Download Immunity

Blood and
Immunity
I. Blood
• Is the liquid tissue of transport in
humans
• Average human has 5-6 liters of blood
• Blood is composed of:
red blood cells
white blood cells
platelets
plasma
Blood serves as a
transport medium that
helps to maintain
homeostasis for all cells
of the body.
Ex: hormones are secreted
into blood to help regulate
certain activities in the body.
(A) Plasma
• Consists of 90% water
• Plasma contains:
proteins
antibodies
nutrients
enzymes
hormones
clotting factors
(B) Red Blood Cells
• Also known as Erythrocytes.
• 30 trillion red blood cells in human body.
• Transports O2 from lungs to body tissue
(cells).
• Transports CO2 to the lungs from the body
tissue.
• Lack a nuclei when mature.
• Contain hemoglobin.
(C) White Blood Cells
• Also known as Leukocytes.
• 60 billion white blood cells in the
body.
• WBC’s are larger than RBC’s
• WBC’s contain a nucleus.
• Main purpose is to fight off
disease.
Types of White Blood
Cells
Phagocytes
Lymphocytes
Phagocytes
• Engulf and destroy bacteria
at the site of infection by the
process of phagocytosis.
• This is the normal defense
against disease for the body.
•
Lymphocytes
• Produce antibodies which act
against foreign molecules
known as antigens.
• An antigen-antibody reaction
is referred to as an
immune response
(D) Platelets
• Are smaller than RBC’s and
WBC’s.
• Play a key role in blood clot
formation.
• 1.5 trillion platelets in the
blood.
III. Diseases
• Is any condition that
prevents the body from
working as it should.
• As a result the body may fail
in maintaining homeostasis.
Diseases in Humans may result
from:
1. Pathogens
2. Inheritance
3. Microorganisms
4. Pollutants
5. Organ Malfunction
6. Harmful Lifestyle
1. Pathogens
• Are potentially dangerous
disease-causing organisms
in the air, water and food we
take in every day.
• Ex: viruses, bacteria, fungi,
and parasites.
2. Inheritance
• Defective genetic traits can be passed
from parent to offspring.
• Ex: Sickle-cell anemia
- in this disease the hemoglobin
is flawed and as a result the red blood
cells may get twisted and out of
shape. The red blood cells cannot
carry oxygen in this state.
3. Microorganisms
• Microorganisms that cause disease
include certain fungi, bacteria,
protozoa, and viruses.
• Some diseases caused by
microorganisms may be passed
from one person to another.
• Therefore, these diseases are
known as infectious diseases.
4. Pollutants
• Are chemical agents present in
the environment that may upset
the body’s normal functioning
and produce disease.
• Ex: Asbestos
PCB’s
5. Organ Malfunction
• Diseases may develop when one or
more of the body’s organs
malfunction.
• Ex: Kidney failure
- The kidneys no longer filter
the blood to remove toxins. As a
result, a Dialysis machine is used.
6. Harmful Lifestyles
• The way one lives can be an
important factor in causing
disease.
• Ex:
tobacco
alcohol
drugs
unsafe sexual experiences
IV. Immune System
• Defends our bodies against invaders.
• Each invader, usually a bacterium or virus,
has a specific protein molecule attached
to its surface called an antigen.
• When the immune system detects an
antigen, it produces antibodies that bind
to the antigen.
• The antibody then destroys the antigen.
Active Immunity
• Results when antibodies are produced
by the body in response to a foreign
substance (antigen) in the body.
Ex: A person gets chicken pox
1. Antibodies are produced by the
body (lymphocytes) to fight the
disease-causing organism (antigen).
2. After the illness is over, antibodies
against the disease remain in the blood
and protect against re-infection.
Passive Immunity
• Develops when an individual
receives antibodies from an outside
source (medication).
• This provides temporary immunity to
a particular disease.
• However, the “borrowed” antibodies
are gradually destroyed and the
immunity they provide ends.
• Vaccinations- Scientists have
developed vaccines by using
weakened pathogens to
stimulate the immune system
to react.
• Antibiotics- Chemicals
produced outside the human
body, usually by fungi, that can
be given to a person to kill the
bacteria causing an infection
A
Closer Look
At
White
Blood Cells
B-cells
• Respond to specific antigens by
producing antibodies that will bind
only to the antigen.
• Memory B cells remain in the body
in case you encounter the same
invading microorganism again.
• This is why you usually only get
chicken pox once (active immunity)
•
Killer T-cells
• Detect infected cells with the antigen
in it.
• The killer T-cells attach to the cell
membrane of your infected body cell.
• It then punches holes into the
membrane of the infected cell,
injecting poison into it.
• As a result, the infected cells are killed
and the invaders in these cells are
destroyed.
Helper T-cells
• Assist both B-cells and Killer
T-cells.
• Without Helper T-cells, the immune
system cannot do its job
effectively.
• Helper T-cells are destroyed by the
human immunodeficiency virus
(HIV), which results in the disease
called AIDS.
V. Diseases
of the
Immune
System
Allergic Reactions
• Results from the over activity of the immune
system to common substances such as dust,
mold, pollen, or certain foods.
• The immune system begins to make antibodies,
which causes the body to release substances,
including histamines.
• This causes many allergic reactions such as:
extra fluid in nasal pathways, difficulty breathing,
and hives (inflammation).
• Allergies are treated with antihistamines which are
drugs that stop the release of histamine.
Dust Mite
•
• Living in rugs
and furniture,
these tiny
arthropods can
cause major
problems if you
are allergic.
Autoimmune Diseases
• Results from when the immune
system begins to attack normal
body tissue.
• The body is literally rejecting its
own tissue.
• Ex: Rheumatic fever
Lupus
Immunodeficiency
Diseases
• Ex: AIDS (Acquired immunodeficiency syndrome)
• Develops when the HIV virus
destroys the Helper T-cells and
the body is no longer able to
protect itself from diseases that
may attack it.
VI. Disorders of
Blood
Anemia
• A condition in which blood
cannot carry sufficient
amounts of oxygen to body
cells.
• This is due to reduced
amounts of hemoglobin
and/or red blood cells.
Leukemia
• A form of cancer in which
the bone marrow
produces non-functional
white blood cells.
VII. Blood Types
Blood
Type
A
B
AB
O
Antigen
Antibodies
A
B
A and B
none
anti-B
anti-A
none
anti-A and
anti-B
Transfusion- when a person receives
blood from an outside source
Donor
Recipient
(donates blood)
type O
(receives blood)
type O
type A or O
type A
type B or O
type B
type A, B, AB, or
O
type AB
• Keep in mind:
The person receiving the
blood, look at the antibody
for their blood type; and the
person donating the blood,
look at the antigen for their
blood type.
Type O- universal donor
Type AB- universal recipient
VIII. Human
Lymphatic System
Intercellular Fluid
• All cells of the body are bathed in a
colorless, watery fluid called
intercellular fluid (ICF).
• All substances exchanged between the
blood and the body cells must diffuse
through the ICF.
• Excess ICF is drained from the tissues
by vessels of the lymphatic system.
Lymphatic System
1. Excess ICF is returned back
to the blood by a system of
vessels called the lymphatic
system..
2. Tiny lymph vessels are
present in all body tissue.
3. Excess ICF diffuses into
lymph vessels and is now
called lymph.
4. These small lymph vessels
join larger lymph vessels and
ultimately join into the
thoracic duct, which is the
largest lymphatic vessel in the
body.
5. Lymph from the thoracic
duct is emptied into a large
vein in the neck.
6. It is in this way that fluid lost
from the blood is returned to
the blood.
7. Lymph vessels in the villi of
the small intestine are called
lacteals.
8. Major lymph vessels have
enlarged regions called lymph
nodes in which lymphocytes
(WBC’s) destroy bacteria and
other foreign substances from
the lymph before the fluid is
returned back into the blood.