unit 3 Flashcards
(133 cards)
1
Q
what are the two parts of the nervous system
A
the central nervous system and the peripheral nervous system
2
Q
some examples of functions of the nervous system
A
- analysing sensory information
- storing information
- making decisions
3
Q
what is the CNS made up of
A
the brain and spinal cord
4
Q
what is the PNS made up of
A
the somatic nervous system and the autonomic nervous system
5
Q
what does the somatic nervous system contain (voluntary)
A
sensory and motor neurons
6
Q
what do sensory and motor neurons do
A
- sensory neurons take impulses from sense organs to the CNS
- motor neurons take impulses from the CNS to the muscles and glands
7
Q
what does the autonomic nervous system consist of (involuntary)
A
the sympathetic and parasympathetic systems
8
Q
what does the sympathetic system do
A
speeds up heart rate and breathing rate while slowing down peristalsis and production of intestinal secretions
-the parasympathetic system changes these in the opposite way
9
Q
what happens in a converging neural pathway
A
impulses from several neurons travel to one neuron
-this increases sensitivity to excitatory or inhibitory signals
10
Q
what happens in a diverging neural pathway
A
impulses from one neuron travel to several neurons so affecting more than one destination at the same time
11
Q
what happens in a reverberating pathway
A
neurons later in the pathway link with earlier neurons, sending the impulse back through the pathway
-this allows repeated stimulation of the pathway
12
Q
what is the cerebral cortex
A
the cerebral cortex is the centre of conscious thought
-it also recalls memories and alters behaviour in the light of an experience
13
Q
what does cerebral cortex contain
A
there is localisation of brain functions in the cerebral cortex, it contains sensory areas, motor areas and association areas
-there are association areas involved in language processing, personality, imagination and intelligence
14
Q
where is the information from the right visual field and controls of the right side of the body dealt with
A
the left hemisphere
15
Q
where is information from the left visual field and controls of the left side of the body dealt with
A
the right hemisphere
16
Q
where does the transfer of information between the cerebral hemispheres occur
A
the corpus callosum
17
Q
what three things does memory involve and what three things does it include
A
encoding, storage and retrieval of information
and
past experience, knowledge and thoughts
18
Q
where does information entering the brain pass though and enter
A
passes through the sensory memory and enters the STM
19
Q
how is information transferred from the STM to the LTM
A
rehearsal, organisation and elaboration
20
Q
what does the sensory memory retain
A
all the visual and auditory input received for a few seconds
21
Q
does the STM have a big capacity
A
no, it has a limited capcity
22
Q
how many pieces of information can the STM hold
A
7 items
23
Q
what is the serial position effect
A
Items at the start of a long list are remembered through rehearsal and those at the end are remembered because they are still in the STM, and the ones in the middle are lost
24
Q
how can the capacity of the STM be improved by
A
chunking
25
what happened to information if they aren’t transferred to the LTM
it is lost by displacement or decay
26
what is displacement
when information is pushed out of the STM by new information
27
does the LTM have a limited capacity
no it had an unlimited capacity and can hold information for a long time
28
what is ROE
R- rehearsal (shallow form of encoding information into the LTM)
O- organisation (when information is organised into logical categories)
E- elaboration (deeper form of encoding which leads to improved information retention)
29
what is retrieval aided by
use of contextual cues
30
what are contextual cues
relating information to the time and place it was initially encoded into the LTM
31
what is the structure of neurons
dendrites - cell body- axons
32
what do dendrites do
receive nerve impulses and carry them towards the cell body
33
what do axons do
carries nerve impulses away from the cell hodu
34
what does the cell body contain
a nucleus and cytoplasm, the cytoplasm contains organelles such as mitochondria to provide energy for impulses and ribosomes which synthesises proteins for the synthesis of neurotransmitters
35
what are the axons surrounded by
the myelin sheath
36
what is the myelin sheath
a layer of fatty material that insulates the axon and increases the speed of nerve impulse conduction
37
what is myelination
the extent to which an axon is covered in myelin (this continues from birth to adolescence)
38
what diseases can damage the myelin sheath
multiple sclerosis (MS) which results in a loss of muscular co-ordination
39
what do glial cells do
- support neurons
| - produce the myelin shesth
40
what are the types of neurons
- sensory neuron
- inter neuron
- motor neuron
41
what is the space between the ends of neurons knows as
a synapse
42
how are impulses related across synaptic clefts
by chemicals called neurotransmitters
43
2 examples of neurotransmitters and how and why are they are removed
-acetylcholine (enzyme degradation)
-noradrenaline (re-uptake)
they are removed to prevent continuous stimulation of postsynaptic neurons
44
what is the neuron before the synaptic cleft known as
the pre-synaptic neuron
45
what is the neuron after the synaptic cleft known as
post-synaptic neuron
46
where are neurotransmitters stored
in vesicles in the axon endings of the presynaptic neuron
47
action of neurotransmitters
* A nerve impulse passes through a neuron and reaches the end of the presynaptic neuron
* Neurotransmitters are released from vesicles into the cleft on arrival of the impulse
* Neurotransmitters diffuse across the synaptic cleft
* Neurotransmitter binds to receptors on the membrane of the postsynaptic neuron
48
what do receptors found on the postsynaptic neuron determine
whether the signal is excitatory (causes an increase in action) or inhibitory (causes a decrease in action)
49
what is the sufficient number of neurotransmitter molecules known as
the threshold
50
what are weak stimuli known as
sub-threshold stimuli and are too weak to cause the transmission of a nerve impulse
51
what can synapses do with weak stimuli
filter them out
52
what is summation
a series of weak stimuli which trigger an impulse
53
what are endorphins
endorphins are neurotransmitters which act like natural painkillers by stimulating neurons which are involved in reducing the intensity of pain
54
what does endorphin production increase in response to
- severe injury
- prolonged and continuous exercise
- physical and emotional stress
- certain foods (e.g chocolate and chillis)
55
increased levels of endorphins are also linked to what
feelings of pleasure obtained from activities such as:
- eating
- sex
- prolonged exercise
56
what is dopamine
dopamine is a neurotransmitter that induces the feeling of pleasure and reinforces particular behaviour by activating the reward pathway in the brain
57
what does the reward pathway involve and how is it activated
neurons which secrete or respond to dopamine
| it is activated when an individual engages in a behaviour that is beneficial to them e.g eating when hungry
58
what are some neurotransmitter related disorders
- alzheimer’s disease (cause: loss of cells synthesising acetylcholine)
- parkinson’s disease (cause: loss of dopamine synthesising neurons)
- schizophrenia (cause: overactive dopamine system)
59
what is an agonist
agonists are chemicals that bind to and stimulate specific receptors mimicking the action of a neurotransmitter at the synapse
60
what is an antagonist
antagonists are chemicals that bind to specific receptors blocking the action of a neurotransmitter at a synapse
61
what can recreational drugs act as
agonists or antagonists
62
what can recreational drugs affect
neurotransmission is reward pathway of the brain
63
what is drug addiction caused by
drugs that act as antagonists
antagonists block specific receptors causing the nervous system to increase the number and sensitivity of these receptors, the sensitisation leads to addiction
ANT I A
64
what is drug tolerance caused by
drugs that act as agonists
agonists stimulate specific receptors causing the nervous system to decrease the number and sensitivity of these receptors, this desensitisation leads to drug tolerance
A D T
65
what is drug addiction
when the individual craves more of the drug
66
what is drug tolerance
when the individual must take more of the drug to get the effect
67
what can recreational drugs affect
- mood (e.g happier/more confident/more aggressive)
- cognition (person becomes poorer at mental tasks such as problem solving and decision making)
- perception (misinterpretation of environmental stimuli e.g colours, sounds, sense of time)
- behaviour (person is able to stay awake for longer and talk about themselves endlessly)
68
what is immunity
the ability to resist infection by a pathogen or to destroy it if it invades
69
what is the body’s first line of defence
epithelial cells form a physical barrier
70
where are epithelial cells found
in the skin and inner linings of the digestive respiratory systems
71
what are chemical secretions produced against
invading pathogens
72
examples of chemical secretions
tears, saliva and stomach acid
73
what can epithelial cells produce
secretions such as enzymes, hormones and lubricating fluids that can defend against infection
74
what is a pathogen
an organism that can cause disease
75
what is the inflammatory response
a localised defence mechanism at an affected site
76
examples of the inflammatory response
acne, response to bee/wasp stings, tonsillitis
77
what are mast cells
specialised immune cells present in most tissues surrounding blood vessels and nerves
78
what releases histamine
mast cells
79
what does histamine do
causes the typical inflammatory response
| -causing vasodilation and increased capillary permeability
80
what does increased blood flow because of histamine lead to
the accumulation of phagocytes and clotting elements at the site of infection
81
what do phagocytes do
recognise pathogens and destroy them by phagocytosis
82
how do immune cells recognise foreign pathogens
they have different antigens
83
what is phagocytosis
the engulfing of pathogens and their destruction by digestive enzymes contained in lysosomes
84
what do phagocytes release
cytokines which attract more phagocytes to the site of infection
85
what are cytokines
protein molecules that act as a signal to phagocytes causing them to accumulate to the site of infection
86
what are lymphocytes
white blood cells involved in the specific immune response
87
where are lymphocytes made
in the bone marrow from stem cells
88
where do t-lymphocytes mature
the thymus gland
89
where do b-lymphocytes mature
in the bone marrow
90
what do lymphocytes respond to
specific antigens found on invading pathogens
91
what are antigens
antigens are molecules, often proteins found on the surface of cells that trigger a specific immune response
92
what does each lymphocyte have
type of membrane receptor which is specific for one antigen
93
what does antigen binding lead to
repeated division resulting in the formation if a clinal population of identical lymphocytes
94
what are the two types of lymphocytes
B lymphocytes and T lymphocytes
95
What do B lymphocytes produce
antibodies against antigens and this leads to the destruction of the pathogen
96
what are antibodies
Y shaped proteins that have receptor binding sites to a particular antigen
97
what is produced when an antibody binds to a particular antigen
an antigen antibody complex
98
what can an antigen-antibody complex be destroyed by
phagocytes
99
What do B lymphocytes respond to
antigens on the substances that are harmless to the body e.g pollen
100
what is an allergic reaction
a hypersensitive response
101
What do T lymphocytes do
destroy the infected body cells by recognising antigen of the pathogen on the cell membrane and inducing apoptosis 
102
what is apoptosis
programmed cell death
103
what do T lymphocytes do to infected cells
attach on to infected cells and release proteins, these proteins diffuse into the infected cells causing the production of self-destructive enzymes which cause cell death
the remains of the cell are then removed by phagocytosis
104
what is autoimmunity
T lymphocytes can normally distinguish between self antigens ok the boys own cells and non self antigens on infected cells.
Failure of the regulation or the immune system leads to T lymphocytes responding to self antigens, this causes autoimmune diseases
105
examples of autoimmune diseases
type 1 diabetes and rheumatoid arthritis
106
what is immunological memory
some of the cloned B and T lymphocytes survive long term as memory cells
107
what is the primary response
when’s. pathogen infects the body, it takes time to raise an immune response and select the correct T and B cells and produce antibodies
108
what is the secondary response
when a secondary exposure to the same antigen occurs, the memory cells rapidly give rise to more new clones of specific lymphocytes, these destroy the invading pathogens before the individual shows symptoms
109
is the primary or secondary response faster
during the secondary response, antibody production is greater and more rapid than during the primary response
110
what is HIV
the human immunodeficiency virus attacks and destroyed T lymphocytes.
HIV causes depletion of T lymphocytes which, over a long time, leads to the development of AIDS
111
what happens to an individual with AIDS’s immune system
they have a weakened immune system and so are more vulnerable to opportunistic infections such as pneumonia
112
how can immunity be developed
by vaccination using antigens from infectous pathogens, creating memory cells
113
what are the antigens used in vaccines
they can be inactivated pathogen toxins, dead pathogens, parts of pathogens and weakened pathogens
114
what are antigens mixed with when producing the vaccine
an adjuvant
| an adjuvant is a substance which makes the vaccine more effective so enhancing the immune response
115
what is herd immunity
hers immunity occurs when a large percentage of a population is immunised
116
what is establishing herd immunity important for
reducing the spread of disease
117
how does her immunity protect non immune individuals
they are protected as there is a lower probability they will come into contact with infected individuals
118
what does the herd immunity threshold depend on
the type of disease, the effectiveness of the vaccine and the density of the population
119
what prevents mass vaccination in developing countries
malnutrition and poverty
120
what prevents mass vaccination in developed countries
adverse publicity
121
what are mass vaccination programmes designed for
to establish herd immunity to a disease
122
what is antigenic variation
some pathogens can change their antigens so that antibodies and memory cells are not effective against them
123
what virus does antigenic variation occur in
influenza virus, this is whit it remains a major public health problem and why individuals who are at risk require to be vaccinated every year
124
what are clinical trials
vaccines and drugs are subjected to clinical trials to establish their safety and effectiveness before being licensed for use
125
what is the design of clinical trials for
to test vaccines and drugs, it involves randomised double-blind and placebo-controlled protocols
126
what are randomised clinical trials
subjects in clinical trials are divided into groups i a. randomised way to reduce bias in the distribution of characteristic such as age and gender
127
what is double blind testing in clinical trials
in a double blind trial, neither the subjects nor the researchers know which group subjects are in to prevent biased interpretation of the results.
Neither the doctor or the patient know if they are receiving the treatment or the placebo
128
what is a placebo
A pull exactly the same but without the active ingredient
129
what is group size in clinical trails
the importance of group size in reducing experimental error and establishing statistical significance.
At the end of the trail, results from the two groups, which must be of a suitable size to reduce the magnitude of experimental error ,are compared to determine whether there are an statistically significant differences between the group
130
what is control in clinical trials
used as a comparison to show that the factors being investigated is responsible for the changes observed
131
structure of sensory neuron
- has dendrites in contact with receptions in sense organs
- these dendrites merge to form a myelinated fibre which carries impulses to the cell body
- has a short axon
- axon branches form connections with neurons in the CNS
132
structure of an inter neuron
- connects sensory neurons to motor neurons
| - has many dendrites which form many complex connections
133
structure of a motor neuron
- has short dendrites which connect to neurons in the CNS
- has a long myelinated axon
- axon carried nerve impulses to muscle connectives via axon terminals
