WEEK 10 Flashcards
What is global health?
The health of populations in a global context
It has been defined as “the area of study, research and practice that places a priority on improving health and achieving equity in health for all people worldwide”.
What are the 5 metaphors applied to global health? Describe them.
- AS FOREIGN POLICY – using global health policies to create positive worldwide reputation and exert political influence, forging alliances with countries where they have strategic interests
- AS SECURITY – health policy seeks to protect ones own population, focusing mainly on communicable diseases that threaten this population. Only diseases of poor countries that pose a potential threat to citizens of rich countries matter
- AS CHARITY - promotion of health as a key element in the fight against poverty
- AS INVESTMENT - use of health as a means of maximising economic development
- AS PUBLIC HEALTH – seeks to decrease the worldwide burden of disease, with priority given to those risk factors and diseases that make the greatest contribution to this burden
Describe and explain global in equity.
Arises from the uneven distribution of power, resources, and status
Inequities are a matter of social injustice:
– can influence patterns of advantage and disadvantage
across the globe
– can have significant and unfair adverse effects on the health of individuals and groups
Inequity can result in the unequal attainment of the human right to health
What is globalisation?
the incorporation of national economies and societies into a world system ‘through movements of goods and services, capital, technology and (to a lesser extent) labour’
What are the (i) challenges (ii) benefits of globalisation?
(i) Population growth fuels resource competition and food price rises.
Already challenged infrastructures struggle to cope.
Tribal and ethnic tensions may increase and violence may result.
Devastating effects on specialist local communities (e.g. coal mining in South Wales) and may lead to exploitation.
(ii) Economic developments lift people out of poverty.
Opportunities for education and participation.
Usually results in improvements in health.
But, the transition can be difficult and the benefits unevenly distributed.
What is the value of the resting membrane potential? What ion is the membrane more permeable to as a result of this? What does the value of the resting potential depend upon?
-70mV
More permeable to K+ than Na+
Dependent upon the ratio between PNa:PK
If the potassium permeability increased by a factor of 50, how would Em be affected – would the membrane potential depolarize (become more positive) or would it hyperpolarise (become more negative)?
Hyperpolarise (more + charged ions leaving the cell)
If the sodium permeability increased by a factor of 100, how would Em be affected – would the membrane potential depolarize (become more positive) or would it hyperpolarise (become more negative)?
Depolarise (more + charged ions entering the cell)
Would the following make it harder or easier to reach the threshold potential compared to the normal situation (i) An increase in the [K+] concentration of extracellular fluid to 10 mM (ii) A decrease in the [K+] concentration of extracellular fluid to 2 mM ? (HINT: think of the gradient)
(i) EASIER: increasing the extracellular [K+] will cause depolarisation and move the resting membrane potential nearer to the threshold
(ii) HARDER: decreasing the extracellular [K+] will cause hyperpolarisation and move the resting membrane potential away from threshold
(NB: the resting potential is -70mV and the threshold is -50mV) IC = 140 EC = 5
Would the following make it harder or easier to reach the threshold potential compared to the normal situation (i) Increase in the [Na+] concentration of extracellular fluid to 180 mM (ii) Decrease in the [Na+] concentration of extracellular fluid to 110 mM ?
(i) EASIER: increasing the extracellular [K+] will cause depolarisation and move the resting membrane potential nearer to the threshold
(ii) HARDER: decreasing the extracellular [Na+] will cause hyperpolarisation and move the resting membrane potential away from the threshold (fewer + ions entering the cell down the concentration gradient)
(NB: the resting potential is -70mV and the threshold is -50mV) IC = 10 EC = 140
(i) Interpret the graph showing the relationship between the extracellular concentrations of Na+ and K+ the membrane potential
(ii) Explain the ionic basis of an action potential with reference to the initial resting membrane potential and subsequent changes in membrane permeability
(i) Changing the EC potassium concentration has a much greater effect on the membrane potential than changing the extracellular Na concentration confirming that the membrane is more permeable to K+ than it is to Na+ (at rest)
(ii) During the action potential the membrane becomes much more permeable to Na+ than to K+ as a consequence of the opening of Na channels – the membrane potential approaches the Na+ equilibrium potential. Repolarisation occurs as a result of the closing of the Na channels and the delayed opening of K channels – both processes bring about repolarisation as the membrane potential moves closer to the to K+ equilibrium potential
Why does changing the extracellular concentration of K+ have a greater effect on the membrane potential than changing the extracellular Na+ concentration?
The membrane is more permeable to K+ than it is to Na+
Why is the graph of extracellular K+ v membrane potential (Em) not linear?
Because the relationship between the concentrations of ions, equilibrium potentials and membrane potential is not linear (LOGARITHMIC).
The deviation from linearity at low [K+]o is due to the increasing contribution of the Na+ at low values of [K+]o
At what concentration of extracellular K+ does Em = 0 mV (approximately)? Why does this concentration of extracellular K+ give an Em = 0?
140mM
The intracellular and extracellular K+ concentrations are equal (no gradients therefore no potential!)
At the peak of an action potential, when Em = 30 mV, would you expect changing the extracellular Na+ concentration to have a greater or smaller effect on Em?
GREATER EFFECT – at the peak of the action potential the membrane is more permeable to Na+ than it is to K+. Therefore changing the extracellular Na+ concentrations will have a greater effect.
Which ionic gradient is most important in the generation of the membrane potential?
K+
What are the 4 criteria required for valid consent?
- Patient must have CAPACITY - a person is able to understand, retain and use the information as well as communicate their decision.
- Patient must give consent VOLUNTARILY - must be no coercion or undue pressure.
- Patient must be INFORMED - must be informed of and understand the treatment that is going to take place
- Consent must be CONTINUING - has the right to withdraw consent at any point
What are the three types of form consent can be?
- WRITTEN CONSENT
- fertility treatment
- good practice in surgery - ASSUMED CONSENT
- conduct: seeking and complying with treatment - VERBAL CONSENT
What are the 2 approaches to capacity?
- Status
2. Function
What are the 4 criteria for adult capacity?
A person is able to make decisions for themselves if they are able to:
- UNDERSTAND the information
- RETAIN the information
- USE OR WEIHG the information
- COMMUNICATE their decision
What makes assessing capacity difficult? (NOTE: there’s 5 points)
- It’s not a once and for all judgement
- Non-cooperation - they don’t want to be there and don’t want to speak to you, this does not mean that they lack capacity
- Just because the decision is irrational or bizarre, does not mean patient lacks capacity
- Underlying conditions may cloud your judgment (and may or may not affect patient’s capacity)
- Communication problems
What are the ways in which decisions can be made on behalf of a patient who lacks capacity?
PROXY DECISION MAKERS:
- LPA (Lasting Power of Attorney)
- Advance Directives
- Best interests test (HCP, relatives, carers)
What are the problems with proxy decision makers? (HINT: there’s 2)
- Proxy and patient do not always agree (~68%
accurate) - Proxy decisions are normally subject to “best interests”…not so our own decisions
What is a Gillick-competent patient?
Used to decide whether a child (16 or younger) is able to consent to his or her own medical treatment, without the need for parental permission or knowledge.
“…it is not enough that she should understand the nature of the advice which is being given: she must also have a sufficient maturity to understand what is involved.”
- Respect for mature minor’s autonomy
- Q’s exist around consent, refusal and seriousness of decision
What are the rights of a capacitous patient as regards refusal of, preference for and demanding of treatment?
REFUSAL - within rights, does not have to seem rational
PREFERENCE FOR - within rights. Can inform of other treatments but must give accurate information for each one.
DEMANDING TREATMENT - NOT within a patient’s right.
What are some of the difficulties around the area of informed consent in practice? (HINT: there’s 3)
How much is enough (“sufficiently” informed)?
Consent is a process (continuing) not an event. Can be withdrawn at any time.
Do patients understand what consent is all about?
Define Evidence Based Medicine.
Use the best evidence in the scientific literature to provide the best care for an individual patient
What are the 3 principles of evidence based medicine (EBM)?
- High quality health care rests on objective and clinically relevant information
- There is a hierarchy of evidence where some types are stronger than others
- Scientific data alone is not a sufficient basis for making clinical decisions
What are the potential sources of bias in medical research?
Selection bias Performance bias Attrition bias Detection bias Reporting bias Publication bias Time-lag bias Language bias Funding bias Citation bias Developed country bias Multiple publication bias
What is a systematic review? What is the strategy used for conducting a systematic review? Why are they viewed as the ‘gold standard’?
A systematic review attempts to identify, appraise and synthesise all the empirical evidence that meets pre- specified eligibility criteria to answer a given research question.
Researchers conducting systematic reviews use explicit methods aimed at minimizing bias, in order to produce more reliable findings that can be used to inform
decision making.
Avoidance and/or the minimisation of bias
What is a meta-analysis? Explain the value of a meta-analysis.
When results of the individual studies are combined to produce an overall statistic.
Data are collected from more than one clinical trial and are combined to generate an average result.
This aims to provide a more precise estimate of the effects of an intervention and to reduce uncertainty.
Explain the importance of a confidence interval.
The point estimate (usually the mean) indicates the magnitude of the effect of the experimental intervention compared to the control intervention (Risk ratio is 0.7 of that in the control group).
The confidence interval describes the uncertainty of this estimate. It describes a range of values within which we can be reasonably sure that the true effect actually lies.
A 95% confidence interval is often interpreted as indicating a range within which we can be 95% certain that the true effect lies. This statement is a loose interpretation of the statistical meaning (but is useful as a rough guide).
What are the boundaries of the vertebral canal?
ANTERIORLY: Vertebral bodies Intervertebral discs Posterior longitudinal ligament LATERALLY: Pedicles (forms the borders of intervertebral foraminae) Intervertebral foramina POSTERIORLY: Laminae Facet (zygapophyseal) joint Spinous processes Ligamentum flavum
What are the contents of the vertebral canal?
Spinal cord Spinal roots that form spinal nerves Meninges: Pia, arachnoid and dura mater Extra dural space and fat Blood vessels
Where does the spinal cord begin and end? What is the name(s) given to the inferior end of the cord?
Begins at the foramen magnum of the skull as the continuation of the brain stem
In adults it ends at L1/L2
Inferior end of cord is conus medullaris which narrows as filum terminale
Between what spinal roots is the (i) cervical enlargement (ii) lumbosacral enlargement?
(i) C4 - T1 (brachial plexus)
ii) T11 - S1 (lumbosacral plexus
Describe and explain the development of the spinal cord.
In the embryo (8 wks), the spinal cord and vertebral canal are equivalent lengths (spinal segments = vertebrae)
In neonates, the spinal cord ends at L3 vertebra
BUT In adults, the spinal cord exists in upper 2/3 of vertebral column (foramen magnum to disc between L1/L2)
The vertebral column grows faster than spinal cord
