AOS 1 Flashcards
nervous system, stress, learning
Central Nervous System
The major division of the n.s comprising of the brain and spinal cord which receives neural messages to the peripheral n.s
Spinal Cord
SAME
S - sensory
A - afferent
M - motor
E - efferent
Peripheral Nervous System
Is the major division of the ns comprising every neuron in the body outside the CNS
Somatic ns
Division of the PNS that transmits neural messages to voluntary motor movement
Comprises of:
* Sensory neural pathways - sensory neurons
* Motor neural pathways - motor neurons
Pathway
1. Sensory neural messages travel from sensory receptors to cns via afferent neural pathways in the somatic ns
2. Motor messages travel from CNS to skeletal muscles that carry out voluntary motor movement via efferent neural pathways
Autonomic ns
Division of PNS that regulates visceral muscles, organs, and glands and transmits neural messages to the CNS about their activity
- unconscious response
Sympathetic ns
activates visceral muscles, organs, and glands preparing for the body to respond to a threat or stressor.
- energizes the body
fight flight freeze response
- increased heart rate
- dilated pupils
- inhibits digestion
- stimulates glucose
- contracts bladder
Parasympathetic ns
maintains the optimal and balanced functioning of visceral muscles, organs and glands
Returning the body to optimal or balanced functioning after heightened body arousal due to sympathetic response
- Contracts pupils
- Slows heat rate
- Stimulates digestion
- Stimulates gallbladder
- Relaxes bladder
enteric ns
The network of nerves in the gut and is a subdivision of the Autonomic ns
Conscious response
deliberate and voluntary actions that is initiated by the brain and is performed intentionally by the body
- CNS & somatic ns
process
1. Sensory stimuli is contacts w sensory receptors
2. The sensory neural messages are transmitted via afferent pathways in somatic ns and then to the spinal cord to the brain
3. The brain processes this sensory info - initiating a conscious motor response
4. This motor neural messages is transmitted via efferent pathways in the spinal cod and then through the somatic ns to skeletal muscles
These skeletal muscles carry out conscious motor response
Unconscious response
An automatic and involuntary action that is performed by the body independently of the brains
- Physiological response o the autonomic ns
- Spinal reflex
Physiological response of the autonomic ns
Relates to the role of the autonomic ns through the sympathetic and parasympathetic responses.
sympathetic
- high HR
- High breath rate etc.
Parasympathetic
- pupils constrict
- digestion occures normally etc.
Spinal reflex
An unconscious response to sensory stimuli that is initiated by the interneurons in the spinal cord independently of the brain
1. A dangerous of harmful stimuli is detected by sensory receptors that transmit the sensory message via sensory neurons in the somatic ns to the spinal cord
2. Interneurons in the spinal cord immediately relays this sensory neural signal from a sensory neuron to a motor neuron as a motor neuron signal, initiating an automatic and unconscious motor response
3. The motor message is transmitted via motor neurons in the somatic ns to skeletal muscles, which carry to this unconscious motor response to the harmful stimuli
The sensory message continue to travel via afferent tracts in the spinal cord to the brain. Then the brain independently registers the sensation that triggered the spinal reflex
Communication within Neurons
- Info is received by receptor sites on the
dendrites- This may trigger an action potential
- This electrical message travels along the axon
Reaching the axon terminal
Neurochemical Transmission across the synapse - lock key method
- Each type of nc has a chemically distinct shape (key)
- The NC will search for a receptor site that has a complementary shape (lock
- Once the NC finds the matching receptor it then binds to it
This then unlocks postsynaptic neuron, having either an inhibitory or excitatory effect
Neurotransmitters
Chemical molecule that has an effect on 1 or 2 postsynaptic neurons.
These inhibitory/excitatory neurotransmitters have diff. influences of the postsynaptic neurons firing of an action potential (electrical impulse that travels downs the axons of the neuron)
Excitatory effects - glutamate neurotransmitter
increases the likelihood of the postsynaptic neuron firing and action potential
Glutamate
- Important role in learning and memory
- Form and strengthen synaptic connections b/w neurons that are repeatedly coactivated during learning
Enables synaptic plasticity
Inhibitory Effect - GABA neurotransmitter
When the neurotransmitter decreases the likelihood of the postsynaptic neuron firing an action potential
* Suppress neural transmission
GABA
* Reduces anxiety
* Preventing seizures
* Regulates postsynaptic activation by preventing
the overexcitation of neurons
Neuromodulators
A chemical molecule that has an effect on multiple postsynaptic neurons
Released in multiple neural synapses therefore affect multiple postsynaptic neurons
Dopamine - Neuromodulator
Responsible for:
* Voluntary movement
* Pleasure
* Reward based learning
Motivation due to rewarding behaviour releasing dopamine therefore more likely to be repeated
Addiction - often provide intense dopamine release which motivates them to repeat behaviour
-Effect-
Has either an excitatory or inhibitory effect on the postsynaptic neuron
Depends on the type of receptor present
Serotonin - Neuromodulator
A neuromodulator primarily responsible for the regulation of mood and sleep
Effect
* Inhibitory effect on postsynaptic neuron
Role in functioning
* Mood regulation
Appropriate serotonin levels enable stable moods
- improving wellbeing
Low levels = mental health disorders like
depression
* Regulating sleep-wake cycle
Influences quality and quantity
* Appetite
* Digestion
* Arousal
Synaptic Plasticity
The ability of synaptic connections to change overtime in response to activity
* Sprouting - dendrites or axons develop new extensions
- Growth of dendritic spines
- Growth of filigree appendages
- Synaptogenesis (new synapses)
* Rerouting - create alternative synaptic connection with undamaged neuron
- Pruning - elimination of synaptic connections that are not adequately activated
Long-term Potentiation - LTP
Long-lasting and experience dependent strengthening of synaptic connections that are regularly coactivated
Structural changes include
* Increased no. of receptor sites on dendrites of
the postsynaptic neuron
* Bushier dendrites on the postsynaptic neuron -
sprouting
* Increased no. of synaptic connections b/w
neurons - sprouting
Learning and memory influences
* When neurotransmitters are repeatedly released into the synaptic gap and received by the receptor sites this causes long-term potentiation.
Long-term Depression
The long-lasting and experience dependent weakening of synaptic connections b/w neurons that are not regularly coactivated
Structural changes include
* Decreased number of receptor sites on the dendrites of the postsynaptic neuron
* Decreased no. of dendrites on the postsynaptic neuron due to pruning
* Decreased number of synaptic connections b/w neurons due to pruning
In terms of memory and learning
When memories or information learnt are not repeatedly coactivated then long-term depression will weaken the synaptic connections through the release of appropriate neurotransmitters
Communication b/w neurons
- The neural impulse reaches the axon terminals of the presynaptic neuron
- This causes the vesicles to release the neurotransmitter into the synaptic gap
- The neurotransmitters then binds to the complementary receptor site on the dendrites of the post synaptic neuron
- The neurotransmitter then makes
- The postsynaptic neuron more/less likely to fire
Stress
Psychological and physiological experience that occurs when and individual encounters something of significance that demands their attentions and/or efforts to cope
Acute Stress
Form of stress characterized by intense psychological symptoms that are brief in duration