BODIES DEFENCES.pptx

BODIES
DEFENCE
MECHANISM
Dr. Abhay M. Shankaregowda, BNYS., MD Yoga (Clinical)
HOD, Department of Philosophy of Nature Cure
SDM College of Naturopathy & Yogic Sciences, Ujire - 574240
1
Dr. Abhay M. Shankaregowda

• Natural Immunity
• Phylogenetically older: Present in all
Multicellular Organisms
• Use Proteins Encoded in the Germline
(Elements an Individual is born with:
Standard Equipment-Hard-Wired.
Non Specific Immunity
The body's defense mechanisms are divided into two categories.
Non-specific mechanisms and Specific mechanisms.
2

• Preformed: Rapid-Available on Short
Notice
• No Memory:Not Enhanced by Prior
Exposure:
• Broad Specificity
• Dependent on species, strain, sex.
3

Acquired/Specific Immunity
• Acquired Following Exposure to
the Microorganism.
4

Acquired/Adaptive/Specific
Immunity Features
• Specificity
• Memory
• Specialization
• Self/Nonself recognition
5

Non Specific v/s Specific
Immunity
Innate/Natural/ Nonspecific
– present from birth
– operates against any
substance
– not enhanced by prior
exposure
Acquired/Adaptive/Specific
– After Birth
– tailored to individual
pathogens
– enhanced by prior
exposure
6

In non-specific mechanisms have the basic reaction of any kind infections
This mechanism consists of four types of defensive barriers:
1. Anatomic barriers (skin, Mucous membranes)
2. Physiological barriers (temperature, pH, strain)
3. Cellular Barriers (endocytosis and phagocytosis)
4. Inflammatory Barriers (blood vessel dilation, increased
permeability of capillaries in tissue)
7

Anatomic Barriers
• External/First line of defenses
• Epithelial Barrier
– Skin
– Mucous membranes
• Conjunctivae, GI, resp, urogenital tracts
• secretions (saliva, tears, urine, mucus)
–wash/trap/inhibit growth
• cilia
8

THE
SKIN 9

•The skin is tough, dry, salty, oily, rich in fatty acids and urea, low in
nutrients (lots of dead, empty cells) & thick.
•The sweat glands secrete a mixture of salt, & fatty acids that inhibit
many microbes.
•It also is home for a host of NORMAL FLORA organisms that are
ANTAGONISTIC to potential pathogens.
•Also, the normal flora scarf up potential nutrients on the skin surface.
•We are taught by our mothers from an early age to keep our skin clean,
usually to forestall a serious antisocial ODOR PROBLEM.
•However, the real benefit of this training is that it serves to PROTECT US
from potential pathogens.
10

•The skin contains glands known as sebaceous glands associated with the hair
follicles and are most numerous on the scalp, the face, the middle
of the back and around the genitalia.
•They produce a substance known as sebum which comprises triglyceride,
waxes, paraffins and cholesterol.
•The main function of the sebum is to waterproof the skin but it is also
thought to have an anti-bacterial action.
•When intact, the skin is virtually impermeable to micro-organisms, and also
protects from chemicals (weak acids, alkalis etc.) and most gases -
although same gases developed for use in chemical warfare can be
absorbed through the skin.
11

•The integument gives some protection from physical trauma, for instance
from some forms of particulate radiation such as alpha rays and, to a
lesser extent, from beta rays. beta rays can only penetrate a few
millimetres thus protecting the underlying organs from their
potentially harmful effects.
•In addition the skin is protected from the harmful effects of ultra-
violet radiation by the production of melanin within it.
12

•On each square centimetre of skin there may be up to 3 million
micro-organisms.
•The skin does not provide a very hospitable environment for bacteria
unless they have become adapted through evolution to live
there.
•The micro-organisms tend to live in the deeper layers of the stratum
corneum near to their food source.
•The application of strong deodorants, and the use of strong soaps
that alter the skin pH from acid to alkaline upset the fine
balance that exists between our parasites and us.
•These tend to kill or inhibit the normal flora, leaving the area open to
potential colonisation by pathogens.
13

•Arms and legs have the fewest micro-organisms (only one thousand to ten
thousand per square centimetre, whereas on the forehead there may
be as many as one million per sq. cm. and between the toes up to a
thousand million per sq. cm.
•Micro-organisms thrive in moist conditions, and so the axillae (armpits) and
groin provide favourable areas for their growth.
•A waterproof plaster applied to a cut on the forearm for one or two days
causes an increase in the resident population and washing and
bathing both increase the numbers of bacteria released from the
skin for up to 10 hours.
• Heat and moisture cause the break-up of large colonies, so more organisms
tend to be shed.
14

•Consider these steps to improve skin immunity:
•Vegetables and fruits are loaded with anti-oxidants which deal with free
radicals. So make sure that you include 3-4 portions of nutritious
fresh vegetables at each meal..
•Protect your skin from external threats and prevent excess moisture loss
•When skin immunity is weakened, it is more prone to allergy/rash. So
replenish the protective layer of skin by applying the right skin
products and following a skin care regime.
•Keeping the tummy fit and bowel clean helps a lot in avoiding skin allergies.
•Sunscreens help a lot in delaying photoaging which further help in boosting
skin immunity and keep skin younger and wrinkle-free.
15

•Use a mild soap or a face wash to clean your skin.
•Pamper your skin occasionally with facials and massages. But take care to
go light on the cosmetics and chemicals
•Regular use of scrubs helps to remove dead cells from your skin.
•Use of herbs like aloe vera and neem helps to cleanse the skin.
•Use steam to cleanse your face once a week
•Drink 8-10 glasses of water daily.
•Ensure that you get enough sleep; at least 6-8 hours daily and on a regular
basis.
•Go for walks whenever possible. This will ensure you receive plenty of
beneficial oxygen needed to cleanse your system.
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The mucous membranes (or mucosae; singular mucosa) are linings
of mostly endodermal origin.
They cover, protect, and provide secretory and absorptive functions
in the channels and extended pockets of the outside world
that are incorporated in the body. This applies to: the whole of
the alimentary tract from the mouth to the anus; the
respiratory tract the urogenital tract .
The sticky, thick fluid secreted by the mucous membranes and glands
is termed mucus. The term mucous membrane refers to where
they are found in the body and not every mucous membrane
secretes mucus
17

The mouth
18

 The mouth harbors a host of microbes that live more or less
permanently
 These microbes are mostly symbiotic and usually do us little harm
as long as we remain healthy.
 Regardless of how thoroughly we brush our teeth this NATURAL
FLORA remains literally attached to us.
 The mouth, or buccal cavity, is lined with a reasonably tough
mucous membrane that is constantly irrigated by a back flow of
saliva.
 This flow is directed towards the throat and has the dual purpose
of preventing micro-organisms from infecting the salivary glands
and also trapping the organisms so that they can be swallowed
19

 Saliva contains an enzyme called lysozyme, which is
antibacterial and mucous which in turn contains the
immunoglobulin IgA.
 Patients who have become dehydrated and hence have a
reduced flow of saliva are at a higher risk of mouth
infections.
 The resident bacteria of the mouth are generally harmless.
 Some such as alpha haemolytic Streptococcus are of a
positive benefit as they produce hydrogen peroxide (a
bleaching agent) which helps to keep the mouth clean.
20

 Patients who are on a prolonged course of oral antibiotics run the
risk of having their normal flora wiped out.
 Tonsils also assist in the protection of the buccal cavity.
 The outer covering of the tonsils is extremely thin and is easily
traumatised and as such the tonsils themselves become prone to
infection especially during childhood.
21

The Nose
22

The nose is designed so that the TURBULENT FLOW of air throws
particulate matter onto the sticky mucous lining .
The cells lining these channels secrete DEFENSINS that punch holes in
the membranes of many bacteria and destroy them.
In addition, this circuitous route through the nasal passages WARMS
cold air and COOLS hot air as it contacts the tissues along the
way.
The ciliated nasal mucosa secretes a backward-flowing stream of mucus
that traps smaller particles and has both bactericidal and
virucidal properties.
Lysozyme is also present in nasal secretions.
Sneezing is a protective reflex that expels irritants
23

Trachea
and
Lungs
24

Ciliated mucous membrane serves to trap any organisms in debris
that may have escaped through the upper tract.
Here the cilia beat upwards, and shift a stream of mucus towards the
pharynx to be swallowed.
The lungs, with their large surface area and numerous small
chambers, offer a rich source of nutrients and a great
potential for concealing pathogens .
Any organisms reach the alveoli, alveolar macrophages phagocytose
them.
The hilum of the lung is well supplied with lymph nodes that act as a
further filter.
Coughing is a defensive reflex that removes particulate matter or
excess mucus in the lower tract
Trachea and lungs
25

The Stomach
26

 Contains a strong (hydrochloric) acid.
 Many microbes are killed by this acidic environment and digested
by the proteolytic enzymes in the digestive system.
 Until fairly recently it was even suggested that the stomach was
essentially sterile due to the low pH.
 Discovery of the bacterium Helicobacter pylori that lives happily in
the stomach and causes dreadful things like ulcers and stomach
cancer .Some organisms however can resist this strong acid.
 Both milk and proteins are effective buffers against the stomach’s
acid .
 Vomiting can also be regarded as a defence mechanism by ridding
the body of irritants and toxins . 27

The small intestine is full of DIGESTIVE ENZYMES and
DETERGENTS (bile) that agreeably digests microbes
as well as hamburger & pizza.
The small intestine may be full of nutrients, the adsorption
system of the healthy body is so efficient that these
nutrients are ABSORBED from the intestine so rapidly
that residential microbes have little to live on.
Further, the intestines are anaerobic, so obligate aerobes
are unable to grow there even if they should survive
the trip through the stomach.
The small intestine
28

The large intestine collects and processes undigested material
that passes through the small intestine.
Bacteria, including some very nasty potential pathogens, grow
robustly on this debris and yet they rarely manage to
invade the body.
The wall of the large intestine is coated with a PROTECTIVE
MUCOUS LAYER that separates the contents from direct
contact with the cells lining the large intestine.
The normal flora of the large intestine evolved to live on the
available food supply in the anaerobic conditions found
there.
The large intestine
29

The small and large intestines rely to a great extent upon
the stomach’s bactericidal action.
The administration of broad-spectrum antibiotics or
indiscriminate use of laxatives can lead the intestines
open to colonisation by pathogens
Intestines are liberally supplied with lymphatic tissue
throughout their length.
Diarrhoea & vomiting, may also be regarded as a defence
mechanism although in most instances it occurs far too
late in the course of an infection to be of much benefit
The Intestines…..
30

Genitourinary
Tract
31

This region of the body is a rich source of infection for obvious reasons.
Micturition itself irrigates the urethra .The urine is a good nutrient for
many microbes
Sexual activity SIGNIFICANTLY INCREASES the exposure to potential
pathogens.
However, because the urethra is shorter in women than men, bladder
infections are more common in women.
Microbial pathogens that infect this region have adhesive pili that attach
them to the cells lining the urethra and bladder.
Faulty aseptic technique during catheterisation can therefore result in
urinary tract infections, which is one of the most common
hospital acquired infections
Genitourinary tract
32

The anal region is continually exposed to fecal microbes, that
can produce serious or even fatal diseases if they are
introduced into the blood or tissue.
The mucous covering, while protective as long as it is
maintained, is easily breached as is the delicate anal membrane
lining itself.
The vaginal area is another region where infections are easily
established.
The vaginal lining is THIN AND EASILY DAMAGED and its rich
blood supply makes it an easy entry point for pathogens & is
a major reason why women are more likely to become infected
with the HIV from fewer exposures.
Genitourinary tract….
33

The Eye
34

The surface of the eyeball is constantly irrigated with tears produced
by the lachrymal glands.
Tears contain high levels of lysozyme forms an effective barrier
against infection.
Blinking is a defence reflex that both eliminates irritants and ensures
even distribution of the tears.
In some conditions such as facial paralysis or stroke this reflex is lost
and it becomes necessary to prevent the eye from drying up by
keeping it closed or covered and by regular irrigation
If the diet is lacking in Vit A the production of lysozyme in the tears
decreases and can result in a predisposition to eye infection.
The Eye
35

The Ear
Ceruminous glands located in
the outer ear canal are
modified sweat glands
that produce cerumen
or ear wax.
This provides a sticky
barrier to foreign
agents entering the ear
canal
36

Physiological Barriers
• Temperature-Fever
• pH-Stomach, vagina, and skin
• Normal microflora of GI tract, skin
Superinfection
• Chemical Mediators
– Defensins-Secreted by Epithelia
– Hydrolytic enzymes of Saliva
– Lysozyme in tears
– Interferons-viral infection
37

Fever is a common medical sign characterized by an elevation
of temperature above the normal range of 36.5–37.5 °C
(98–100 °F) due to an increase in the body temperature
regulatory set-point.
Fever is considered a nonspecific defense mechanism because
it develops in response to numerous traumas.
Fever is initiated by circulating substances called pyrogens,
which affect the brain's hypothalamus and cause the
latter to raise the temperature.
A Finnish study suggested reduced mortality in bacterial
infections when fever was present.
Temperature-Fever
38

 There are certainly some important immunological reactions
that are sped up by temperature.
 Fevers may be useful to some extent since they allow the
body to reach high temperatures, creating hostile
environment for some pathogens with strict temperature
preferences .
 White blood cells also rapidly proliferate due to the suitable
environment and can also help fight off the harmful
pathogens and microbes that invaded the body
Temperature-Fever
39

Skin flora
A study of 20 skin sites on each of 10 healthy humans
found 205 identified genera in nineteen bacterial
phyla.
Conjunctival flora
A small number of bacteria are normally present in the
conjunctiva.
Tears contain bactericides such as lysozyme, so that
microorganisms have difficulty in surviving the
lysozyme and settling on the epithelial surfaces.
Normal microflora
40

Gut flora
The average human body, consisting of about
(10,000,000,000,000 or about ten trillion) cells, has about
ten times that number of microorganisms in the gut.
Somewhere between 300 and 1000 different species live in
the gut, with most estimates at about 500.
The metabolic activity performed by these bacteria is equal to
that of a virtual organ, leading to gut bacteria being termed a
"forgotten" organ. Bacteria make up most of the flora in
the colon and 60% of the dry mass of feces.
Vaginal flora
Oral cavity
Normal microflora
41

Defensins are found in both vertebrates and invertebrates.
and also been reported in plants.
They are active against bacteria, fungi and many enveloped
and nonenveloped viruses.
Most defensins function by binding to the microbial cell
membrane, and, once embedded, forming pore-like
membrane defects that allow efflux of essential ions
and nutrients
Chemical Mediators
42

Interferon is a group of antiviral substances produced by body cells in
response to the presence of viruses.
Lymphocytes and macrophages produce alpha-interferon, epithelial
cells produce beta-interferon, and T-lymphocytes produce
gamma-interferon.
The interferons do not directly inhibit viruses. Instead, they stimulate
adjacent cells to produce substances that inhibit the replication
of viruses in those cells.
Interferons produced in response to one virus will protect against
many other types of viruses, and for this reason, interferon is
considered a nonspecific form of defense.
Chemical Mediators
43

Cellular
Barriers
44

Phagocytosis is a highly efficient cellular barrier against the
pathogenic microorganisms and is met out by uptake and digestion
of microorganisms by a variety of cells of the body’s defence system.
Includes Phagocytes (macrophages, neutrophils, and dendritic
cells), Mast cells, Eosinophils, Basophils, and Natural killer cells.
These cells identify and eliminate pathogens, either by attacking
larger pathogens through contact or by engulfing and then killing
microorganisms.
Cellular Barriers
45

Neutrophils and Macrophages are phagocytes that travel throughout the body
in pursuit of invading pathogens.Neutrophils are normally found in the
bloodstream.
Dendritic cells (DC) are phagocytes in tissues that are in contact with the
external environment; they are located mainly in the skin, nose, lungs, stomach,
and intestines
Natural killer (NK cells) cells are leukocytes that attack and destroy tumor cells, or
cells that have been infected by viruses
Mast cells reside in connective tissues and mucous membranes, and regulate
the inflammatory response.
Basophils and Eosinophils are related to neutrophils. They secrete chemical
mediators that are involved in defending against parasites and play a role in
allergic reactions .
46

Inflammation
Barrier
47

Inflammation helps localizing invading microorganisms to arrest the spread of
the infection.
Characterized by the symptoms of redness, swelling, pain, and elevated
temperature of a localized area.
Redness is due to capillary dilation allowing more blood to flow.
Swelling is due to increased capillary permeability allowing accumulation of
fluids in the bases surrounding tissue cells.
Pain is due to lysis of blood cells that triggers the production of prostaglandins
and bradykininwhich alter the threshold and intensity of the nervous system
response to pain.
Elevated temperature in localized area occurs because of high metabolic
activities of neutrophils and macrophages in the increased blood flow in that
area.
48

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