Transcript Human Immune System

Human Immune System
How our cells work to fight disease.
Lymphatic System
 Excretes excessive fluid from tissue to
blood stream
 Absorbs fats in the intestine and puts
it n the blood system
 Defends the body against disease
 What we are most interested in
Lymph
 Excessive fluid found in blood
 Carried by lymphatic vessels
 A one way system to drain the body
 The fluid enters the blood stream at
the subclavian vein
Organs of the system
 Spleen
 Blood is cleaned by macrophages and
lymphocytes
 Lymph nodes
 Placed along lymphatic vessels
 Tonsils, adenoids
 Inguinal and AXILLARY nodes
Diseases of the lymph nodes
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Lymphadenitis
Lymphagitis
Elephantiasis
Pulmonary edema
Lymphoma
Hodgkin’s disease
Thymus
 Just under the sternum
 Thymus lymphocytes (T cells) mature
in these lobules
 Secretes thymosin
 Causes pre-T cells to become
Bone Marrow
 Creates blood cells – red and white
 White cells are necessary for the
development of immunity
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Neutrophils
Eosinophils
Basophil
Lymphocytes
Monocytes
Immunity
 The immune response is the ability to
distinguish between "self" and "nonself."
 Every cell in your body carries the
same set of distinctive surface
proteins that distinguish you as "self."
Non-Specific Defenses
 Barriers to entry
 Mechanical barriers stop pathogens from
entering the body
 Skin secretes oil containing a chemical that
weakens or kills bacteria
 Respiratory track lined with cells with cilia
that sweep mucus and trapped particles
into throat to be expelled
 Stomach with high pH that inhibits growth
of bacteria
 Other organs with good bacteria that
prevent pathogens from lodging
 Stomach with high pH that inhibits growth
of bacteria
 Other organs with good bacteria that
prevent pathogens from lodging there
 Non-specific means that the body
doesn’t know what it’s fighting, just
knows that it is not “self”
Inflammatory reaction
 When skin is broken there is
reddening and swelling at the site of
the injury
 The capillaries rupture and release
histamine
 Histamine causes capillaries to dilate and
become more permeable
 Bradykinin increases the effects of
histamine and begins nerve impulses
that result in pain
 Larger capillaries are the redness
 Increased permeability allows fluid
and cells from the blood stream to
escape and that results in the
swelling surrounding an injury
 A break in the skin allows pathogens
to enter
 Neutrophils and monocytes enter
tissue with the fluids and carryon
phagocytosis
 Steps of phagocytosis
 short animation of phagocytosis in
action
Macrophages
 Monocytes turn into macrophages
 These are large phagocyte cells that can
kill many invaders and survive
 Some organs have resident macrophages
that act as the body’s scavengers
 They also cause the body to greatly
increase production of leukocytes –
specifically neutrophils
 Pus is dead tissue, cells, bacteria and
living wbc
Protective Proteins
 Complement has plasma proteins
named letter C and a number or
letter.
 Once activated it increases other
proteins in a set series of reactions
 Creates a cascade response
 Wiki – complement Honors students
must read and take notes.
How they work
 The complement forms holes in cell
walls and it allows fluids to enter
 The cell then lyses (bursts like a
water balloon)
Specific Defense
 The immune system must identify self
v. non-self.
 The proteins on the out side of
human cells, foreign cells or
cancerous cells are not like the ones
on the body cells
 The part of the protein that is
recognized is called an antigen
 The body fights these antigens with a
molecule called an antibodies
 These molecules are made by cells
called B lymphocytes – B stands for
bone marrow
 Antibodies can combine with and stop
antigens from harming the body
 They work like a key/lock system; a
specific type of antibody disables a
specific antigen (marker molecule)
Honors read for understanding and
take notes
T Lymphocytes
 T stands for thymus where these
lympocytes mature in the thymus
grand.
 Called T cells; they do not produce
antibodies but directly attach cells
that have antigen marker proteins
they recognize
 Will be important when we discuss
HIV
Go to Antibodiy-