Unit 3 AOS 1- Nervous system Functioning Flashcards
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The Three types of Neurons
- Motor neurons (efferent neurons) which transmit neural messages about motor movement from the CNS to the PNS
- Sensory neurons (Also known as afferent neurons) which transmit neural messages about bodily sensations from the PNS to the CNS
- Interneurons, which transfer neural messages between sensory neurons and motor neurons. The central nervous system, including the brain and spinal cord, is made up of interneurons.
Unconscious response
Automatic and involuntary actions that are performed by the body independently of the brain. Occur without conscious awareness in response to internal and external stimuli.
Conscious response
Conscious responses are delibrate and voluntary actions that are intentionally initiated by the brain and performed by the body.
Involve the CNS because the brain is a component
Also involves the Somatic Nervous system
Role of the central nervous system (CNS)
Is a cable of nerve tissue that extends from the brain, and connects it to the peripheral nervous system.
There are ascending tracts
and descending tracks
Ascending tracts
(Towards the brain, they go up)
Transmit sensory messages from the peripheral nervous system to the brain
Descending tracts
Transmit motor messages from the brain to the peripheral nervous system (PNS)
The peripheral nervous system
A major division of the nervous system comprising every neuron in the body outside the central nervous system. The peripheral NS includes the somatic and the autonomic nervous system.
Somatic nervous system
Transmits neural messages related to voluntary motor movement (skeletal muscles).
What is an example of the somatic nervous system???(7 steps)
1) Sensory receptors
2) Sensory neurons -> Afferent pathway
3) Towards spinal cord, afferent neurons move, through ascending tracts towards brain
4) Brain reviews, interprets and initiates motor response
5) Motor muscles travels down descending spinal cord to PNS
6) Motor neurons carry message -> efferent path
7) Skeletal muscle moves
Autonomic nervous system
Regulates visceral muscles, organs, and glands, and transmits neural messages to the central nervous system about their activity.
Branches of the ANS
- Sympathetic
- Parasympathetic
*The sympathetic nervous system becomes dominant when a person is confronted with a threat, or stressor whereas the parasympathetic nervous system is dominant during rest and physical inactivity.
Sympathetic response example (Heart)
Heart rate increases to increase blood flow, enabling high levels of physical activity
Sympathetic response example (BREATHE)
Breathing rate increases and long airways expand to increase oxygenation, enabling high levels of physical activity
Sympathetic response example (EYES)
Pupils dilate to allow more light to enter the eyes improving vision.
Parasympathetic response (heart)
The hearts beat at a steady and regular rate that supports optimal and balanced functioning.
Parasympathetic response (Breathe)
Lung airways constict, enhabling a steady and regular breathing rate.
Parasympathetic response (eyes)
Pupils constrict according to external light levels, allowing an appropriate amount of light to enter her eyes for adequate vision.
Spinal reflex
An unconsious response to sensory stimuli that is initiated by interneurons in the spinal cord independently of the brain.
Purpose: To protect the body from harm/injury and increase chances of survival
Spinal cord involves three types of specialized neurons
- Sensory or afferent
- Interneuorn or relay neuron
- Motor or efferent
Describing the neural pathway
1
The presynaptic nueron is the neuron that releases neurochemical into the neural synapse. Axon terminals are the ends of the neuron that release neurochemicals into the nueral synapse
Describing the neural pathway
2
The synaptic gap is the space between presynaptic neuron and the postsynaptic neuron. In this way, despite being very close, neurons do not touch each other.
Describing the neural pathway (3)
The postysynaptic neuron is the neuron that recives neurochemicals from the neural synapce. Dendrites are branched extensions of a neuron on which receptor sites are located.
Process of synpatic transmission
1) Neurochemical are produced in the axon terminals of the presynaptic neuron
2) Neurochemical are released from the axon terminals of the postsynaptic neuron into the synaptic gap
3) Neurochemicals bind to receptor sites on the dendrites of postsynaptic neurons
4) Neurochemicals affect the postsynaptic neuron either triggering or inhibiting a response
Neuromodulators
Chemical molecules that have an effect on multiple postsynaptic neurons. Widespread modulatory effects
Neurotransmitters
Chemical molecules that have an effect on one or two postsynaptic neurons. Enhables rapid communication between two neurons across the neural synapses.
Seretonin
- Neuromodulator
- Inhibitory effects on the postsynaptic neuron
- Mood regulation and stabilisation
- Sleep-wake cycle
Dopamine
- Neuromodulator
- Both excitatory and inhibitory effects on the postsynaptic neuron
- Reward based learning
- Motivation
GABA
- Inhibitory neurotransmitter
- Decreases the likelihood of the postsynaptic neuron firing an action potential
- Important role in reducing anxiety
Glutamate
- Excitatiry neurotransmitter
- Increases likelihood of postsynaptic neuron firing an action potential
- Learning and memory
Synpatic plasticity
The ability of synaptic connections to change over time in responce to activity or experinece.
Long Term Depression (LTD)
Long-lasting and experience-dependent weakening of synaptic connections between neurons that are not regularly coactivated. The weakening of a neural synapse involves the infrequent release of neurotransmitters into the synaptic gap by axon terminals
Long Term Potentiation (LTP)
The long-lasting experience-dependent strengthening of synaptic connections that are regularly activated to high intensity stimulation.
Sprouting
The ability of dendrites or axons to develop new extensions on branches. This increases the reach of the neuron and enables the formation of new synaptic connections.
Pruning
The elimination of synaptic connections that are not adequately activated. When neural synapses are not used they are removed or ‘pruned’. This is necessary to accommodate stronger and more essential synaptic connections.
Rerouting
The ability of a neuron that is connected to a damaged neuron to create an alternative synaptic connection with an undamaged neuron. The neuron abandons its synaptic connection with the damaged neuron and forms a new synaptic connection with an undamaged neuron.
Stressor
The term used to describe the stimulus (internal and external) that prompts the stress response.
Stress
A psychological and physiological experience that occurs when an individual encounters something of significance that demands.
Internal stressors
originate from within the individual
psychological and biological processes
Example: low self-esteem
External stressors
- Originate from outside of the individual, external stimuli
Example: exams
Eustress
excited for something, feeling prepared
Distress
unprepared, worried, not excited
Acute stress
fight, flight or freeze
Chronic stress
Sustained release of cortisol
flight
An organism flees from the stressor
generally because escaping the situation is the safest option.
- Acitvation of sympathetic nervous system
fight
organism confronts stressor. symapathetic nervous ssystem
freeze
- breif activation of the parasympatehtic nervous system
Chronic stress response
Chronic stress is a form of stress that endures for several months or longer. Cortisol is the stress hormone and does not demand an immediate response.
- Alarm- shock stage of GAS model
- Paraysmpathetic response/activation
- Momentary decrease in bodily arousal
- Heart rate goes down
- muscle tone decreaseed
- breathing rate decreased
- body reacts as if injured
- Alarm- countershock stage of GAS model
Sympathetic response/activation
- Increase in bodily arousal
- Breathing rate increases
- Muscle tone increases
- Heart rate increases
- Ability to deal with the stressor increases above normal
- Resistance stage of GAS model
-
Bodily resources are used at an increased rate to maintain the state of heightened arousal
- Can do normal tasks usually
- Exhaustion stage of GAS model
- By the time a person, has entered exhaustion, exposure to the stressor has been prolonged and pressistant
- The body has been required to maintain the heightned physicological state for as long as the stressor has been present, which is now an extended period of time.
