Unit 3- Neurobiology and Immunology Flashcards
what does a reverberating neural pathway allow for?
repeated stimulation
how could a weak stimuli pass on the signal?
if the the post synaptic neuron were to receive several smaller stimuli
Aka SUMMATION
what does the CNS consist of?
the brain and the spinal cord
what does the PNS consist of?
the somatic and the autonomic nervous systems
what do peripheral nerves do?
allow information to be sent to and from the CNS
what does the somatic nervous system do?
takes messages from the sense organs to the muscles and glands
how does the somatic nervous system work?
it takes impulses along SENSORY NEURONES to the CNS and along MOTOR NEURONES to the muscles and glands
what are the 2 systems that make up the autonomic nervous system?
sympathetic system and parasympathetic system
what does the sympathetic system do?
prepare the body for action (fight or flight)
describe what the sympathetic system does to the heart rate, breathing rate, peristalsis and intestinal secretions
increased heart rate
increased breathing rate (allowing bronchioles to take in more air)
decreased peristalsis
decreased intestinal secretions
describe what the parasympathetic nervous system does to the heart rate, breathing rate, peristalsis and intestinal secretions
decreased heart rate
decreased breathing rate
increased peristalsis
increased intestinal secretions
what does the parasympathetic nervous system do?
return the body back to normal (rest and digest)
which gland is the only gland to be solely controlled by the sympathetic system?
the adrenal gland
what are the 3 types of neural pathway?
converging
diverging
and reverberating
what is a converging neural pathway?
many nerve impulses from several neurones travel to one
what does a converging neural pathway cause?
the sensitivity to excitatory and inhibitory signals is increased
what is an example of a converging neural pathway?
rods and cones in the eye
what is a diverging neural pathway?
impulse from one neuron splits and travels to several neurones
What is the axon?
A single nerve fibre that carries impulses away from the cell body
what does a diverging neural pathway cause?
the impulse can affect more than one destination at a time
what is an example of a reverberating neural pathway?
breathing
what is an example of a diverging neural pathway?
temperature control
what is a reverberating neural pathway?
neurones later in the pathway create synapses with neurones earlier in the pathway creating loops
What are the three main parts of neurone structure?
Cell body
Axon
Dendrites
what is the PNS?
the peripheral nervous system
what is the cerbral cortex?
the outside layer of the brain which is split into two cerebral hemispheres
it is the centre for conscious thought where memories are recalled and what alters behaviour in light of experience
what are the 3 stages of memory?
encoding, storage and retrieval of information
what are the 3 types of memory?
sensory memory
short term memory
long term memory
what is retained in the sensory memory?
all visual and auditory input
what happens during drug addiction?
antagonists block specific receptors causing the nervous system to compensate by INCREASING THE NUMBER and SENSITIVITY of these receptors
leading to sensitisation
this leads to the individual craving more of the drug
what is the serial position effect?
that items at the start of a list and items at the end are remembered more than those in the middle
how are items lost in the short term memory?
by either displacement (pushed out by new information) or decay (breakdown of memory trace)
what is encoded from the sensory memory to the short term memory?
only selected images and sounds
what are the two ways to increase the capacity of short term memory?
chunking and rehearsal
What is a randomised clinical trial?
All relevant details are entered into the computer and the computer randomly sorts the members into two groups to reduce bias in the distribution of age and gender
how much information can the long term memory hold ?
unlimited
how is information transferred from STM to LTM?
rehersal, organisation and elaboration
what is the CNS?
the central nervous system
what does transfer between the two cerebral hemispheres occur through?
the corpus callosum
how is retrieval of items from the LTM aided?
the use of contextual cues related to the time and place that were present when information was encoded
describe the inflammatory response.
injury
mast cells become activated and release large quantities of histamine
histamine causes vasodilation and the capillaries to become more permeable
increased blood flow leads to accumulation of phagocytes and clotting factors
What are the 3 types of neuron?
Sensory neurones
Inter neurones
Motor neurones
What is the function of the cell body in a neurone?
Contains nucleus so is the control centre
What is the function of the dendrites?
To pass impulses to the cell body
What is the myelin sheath?
A layer of fatty material that insulates the axon
What is the function of the myelin sheath?
To greatly increase the speed of impulse conduction
what is the region of contact between the axon ending of the pre synaptic neuron and the dendrites of the post synaptic neuron called?
the synapse
What is myelination and when does it occur?
The development of myelin and it occurs from birth to adolescence
what is the gap between the pre synaptic neuron and the post synaptic neuron called?
the synaptic cleft
What is the result of myelination occurring until adolescence?
Response to stimuli in the first 2 years of life is not as rapid or coordinated
what are neurotransmitters stored in in synapses?
vesicles
What do certain diseases do to the myelin sheath?
Destroy it causing loss of coordination
Why is it important to use a large group size for a clinical trial?
To reduce experimental error and improve statistical significance
what is chunking?
breaking the information down into meaningful units to make it easier to remember
how does direct re absorption work when reuptaking neurotransmitter?
neurotransmitter are absorbed directly without being broken down
how do neurotransmitters work at synapses?
when an impulse passes through the PRESYNAPTIC NEURON the it stimulates several vesicles to move to the synapse and fuse with the membrane
the neurotransmitters are then released across the synaptic cleft by diffusion and bind with receptors on the POST SYNAPTIC NEURON
what are the areas of the cerebral cortex?
sensory areas
motor areas
association areas
what are the two ways neurotransmitters are reuptaken at synapses?
enzyme degradation
direct re absorption
name 4 neurotransmitters
acetlycholine
noradrenaline
endorphins
dopamine
what are endorphins?
neurotransmitters that stimulate neurones involved in reducing the intensity of pain
why can the short term memory perform simple cognitive tasks?
the short term memory can process data to a limited extent, as well as store it, this is known as the working memory
what determines whether or not a signal is excitatory or inhibitory?
receptors on the post synaptic neuron
what must be acquired for a signal to be transmitted?
a certain threshold of neurotransmitter
how do endorphins reduce the intensity of pain?
By combining with receptors at synapses blocking the transmissions of the pain signal
where are endorphins produced?
the hypothalamus
what are increased levels of endorphins in response to?
severe injury
prolonged and continuous exercise
physical and emotional stress
certain foods such as chocolate
what are increased levels of endorphins linked to?
the feelings of pleasure obtained from:
eating
sex
prolonged exercise
what is dopamine?
neurotransmitters that induce feelings of pleasure by stimulating the reward pathway which reinforces certain behaviour to satisfy a need that is beneficial such as hunger or thirst
give 2 examples of neurotransmitter related disorders
alzheimers and schizophrenia and depression
how can neurotransmitter related disorders be treated?
by agonist or antagonist drugs
how do agonist drugs work?
they bind to and stimulate specific receptors on postsynaptic neurone, mimicking action of naturally occurring neurotransmitters triggering normal cellular response
how do antagonist drugs work?
they bind to specific receptors on postsynaptic neurone and block the action of the neurotransmitter, inhibiting normal cellular response
how do inhibitor drugs work?
act by preventing the removal of the normal transmitter causing an enhanced effect
how to recreational drugs act?
like both agonists and antagonists
how is drug tolerance caused?
the repeated use of drugs that act as agonists
in individuals what do recreational drugs affect and alter?
mood (happier, more confident, aggressive)
cognition (cant carry out complex mental tasks such as problem solving and decision making)
perception (misinterpretation of stimuli)
behaviour (stay awake for longer, talk endlessly about themselves)
what happens during drug tolerance?
agonists stimulate specific receptors causing the nervous system to compensate by DECREASING THE NUMBER and SENSITIVITY of these receptors
leading to desensitisation
this leads to the individual needing to take more of the drug to get an effect
what do recreational drugs do to the reward circuit?
affect them and cause them do be overstimulated
what are the 2 types of non-specific body defences?
physical and chemical defences
how is drug addiction caused?
the repeated of drugs that act as ANTAGONISTS
what is the physical non-specific body defence?
closely packed epithelial cells found on the surface of skin and lining the body’s digestive system and respiratory systems
offer a physical barrier against bacteria and viruses
what is the chemical non-specific body defence?
secretions including tears, saliva, mucus and stomach acid are produced against invading pathogens
what is the name of the response to a cut or physical injury?
the inflammatory response
What is a placebo controlled clinical trial?
Members of the control group are given a placebo which allows a valid comparison to be made
what are cytokines?
protein molecules released by phagocytes which attract more phagocytes to the site of infection.
describe phagocytosis
phagocytes recognise pathogens and engulf them
they then destroy them using digestive enzymes that are stored in lysosomes
what must happen after neurotransmitter bind with receptors on the post synaptic neuron?
re uptake of neurotransmitter to prevent continuous stimulation.
what are lymphocytes and how do they work?
white blood cells involved in the specific immune system
they work by responding to specific pathogens because they have a specific type of membrane receptor which is specific for one antigen
what are antigens?
molecules located on the surface of cells which trigger the immune response
how is a clonal population achieved?
the binding of the membrane receptor and the antigen leads to the lymphocyte repeatedly dividing resulting in a clonal population of identical lymphocytes
what are the 2 types of lymphocytes?
b lymphocytes and t lymphocytes
how do b lymphocytes work?
they produce antibodies which bind to antigens inactivating the pathogen.
this antibody-antigen complex can then be destroyed by phagocytosis
how do b lymphocytes result in allergies?
b cells respond to antigens on substances that are harmless to the body resulting in an allergic reaction.
how do t lymphocytes work?
t lymphocytes destroy infected cells by recognising antigens and inducing apoptosis
What is the role of glial cells?
To produce myelin and support the neurones
what are antibodies?
y shaped proteins that have receptor binding sites which are specific to a particular antigen
what is apoptosis?
programmed cell death
how does apoptosis work?
t lymphocytes attach to infected cells and release a protein which diffuses into the cell causing production of self-destructive enzymes
the remains are removed by phagocytosis
what allows t lymphocytes to distinguish between self and non-self?
specific surface proteins
in terms of t lymphocytes what does immune system regulation failure lead to?
t cell immune response to self-antigens meaning they attack the body’s own cells resulting in an autoimmune disease
what are 2 examples of autoimmune diseases?
rheumatoid arthritis and type 1 diabetes
What is the primary response?
When a person is infected by a pathogen or toxin and their body produced antibodies for the first time
How are memory cells formed?
Some t and b lymphocytes produced in the primary response survive long term as memory cells
What is the role of memory cells?
To allow for a secondary response
Meaning that they give rise to a new clone of lymphocytes producing a rapid and greater antibody production so the invading pathogen is destroyed before the individual develops symptoms
What does AIDS stand for?
Acquired immune deficiency disease
What does HIV stand for?
Human immunodeficiency virus
How does HIV work?
By attacking and destroying t lymphocytes by hiding in them causing a depletion of their numbers
how does enzyme degradation work when reuptaking neurotransmitters?
enzymes break down neurotransmitter which is the reabsorbed and turned back into new neurotransmitters
What is meant by immunisation?
The process by which a person develops immunity to a disease causing organism
what do mast cells produce?
histamine
How can immunity be acquired?
By vaccination using antigens from an infectious pathogen to create memory cells
What are antigens from infectious pathogens mixed with to create a vaccine?
An adjuvant
What is an adjuvant?
A chemical mixed with the antigen to increase the immune response
What are the forms of pathogen used in vaccines?
Inactivated pathogen
Dead pathogen
Parts of pathogen
Weakened pathogen
What is herd immunity?
When a large percentage of the population are immunised which helps reduce the spread of diseases
Protecting non immune people as there is less chance they will come into contact with an infected individual
What is the herd immunity threshold?
The percentage of the population that must be vaccinated to reach herd immunity status
What does the herd immunity threshold depend on?
The type of disease
Effectiveness of the vaccine and
Density of the population
When do difficulties arise in vaccine programmes?
When widespread vaccination isn’t possible due to poverty in the developing world and
A percentage of the developed world rejecting vaccines
What is antigenic variation?
When some pathogens can change their antigens meaning memory cells are not as effective against them
What does HIV become if left untreated?
AIDS
What must vaccines and drugs go through before being licensed for use in the public?
A clinical trial on humans
What are the 3 different types of clinical trial?
Placebo controlled
Double blind
Randomised
What is a double blind trial?
Neither members non doctors know whether they are receiving the active ingredient or the placebo to prevent bias
What does AIDS do to an individual?
Weakens their immune system making the person more vulnerable to infections
