Transcript Health

A Search For Better Health
Topic 1: What is Health
Biology in Focus, HSC Course
DOT Point(s)
 discuss the difficulties of defining the terms ‘health’ and
‘disease’
 outline how the function of genes, mitosis, cell differentiation
and specialisation assist in the maintenance of health
 use available evidence to analyse the links between gene
expression and maintenance and repair of body tissues
world.edu
Introduction
Since the beginnings of recorded
history, humans have shown
great interest in the state of their
health and have recognised that
living things do not always
function properly. The presence
of ‘symptoms’ is a clear
indication that all is not well
with the animal or plant.
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Introduction
Over time, many different approaches to the treatment and
management of these symptoms have been implemented, and as
technology has developed, these approaches have changed in order
to help maintain the health of an organism.
www.nlm.nih.gov
Health and Disease
Health is more than merely the absence of disease. Health is
defined by the World Health Organization (WHO) as:
Health: a state of complete physical, mental and social wellbeing, and not merely the absence of disease or infirmity.
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Health and Disease
This definition allows the ‘whole’ person to be taken into account
rather than just whether they have a disease or not. An individual
who does not have a disease may still not be considered healthy.
On the other hand, an individual who suffers from a disease could
still be classed as healthy.
slowbuddy.com
Health and Disease
Physical health refers to the physical state of the body and
includes such things as our level of fitness, body weight, amount of
energy and the proper functioning of the systems in the body.
healthybodylife.com
Health and Disease
Mental health is related to our ability to function effectively in
society and to cope with changing situations in our lives.
Social health is our ability to interact, communicate and
socialise effectively.
www.guardian.co.uk
Health and Disease
One problem with the WHO definition of health is that it is very
broad, and if taken literally it would be very difficult to achieve a
healthy status. It would be very unlikely that a person has a
‘complete’ state of physical, mental and social wellbeing at any one
time.
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Health and Disease
The concept of health for
individuals is very subjective and
depends on their life’s
circumstances. What is healthy
for one may not be regarded as
healthy for another. Different
individuals have different ideas
about what is considered an
appropriate level of physical,
social and mental health.
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Health and Disease
A person who is physically fit and
not suffering from any disease
would consider themselves to be
healthy whereas a person who has a
disability or a chronic disease, may
describe themselves as healthy
because they have learnt to adapt
and cope with this disability or
disease in their everyday life.
 Health is a constantly changing
state and is relative to others and
ourselves over a period of time.
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Health and Disease
Disease can be defined in many
ways, but one of the most
common is:
Disease: any condition that
adversely affects the normal
functioning of any part of a
living thing.
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Health and Disease
 A problem with most definitions of disease is that they are quite
broad and imprecise.
Conditions that would not normally be classed as diseases could
be, if the above definition of disease were to be taken literally. It
could mean that a broken arm would be classed as a disease
because it adversely affects the normal functioning of the body.
Similarly, pregnancy could also be considered to be a disease.
www.salon.com
Health and Disease
 The ‘normal functioning’ referred to in the definition may be at
different levels for different individuals.
For example, absent-mindedness in the elderly may be a normal
facet of aging whereas it could be a manifestation of a disease in
the young.
umanitoba.ca
Maintenance of Health
The function of genes, mitosis, cell differentiation and
specialisation assist in the maintenance of health.
www.ygyh.org
Maintenance of Health
Differentiation: cells mature
and take on different structural
features, so that they become
structurally suited to perform a
specific function in the body.
Specialisation: specific genes
are ‘switched on’ in order to
perform a particular function in
the body.
www.systembio.com
Maintenance of Health
For example, nerve cells (pictured here) have a particular
structure, and specific genes ‘switched on’ that allow the transfer
of electrochemical messages. Macrophages are cells that carry out
the specific function of phagocytosis to help the body fight disease.
www.biotechnikum.eu
Maintenance of Health
 Differentiation and
specialisation enable cells to
work together in a healthy
body to carry out complex
functions in a controlled and
co-ordinated way in order to
maintain and repair tissues.
www.dynamicscience.com.au
Maintenance of Health
The function of genes and mitosis
 The maintenance of health is dependent on the information
stored in the DNA of each cell. Remember: A gene is a hereditary
unit that controls the production of polypeptides that make up the
proteins in the cell.
science.howstuffworks.com
Maintenance of Health
These proteins are responsible
for normal cell functioning,
growth and repair.
 A malfunction in a particular
gene may result in the
inability of the cells to
function properly and lead to
the onset of disease.
For example, cystic fibrosis is a
genetic disease that is caused by
a mutation to the CFTR gene.
www.daviddarling.info
Maintenance of Health
The information contained in genes also prescribes how and when
an organism’s body tissues are maintained and repaired, so that any
malfunction in these genes will be detrimental to healthy cells.
questgarden.com
Maintenance of Health
Mitosis is the process of cell division by which identical body cells
are produced to allow for:
 growth
 repair of damaged tissue, replacement of worn out cells, and
 genetic stability in which there is a precise and equal distribution
of chromosomes to each daughter nucleus, so that all resulting
cells contain the same number and kind of chromosomes as each
other and the parent cell.
Maintenance of Health
 Mitosis allows all cells to function normally and tissues in the
body to be repaired and maintained.
If cells are damaged through injury or disease, they are replaced by
the division of healthy cells close to the injury or disease site.
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Maintenance of Health
Genes code for the proteins that are responsible for the regulation
of the cell cycle and mitosis in healthy cells.
The types of genes responsible for the regulation of the cell cycle
and mitosis are:
 DNA repair genes
 Proto-oncogenes
 Tumour suppressor genes
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Maintenance of Health
 DNA repair genes: these code for proteins that are
responsible for the stopping of the cell cycle while other
proteins remove the damaged regions of DNA and replace them
with a new correct sequence.
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Maintenance of Health
If these genes mutate they will no longer function correctly, the
DNA is not repaired, and the damaged DNA is replicated. As a
result the correct proteins/enzymes necessary for normal cell
functioning, growth and repair will not be produced and disease
will occur.
medimoon.com
Maintenance of Health
 Proto-oncogenes: these code for proteins that stimulate cell
growth and mitosis.
aiss-biology-11.wikispaces.com
Maintenance of Health
 Tumour suppressor genes: these code for proteins that slow
down or stop cell growth and mitosis. These genes also code for
proteins that induce cell death if there is an uncontrolled
increase in cell numbers.
scitechdaily.com
Maintenance of Health
In a healthy cell, these genes tightly regulate cell growth and
mitosis. If these genes are damaged or mutated, this regulation is
disrupted.
spotonlists.com
Maintenance of Health
Mutations to proto-oncogenes
lead to the expression of
oncogenes that would normally
be ‘silent’. This causes
uncontrolled production of cells
and prevents cell death.
Mutations to tumour suppressor
genes halt the production of
proteins that control cell
division and cell death.
www.healthspablog.org
Maintenance of Health
This disruption of the normally
regulated cell cycle leads to
uncontrolled cell replication which:
 does not allow cells to
differentiate, so they cannot
perform the specialised functions
necessary for normal body
functioning
 causes the formation of tumours.
If the tumour spreads to other
tissues, cancer results.
www.environmentalgraffiti.com
Maintenance of Health
In some cases, mutations to certain genes could cause uncontrolled
cell death, which leads to degenerative conditions such as
Alzheimer’s disease.
biol1020-2012-1.blogspot.com
Homework
-Students to complete Maintenance and repair of body tissue