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

•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.

Lungs (cont)

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.

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)

Lungs (cont)

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.

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.

Immune System (cont)

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.

•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.

Immune System (cont)

Sunburn Animation

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 System (cont)

Immune Response Animation

Lymph Node Animation

Immune Response (white Blood Cells)

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.

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 CellsThe 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 HIV-producing factorie

Immune System (cont)

•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

Blood Flow Animation

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]

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.