Bring fact-checked results to the top of your browser search. The mechanics of breathing Air moves in and out of the lungs in response to differences in pressure.
Blood type AB means both antigens are present and type O means both antigens are absent. Type A blood has A antigens and type B blood has B antigens. Some of the blood, but not red blood cells RBCsis pushed through the capillaries into the interstitial fluid.
It flows in the lymphatic vessels and bathes tissues and organs in its protective covering. There are no RBCs in lymph and it has a lower protein content than blood. The lymph flows from the interstitial fluid through lymphatic vessels up to either the thoracic duct or right lymph duct, which terminate in the subclavian veins, where lymph is mixed into the blood.
The right lymph duct drains the right sides of the thorax, neck, and head, whereas the thoracic duct drains the rest of the body. Lymph carries lipids and lipid-soluble vitamins absorbed from the gastrointestinal GI tract. Since there is no active pump in the lymph system, there is no back-pressure produced.
The lymphatic vessels, like veins, have one-way valves that prevent backflow. Additionally, along these vessels there are small bean-shaped lymph nodes that serve as filters of the lymphatic fluid. It is in the lymph nodes where antigen is usually presented to the immune system. The human lymphoid system has the following: Innate Immunity The innate immunity system is what we are born with and it is nonspecific; all antigens are attacked pretty much equally.
It is genetically based and we pass it on to our offspring. Surface Barriers or Mucosal Immunity The first and, arguably, most important barrier is the skin. The skin cannot be penetrated by most organisms unless it already has an opening, such as a nick, scratch, or cut.
|Celebrating 20 years online: 1998 - 2018||Lung Diseases Affecting the Chest Wall Lung diseases are some of the most common medical conditions in the world. Tens of millions of people suffer from lung disease in the U.|
|The lung–chest system||A system of human body means a collective functional unit made by several organs in which the organs work in complete coordination with one another.|
Mechanically, pathogens are expelled from the lungs by ciliary action as the tiny hairs move in an upward motion; coughing and sneezing abruptly eject both living and nonliving things from the respiratory system; the flushing action of tears, saliva, and urine also force out pathogens, as does the sloughing off of skin.
Sticky mucus in respiratory and gastrointestinal tracts traps many microorganisms. Hair follicles secrete sebum that contains lactic acid and fatty acids both of which inhibit the growth of some pathogenic bacteria and fungi.
Areas of the skin not covered with hair, such as the palms and soles of the feet, are most susceptible to fungal infections. Saliva, tears, nasal secretions, and perspiration contain lysozyme, an enzyme that destroys Gram positive bacterial cell walls causing cell lysis.
Vaginal secretions are also slightly acidic after the onset of menses. Spermine and zinc in semen destroy some pathogens. The stomach is a formidable obstacle insofar as its mucosa secrete hydrochloric acid 0.
The stomach can even destroy drugs and other chemicals.
Normal flora are the microbes, mostly bacteria, that live in and on the body with, usually, no harmful effects to us. We have about cells in our bodies and bacteria, most of which live in the large intestine. There are — microbes per cm2 on the skin Staphylococcus aureus, Staph. Various bacteria live in the nose and mouth.
Lactobacilli live in the stomach and small intestine. The urogenitary tract is lightly colonized by various bacteria and diphtheroids.
After puberty, the vagina is colonized by Lactobacillus aerophilus that ferment glycogen to maintain an acid pH. Normal flora fill almost all of the available ecological niches in the body and produce bacteriocidins, defensins, cationic proteins, and lactoferrin all of which work to destroy other bacteria that compete for their niche in the body.
The resident bacteria can become problematic when they invade spaces in which they were not meant to be.
This causes an overgrowth of Clostridium difficile, which results in pseudomembranous colitis, a rather painful condition wherein the inner lining of the intestine cracks and bleeds. A phagocyte is a cell that attracts by chemotaxisadheres to, engulfs, and ingests foreign bodies.
Promonocytes are made in the bone marrow, after which they are released into the blood and called circulating monocytes, which eventually mature into macrophages meaning "big eaters", see below. Some macrophages are concentrated in the lungs, liver Kupffer cellslining of the lymph nodes and spleen, brain microglia, kidney mesoangial cells, synovial A cells, and osteoclasts.
They are long-lived, depend on mitochondria for energy, and are best at attacking dead cells and pathogens capable of living within cells. Once a macrophage phagocytizes a cell, it places some of its proteins, called epitopes, on its surface—much like a fighter plane displaying its hits.
These surface markers serve as an alarm to other immune cells that then infer the form of the invader. All cells that do this are called antigen presenting cells APCs. The non-fixed or wandering macrophages roam the blood vessels and can even leave them to go to an infection site where they destroy dead tissue and pathogens.
Emigration by squeezing through the capillary walls to the tissue is called diapedesis or extravasation.Human respiratory system - The mechanics of breathing: Air moves in and out of the lungs in response to differences in pressure.
When the air pressure within the alveolar spaces falls below atmospheric pressure, air enters the lungs (inspiration), provided the larynx is open; when the air pressure within the alveoli exceeds atmospheric pressure, .
SOURCE: Mason, R. Murray & Nadel's Textbook of Respiratory Medicine 5th Edition, Elsevier Saunders, Clinical signs in anemic animals depend on the degree of anemia, the duration (acute or chronic), and the underlying cause. Acute anemia can result in shock and even death if more than a third of the blood volume is lost rapidly and not replaced.
This video continues our look at the Respiratory System, with the trachea and the bronchi. This is Lesson 4 in our Respiratory System series. Human Body Organ Systems.
The human body is made up of 11 organ systems that work with one another (interdependantly). These systems include the integumentary system, skeletal system, muscular system, lymphatic system, respiratory system, digestive system, nervous system, endocrine system, cardiovascular system, urinary system.
Human muscle system: Human muscle system, the muscles of the human body that work the skeletal system, that are under voluntary control, and that are concerned with movement, posture, and balance.
Broadly considered, human muscle--like the muscles of all vertebrates--is often divided into striated muscle, smooth muscle, and cardiac muscle.