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Flashcards in Test 1 Deck (51)
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1

Disease =

An impairment of normal physiological function of a part, organ, or system of an organism resulting from various causes (such as infection, inflammation, environmental factors, or genetic defect) and characterized by an identifiable group of signs or symptoms.

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Aetiology =

the underlying cause of a disease

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Carrier =

an individual who harbours the disease-causing entity but has no symptoms of disease

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Epidemiology =

The study of how often diseases occur in different groups of people

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Genotype =

The precise gene sequence in the DNA of an organism.

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Incidence =

The rate at which a particular event or disease arises in a population (# incidents/time)

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Idiopathic =

Disease of unknown aetiology

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Morbidity =

State of ill-health produced by a disease

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Mortality rate =

The per capita death rate caused by a disease in a population

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Pathogen =

A disease causing organism such as bacteria or virus

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Pathogenesis =

The manor by which a disease develops

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Phenotype =

Observable characteristics of an organism (typically linked with other information regarding that organism, e.g. genetics, environmental conditions).

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Prevalence =

The proportion of the population affected by a disease at a particular time.

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Prognosis =

Probable outcome of a disease (e.g. in terms of severity/timing).

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Symptom =

Subjective manifestation, such as weakness or pain, in an affected individual. (Objective manifestations detectable by a clinician are usually referred to as signs or physical findings)

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Diseases are caused by...

a combination of both genetic and environmental factors

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Hereditary =

derived from one´s parent

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Familial =

transmitted through generations and affecting several members of a family

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Congenital =

present at birth

not all genetic disorders are congenital (Huntington disease: 3rd-4th decade)

not all congenital diseases are of genetic origin (congenital syphylis, toxoplasmosis)

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Autosomal dominant:

One mutated copy of the gene in each cell is sufficient for a person to be affected

Typically - an affected person inherits the condition from an affected parent

Occasionally - the condition may result from a new mutation in the gene and occur in people with no history of the disorder in their family

Examples: Huntington's disease, Marfan syndrome

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Autosomal recessive:

Both copies of the gene have mutations in affected individuals.

The parents of an individual with an autosomal recessive condition each carry (at least) one copy of the mutated gene, but they (typically) do not show signs and symptoms of the condition.

Examples: Cystic Fibrosis, sickle cell disease

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X-Linked dominant:

A mutation in one copy of the gene in each cell is sufficient for a person to be affected.

Both genders are affected, but males are typically more severely affected in females, due to X chromosome inactivation (lyonisation). Fathers do not pass on the affected allele to sons (no male-to-male transmission).

Example: Fragile X syndrome

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X-linked recessive:

All copies of the gene have mutations in affected individuals (one in males, two in females).

These diseases occur predominantly in males because it is less likely that a female will inherit two copies (or that selective X-inactivation would occur favouring the non-mutated allele). Fathers do not pass on the affected allele to sons (no male-to-male transmission).

Examples: Hemophilias, Fabry disease

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Y-linked:

Caused by of the gene mutations on the Y chromosome. Occurs only in males.

Example: Y-chromosome infertility

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Examples of genetically determined diseases...

congenital and hereditary = Duchenne Muscular Dystrophy (Recessive X-linked form of muscular dystrophy)

hereditary = Huntington’s disease (Autosomal dominant progressive brain disorder)

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Examples of diseases caused by genetic and environmental factors...

epilepsy = environmentally caused by head injury or malnutrition, some genetic influence

bipolar disorder = 60-80% caused by genetics, environmentally caused by stressful childhood events

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Inflammation =

A protective response involving host cells, blood vessels, and proteins and other mediators that is intended to eliminate the initial cause of cell injury, as well as the necrotic cells and tissues resulting from the original insult, and to initiate the process of repair

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Acute wound healing -

inflammatory response is initiated by release of cytokines and growth factors = vasodilation = increased in blood flow to site of injury

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Chronic wound healing -

inflammatory response is persistent

localised thrombosis and vasoconstriction lead to tissue hypoxia

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Homeostasis and thrombosis:

Platelets prevent blood loss (haemostasis) and promote tissue repair