Neurobiology and communication Flashcards
What does the nervous system do?
- Detects information from both the body and from the external environment
- analyses the sensory information
- stores some of it
- makes decisions about appropriate responses and behaviours
- makes rapid motor responses by sending electrical impulses to muscles and glands
What do sensory nerves carry?
Sensory neurons carry nerve impulses
What do motor neurons carry?
Motor neurons carry nerve impulses
How can the nervous system be divided?
The nervous system can be divided by structure or function
What are the main parts of the nervous system?
The main parts of the nervous system are the central nervous system, spinal cord, peripheral nervous system and the spinal nerves.
What makes up the Central nervous system?
The brain and the spinal cord makes up the central nervous system
What makes up the peripheral nervous system?
The cranial nerves and the spinal nerves make up the peripheral nervous system
Describe the brain?
The brain receives signals from all parts of the body and sends out orders to all parts, protected by the cranium?
Describe the spinal cord?
The central mass of nerves running from the brain down the inside spinal column. protected by the vertebrae
Describe the cranial nerves?
The cranial nerves carry messages directly to and from the brain without going through the spinal cord.
Describe the spinal nerves?
The spinal nerves connect to the spinal cord. messages travel to and from the brain via the spinal cord.
What is the somatic nervous system?
The somatic nervous system controls the body’s skeletal muscles.
This involves sensory and motor pathways
The somatic nervous system brings about certain involuntary reflex actions but mostly it controls voluntary actions.
What is the autonomic nervous system?
The autonomic nervous system regulates internal structures and organs such as the heart, blood vessels, bronchial tubes, etc
How does the autonomic nervous system work?
The autonomic nervous system works automatically without conscious control. The nerves of the autonomic nervous system arise from the medulla oblongata and emerge at various points down the spinal cord to reach the organs they stimulate.
What are the two systems that regulate the autonomic nervous system?
The sympathetic nervous system and the parasympathetic nervous system
The sympathetic nervous system and the parasympathetic nervous system work in what?
Opposition
The sympathetic system does what and how?
The sympathetic system prepares the body for action by speeding up heart rate, increase blood pressure, decreases blood flow to digestive organs, increases blood to the muscles, increases the activity of the sweat glands.
The parasympathetic system does what?
The parasympathetic system calms the body down and returns it to normal. it helps to conserve resources store energy and prevent excessive strain on organs.
How does the parasympathetic system conserve resources?
- slows down heart rate
- decreases blood pressure
- increases blood flow to digestive organs
- decreases blood flow to the muscles
The vast amount of extra energy required by the skeletal muscles is supplied by what?
The vast amount of extra energy required by the skeletal muscles is supplied by adrenaline increasing blood flow?
What three interconnected layers is the brain organised into ?
- The central core
- the limbic system
- the central cortex
The human brain is a large organ made of what?
billions of organs
What does the central core of the brain contain?
- the medulla oblongata which regulates breathing, heart rate, arousal and sleep
- The cerebellum which controls balance, posture and movement
What does the limbic system contain?
the hypothalamus which influences hormonal secretions of the pituitary and regulates homeostatic mechanisms such as temperature control and water balance.
What does the limbic system do?
The limbic system processes information for memories and influences emotional and motivational states
What is the cerebral cortex?
The cerebral cortex is the outermost part of the cerebrum. it is the largest part of the human brain that is split by a deep cleft into two halves called cerebral hemispheres
Describe the hemispheres of the cerebral cortex?
The left hemisphere controls the right side of the body and vice versa
this is linked by fibres called corpus callosum
this link allows information to be transmitted from one side of the brain to the other, coordinating brain function.
What are the three types of functional areas the cerebrum has?
Sensory area
Association area
Motor area
Describe the sensory area of the cerebrum?
The sensory area receives information as sensory impulses from the body receptors
Describe the association area of the cerebrum?
The association area analyses and intercepts these impulses and takes decisions if necessary. some association areas deal with thought processes.
Describe the motor area of the cerebrum?
The motor area receives information from the association areas and send motor impulses to the appropriate effectors
Each area of the cerebrum is mirrored on both sides except what?
The speech motor area.
What percentage of the population have only ne speech motor area in the left cerebral cortex.
90%
each cerebral hemisphere only receives information about what?
Half of the visual field
A person whose corpus callosum has been cut is said to be a what?
A split- brain patient
What is perception?
Perception is the process where the brain analyses and makes sense of incoming sensory information
What does perception allow us to do?
Perception allows us to segregate objects from one another and their background, recognise what they are and to judge their distance from us.
What are the three areas of perception?
The three areas of perception are: segregation of objects, perception of distance, recognition
What is the segregation of objects?
This is the organisation of objects into figure and ground
What is the perception of distance?
Perception of distance is when we judge distance between ourselves and others by using one or both eyes and visual cues such as relative size or height.
What is recognition part of perception?
Recognition is that shape is more important than detail in the recognition of objects.
What is memory?
Memory is used to store, retain and retrieve information
What do memories include?
Memories include past experiences, knowledge and thoughts
What are the three stages to memory?
Sensory memory
Short term memory
long term memory
Describe sensory memory?
All visual or auditory input passes to the sensory memory where they are retained for a few seconds.
Describe short term memory?
To become part of memory the selected sensory images must first be encoded and converted into a form the brain can process and store
What does chunking do?
Chunking maximises the amount of information that can be held in each item in STM
What are the three process used to transfer and encode information from the STM to LTM?
Rehearsal
organisation
Elaboration
What is rehearsal?
Rehearsal is repeating the information over and over again
What is organisation?
Organisation is grouping items together in an organised fashion
Describe long term memory?
Long term memory holds an unlimited amount of information. Information is encoded by either repetition or linking it with previous memories.
Describe encoding?
Encoding is when sensory images are converted into a form that the brain can process and store.
Describe storage?
Storage is retaining the information over a period of time
Describe Retrieval?
Retrieval is the recovery of the stored material from either the short term or long term memory
What are contextual cues?
The brain uses contextual cues to aid retrieval of memories. Contextual cues relate to the conditions present when the information was encoded and how it was encoded.
Where is memory located?
The temporal lobes at the side of the cerebrum
The hippocampus
The limbic system
The cerebellum
What is Episodic memory?
Episodic memory is the memory of events and experiences
What is semantic memory?
Semantic memory is the recording of facts and concepts
What do emotional memories involve?
Emotional memories involve the cortex and limbic system
Where is spatial memory located?
Spatial memory is located in the limbic system
What are procedural memories linked to?
Procedural memories are linked to the motor cortex
What does the nervous system consist of?
The nervous system consists of a complex network of nerve cells called neurons
Describe neurons?
Neurons receive and transmit electrical impulses and provide the body with rapid means of communication and control
What are the three types of neuron?
Sensory
Inter
Motor
Describe sensory neurons?
Sensory neurons carry signals from receptors to the spinal cord and brain
Describe inter neurons?
Inter neurons carry messages from one part of the CNS to another
Describe motor neurons?
Motor neurons carry signals from CNS to effectors.
What is the basic structure of a neuron?
Each has several dendrites, a cell body and one axon.
How does a nerve impulse always travel?
Dendrites to cell body to axon
Describe the function of a dendrite?
Dendrites receive nerve impulses and pass them to the cell body
Describe the function of the cell body?
The cell body contains the nucleus and most of the cytoplasm. it is the control centre of the cells metabolism and contains all the used organelles, including ribosomes.
ribosomes are required to make various particles including the enzymes needed for synthesis of neurotransmissions
Describe the function of an axon.
An axon caries impulses away from a cell body and onto the next cell.
What are axons surrounded by?
Axons are surrounded by a myelin sheath
What does a myelin sheath do?
A myelin sheath insulates the axon and increases the speed of impulse conduction from node to node.
When is myelination completed?
Myelination is not completed at birth but continues from birth to adolescence
Some diseases like motor neurone disease cause the myelin sheaths to what?
The myelin sheaths break down causing a loss of coordination in the sufferer
What do Glial cells do?
Glial cells support and maintain interconnecting neurons
Describe Glial cells?
Glial cells physically support neurons and produce the myelin sheath. they also maintain a homeostatic environment round the neurons and remove debris by phagocytosis
What is a synapse?
A synapse is a region/junction between the axon ending of one neurone and the dendrite of another neurone.
What are the neurons before and after a synapse called.
The neurone before the synapse is called the pre-synaptic neurone and the neurone after the synapse is called the post-synaptic neurone.
What are the three key neurotransmitters?
- Acetylcholine
- noradrenaline
- Dopamine
How are nerve impulses passed across a synapse?
Nerve impulses are passed across a synapse by a neurotransmitter
Why can nerve impulses only be transmitted in one direction?
Nerve impulses can only be transmitted in one direction as vesicles contacting neurotransmitters are only found on one side of a synapse.
What happens if neurotransmitters are not removed quickly after each impulse.
If neurotransmitters are not removed quickly after each impulse then only a limited number of impulses would be able to pass in any given time.
How is acetylcholine removed?
Acetylcholine is removed by being broken down by a degrading enzyme that is present on the post synaptic membrane.
How is noradrenaline reabsorbed?
Noradrenaline is reabsorbed by the presynaptic membrane which stores it in vesicles for re-use
For a nerve impulse to be transmitted what must be reached?
For a nerve impulse to be transmitted a threshold must be reached where enough receptor’s are stimulated
what happens if the threshold is not reached?
The stimulus is too weak and filtered out by the synapse
What is summation?
Summation is when a series of weak stimuli are added together to release enough neurotransmitter to fire a nerve impulse
What are the two signal types?
Nerve impulses can be excitatory or inhibitory
Describe excitatory?
Excitatory signals increase the chance of the impulse being transmitted
describe inhibitory signals?
inhibitory signals reduce the chance of the impulse being transmitted
What are the three types of neural pathways?
- Converging
- Diverging
- Reverberating
Describe converging neural pathways?
- nerve impulses from different sources come together and meet at a common point
- They increase sensitivity to excitatory or inhibitory signals
- They are found in the rods and cones in the eye bringing about light sensitivity
Describe diverging neural pathways?
- information is transmitted from one original source to several destinations
- They bring about fine motor control allowing fingers and thumb to operate in unison
Describe reverberating neural pathways?
- Neurons further down the pathway synapse with neurons near the start of the pathway, sending nerve impulses back through the circuit.
- this allows nerve impulses to be recycled and repeatedly stimulate the presynaptic neurons
What is the plasticity of response?
The plasticity of response is created when new neural pathways are developed to create new responses, bypass areas of brain damage and suppress some reflexes or responses to sensory impulses by conscious action.
What are Endorphins?
Endorphins are chemicals that function like neurotransmitters that:
- give euphoric feelings
- involved in control of appetite
- stimulate the release of sex hormones
- reduce the intensity of pain
Endorphin production increases in response to what things?
- Stress
- severe injury
- prolonged continuous exercise
- certain foods.
What is dopamine?
Dopamine is a neurotransmitter produced in several regions of the brain
Dopamine induces the feeling of what? and reinforces particular what?
Dopamine induces the feeling of pleasure and reinforces particular behaviours
What drugs are used to treat neurotransmitter disorders?
- Agonists: bind to and stimulate receptors, mimicking the neurotransmitter
- Antagonists: bind to specific receptors and block the action of the neurotransmitter
- Other drugs: inhibit the enzymes involved in recycling neurotransmitters after an impulse has been transmitted
Recreational drugs affect neurotransmission in the reward circuit of the brain by?
- stimulating the release of neurotransmitters
- imitating the action of neurotransmitters
- blocking their receptors
- inhibiting re-uptake after an impulse
- inhibiting enzymatic degradation after an impulse
What is sensitisation?
Sensitisation is an increase in the number and sensitivity of receptors as a result of exposure to drugs which are antagonists which leads to addiction.
What is Desensitisation?
Desensitisation is a decrease in the number and sensitivity of receptors as a result of exposure to drugs that are agonists. this leads to drug tolerance.
