The immune System
Immunity is the body’s resistance to injury from invading organism. It may develop either
naturally or artificially. The microbe that causes infection are transmitted to people in 4
1. Direct transmission involved bodily contact, kissing
2. Indirect transmission: occurs when microbes are passed to an individual via airborne
particles, dust, water and soil or food. Influenza is an example of an environmentally
3. Biological transmission: occurs when a transmitting agent, such as a mosquito, picks
up microbes, changes them into a form conductive to growth in the human body, and
passes on the disease to the human. The transmission of yellow fever, for example oc-
curs by this method
4. Mechanical transmission: is the passage of a microbe to an individual by means of a
carrier that is not directly involved in the disease process. Transmission of an infection
by means of dirty hands, bad water, rats, mice or flies are examples of mechanical
Natural Immunity- mothers breast milk, temporarily
Artificial immunity- shots we receive through vaccinations and inoculations for certain
diseases ex. hepatitis, whooping cough
Non-specific immune mechanisms- are a general set of responses to any kind of of
infection or disorder
Specific Immune mechanisms- always required after birth, fight particular microorgan-
isms and their toxins
NON specific immunity is mediated in 4 ways: anatomical barriers (the skin), phagocy-
tosis, antimicrobial substances and inflammatory responses.
Phagocytosis is the process by which certain white blood cells (called phagocytes) in-
gest microbes. they are usually overproduced when there is a bodily infection so that
sufficient numbers can be sent to the site of infections to ingest the foreign particles Antimicrobial Substances are chemicals mobilized by the body to kill invading micro-
The inflammatory response is a local reaction to infection. At the site of infection, the
blood capillaries , first enlarge and a chemical called histamine is released into the area.
Familiar examples of the inflammatory response are the reddening, swelling, discharge
and clotting that result when you accidentally lacerate tour skin and the sneezing, runny
nose, and teary eyes result from that allergic response to pollen or dust.
Humoral Immunity: is mediated by B lymphocytes. The function of B lymphocytes in-
clude providing protection against bacteria, neutralizing toxins produced by bacteria and
preventing viral infection.
-humoral immunity is particularly effective in defending the body against bacterial infec-
tions and against viral infections that have not yet invaded.
Cell mediated immunity- involved T lymphocytes from the thymus gland, is a slower act-
ing response. Rather than releasing antibodies into the blood, as humoral immunity
does, cell mediated immunity operates at the cellular level.
-there are 2 types of major lymphocytes cytotoxic T (tc cells) and helper T (tH cells).
The lymphatic systems role in immunity- is a drainage system of the body, is in-
volved in important ways in immune functioning.
There is lymphatic tissue throughout the body, consisting of lymphatic capillaries, ves-
sels, and nodes.
lymphatic capillaries drain water, proteins, microbes and other foreign materials from
space between the cells and lymph vessels.
The lymphatic vessels drain any remaining substances into the blood.
Disorders related to the immune system:
AIDS- progressive impairment of immunity
Lymphoma- tumor of the lymphatic tissue
Hodgkin’s disease- a malignant lymphoma
tonsillitis - inflammation of the tonsils that interfere with their ability to filter out bacteria Auto immunity- is a condition characterized by a specific humoral or cell-mediated im-
mune response that attacks the body’s own tissue
examples include : Multiple sclerosis, and arthritis.
Chapter 3: Health Behaviours
Health promotion: is a general philosophy that that has at its core the idea that good
health, or wellness is a personal collective achievement
-the process of enabling people to increase control over and improve their, “health.”
-health promotion involves developing a program of good health habits early in life and
carrying them though adulthood and old age.
-half of the deaths in canada (cancer deaths) can be prevented because they are due
from modifiable factors
health behaviours- are behaviours undertaken by people to enhance or maintain their
Health habit- is a health related behaviour that is firmly established and often per-
formed automatically, without awareness. -these habits usually develop in childhood at around age 11 to 12
examples include: brushing teeth, wearing seatbelt, eating healthy
7 IMPORTANT GOOD HEALTH HABITS:
1. sleeping 7 to 8 hours
2. not smoking
3. eat breakfast each day
4. having no more than one or 2 alcoholic beverages each day
5. getting regular exercise
6. not eating between meals
7. being no more than 10 percent overweight
Primary prevention: instilling good health habits and changing poor ones
-this means taking measures to combat risk factors for illness before an illness ever has
a chance to develop.
General strategies are to keep people from developing poor health habits from the be-
ginning and to employ behaviour-change methods to get people to alter their problemat-
ic health behaviours
What factors influence the practice of Health behaviours
1.Socio-economic factors, people with low levels of stress typically practice better
2.Age- health habits are good in childhood, deteriorate in adolescence, improve again
among retired adults under 73, and then worse after 73
3.Gender- females eat better lunches, but worse dieting and meal skipping. boys take
part in more sports
4. Values- one culture may desire exercise while one does not
5. personal control- Health locus of control.. people may see themselves under their
control, or others, or chance, those who see themselves under full control tend to prac-
tice better health habits
6. social influence- family friends, workplace, companion
7. personal goals-
8. perceived symptoms-smoker who wakes up thinking they have smokers cough, be-
lieving they are vulnerable to health problems at that time 9. access to health care services-
10. place- depends where you live, rural areas with less access to health care ser-
vices make it difficult
11. cognitive factors- being more health conscious
-the belief that certain health behaviours are beneficial
Intervening with Children and Adolescence
Health habits are strongly affected by early socialization, especially the influence or par-
ents as role models.
-They can instill certain health habits in their children that become automatic, such as
wearing their seatbelt, brushing teeth regularly, eating breakfast every day
-adolescents are vulnerable to an array of problematic health behaviours, including ex-
cessive drinking and smoking, drug use and sexual risk taking.. If parents aren’t moni-
toring their children and peers around them.
-Consequently, interventions with children and adolescents are high priority.
The teachable Moment- certain times are better than others for teaching particular
-many arise in early childhood, seatbelt, looking before crossing street
Pregnancy represents a teachable moment for several health habits such as quitting
smoking and eating healthier
Window of Vulnerability- There is a window of vulnerability for smoking and drug use
that occurs in junior high school students when they are first exposed to these habits in-
cluding smoking and drug use, drinking, dieting , snacking, eating bad by their peers
and older siblings.
Adolescence Health behaviours Influence Adult Health
This means that the health habits people practice as a teenager or college students may
well determine the chronic diseases they have and what they ultimately die of in adult-
hood. for adults who decide to make changes in their lifestyle, it may already be too late.
research suggests that this is true for sun exposure, and for calcium consumption for the
prevention of osteoporosis. Diet, especially dietary fat intake and protein consumption in
adolescence, may have also predict adult cancers. Adolescents be actually be a highly vulnerable time for a variety of poor health behaviours that lay the underground work for
suture problems in adulthood.
Health Promotion and the Elderly.
Frank Ford, 91.. he says its all about “exercise, friends and mental challenge.”
- and elderly population is essential for increasing the quality of life of this growing group
of citizens now and in the years to come.
- Exercise is one of the most important health behaviours because exercise keeps peo-
ple mobile and able to care for themselves.
- reduces the risk of mortality, perhaps by providing social support or a general sense of
- The MUST control alcohol consumption .. they try and maintain their drinking habits
they had when they were young.
- Many old people are on medications which may interfere with alcohol
- alcohol increases the risk of gastrointestinal disorders and accidents, with in conjunc-
tion of osteoporosis can produce broken bones, which limit mobility
- They must get their vaccines against influenza, which is a major cause of death in el-
derly. Moreover it increases the risk of heart disease and stroke because it exacerbates
other underlying disorders that an elderly person may have.
Ethnic and Gender differences in health risks and habits
-Chinese have more abdomen fat that canadians, putting them at risk for cardiovascular
-men smoke and drink more
-the rate of diabetes for Canada s Aboriginal people is an epidemic, they are also over-
Attitude Change and Health Behaviour
Through Educational Appeals!!
1. Communications should be colourful and vivid rather than steeped in statistics and
2. The communicator should be an expert, prestigious and trustworthy, likable and simi-
lar to the audience 3. Strong arguments should be presented at the beginning and end of an argument not
in the middle
4. Messages should be short, clear and direct
5. Messages should state conclusions explicitly
6. Extreme messages produce more attitude change, but only up to a point.
7. For illness detection behaviours (such as HIV testing or a mammogram), emphasizing
the problems that may occur if it is not undertaken
8. If the audience is receptive to changing a health habit, then the communication
should include only favourable points, but if the audience is not inclines to accept the
message, the communication should discuss both sides of the issue
Fear Appeals: This approach assumes that if people are fearful that a particular habit is
hurting their health, they will change their behaviour to reduce their fear, Common sense
suggests that the relationship between fear and behaviour change should be direct: The
more fear an individual has, the more likely he/she will be more likely to change the rele-