Physiology III

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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
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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

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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.
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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

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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
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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.

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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.
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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
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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 Animation Lymph Node Animation
Immune Response (white Blood Cells)
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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 marrowBone 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.

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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

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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
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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.

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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 HIV-producing
  factorie

HIV Replication Animation

• 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.

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Immune System (cont)
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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
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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 substances
  between blood and tissue cells.1

Blood Flow Animation
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Prostate

• The prostate is located just below the bladder
  and is a gland. The prostates 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
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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.