Download Nervous, Immune , & Endocrine Systems

http://www.youtube.com/watch?v=DStwXsmZ3OE
 Pathogens
 Not
= disease-producing agents
all microorganisms are pathogenic
 Microorganisms
live on skin, in the intestines,
upper respiratory tract, lower urinary tract,
reproductive tract, etc…
 Some
have symbiotic relationships with our
bodies, help maintain equilibrium
 In
order for pathogens to enter…
they must first penetrate your
skin
 They
will encounter the body’s
secretions (sweat, oil, mucus,
tears, saliva)
 Main
function of mucus is to
prevent areas from drying out.
It also traps microorganisms
 Mucus
is continually
swallowed and passed
to the stomach where
acidic gastric juice
destroys it
 Sweat,
tears, saliva all
have the enzyme
lysozyme (breaks down
cell walls of some
bacteria)
 Your
skin is a part of your first line of defense
against pathogens. It is included in the
category titled “non-specific defense
mechanisms”



The first line of nonspecific defense = external
The second line of nonspecific defense = internal.
They indiscriminately attack invaders that
penetrate the body’s outer barriers.
The third line of defense (the immune system)
responds in a specific way to particular
substances marked by foreign molecules.
 Inflammation
is an example of a
second line of defense kicking in.
•
Redness, swelling, pain, and heat
•
Cells damaged by invading
microbes release chemical signals
that attract white blood cells
called phagocytes
•
A neurotransmitter generated by
white blood cells, histamine, is
released and causes blood vessels to
dilate in that area
 The
steps taken by white blood cells
(phagocytosis)
 The
pus that accumulates at the site of some
infections consists mostly of dead phagocytic
cells, fluid, and proteins that leaked from
capillaries during the inflammatory response.
 Phagocytes
take action. They are white
blood cells that destroy pathogens by
surrounding and engulfing them

Specific examples = monocytes, macrophages,
neutrophils
 Some
macrophages (phagocytes) migrate
throughout the body, while others reside
permanently in certain tissues.
Helps body
defend itself
against disease
& maintains
homeostasis by
keeping body
fluids at a
constant level
Lymphocyte
= type of white blood
cell that defends the body against
foreign substances



B lymphocytes (B cells)- make antibodies against
antigens. Memory cells.
T lymphocytes (T cells)- play a role in cell
mediated immunity (no antibodies). Killer T,
Helper T, ect. Made in Thymus.
Both types of lymphocytes circulate
throughout the blood and lymph and are
concentrated in the spleen, lymph nodes, and
other lymphatic tissue.
 Lymph
nodes = small mass of tissue that
contains lymphocytes and filters pathogens
from the lymph

Made of interlaced network of connective tissue
fibers that hold lymphocytes
 Antigens
(foreign molecules)
are identified by B cells.
The B cell with the correct
antibody receptor on its
antibody then duplicates.
 Tonsils
are larger clusters of lymph
tissue located at the back of the mouth
cavity and throat
 They
produce lymphocytes & protect
the throat from potential infections
 Spleen
= another organ that stores
lymphocytes

It filters out and destroys bacteria &
worn-out red blood cells
Thymus
gland = stores immature
lymphocytes until the are ready to be
released into the body’s defense system
Spleen
Endocrine Disorders
Turner Syndrome
http://www.youtube.com/watch?v=ldjb-FRPKo
Pituitary Gigantism
http://www.youtube.com/watch?v=Ebhf1qKV
A9A