Biological Foundations Final Exam

Define inflammation

It is the body's local vascular and cellular response to injury caused by factors that invade and injure the body from:

-the outside (exogenous factors)

examples: foreign bodies, bacteria, viruses

-factors within the body (endogenous factors) that result in cellular or tissue injury

examples- produced from within the immune system itself as well as other systems- e.g. histamines or peptide fragments

Exists as a part of almost ALL chronic diseases (arthritis, hepatitis, cardiovascular disease, Alzheimer's)

It is part of an innate immune response: requires no previous exposure to the insult.

Response is rapid

Difference between acute versus chronic inflammation based on duration, cellular response (which types of cells respond first), and clinically distinctive features (what would you expect to see clinically)

ACUTE

-Short-term (hours or days).

-Abrupt in onset.

-Nonspecific/innate response.

-5 main symptoms: warmth, redness in area of injury, pain (throbbing), localized swelling, loss of function in the site of injury

CHRONIC

-Lasts for weeks, months, or longer

-Occurs when inciting stimuli (chronic infections, tissue irritants, or altered proteins) for inflammation cannot be removed from the body.

-Prolonged activation of the inflammatory response.

-Lymphocytes and macrophages predominate rather than neutrophils (acute).

-Ongoing tissue injury incites an ongoing effort to heal - causes a progressive increase in the accumulation of collagen and scar formation in the tissue

Role (of chronic inflammation) in chronic diseases?

-Associated with many major chronic organ system diseases.

-The progressive loss of functional tissue and the increase of scar tissue in the organ impact on the function of the organ and ultimately results in its failure.

Examples include:

-Chronic Hepatitis caused by Hepatitis C virus infecting the liver; can lead to Cirrhosis.

-Atherosclerosis.

-Chronic Bronchitis.

-(rheumatoid arthritis).

-Inflammatory bowel disease.

Type of immune response involved in inflammation

It is part of an innate immune response: requires no previous exposure to the insult.

Speed of inflammation response

response is rapid

Perspectives from the "seed versus the soil" debate. What is the current prevailing thought?

-Louis Pasteur: countered claiming that diseases would result mainly from external threats ("seed") to the well-being of the organism - the body's responses would be relatively unimportant

-Bernard:

Disease is also due to a failure of the body to maintain equilibrium ("soil"). It is not just the seed that matters but ALSO the soil.

With increasing recognition that diseases often stem from harmful interactions between heredity and environment, or from genetic flaws, Bernard's theory has been proven correct over Pasteur's

Difference between homeostasis and allostasis.

Homeostasis- all internal parameters remain constant

Allostasis- all internal parameters are varied in order to appropriately match them to external stressors

Example of integrative medicine.

acupuncture

meditation

music therapy

aromatherapy

Examples of how our bodies maintain equilibrium internally. What systems are involved in this process? What role does the brain play?

We maintain equilibrium internally:

-Body temperature

-Blood flows to organs

-Many more "variables" depend on complex coordination by the brain

The brain regulates the inner world by maintaining apparent constancy despite continual changes - it does so via systems

The brain receives information from internal sensors and acts on that information to regulate the inner world

The brain tracks many monitored variables, by way of internal sensory information

It acts on this information to maintain levels of monitored variables at controlled, steady values by modulating numerous effectors that work simultaneously

Brain regulates the inner world, to maintain apparent constancy despite continual changes

Define homeostasis

the tendency of an organism or cell to regulate its internal environment and maintain equilibrium, usually by a system of feedback controls, so as to stabilize health and functioning"

Every organ in the body contributes to homeostasis.

Long terms effects of allostatic load

Allostatic load:

-brain's aims to resolve uncertainty- when it cannot do this the situation may become chronic and result in the experience of "allostatic load"

-it is the long term effects of a continuously activated stress response

-results in accelerated disease progression

-can diminish effectiveness of allostatic response

-thus potentially triggering physiological/psychological disorders

-measured through a composite index of indicators of cumulative strain on several organs and tissues

Negative and positive feedback loops

NEGATIVE

-Almost all homeostatic control mechanisms are negative feedback mechanisms.

-These mechanisms change the variable back to its original state or "ideal value."

POSITIVE

-Opposite of a negative feedback mechanism.

-With negative feedback, the output reduces the original effect of the stimulus.

In a positive feedback system, the output enhances the original stimulus.

-Positive feedback mechanisms enhance the original stimulus and negative feedback mechanisms inhibit it.

Difference between an endemic disease, epidemic and pandemic

-ENDEMIC: (of a disease or condition) regularly found among particular people or in a certain area

-EPIDEMIC: An epidemic occurs when an infectious disease spreads rapidly to many people (the rate of disease is above what is normally expected in a population),

-PANDEMIC: "An epidemic occurring worldwide, or over a very wide area, crossing international boundaries and usually affecting a large number of people"

Examples of recent pandemics

Recent Pandemics:

-Severe Acute Respiratory

Syndrome (SARS) (2005)

-H1N1 Outbreak (2009)

-Ebola (2014)

-Coronvirus (2019)

Frequency of pandemics over time

Historically, emerging or re-emerging infectious disease pandemics occur once every 10 years

however evidence shows increasing frequently:

-2003 (SARS)

-2007 (bird flu)

-2009 (swine flu)

-2012(MERS)

-2014 (ebola)

-2019(covid-19)

Global regulations that govern international response to pandemics (name and scope)

Public Health Emergency of International Concern (PHEIC): Defined by the IHR as "an extraordinary event which is determined to constitute a public health risk to other States through the international spread of disease and to potentially require a coordinated international response."

-The WHO Director General and the IHR Emergency Committee determine when an event is a PHEIC

-IHR mandates WHO to perform public health surveillance and risk assessment and to coordinate international response to significant international public health risks (PHEICs)

-WHO issues advice on trade and travel to uphold IHR objective to limit interference with international traffic and trade

Factors contributing to increasing pandemics

-Overpopulation

-Poverty

-Global Warming

-Environmental Degradation

-Habitat Destruction

-Increased Human/Host/Reservoir Interaction - Urban Population Density

-Globalization

Four phases of WHO's response to a pandemic (including brief description of each)

1. Interpandemic phase: support emergency risk management capacity development

2. Alert phase:

-conduct global risk assessment through IHR mechanisms

-provide advice to Member States

-activate support networks

-deploy antivirals

-intensify regulatory preparedness

3. pandemic phase

-scale response as indicated by the global risk assessment

-declare a pandemic

-provide continues support to affected Member States

4. transition phase:

-scale response as indicated by global risk assess.

-consider the modification or termination of temporary measures and termination of a PHEIC

One countries preparedness for a pandemic (Africa)

-Many African nations (35/53 in 2008) have pandemic preparedness plans, but most lack clear, operational strategies

-Ebola outbreak exposed weaknesses:

--Poor infection control that put health workers at risk

--Insufficient community-based health workforce

--Lack of routine surveillance to detect unusual patterns

--Rumors and public distrust impeding behavior change

Prevention of HIV/AIDS: PrEP basics- purpose, how taken; Vaccine availability?

Daily dose of tenofovir disoproxil fumarate (TDF)/emtricitabine can effectively prevent new HIV infections in seronegative persons at a high risk of contracting HIV

-Contingent on high adherence, taken daily regardless of anticipated sexual activity

-Can reduce the risk of HIV infection by over 80%.

Adherence to a full 28-day course of ARVs is critical to the effectiveness

-HVTN Study demonstrates anti-HIV antibody responses within 6 weeks of initial HIV-vaccination

-MORE ONGOING RESEARCH IS NEEDED- future analysis in larger trials

Treatment for HIV

1. Antiretroviral treatement

2. prophylactic treatment for exposed babies

Cause of AIDS

FROM HIV TO AIDS

-First symptoms after infection may mimic the flu

-No other symptoms may occur until enough CD4 cells have been destroyed by HIV

-With loss of CD4 cells, the immune system cannot protect

-When CD4 count reaches 200 - person considered to have AIDS

-Without therapy, the time from infection to AIDS = approximately 8-10 years

-Antiretroviral therapy can prolong this time span

-Some people naturally have not progressed from HIV infection to AIDS- Referred to as long-term nonprogressors

Populations at greatest risk for HIV/AIDS

-gay or bisexual men

-drug users

-women (pregnant)

Public health strategies for addressing bioterrorism (2)

1. Prophylaxis—medical intervention to prevent disease; antibiotics, antivirals and vaccines are used

2. Quarantine—enforced isolation of the sick or exposed from healthy people to contain the spread of disease

3. Surge capacity—the ability to expand healthcare during periods of excessive and/or prolonged demand

Risk factors for cardiovascular disease (3)

-older age

-family history

-poor diet, high blood pressure

-physical inactivity, obesity

Role as a leading cause of death in the US or globally?

CVD is the leading cause of death for both men and women in the United States

Most common type of CVD

Coronary heart disease is the most common type of CVD

Strategies for addressing the burden of CVD globally

(based on in-class exercise 'CVD is a major threat to worldwide global health') (2)

1. public health communities need to increase focus on CVD in all of these locations, not just in high-income countries

2. Health professionals and the government can use evidence-based interventions, such as improving access to healthy food, healthcare, and increasing taxes on tobacco products

-City planning that considers access to good food and promotes routine physical activity

Role of genetics in cancer. Most common type of cancer gene

-Cancer cells behave in this abnormal manner because of changes in the DNA sequence of key genes, which are known as cancer genes. Therefore all cancers are genetic diseases.

-There are two types of cancer genes:

1. Tumour suppressor genes - prevent cell growth and division

2. Oncogenes - help cell growth and division

To date, we know of approximately 400 somatic "cancer genes"

External risk factors for cancer

-ultraviolet

radiation

-tobacco smoking

-diet

Proportion of cases of cancer can be prevented by avoidance of risk factors for cancer?

As much as 50% of cancers can be prevented through avoidance of known risk factors

For the rest, early detection and treatment could reduce mortality

Role as a leading cause of death in the US or globally?

globally

Where in the world do most cancer deaths occur?

Low and Middle Income Countries (LMICs) at a disadvantage

65% of cancer-related deaths occur in LMICs, yet only 5% of global health resources go to LMICs

Barriers to cancer prevention in treatment in low resources settings (2)

health literacy, health service utilization, public health communication, and primary care access all need to be improved or increased for early detection

fragmented healthcare delivery, costs