Download DEFENSE - Immune 15-16

3/8
• Pick up quiz answer sheet from the front and
graded work from the back.
• Reminders:
– TEST ON FRIDAY 3/11 OVER ALL BODY SYSTEMS
– Make-Up Chicken Wing Dissection today after school
or tomorrow afterschool.
• No warm up. 5 min to finish and turn in Chicken
Wing questions pg 65-66
Animal Systems: DEFENSE
Immune System
DEFENSE
How do the integumentary, immune and
lymphatic systems work together to
defend the body?
These systems work to
protect the body from
pathogens. The
integumentary system
(skin) is the first barrier
against infection, and any
invading pathogens are
destroyed and removed
via the immune and
lymphatic systems.
Immune System
Purpose: The immune system protects the body
from disease by producing specialized cells that
inactivate or destroy pathogens.
Parts of the System - consists of specialized cells and organs
that respond to the presence of a pathogen
• skin – body’s first line of defense (also part of integumentary
system)
• white blood cells – recognize disease agents (antigens) and
create antibodies to tag and remove these antigens.
Macrophages are the white blood cell type that actually
eat and destroy these antigens.
Macrophage of a mouse
stretching its “arms”
(pseudopodia) to engulf 2
pathogens
How the Immune System works:
1. First line of defense (pathogen does not
enter body)
o Skin & other non-specific defenses such
as mucous, saliva, and tears trap and
destroy pathogens.
2. Second line of defense (pathogen enters body)
o If pathogen does enter the body, this triggers
the inflammatory response – Tissue
becomes swollen and painful due to white
blood cell accumulation.
o Chemicals are released by immune system to
cause fever (increased body temperature);
increased temperature can kill some bacteria
and viruses.
o White blood cells called macrophages engulf
and destroy pathogens.
3. Third line of defense (pathogen gets past first and second
line of defense)
• Immune response
1. Triggered by an antigen; virus, bacteria or other
Antigen
pathogen.
binding
sites
2. T cells and B cells recognize the
Antigen
specific pathogen and produce
antibodies that will help destroy
the invader and protect us the next
time it enters the body. This process
is called immunity.
3. The reaction to a second infection by
the same pathogen is much faster.
Antibody
Lymph & Immune System
Levels of Organization
White Blood Cells, B-cells, Tcells, macrophages
Lymph nodes, bone marrow
Spleen, Liver
Lymph and Immune
**H.I.V. is the virus that causes AIDS, or acquired immune
deficiency syndrome. It attacks a special T cell known as a helper
T cell.
**Penicillin and other antibiotics can also be used to
help the immune system, but it is important to remember that
antibiotics only kill bacteria!
**Vaccines work by mimicking the body’s natural
immune response. A small amount of the specially
treated virus, bacterium or toxin (vaccine) is injected
into the body. The body then makes antibodies. If a vaccinated
person is exposed to the actual virus, bacterium or toxin, they
won’t get sick.
Interactions with other Body Systems
Skin of the integumentary system is
the first line of defense of the
immune system.
The circulatory system transports
immune cells around the body.
Bones of the skeletal system
produce lymphocytes and
macrophages.
What is happening in the diagram?
Vitamin-D Production and
Metabolism
• Basically, UV light triggers a change of a cholesterol-related
molecule in the membrane of skin cells. The vitamin D that is
created is then released from the membrane into our circulatory
system, where it travels to the liver. In this organ, it is transformed
into 25-hydroxyvitamin D (big fancy molecule)
• The kidney, as well as some other tissues, further convert this into
1,25-hydroxyvitamin D, which is also called calcitrol. Calcitrol
together with parathyroid hormone (PTH), regulates blood calcium
levels and, in turn, bone density.
• Calcitrol targets the intestine, where it promotes calcium
absorption; and bone, where it starts calcium release to help
restore depleted blood calcium levels.
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