transfer neural messages between sensory neurons and motor neurons
Role of autonomic nervous system
Relays messages between CNS and involuntary muscles
Operates without conscious awareness
Consists of sympathetic & parasympathetic nervous system
responsible for bodies internal environment
Role of sympathetic nervous system
Activates tight-flight-freeze response
Releases Adrenalin and monadrenalin to cause some body functions to speed up
Dominates under threat
Assists in physiological changes assisting in survival
roles of the Parasympathetic nervous system
Dominates normal day to day when we are relatively calm
Returning body to calm state after threatening/stressful situations
Autonomic functioning - sympathetic nervous system responses
Pupils dilate
Bronchioles relax
Heart rate increases
Digestion is inhibited
Bladder relaxes
Gull bladder stimulates glucose levels
Autonomic functioning - parasympathetic nervous system
Constricts pupils
Constricts bronchioles
Decreases heart rate
Enables digestion
Gall bladder stimulates bile production
Bladder contracts
Steps of conscious response
- Sensory stimulus (cold water) comes into contact with sensory receptors (on persons hand) detect internal sensations in body and external sensations from environment (cold sensation)
- Sensory neural (cold sensation) is transmitted via afferent pathways in somatic nervous system, and then spinal cord, to brain
- Brain processes (receives and processes cold sensation) sensory information, coordinating and initiating a conscious motor response (turn on ‘hot’ tap to increase water temperature)
- Motor neural message is transmitted via efferent pathways in spinal cord, and then somatic nervous system, to skeletal muscles
- Skeletal muscles carry out conscious motor response to sensory stimuli (skeletal muscles move person’s hand towards ‘hot’ tap to increase water temperature)
Unconscious response - physiological responses of autonomic nervous system
Breathing, digestion, blinking, spinal reflexes
Steps of spinal reflex
- Dangerous or harmful sensory stimulus (extremely hot pan) is detected by sensory receptors, which transmit sensory message via sensory neurons in somatic nervous system to spinal cord
- Interneuron in spinal cord immediately relays sensory neural signal from sensory neuron to motor neuron as a motor neuron signal, initiating automatic and unconscious motor response (quickly withdraw hand from hot pan)
- Motor message is transmitted via motor neurons in somatic nervous system to skeletal muscles, which carry out unconscious motor response to dangerous or harmful sensory stimulus
- Sensory message continues to travel via afferent tracts in spinal cord to brain. Brain independently registers sensation that triggered spinal reflex
Process of synaptic transmission.
- Neurochemicals produced in ancon terminals of presynaptic neuron
- Neurochemicals are released from axon terminals of presynaptic neuron into the synaptic gap
- Neurochemicals bind to receptor sites un dendrites of postsynaptic neuron
- Neurochemicals affect postsynaptic neuron, either triggering or inhibiting a response
Glutamate - type, effect, role in functioning
Type - excitatory neurotransmitter
Effect - increases likelihood of postsynaptic neuron firing an action potential
Role in functioning - important role in learning and memory. Strengthens synaptic connections between neurons that are repeatedly activated during learning.
GABA - type, effect, role in functioning
Type - inhibitory neurotransmitter
Effect - decreases likelihood of postsynaptic neuron firing an action potential
Role in functioning - regulates postsynaptic activation in neural pathways, preventing overexcitation of neurons. Reduces anxiety by inhibiting excitatory neural signals contributing to anxiety. Also inhibits uncontrolled firing an action potentials, GABA has important role in preventing seizures
How can neuromodulators modulate effects of neurotransmitters?
Change responsiveness of receptor sites of particular neurotransmitter, enhancing excitatory or inhibitory effects of neurotransmitters
Changing neurotransmitter release pattern of presynaptic neuron
What are the two neuromodulators?
Dopamine and serotonin
Dopamine - pathways, effects, role in functioning
Pathways -
Effects - can have excitatory effect and inhibitory effects on postsynaptic neuron, effect depends on type of receptor sites present at particular brain location.
Role in functioning - coordinating voluntary motor movement. Dopamine has important role in reward-based learning. When person is rewarded for doing behaviour, dopamine produced in ventral segmental area is released, associated with experience of pleasure. Dopamine can motivate person to engage in rewarding behaviours to experience pleasure once again
Serotonin - pathways, effects, role in functioning
Pathways -
Effect - has inhibitory effect on postsynaptic neuron
Role in functioning - important role in mood regulation and stabilisation. Appropriate levels of serotonin in brain enable person to experience positive and stable moods, promoting wellbeing. Regulates sleep-wake cycle, influencing quality and quantity of sleep
sprouting, rerouting, and pruning - what do they do?
Sprouting - increases reach of neuron and enables formation of new synaptic connections
Rerouting - neuron abandons its synaptic connection with damaged neuron and forms new synaptic connections with undamaged neuron. Synaptic connection is reestablished via an alternative route, restoring brain function.
Pruning - when neural synapses aren’t used they are removed or ‘pruned’. This is necessary to accomodate stronger and more essential synaptic connections, consequently enhancing the efficiency of brain functioning.
structural changes to long-term potentiation
- Increased number of receptor sites on dendrites of postsynaptic neuron
- Bushier dendrites on postsynaptic neuron due to sprouting
- Increased number of synaptic connections between neurons due to sprouting
structural changes of long-term depression
- Decreased number of receptor sites on dendrites of postsynaptic neuron
- Decreased number of dendrites on postsynaptic neuron due to pruning
- Decreased number of synaptic connections between neurons due to pruning
what can internal stressors include?
- Negative attitude
- Rumination - repeatedly thinking about negative components of event
- Low self-esteem
- Nervous system dysfunction
what can external stressors include?
- Test or exam
- Meeting new people
- Arguments with friends and/or family members
- Working long hours
- Financial difficulties
psychological stress response - what happens in each stage of flight-fight-freeze
Flight:
Organism flees from stressor
Fight:
Organism confronts stressor
Freeze:
Body’s immobility and shock in response to stressor
role of cortisol in chronic stress
- Increases blood sugar levels
- Improves metabolism
- Energises body
- Reduces inflammation
GAS - what happens in alarm reaction?
Occurs when individual first encounters and becomes aware of stressor
Divided into: shock and counter shock
GAS - what happens in shock?
Body experiences temporary state of shock
Bodily arousal levels, and therefore ability to deal with stressor, are reduced to below normal
Lasts for only brief period of time before person enters second substage of GAS
GAS - what happens in counter shock
Activation of sympathetic nervous system causes physiological reactions to occur
When person enters counter shock, their levels of bodily arousal, and therefore their ability to deal with stressor, increase above normal
This marks the beginning of the increase in levels of resistance to stress that continues into the second stage of GAS
GAS - what happens in resistance
Increased cortisol levels contribute to maintenance of heightened physiological state
Adaptive stage because body adjusts to physiological changes occurring during counter shock, including increased hormone levels and increased bodily arousal
Majority of energy is directed towards confronting stressor
Prolonged presence of stress hormones in bloodstream begins to suppress immune system functioning, which increases susceptibility to illness
Bodily resources are used at increased rate to maintain state of heightened arousal
GAS - what happens in exhaustion
Body becomes unable to maintain heightened physiological arousal because bodily resources, such as energy and stress hormones, have been depleted
Person can no longer cope with demands of stressor und is also unequipped to confront any other stressors that may arise
