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IMMUNE SYSTEM
GROUP-1
IMMUNE SYSTEM
 The immune system is a biological structure within an
organism that act as protection against diseases.
 Most vertebrates have a general protective mechanism
within their body that protects them against pathogens
(disease causing) or infectious such as bacteria, viruses,
some fungi, and other parasites.
 The human immune system is the most complex. The
human body has three cooperating lines that defense that
the new threats as quickly as possible.
FIRST LINE OF DEFENSE
 The human body has important parts that support the
immune system that are not actually part of the system
 There are a combination of physical and chemical barriers
that prevent all types of foreign agents from penetrating
the outer layer of the body. No specific foreign agent is
targeted at this level.
First line of defense:
Physical Barriers
Skin
Cells filled with keratin, making skin
impenetrable, waterproof, and resistant to
disruptive and most invaders
Dead cells are shed and replaced (1 million
every 40mins), taking microbes with them
Mucous Membranes
The inner surfaces of the body are guarded
by mucous membranes that line the
respiratory, digestive, urinary, and
reproductive systems and protect the
internal lining.
Hair in the nose act as a coarse filter
First line of defense cont.
• The airborne pathogens are
prevented to go further the
respiratory system as they are
trapped by the mucus.
• These organs are lined with small
hair like projective called cilia
which sweep out mucus with its
trapped dirt and bacteria.
• Most invaders do not survive the
stomach acid which is strong
enough to kill them.
• Dead pathogens ate then
eliminated from the body.
The first line of defense:
Chemical Barriers
Sweat produced by glands in the
skin wash away microbes in their
acidity slows bacterial growth.
Mucous membranes produce sticky
mucous that traps many microbes
Saliva and tears contain an enzyme
called lysozyme that kills bacteria
by rupturing their cell walls
Cerumen (ear wax)- produced in the
ear canal and protects the canal by
trapping dirt and dust particles
Second line of Defense
 Microbes that can able get into
the body encounter the second
line of defense. This limits the
spread of the invaders in advance
of the specific immune responses
 The second line of defense
includes the inflammatory
responses, phagocytes,
interferons, and natural
killer(NK) cells.
The second line of
defense: Defensive
Proteins
COMPLEMENT SYSTEM
Destruction of pathogens
(Cell lysis)
Enhancement of
phagocytosis
(Opsonization)
Stimulation of
inflammation
Chemotaxis –attracting
macrophages and
neutrophils
The Second Line of
defense: Inflammation
 Chemokines- secretes by blood
vessel endothelium and monocytes
also attract phagocytes to the area.
 Pyroxenes- released by certain
leukocytes, increase the body
temperature to speed up the
immune response and prevent the
microbes to functions normally.
Histamine -is secreted by
basophils (a type of white blood
cell)and of in mast cells triggers
the inflammation.
This inflammation is caused by the
vasodilation (enlargement of the
blood vessels) that increases the
blood supply bringing more
phagocytes in the area of
infection.
Second line of defense
Two types of phagocytes
Neutrophils – engulf
microbes and kill them
within a few days
Monocytes on the other
hand, transform into
macrophanes, “giant
eaters”
Inflammation and
phagocytes
 The body has other second
line of defense called
interferons.
 Interferons are
signalingproteins produces by
body cells when they attacked
by microbes, especially viruses.
 The invaded cell will produce
interferon to signal the other
cells causing them
“
”
Third line of defense
o Both first and second line of defense are nonspecific responses,
meaning they respond to all kind of infections- they do not target
a specific.
o Third lines of defense is specific and relies on B lymphocytes and T
lymphocytes, which come from the bone marrow.
Second line of defense:
B lymphocytes
 Mature in the bone marrow
and fight disease in humoral
immunity
 Activated B lymphocytes
secrete 2000 antibodies per
second over the cell’s lifespan
(4 to 5 days
T lymphocytes
 Mature in the thymus and fight the
pathogens by the cell- mediated
 There are two types of T lymphocytes: the
cytotoxic and helper T cells
 Cytotoxic T(Tc) cells which kill infected cells
with pathogens and cancer cells
 Helper (Th) T cells they announce to the
immune system, with the aid of the
macrophages and some B cells
 They release cytokines that stimulate the Tc
cells, B lymphocytes, and other helper cells.
IMMUNE SYSTEM-1 (1).pptx

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IMMUNE SYSTEM-1 (1).pptx

  • 2. IMMUNE SYSTEM  The immune system is a biological structure within an organism that act as protection against diseases.  Most vertebrates have a general protective mechanism within their body that protects them against pathogens (disease causing) or infectious such as bacteria, viruses, some fungi, and other parasites.  The human immune system is the most complex. The human body has three cooperating lines that defense that the new threats as quickly as possible.
  • 3. FIRST LINE OF DEFENSE  The human body has important parts that support the immune system that are not actually part of the system  There are a combination of physical and chemical barriers that prevent all types of foreign agents from penetrating the outer layer of the body. No specific foreign agent is targeted at this level.
  • 4. First line of defense: Physical Barriers Skin Cells filled with keratin, making skin impenetrable, waterproof, and resistant to disruptive and most invaders Dead cells are shed and replaced (1 million every 40mins), taking microbes with them Mucous Membranes The inner surfaces of the body are guarded by mucous membranes that line the respiratory, digestive, urinary, and reproductive systems and protect the internal lining. Hair in the nose act as a coarse filter
  • 5. First line of defense cont. • The airborne pathogens are prevented to go further the respiratory system as they are trapped by the mucus. • These organs are lined with small hair like projective called cilia which sweep out mucus with its trapped dirt and bacteria. • Most invaders do not survive the stomach acid which is strong enough to kill them. • Dead pathogens ate then eliminated from the body.
  • 6. The first line of defense: Chemical Barriers Sweat produced by glands in the skin wash away microbes in their acidity slows bacterial growth. Mucous membranes produce sticky mucous that traps many microbes Saliva and tears contain an enzyme called lysozyme that kills bacteria by rupturing their cell walls Cerumen (ear wax)- produced in the ear canal and protects the canal by trapping dirt and dust particles
  • 7. Second line of Defense  Microbes that can able get into the body encounter the second line of defense. This limits the spread of the invaders in advance of the specific immune responses  The second line of defense includes the inflammatory responses, phagocytes, interferons, and natural killer(NK) cells.
  • 8. The second line of defense: Defensive Proteins COMPLEMENT SYSTEM Destruction of pathogens (Cell lysis) Enhancement of phagocytosis (Opsonization) Stimulation of inflammation Chemotaxis –attracting macrophages and neutrophils
  • 9. The Second Line of defense: Inflammation  Chemokines- secretes by blood vessel endothelium and monocytes also attract phagocytes to the area.  Pyroxenes- released by certain leukocytes, increase the body temperature to speed up the immune response and prevent the microbes to functions normally. Histamine -is secreted by basophils (a type of white blood cell)and of in mast cells triggers the inflammation. This inflammation is caused by the vasodilation (enlargement of the blood vessels) that increases the blood supply bringing more phagocytes in the area of infection.
  • 10. Second line of defense Two types of phagocytes Neutrophils – engulf microbes and kill them within a few days Monocytes on the other hand, transform into macrophanes, “giant eaters” Inflammation and phagocytes  The body has other second line of defense called interferons.  Interferons are signalingproteins produces by body cells when they attacked by microbes, especially viruses.  The invaded cell will produce interferon to signal the other cells causing them
  • 11. “ ” Third line of defense o Both first and second line of defense are nonspecific responses, meaning they respond to all kind of infections- they do not target a specific. o Third lines of defense is specific and relies on B lymphocytes and T lymphocytes, which come from the bone marrow.
  • 12. Second line of defense: B lymphocytes  Mature in the bone marrow and fight disease in humoral immunity  Activated B lymphocytes secrete 2000 antibodies per second over the cell’s lifespan (4 to 5 days T lymphocytes  Mature in the thymus and fight the pathogens by the cell- mediated  There are two types of T lymphocytes: the cytotoxic and helper T cells  Cytotoxic T(Tc) cells which kill infected cells with pathogens and cancer cells  Helper (Th) T cells they announce to the immune system, with the aid of the macrophages and some B cells  They release cytokines that stimulate the Tc cells, B lymphocytes, and other helper cells.