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Physiology III
•Lungs
•Immune System
•Bacteria and Virusus
•Epidermis (skin)
•Lymph system
•Tymus
•Antibodies
•White Blood Cells
•Leukocytes
•Strokes
•Blood Flow
•Arteries
•Veins
•Capillaries
•Prostate
HIV Replication Animation
Lungs
•They take in a gas that your body needs oxygen
and get rid of get rid of waste carbon dioxide
made by your cells.
•You breathe in and out anywhere from 15 to 25
times per minute
•They also help in regulating the concentration of
hydrogen ion (pH) in your blood.
•You don't have to think about breathing because
your body's autonomic nervous system
controls it.
•The respiratory centers that control your rate of
breathing are in the brainstem or medulla. The
nerve cells that live within these centers
automatically send signals to the diaphragm and
intercostal muscles to contract and relax at
regular intervals
Lungs (cont)
•When you inhale, the diaphragm and intercostal
muscles (those are the muscles between your ribs)
contract and expand the chest cavity.
•This expansion lowers the pressure in the chest
cavity below the outside air pressure. Air then flows
in through the airways (from high pressure to
low pressure) and inflates the lungs.
•When you exhale, the diaphragm and intercostal
muscles relax and the chest cavity gets smaller.
•The decrease in volume of the cavity increases the
pressure in the chest cavity above the outside air
pressure. Air from the lungs (high pressure) then
flows out of the airways to the outside air (low
pressure). The cycle then repeats with each breath.
As you breathe air in through your nose or mouth, it goes past the epiglottis and
into the trachea. It continues down the trachea through your vocal cords in the
larynx until it reaches the bronchi. From the bronchi, air passes into each lung.
The air then follows narrower and narrower bronchioles until it reaches the
alveoli.
Lungs (cont)
What Happens When the Air Gets
•There within each air sac, the oxygen
concentration is high, so oxygen passes or
diffuses across the alveolar membrane into the
pulmonary capillary.
• At the beginning of the pulmonary capillary, the
hemoglobin in the red blood cells has carbon
dioxide bound to it and very little oxygen.
•The oxygen binds to hemoglobin and the
carbon dioxide is released. Carbon dioxide
is also released from sodium bicarbonate
dissolved in the blood of the pulmonary
capillary. The concentration of carbon dioxide
is high in the pulmonary capillary, so carbon
dioxide leaves the blood and passes across
the alveolar membrane into the air sac. This
exchange of gases occurs rapidly (fractions
of a second). The carbon dioxide then leaves
the alveolus when you exhale and the
oxygen-enriched blood returns to the heart
Lungs (cont)
Anatomy of the Lung
•alveolus - tiny, thin-walled air sac at the end of the bronchiole branches where gas
exchange occurs (plural - alveoli).
•bronchioles - numerous small tubes that branch from each bronchus into the lungs. They
get smaller and smaller.
•bronchus - a branch of the trachea that goes from the trachea into the lung (plural - bronchi)
diaphragm - muscle at the base of the chest cavity that contracts and relaxes during
breathing
•epiglottis - a flap of tissue that closes over the trachea when you swallow so that food does
not enter your airway
intercostal muscles - muscles along the rib cage that assist in breathing
•larynx - voice box where the vocal cords are located.
nasal cavity - chamber in from the nose where air is moistened and warmed
•pleural membranes - thin, membranes that cover the lungs, separate them from other
organs and form a fluid-filled chest cavity.
•pulmonary capillaries - small blood vessels that surround each alveolus
•trachea -rigid tube that connects the mouth with the bronchi (windpipe)
Breathing Animation
Lungs Gas Exchange
Immune System
•Inside your body there is a protection mechanism called
the immune system. It is designed to defend you
against millions of bacteria, microbes, viruses, toxins
and parasites that would love to invade your body
•When you get a cut, all sorts of bacteria and viruses
enter your body through the break in the skin.
• Your immune system responds and eliminates the
invaders while the skin heals itself and seals the
puncture. Inflammation are side-effects of the
immune system doing its job.
•
FYI: A virus must have a host cell (bacteria, plant or animal) in which to live and make
more viruses. Outside of a host cell, viruses cannot function. For this reason, viruses tread
the fine line that separates living things from nonliving things. Most scientists agree that
viruses are alive because of what happens when they infect a host cell.
•Colds and flu (influenza) are caused by viruses.
•Viruses responsible for many other serious, often deadly, diseases including acquired
immunodeficiency syndrome (AIDS), Ebola hemorrhagic fever, infectious hepatitis and
herpes.
Immune System (cont)
Bacteria and Viruses
•Your body is made up of perhaps 100 trillion cells.
•Each one has a nucleus, energy production equipment, etc.
•Bacteria are single-celled organisms that are much simpler.
•For example, they have no nucleus. They are perhaps 1/100th the size of a human
cell and might measure 1 micrometer long.
•Bacteria are completely independent organisms able to eat and reproduce - they
are sort of like fish swimming in the ocean of your body.
•Under the right conditions bacteria reproduce very quickly: One bacteria divides
into two separate bacteria perhaps once every 20 or 30 minutes. At that rate, one
bacteria can become millions in just a few hours.
•A virus is a different breed altogether.
•A virus is not really alive. A virus particle is nothing but a fragment of DNA in a
protective coat.
•The virus comes in contact with a cell, attaches itself to the cell wall and injects its
DNA (and perhaps a few enzymes) into the cell.
•The DNA uses the machinery inside the living cell to reproduce new virus particles.
•Eventually the hijacked cell dies and bursts, freeing the new virus particles; or the
viral particles may bud off of the cell so it remains alive. In either case, the cell is a
factory for the virus.
Antibodies: Neutralization of viruses
The portion of the antibodies made against of the virus attachment site blocks the virus from
adsorbing to the receptor site on the host cell membrane. As a result, the virus can not penetrate
and replicate.
Immune System (cont)
•The epidermis (skin) contains special cells called
Langerhans cells (mixed in with the melanocytes in
the basal layer) that are an important early-warning
component in the immune system.
•The skin also secretes antibacterial
substances. These substances explain why you
don't wake up in the morning with a layer of
mold growing on your skin -- most bacteria and
spores that land on the skin die quickly.
•it is made up of two main layers:
•The epidermis on the outside and the
•The dermis on the inside.
•The epidermis is the barrier, while the dermis
is the layer containing all the "equipment" -things like nerve endings, sweat glands,
hair follicles and so on.
Sunburn Animation
Immune System (cont)
Lymph System
•The lymph system, lymph nodes, are just one part of a system that extends throughout your
body in much the same way your blood vessels do.
•The main difference between the blood flowing in the circulatory system and the lymph
flowing in the lymph system is that blood is pressurized by the heart, while the lymph system
is passive.
•There is no "lymph pump" like there is a "blood pump" (the heart).
•Instead, fluids ooze into the lymph system and get pushed by normal body and muscle
motion to the lymph nodes.
• Lymph is a clearish liquid that bathes the cells with water and nutrients. Lymph is blood
plasma -- the liquid that makes up blood minus the red and white cells. Think about it -each cell does not have its own private blood vessel feeding it, yet it has to get food,
water, and oxygen to survive.
•Blood transfers these materials to the lymph through the capillary walls, and lymph
carries it to the cells.
•The cells also produce proteins and waste products and the lymph absorbs these
products and carries them away.
•Any random bacteria that enter the body also find their way into this inter-cell fluid.
•One job of the lymph system is to drain and filter these fluids to detect and remove the
bacteria.
•Small lymph vessels collect the liquid and move it toward larger vessels so that the fluid
finally arrives at the lymph nodes for processing.
Immune Response (white Blood Cells)
Immune Response Animation
Lymph Node Animation
Immune System (cont)
Thymus
•The thymus lives in your chest, between your breast bone and your heart
• It is responsible for producing T-cells
Spleen
•The spleen filters the blood looking for foreign cells
•It is so looking for old red blood cells in need of replacement. A person missing
their spleen gets sick much more often than someone with a spleen.
Bone marrow
Bone marrow produces new blood cells, both red and white.
• In the case of red blood cells the cells are fully formed in the marrow and then
enter the bloodstream.
• In the case of some white blood cells, the cells mature elsewhere.
•The marrow produces all blood cells from stem cells. They are called "stem
cells" because they can branch off and become many different types of cells they are precursors to different cell types. Stem cells change into actual,
specific types of white blood cells.
Immune System (cont)
Antibodies
•Antibodies (also referred to as immunoglobulins and gammaglobulins) are produced
by white blood cells.
•They are Y-shaped proteins that each respond to a specific antigen (bacteria,
virus or toxin).
•Each antibody has a special section (at the tips of the two branches of the Y)
that is sensitive to a specific antigen and binds to it in some way. When an
antibody binds to a toxin it is called an antitoxin (if the toxin comes from some
form of venom, it is called an antivenin). The binding generally disables the
chemical action of the toxin. When an antibody binds to the outer coat of a virus
particle or the cell wall of a bacterium it can stop their movement through cell
walls.
•Antibodies come in five classes:
Immunoglobulin A (IgA)
Immunoglobulin D (IgD)
Immunoglobulin E (IgE)
Immunoglobulin G (IgG)
Immunoglobulin M (IgM)
Whenever you see an abbreviation like IgE in a medical document its an
antibody
Immune System (cont)
White Blood Cells
The white blood cells are probably the most important part of your immune system. And it turns
out that "white blood cells" are actually a whole collection of different cells that work
together to destroy bacteria and viruses. Here are all of the different types, names and
classifications of white blood cells working inside your body right now:
Leukocytes
Lymphocyte
Monocytes
Granulocytes
B-cells
Plasma cells
T-cells
Helper T-cells
Killer T-cells
Suppressor T-cells
Natural killer cells
Neutrophils
Eosinophils
Basophils
Phagocytes
Macrophages
Immune System (cont)
Leukocytes
•All white blood cells are known officially as leukocytes.
•White blood cells are not like normal cells in the body -- they actually act like
independent, living single-cell organisms able to move and capture things on
their own.
•White blood cells behave very much like amoeba in their movements and are
able to engulf other cells and bacteria. Many white blood cells cannot divide and
reproduce on their own, but instead have a factory somewhere in the body that
produces them. That factory is the bone marrow.
Leukocytes are divided into three classes:
•Granulocytes - Granulocytes make up 50% to 60% of all leukocytes. Granulocytes are
themselves divided into three classes: neutrophils, eosinophils and basophils.
Granulocytes get their name because they contain granules, and these granules contain
different chemicals depending on the type of cell.
•Lymphocyte - Lymphocytes make up 30% to 40% of all leukocytes. Lymphocytes come
in two classes: B cells (those that mature in bone marrow) and T cells (those that mature
in the thymus).
Monocyte - Monocytes make up 7% or so of all leukocytes. Monocytes evolve into
macrophages.
All white blood cells start in bone marrow as stem cells.
Immune System (cont)
AIDS
•AIDS (Acquired Immune Deficiency
Syndrome) is a disease caused by HIV (the
Human Immunodeficiency Virus). This is a
particularly problematic disease for the
immune system because the virus actually
attacks immune system cells.
• In particular, it reproduces inside Helper
T cells and kills them in the process.
•Without Helper T cells to orchestrate
things, the immune system eventually
collapses and the victim dies of some
other infection that the immune system
would normally be able to handle.
•HIV invades the cells of our immune system
and reprograms the cells to become HIVproducing factorie
•Viruses, like HIV, don't have cell walls or a nucleus.
Basically, viruses are made up of genetic instructions
wrapped inside a protective shell. An HIV virus
particle, called a virion, is spherical in shape and
has a diameter of about one 10,000th of a millimeter.
HIV Replication Animation
Immune System (cont)
Strokes
•A stroke is an interruption of the blood
supply to any part of the brain. A stroke is
sometimes called a "brain attack.“
•A stroke involves loss of brain functions
caused by a loss of blood circulation to areas of
the brain. The blockage usually occurs when a
clot or piece of atherosclerotic plaque
breaks away from another area of the body
and lodges within the vasculature of the brain
•A stroke can occur when an embolism travels
from another part of the body and lodges in
another part of the brain. This animation
illustrates how this occurs.
•A clot that stays in place in the brain is called a
cerebral thrombus.
•A clot that breaks loose and moves through the
bloodstream to the brain is called a cerebral
embolism.
Stroke Animation
Blood Flow
Artery
The primary reason for taking blood from an artery rather than a
vein is to measure blood gases. Because arterial blood is
oxygenated blood flowing directly from the heart, analysis
of arterial blood can determine the chemistry of the blood
before it is used by the tissues.
Veins
•In the circulatory system, a vein is a blood vessel that carries
blood toward the heart. All veins except the pulmonary vein
carry unaerated blood
•Veins serve to return blood from organs to the heart.
•The pulmonary veins carry oxygen-rich blood from the
lungs to the left atrium of the heart They are the only
veins in the post-fetal human body that carry
oxygenated (red) blood.
Capillaries
• are the smallest of a body's blood vessels, measuring 5-10
μm, which connect arterioles and venules, and are important for
the interchange of oxygen, carbon dioxide, and other
Blood Flow Animation
substances between blood and tissue cells.[1]
Prostate
•The prostate is located just below the bladder and
is a gland. The prostate’s main function is to
produce fluid for semen.
•The prostate also surrounds the urethra, the tube
that carries urine from the bladder to the penis. As
the prostate grows, it may eventually put pressure
on the urethra, like a clamp on a garden hose. As
pressure builds and the “clamp” tightens, the result
can be bothersome urinary symptoms. BPH is not
a form of prostate cancer and does not lead to
prostate cancer.
Prostate Animation
Cancer
•Cancer is the second leading cause of death in the United States
next to heart disease, and will claim more than half a million lives this
year
•Cancer" is actually a group of more than one hundred separate
diseases.
•These diseases are all characterized by an abnormal and
unregulated growth of cells. This growth destroys surrounding
body tissues and may spread to other parts of the body in a
process that is known as metastasis.
•Cancer is usually caused by genetic damage that happens inside
an individual cell.
•Cells affected by cancer are called malignant cells. Malignant
cells are different from normal cells in the body in that they
divide (in most cases) much more rapidly than they should.