Unit 3 Flashcards
1
Q
What are the two main parts of the central nervous system (CNS)?
A
The brain and the spinal cord.
2
Q
What does the peripheral nervous system (PNS) consist of?
A
The somatic nervous system (SNS) and the autonomic nervous system (ANS).
3
Q
What are the two components of the autonomic nervous system (ANS)?
A
The sympathetic and parasympathetic systems.
4
Q
What type of neurons are found in the somatic nervous system (SNS)?
A
• Sensory and motor neurons.
5
Q
What is the function of sensory neurons?
A
They take impulses from sense organs to the CNS.
6
Q
What is the function of motor neurons?
A
They take impulses from the CNS to muscles and glands.
7
Q
What does the sympathetic nervous system do to heart rate and breathing rate?
A
It speeds them up.
8
Q
How does the parasympathetic system affect peristalsis and intestinal secretions?
A
It increases peristalsis and intestinal secretions.
9
Q
How do the sympathetic and parasympathetic systems act on the body in relation to each other?
A
They have antagonistic actions (opposite effects).
10
Q
What effect does the sympathetic nervous system have on peristalsis?
A
It slows down peristalsis.
11
Q
What happens in a converging neural pathway?
A
Impulses from several neurons travel to one neuron.
12
Q
How does a converging pathway affect sensitivity to stimuli?
A
It increases sensitivity to excitatory signals.
13
Q
In a diverging pathway, where do impulses from one neuron go?
A
To several neurons.
14
Q
How does a diverging pathway help coordinate a body response?
A
It affects more than one destination at the same time.
15
Q
What is a reverberating neural pathway?
A
A pathway where neurons later in the sequence link back with earlier neurons.
16
Q
What is the purpose of the impulse being sent back through the pathway in a reverberating circuit?
A
It allows repeated stimulation of the pathway.
17
Q
Which type of pathway allows repeated stimulation over time?
A
The reverberating pathway.
18
Q
What is the main function of the cerebral cortex?
A
It is the centre of conscious thought.
19
Q
Which types of mental activities are controlled by the cerebral cortex?
A
Conscious thought, memory recall, and behaviour modification based on experience.
20
Q
What types of areas are found in the cerebral cortex?
A
Sensory areas, motor areas, and association areas.
21
Q
What do sensory areas in the cerebral cortex do?
A
They receive and process information from sense organs.
22
Q
What is the role of the motor areas in the cerebral cortex?
A
They control voluntary movements by sending signals to muscles.
23
Q
What are the association areas of the cerebral cortex responsible for?
A
They are involved in language processing, personality, imagination, and intelligence.
24
Q
Name four functions associated with the association areas.
A
Language processing, personality, imagination, and intelligence.
25
How does the cerebral cortex influence behaviour?
It recalls memories and alters behaviour in the light of experience.
26
Which hemisphere of the brain processes information from the right visual field?
The left cerebral hemisphere.
27
Which side of the body is controlled by the left cerebral hemisphere?
The right side.
28
Which hemisphere of the brain processes information from the left side of the body?
The right cerebral hemisphere.
29
What structure is responsible for the transfer of information between the two cerebral hemispheres?
The corpus callosum.
30
Why is the corpus callosum important for brain function?
It enables communication between the left and right cerebral hemispheres.
31
What are the three stages involved in memory processing?
Encoding, storage, and retrieval are the three stages involved in memory processing.
32
What types of content do memories include?
Memories include past experiences, knowledge, and thoughts.
33
Through which part of the memory system does all information first pass when entering the brain?
All information first passes through sensory memory when entering the brain.
34
What happens to information after it reaches short-term memory?
Information in STM is either transferred to long-term memory (LTM) or discarded.
35
What determines whether information is stored in long-term memory or discarded?
Whether information is stored or discarded depends on processes like rehearsal, organisation, and elaboration.
36
What type of input does sensory memory receive?
Sensory memory receives visual and auditory input.
37
For how long does sensory memory retain information?
Sensory memory retains information for a few seconds.
38
What determines whether visual and auditory input from sensory memory is passed to short-term memory?
Only selected images and sounds are encoded into short-term memory.
39
What is the duration and capacity of short-term memory?
STM has a limited capacity and holds information for a short time.
40
How can the capacity of short-term memory be improved?
STM capacity can be improved through chunking.
41
What is ‘chunking’ and how does it help STM?
Chunking is grouping information into larger, meaningful units to improve memory span.
42
What is memory span?
Memory span refers to the amount of information STM can hold at once.
43
What does the serial position effect describe?
The serial position effect describes better recall of items at the beginning and end of a list.
44
How can items be maintained in STM?
Items in STM can be maintained by rehearsal.
45
What causes the loss of information from STM?
Information can be lost from STM due to displacement (new items pushing out old ones) or decay (fading over time).
46
What is meant by the ‘working memory model’?
The working memory model describes how STM can process as well as store data.
47
How does STM perform cognitive tasks?
STM performs simple cognitive tasks using its processing ability, as part of working memory.
48
What is the capacity of long-term memory?
LTM has an unlimited capacity.
49
For how long can LTM store information?
LTM can hold information for a long time, potentially indefinitely.
50
How is information transferred from STM to LTM?
Information is transferred from STM to LTM through rehearsal, organisation, and elaboration.
51
What is the difference between rehearsal and elaboration in terms of encoding?
Rehearsal is a shallow encoding method, while elaboration is deeper and leads to better retention.
52
Which encoding method is more effective for long-term retention: rehearsal or elaboration?
Elaboration is more effective than rehearsal for long-term retention.
53
What are contextual cues and how do they aid retrieval from LTM?
Contextual cues aid retrieval by linking to the time and place of encoding.
54
Give an example of a contextual cue.
An example of a contextual cue is remembering something better when you are in the same place where you learned it.
55
What are the three main parts of a neuron?
Dendrites, cell body, and axon.
56
What is the function of dendrites in a neuron?
They receive nerve impulses from other neurons.
57
What is the role of the axon in a neuron?
It carries nerve impulses away from the cell body.
58
What is the myelin sheath and what is its function?
It is a fatty layer that surrounds the axon, insulating it and increasing the speed of impulse conduction.
59
How does the myelin sheath affect the speed of nerve impulse conduction?
It increases the speed of impulse conduction.
60
During what stage of life does myelination continue?
From birth to adolescence.
61
Why are responses to stimuli slower in the first two years of life?
Because myelination is not yet complete.
62
What effect do diseases that destroy the myelin sheath have on the body?
They cause a loss of coordination.
63
What type of cells produce the myelin sheath?
Glial cells.
64
Apart from producing myelin, what is another function of glial cells?
They support neurons.
65
Where do neurons connect with other neurons or muscle fibres?
At a synaptic cleft.
66
What is a synaptic cleft?
The small gap between neurons or between a neuron and a muscle fibre.
67
What is the function of neurotransmitters in synaptic transmission?
They relay impulses across the synaptic cleft.
68
Where are neurotransmitters stored before they are released?
In vesicles in the axon endings of the presynaptic neuron.
69
What triggers the release of neurotransmitters from the presynaptic neuron?
The arrival of an impulse.
70
After release, where do neurotransmitters go and what do they bind to?
They diffuse across the synaptic cleft and bind to receptors on the postsynaptic membrane.
71
Why is it important to remove neurotransmitters from the synaptic cleft?
To prevent continuous stimulation of the postsynaptic neuron.
72
What are two ways neurotransmitters are removed from the synaptic cleft?
By being broken down by enzymes or by reuptake into the presynaptic neuron.
73
What type of cells form a physical barrier against pathogens?
Epithelial cells.
74
Where in the body are closely-packed epithelial cells found?
In the skin and inner linings of the digestive and respiratory systems.
75
What is the purpose of chemical secretions in the body?
To protect against invading pathogens.
76
Name four examples of chemical secretions that defend against pathogens.
Tears, saliva, mucus, and stomach acid.
77
What is a pathogen?
A bacterium, virus or other organism that can cause disease.
78
What type of cell releases histamine during the inflammatory response?
Mast cells.
79
What are the two main effects of histamine on blood vessels?
Vasodilation and increased capillary permeability.
80
What is the purpose of vasodilation and increased capillary permeability during infection?
To increase blood flow and allow accumulation of phagocytes and clotting elements at the site of infection.
81
What accumulates at the site of infection due to increased blood flow?
Phagocytes and clotting elements.
82
What do phagocytes do when they recognise pathogens?
They destroy them by phagocytosis.
83
What is phagocytosis?
The engulfing of pathogens and their destruction by digestive enzymes in lysosomes.
84
What organelles in phagocytes contain digestive enzymes to destroy pathogens?
Lysosomes.
85
What signalling molecules do phagocytes release during infection?
Cytokines.
86
What is the role of cytokines in the immune response?
To signal and attract more specific white blood cells (phagocytes) to the site of infection.
87
How can immunity be developed without having the disease?
Through vaccination using antigens from infectious pathogens.
88
What does vaccination create in the immune system?
Memory cells.
89
What types of antigens can be used in vaccines?
Inactivated pathogen toxins, dead pathogens, parts of pathogens, and weakened pathogens.
90
What is the purpose of mixing antigens with an adjuvant in vaccines?
To make the vaccine more effective by enhancing the immune response.
91
What is an adjuvant?
A substance added to a vaccine to increase its effectiveness.
92
What is herd immunity?
When a large percentage of the population is immunised, reducing the spread of disease.
93
Why is herd immunity important?
It protects non-immune individuals by lowering their chances of encountering infected individuals.
94
What factors affect the herd immunity threshold?
The type of disease, the effectiveness of the vaccine, and the density of the population.
95
What is the purpose of mass vaccination programmes?
To establish herd immunity.
96
What are two reasons herd immunity may not be achieved in some populations?
Poverty in the developing world and vaccine rejection in the developed world.
97
What is antigenic variation?
When pathogens change their surface antigens.
98
Why does antigenic variation reduce vaccine effectiveness?
Because memory cells are no longer effective against the new antigens.
99
How does antigenic variation affect the influenza virus?
It causes the virus to remain a major public health issue, requiring new vaccinations each year.
100
Why do at-risk individuals need to be vaccinated against influenza annually?
Because of antigenic variation in the virus.
101
What type of white blood cells are involved in the specific immune response?
Lymphocytes.
102
What type of receptor do lymphocytes have on their membrane?
A single type that is specific to one antigen.
103
What happens when an antigen binds to a lymphocyte receptor?
The lymphocyte divides repeatedly to form a clonal population of identical lymphocytes.
104
What are antigens and where are they found?
Molecules, often proteins, on the surface of cells that trigger a specific immune response.
105
What are the two types of lymphocytes?
B lymphocytes and T lymphocytes.
106
What do B lymphocytes produce in response to antigens?
Antibodies.
107
What is the function of antibodies?
They bind to specific antigens, inactivate pathogens, and mark them for destruction by phagocytosis.
108
What is the shape of antibodies and what makes them specific?
They are Y-shaped proteins with receptor binding sites specific to particular antigens.
109
What happens to the antigen-antibody complex?
It is destroyed by phagocytosis.
110
What is an allergic reaction in terms of B lymphocyte activity?
A hypersensitive response where B lymphocytes respond to harmless antigens such as pollen.
111
How do T lymphocytes respond to infected body cells?
They recognise antigens on the cell membrane and induce apoptosis.
112
What is apoptosis?
Programmed cell death.
113
How do T lymphocytes cause apoptosis?
They release proteins that enter the infected cell and activate self-destructive enzymes.
114
What happens to the remains of cells destroyed by apoptosis?
They are removed by phagocytosis.
115
What is the difference between self and non-self antigens?
Self-antigens are on the body’s own cells; non-self antigens are on infected or foreign cells.
116
What is autoimmunity?
A failure of the immune system where T lymphocytes attack the body’s own cells.
117
Name two autoimmune diseases caused by T lymphocytes attacking the body’s own cells.
Type 1 diabetes and rheumatoid arthritis.
118
What are memory cells?
Cloned B and T lymphocytes that survive long-term after an infection.
119
What happens during a secondary immune response?
Memory cells quickly produce specific lymphocytes to destroy the pathogen before symptoms appear.
120
How does the secondary response differ from the primary response?
It is faster and produces more antibodies.
121
What does HIV do to the immune system?
It attacks and destroys T lymphocytes.
122
What condition is caused by the depletion of T lymphocytes due to HIV?
AIDS (acquired immune deficiency syndrome).
123
Why are individuals with AIDS more vulnerable to infections?
Their weakened immune system cannot effectively fight off opportunistic infections.
124
Why are vaccines and drugs subjected to clinical trials before being licensed for use?
To establish their safety and effectiveness.
125
What are the three key design features of clinical trials?
- Randomisation
- Double-blind procedure
- Placebo control.
126
Why are subjects randomly assigned to different groups in a clinical trial?
To reduce bias in the distribution of characteristics like age and gender.
127
What does “double-blind” mean in the context of a clinical trial?
Neither the subjects nor the researchers know which group the subjects are in.
128
Why is a double-blind trial important?
To prevent biased interpretation of the results.
129
What is a placebo and why is it used in clinical trials?
A placebo is a substance with no therapeutic effect, used as a control to ensure valid comparisons.
130
How is the effectiveness of a vaccine or drug determined in a trial?
By comparing the results from the treatment group and the placebo group.
131
Why is group size important in a clinical trial?
To reduce experimental error and ensure the results are statistically significant.
132
What does it mean if a result is “statistically significant”?
That the observed difference is unlikely to be due to chance.
133
What is the final step in a clinical trial?
Comparing the results of both groups to determine if the treatment had a statistically significant effect.
