Transcript Neck and Bucal Cavity

• Many different organs and systems work
together in an effort to keep us alive and healthy.
• In this ongoing struggle, the lymphatic system
plays a central role.
• The lymphatic system is an extensive drainage
network that helps keep bodily fluid levels in
balance, defends the body against infections,
and assists in tissue repairs.
• The production, maintenance and distribution of
lymphocytes.
– to defend the body against disease by producing
lymphocytes
– The lymphocytes, protect the body against antigens
(viruses, bacteria, etc.) that invade the body.
– Lymphocytes are produced and stored within
lymphoid organs, such as the spleen, thymus and
bone marrow.
• The return of fluid and solutes from the
peripheral tissues of the blood.
– to collect and return interstitial fluid, including
plasma protein to the blood,
and thus help maintain fluid balance.
– The return of fluids through the lymphatic
system maintains normal blood volume.
– The flow is ~3.6 liters per day and a break in a
major lymphatic vessel can cause a rapid and
potentially fatal decline in blood volume.
• The distribution of hormones, nutrients
and waste products from their tissues to
the general circulation.
– to absorb lipids from the intestine and
transport them to the blood.
– Substances that are unable to enter the
blood stream directly can do so via the
lymphatic vessels.
• 3 components
• 1. Vessels– A network of lymphatic vessels that begins in the peripheral
tissues and connects to the venous system.
• 2. Fluid
– Called Lymph (clear and watery), flows through the lymphatic vessels.
– Lymph Fluid contains:
• Fluid from the intestines (chyme), which contains proteins and fats.
• Red blood cells
• White blood cells, especially lymphocytes, the cells that attack
bacteria in the blood
• 3. Lymphoid organs– Lymphoid organs are connected to the lymphatic vessels and
contain large numbers of lymphocytes. (Ex. Lymph nodes,
spleen and thymus).
• Carry lymph from the peripheral tissues to the
venous system in all parts of the body except the
CNS (central nervous system).
• The smallest vessels are called lymphatic
capillaries. These capillaries carry lymph to the
larger lymphatic vessels.
• The lymphatic vessels ultimately empty into two
large collecting ducts: thoracic duct and right
lymphatic duct.
– Lymph organs include the bone marrow, lymph
nodes, spleen, and thymus.
– Human lymph nodes, called lymph glands and “swollen
glands,” are bean-shaped and range in size from a few
millimeters to about 1-2 cm in their normal state.
– They may become enlarged due to a tumor or
infection.
– White blood cells are located within honeycomb
structures of the lymph nodes.
– Spleen- The spleen, which is located in the upper left
part of the abdomen under the ribcage, works as part
of the lymphatic system to protect the body.
– It clears worn out red blood cells and other foreign
bodies from the bloodstream to help fight off infection.
• Tonsil—The tonsils are areas of lymphoid
tissue on either side of the throat.
• An infection of the tonsils is called
tonsillitis.
• Thymus- an organ located in the upper
anterior portion of the chest cavity just
behind the sternum.
• Hormones produced by this organ
stimulate the production of certain
infection-fighting cells.
• Through the hormones it produces, the thyroid
gland influences almost all of the metabolic
processes in your body.
• Thyroid disorders can range from a small,
harmless goiter (enlarged gland) that needs no
treatment to life-threatening cancer.
• The most common thyroid problems involve
abnormal production of thyroid hormones.
• Too much of these vital body chemicals results in
a condition known as hyperthyroidism.
• Insufficient hormone production leads to
hypothyroidism.
• Hyperthyroidism• All types of hyperthyroidism are due to an
overproduction of thyroid hormones, but the
condition can occur in several different ways.
• Hypothyroidism• By contrast, stems from an underproduction of
thyroid hormones.
• For your body to have the energy it needs, it
requires certain amounts of thyroid hormones, a
drop in hormone production leads to lower
energy levels.