Unit 3 - Let’s Achieve Flashcards
What does the CNS consist of?
The central nervous system (CNS) consists of the brain and the spinal cord.
What does the peripheral nervous system consist of?
The peripheral nervous system consists of the somatic nervous system (SNS) and autonomic nervous system (ANS)
What does the Somatic nervous system contain
The somatic nervous system contains sensory and motor neurons.
Sensory neurons take impulses from sense organs to the CNS. Motor neurons take impulses from the CNS to muscles and glands.
What does the autonomic nervous system consist of?
The autonomic nervous system (ANS) consists of the sympathetic and parasympathetic nervous systems.
Difference in sympathetic and parasympathetic nervous systems
Sympathetic and parasympathetic nervous systems work antagonistically (opposite).
Sympathetic nervous system
Increases:
- heart rate
- breathing rate
Decreases
- peristalsis
- gland secretions
Parasympathetic nervous system
Increases
- peristalsis
- gland secretions
Decreases
- heart rate
- breathing rate
Converging neuronal pathways
In a converging pathway, impulses from several neurons travel to one neuron which increases the sensitivity to excitatory or inhibitory signals.
Example: Convergence of neurons from rods in the eye.
Diverging neuronal pathways
In a diverging pathway, impulses from one neuron split to travel along several neurons which affects more than one destination at the same time.
Example: Fine motor control of the fingers.
Reverberating neuronal pathways
In a reverberating pathway, neurons later in the pathway link with earlier neurons which sends the impulse back through the pathway. This allows repeated stimulation of the pathway.
Example: The medullas control of breathing rate.
Cerebral cortex
The cerebral cortex is the centre of conscious thought. It recalls memories and alters behaviour in light of experience.
Cerebral cortex - localised areas
The cerebral cortex contains localisations of areas:
- Sensory areas
- Motor areas
- Association areas – (involves language processing, personality, imagination and intelligence).
Hemispheres of the brain
Information from one side of the body is processed in the opposite side of the cerebrum.
The left central hemisphere deals with information from the right visual field and controls the right side of the body and vice versa.
The transfer of information between the cerebral hemispheres occurs through the corpus callosum.
What does memory involve
Memory involves encoding, storage and retrieval of information.
Information pathways
All information entering the brain passes through sensory memory and enters short term (STM). Information is then either transferred to long-term memory (LTM) or is discarded.
Sensory memory
Sensory memory retains all the visual and auditory input received for a few seconds. Only images and sounds are encoded into short term memory.
Short term memory
Short term memory only has limited capacity (5-9 items) and holds information for a short time. This is known as memory span.
Adding extra items will mean that items are lost or displaced.
Chunking
Chunking has the ability to increase the capacity of the short-term memory by grouping information.
Memory span and the serial position effect
When trying to remember items in sequence or order, the serial position effect can be very important. It will show primacy and recency with items ‘middle items’ being lost.
Working memory model
Our working memory is an extension of our STM.
It is able to process and manipulate the data in our STM.
Long term memory capacity
Long-term memory has unlimited capacity and holds information for a long time.
How is information transferred from short term memory to long term memory
Transfer of information from short-term to long-term memory is by:
rehearsal, organisation and elaboration.
Rehearsal
Rehearsal – is regarded as a shallow form of encoding information
(rehearsing the same information over and over)
Elaboration
Elaboration – is regarded as a deeper form of encoding which leads to improved information retention.
(Makes the information more meaningful and easier to transfer to LTM)
Organisation
Organisation involves organising information into groups
eg colours/shapes/events
What aids retrieval
Retrieval is aided by the use of contextual cues relate to the time and place when the information was initially encoded into LTM.
Neurons
Neurons are specialised cells within the nervous system that transmit information to other nerve cells, muscle, or gland cells.
Most neurons have a cell body, an axon, and dendrites.
Myelin sheath function
The function of the Myelin sheath is to insulate the axon and increase the speed of impulse conduction.
What do Glial cells produce
Glial cells produce the myelin sheath and support neurons.
What does Myelin allow
Myelin enables nerve cells to transmit information faster and allows for more complex brain processes.
Why is the Myelination process important
The myelination process is vitally important for the healthy functioning of the central nervous system
How long does myelination last
Myelination continues from birth to adolescence.
Responses to stimuli in the first two years of life are not as rapid or co-ordinated as those of an older child or adult.
What does loss of myelin sheath cause
Loss of the Myelin sheath is caused by certain diseases and causes loss of coordination
Example: Multiple Sclerosis
What do neurons connect with and where
Neurons connect with other neurons or muscle fibres at a synaptic cleft.
What do neurotransmitters do involving the synaptic cleft
Neurotransmitters relay impulses across the synaptic cleft.
Where are neurotransmitters stored
Neurotransmitters are stored in vesicles in the axon endings of the pre-synaptic neuron.
Neurotransmitters (movement)
They are released into the cleft on arrival of an impulse. They diffuse across the cleft and bind to receptors on the membrane of the postsynaptic neuron.
How do electrical impulses change going across synaptic cleft
The electrical impulse changes to a chemical impulse as it is carried across the synaptic cleft.
What do receptors do involving signals
Receptors will determine whether a signal is excitatory or inhibitory.
Why might neurotransmitters need to be removed and how?
There may be a need for the quick removal of neurotransmitters by enzymes or the reuptake of neurotransmitters to prevent continuous stimulation of postsynaptic neurons.
What can synapses do
Synapses can filter out weak stimuli arising from insufficient secretion of neurotransmitters.
What must attach to receptors and what does this do
A minimum number of neurotransmitter molecules must attach to receptors in order to reach the threshold on the postsynaptic membrane to transmit the impulse.
This mechanism prevents the generation of impulses from weak/harmless stimuli.