UNIT 3 Flashcards
State the function of the central nervous system (CNS)?
It Processes and coordinates sensory information
Name the structures which make up the CNS?
brain and spinal cord
State the function of the peripheral nervous system (PNS)
Carry information to and from the CNS
Name the structures which make up the PNS?
Nerves outside brain and spinal cord
Name the two branches of the PNS?
Somatic and autonomic nervous systems
Name the part of the brain which sends impulses along the autonomic nervous system (ANS)?
medulla
List the effects of the sympathetic and parasympathetic systems on the body
Sympathetic:
increase :heart rate, breathing rate
Decrease: peristalsis and intestinal secretions
- Parasympathetic:
Increase: peristalsis and intestinal secretion
Decrease: heart rate and breathing rate
Explain the term antagonistic?
Have opposite actions/effects
Describe the role of sensory and motor neurons?
- Sensory: take impulses from sense organs to CNS
- Motor : take impulses from CNS to muscle and glands
Describe how the nervous system is divided into branches?
CNS and PNS
Identify converging, diverging and reverberating neural pathways?
- Converging: Impulses from several neurons travel to one
neuron - Diverging: Diverging:
Impulses from one neuron travel to several
neuron so affecting more than one destination
at the same time. - Reverberating: neurons later in the pathway can link with earlier neurons which allows the impulse to travel through the pathway again
Name and identify the parts of a neuron? And their function?
- Dendrites : receive impulses and send them to cell body
- Cell body: Expresses proteins required
for nerve transmission
Contain nucleus and mitochondria for ATP - Axon:Carries impulses away from cell body towards synapse and the next neuron
- Myelin sheath: insulates the axon and increases the speed of impulse conduction
Describe the movement of an impulse through a neuron?
An electrical nerve impulse travels along the axon. of the first neuron
Describe the process of myelination?
The process of forming myelin sheath around an axon
Explain why individuals under 2 years old are not as coordinated as older individuals?
myelination is not complete till they reach adolescense
Explain why multiple sclerosis can cause loss of coordination?
They cause the coordination loss by damaging the myelin sheath
State two functions of glial cells?
1- physically support neuron
2- produce myelin sheath
Name the point where neurons connect with other neurons or muscle fibres?
Synaptic cleft
Describe the role of neurotransmitters?
are chemical messengers that transfer signals across synapses between neurons
Identify the parts of a synapse?
Presynaptic neuron, synaptic cleft , postsynaptic membrane
Name the structures which store neurotransmitters?
Vesicles
Describe what happens to the vesicles upon arrival of an impulse?
They release neurotransmitters into the synaptic cleft
Describe how neurotransmitters travel across the synaptic cleft?
Through diffusion
Name the structures which the neurotransmitters bind to?
Specific receptors on the postsynaptic membrane
Describe the role of the receptors?
determine whether the signal is excitatory or inhibitory
State the term used to describe the minimum number of neurotransmitters required to transmit the impulse?
Stimuli Threshold
Describe two ways neurotransmitters are removed from the synaptic cleft?
By enzymes or reuptake into presynaptic neuron
Explain why neurotransmitters must be removed from the synaptic cleft?
To prevent continuous stimulation of postsynaptic neuron
Describe the process of summation?
When multiple signals are added together to trigger a response in a postsynaptic neuron
Explain how convergent neural pathways can trigger an impulse through summation?
They combine signals from multiple neurons to one neuron to trigger an impulse through summation
Name the neurotransmitter involved in reducing the intensity of pain?
Endorphin
State when endorphin levels will increase and the feelings this will induce?
During stress and prolonged exercise , inducing feeling of pain relief and pleasure
Name the neurotransmitter which activates the reward pathway in the brain?
Dopamine
Describe a situation which would activate the reward pathway?
Food, pleasure activities , taking drugs
Compare the action of an agonist and an antagonist chemical?
Agonist mimic neurotransmitter enhancing their effect
WHEREAS
Antagonist block the action of neurotransmitters at a synapse
Explain how some drugs can cause an enhanced effect at a synapse?
They increase neurotransmitter release or block reuptake causing enhanced effects at synapse
List the different effects of recreational drugs?
Mood , perception and behaviour
Explain how drug addiction arises?
Antagonist block specific receptors increasing both number and sensitivity where the individual craves more of the drug
Explain how drug tolerance develops?
Agonist stimulate specific receptors decreasing both the number and sensitivity where an individual must take more of dug to get an effect
Describe the different roles of the cerebral cortex?
Centre of conscious thought, recall memories and alter behaviour
List the main areas within the cerebral cortex?
Sensory
Motor
Association ( involve language processing , imagination , personality)
Describe how the brain processes information for each side of the body?
Left hemisphere controls the right side and vice verse
Explain how the information is transferred between the two hemispheres of the brain?
Information transferred between hemispheres through corpus callosum
Describe how information passes through the different levels of memory?
Information transfer form sensory memory to short term memories to long term memory or is discarded
State the memory span of the STM?
Can hold up to 9 items and last 30 seconds ish
Explain why the STM is able to perform simple cognitive tasks?
for working model
Explain how chunking information can improve STM?
By breaking large prices of information to several small peices
Describe what is meant by the serial position effect?
Remembering the first and last items in a list better than items in the middle
Explain why items at the beginning and end of a list are more easily remembered than items in the middle?
First items are remembered as there has been time for rehearsal into LTM
Last items as they have not yet been displaced from the STM by new information
Describe how items can be maintained within the STM?
Through rehearsal, by repeating it again and again
State two ways information can be lost from the STM?
Displacement
Decay
State the capacity of the LTM?
Unlimited capacity and holds information for a long time
Give examples of ways to improve encoding of information as memories in the LTM ?
Rehearsal
Organisation
Elaboration
Explain how contextual cues help to retrieve memories?
They relate to the time and place when the information was initially encoded into LTM
Give examples of different contextual cues used to aid retrieval of memories?
Scents, sound, emotions and location
Explain why some organisms are described as pathogens?
They are bacteria , virus , fungi that causes disease
Name the cells which form a physical barrier to invading pathogens and state where they
are found?
Epithelial cells
Give examples of chemical secretions which are produced against invading pathogens?
Tears, saliva , mucus and stomach acid
Name the chemical released by mast cells during the inflammatory response?
Histamine
Describe the effect of histamine on arteries and capillaries?
Vasodilation and increased capillary permeability
Describe how phagocytes and clotting elements accumulate at the site of infection?
Increased blood flow and secretion of cytokines
Describe the process of phagocytosis?
Recognise and engulf pathogens and destroyed by enzymes contained in lysosomes
Name the structures which contain digestive enzymes inside phagocytes?
Lysosomes
Describe the action of cytokines released by phagocytes?
Act as signals molecules to attract white blood cells to site of infection, enhance immune response
Describe how the specific immune response is activated?
They are triggered by antigens
Name the two types of lymphocytes?
B lymphocytes and T lymphocytes
Explain why lymphocytes are specific?
They have one type of membrane which is specific to one antigen
Describe how clonal population of identical lymphocytes are formed?
Antigens binding lead to repeated lymphocytes division
Describe the role of T-lymphocytes in specific cellular defences?
destroy infected body cells by recognising antigens of the pathogen
Describe the process of apoptosis?
1- T lymphocyte attaches onto infected cell
2- releases
proteins which diffuse into infected cell
3- causing Self-destructive enzymes cause cell death
Describe the role of B-lymphocytes in specific cellular defences?
produce antibodies against antigens and this leads to the destruction of the pathogen
Describe the effect of antibodies on pathogens?
They Become bound to antigen and inactivate the pathogen
Describe how memory cells develop?
Some of the cloned B and T lymphocytes survive long-term
Compare the primary and secondary response to the same antigen?
Secondary is faster , long lasting due to memory cell activation
Explain how allergies develop?
when B lymphocytes respond to harmless antigens
Explain why T-lymphocytes usually do not attack self-antigens?
to prevent autoimune disease
Describe how autoimmune diseases develop?
when T lymphocytes fail to distiguish between self and non self antigens
Give examples of autoimmune diseases?
Type 1 diabetes and rheumatoid arthritis,multiple scelosis
Describe the effect of the human immunodeficiency virus on T-lymphocytes?
Attack and destroy T lymphocytes
Explain how HIV can lead to the development of AIDS?
When it causes the reduction of t lymphocytes
Explain why individuals with AIDS are more vulnerable to opportunistic infections?
They have weakened immune system
Explain how memory cells can be created from vaccines?
as vaccination contains weakend , inactivated and dead pathogens
Give examples of sources of antigens used in vaccines?
Dead pathogens, weak pathogens, inactivated pathogen toxins
Explain why adjuvants are added to vaccines?
To enhance immune response
Explain the importance of herd immunity in reducing the spread of disease?
Gives protections against infected individual
Explain how herd immunity protects non-immune individuals?
They’re less likely to come in contact with infect individuals
List the factors which affect the herd immunity threshold?
1- type of disease
2- effectiveness of vaccination
3- density of population
Give examples of difficulties in establishing herd immunity in both developed and developing countries?
Developed: vaccinations being rejected
Developing: due to poverty
Explain why memory cells are not effective against some pathogens?
Some pathogens change their antigens
Explain why vaccines are subjected to clinical trials?
establish their safety and effectiveness before being
licensed for use.
Describe how to reduce bias in the distribution of characteristics in a clinical trial?
- Randomised: such as picking names out of a hat .
Reduces bias such as age and gender - double blind: ither the subjects nor the researchers know which group subjects are in
Prevents biased interpretation of the results - placebo control: One group of subjects receives the vaccine or drug while the second group receives a placebo-control
Describe the role of a placebo in a clinical trial?
To see if the new drug works better than the Treatment with no active drug in it
Explain the importance of having a large sample size when testing vaccines?
To reduce the experimental error
Describe how error bars can be used to determine if a result is statistically significant?
- If the error bars overlap- the results are not
statistically significant - If the error bars do not overlap- the results are
statistically significant
