lymphatic system Flashcards

Question

Innate system: barrier defenses

Answer 1

Prevent pathogens from entering the body, destroy them after they enter, or flush them out before they can establish themselves in the hospitable environment of the body’s soft tissues. Barrier defenses are part of the body’s most basic defense mechanisms. **continuously** working to protect against a broad range of pathogens. **Skin - the primary barrier to the entrance of microorganisms into the body.** Not only is the skin covered with a layer of dead, keratinized epithelium that is too dry for bacteria in which to grow, but as these cells are continuously sloughed off from the skin, they carry bacteria and other pathogens with them. Additionally, **sweat and other skin secretions may lower pH, contain toxic lipids, and physically wash microbes away.**

Answer 2

Saliva - is rich in **lysozyme**—an enzyme that destroys bacteria by digesting their cell walls. **Acidic environment of the stomach - low pH** makes bacteria surviving unlikely **Mucus layer of the gastrointestinal tract, respiratory tract, reproductive tract, eyes, ears, and nose** traps both microbes and debris, and facilitates their removal. In the case of the upper respiratory tract, ciliated epithelial cells move potentially contaminated mucus upwards to the mouth, where it is then swallowed into the digestive tract, ending up in the harsh acidic environment of the stomach.

Answer 3

cell that is able to surround and engulf a particle or cell, a process called **phagocytosis**. The phagocytes of the immune system engulf other particles or cells, either to clean an area of debris, old cells, or to kill pathogenic organisms such as bacteria. The phagocytes are the body’s **fast acting, first line of immunological defense** against organisms that have breached barrier defenses and have entered the vulnerable tissues of the body. mechanism of destroying pathogens during innate immune responses. The phagocyte takes the organism inside itself as a phagosome, which subsequently fuses with a **lysosome** and its digestive enzymes, effectively killing many pathogens.

Answer 4

Macrophages, neutrophils, and dendritic cells are the major phagocytes of the immune system.

Answer 5

irregularly shaped phagocyte amoeboid **most versatile of the phagocytes in the body** Macrophages move through tissues and squeeze through capillary walls using **pseudopodia**. **innate immune responses** and cooperate with lymphocytes **adaptive immune response** as well freely roaming through connective tissues or fixed to reticular fibers within specific tissues such as lymph nodes. When pathogens breach the body’s **barrier defenses**, macrophages are the first line of defense. They are called different names, depending on the tissue: **Kupffer cells** in the liver **histiocytes** in connective tissue, and **alveolar macrophages** in the lungs.

Answer 6

phagocytic cell that is attracted via **chemotaxis** from the bloodstream to infected tissues. spherical type of **granulocyte**: contains cytoplasmic granules, which in turn contain a variety of vasoactive mediators such as histamine. reinforcements that are called into a battle to hasten the destruction of the enemy. Usually thought of as the primary pathogen-killing cell of the **inflammatory process** of the innate immune response - most often against **bacteria.**

Answer 7

circulating **precursor** cell that differentiates into either a **macrophage or dendritic cell** can be rapidly **attracted to areas of infection by signal molecules of inflammation.**

Answer 8

chemical signals that can induce cells to change various physiological characteristics, such as the expression of a particular receptor. These **soluble factors** are secreted during both innate and adaptive immune responses.

Answer 9

Cytokine is signaling molecule that allows cells to communicate with each other over **short distances**. Cytokines are secreted into the intercellular space induces the receiving cell to change its **physiology**. ex. inflammation

Answer 10

Chemokine is a soluble chemical mediator similar to cytokines attract cells (chemotaxis) from longer distances.

Answer 11

those that are not constitutively present in the body made as needed early during the innate immune response. ex. **Interferons** **Cells infected with viruses secrete interferons** that travel to adjacent cells and induce them to make antiviral proteins. Thus, even though the initial cell is sacrificed, the surrounding cells are protected. Other early induced proteins specific for bacterial cell wall components: **mannose-binding protein and C-reactive protein (CRP), made in the liver,** which bind specifically to polysaccharide components of the bacterial cell wall. Phagocytes such as macrophages have receptors for these proteins, and they are thus able to recognize them as they are bound to the bacteria. This brings the phagocyte and bacterium into close proximity and enhances the phagocytosis of bacterium by the process known as **opsonization**: tagging of a pathogen for phagocytosis by the binding of an antibody or an antimicrobial protein. inc. in CRP = inflammation, because it's induced by tissue damage

Answer 12

not cells, but substances series of proteins constitutively found in the blood plasma. not considered part of the early induced immune response Made in the liver, variety of functions in the **innate immune response**, using what is known as the **“alternate pathway” of complement activation.** The complement system consists of several proteins that enzymatically alter and fragment later proteins in a series, which is why it is termed **cascade**. Once activated, is irreversible, and releases fragments that have the following actions: - Bind to the cell membrane of the pathogen that activates it, labeling it for phagocytosis (opsonization) - Diffuse away from the pathogen and act as chemotactic agents to attract phagocytic cells to the site of inflammation - Form damaging pores in the plasma membrane of the pathogen

Answer 13

innate immune response = inflammation. infection and/or tissue damage -> inflammation The inflammatory reaction brings in phagocytic cells to the damaged area to clear cellular debris and to set the stage for wound repair. This reaction also brings in the cells of the innate immune system, allowing them to get rid of the sources of a possible infection. brings fluid and cells into the site to destroy the pathogen and remove it and debris from the site, helps to isolate the site, limiting the spread of the pathogen.

Answer 14

four characteristics: heat, redness, pain, and swelling (and loss of function)

Answer 15

**Acute inflammation** short-term inflammatory response to an insult to the body. caused by allergic reactions, infections, trauma injury. pathogen or injured tissue cells: neutrophils, mononuclear cells (monocytes, macrophages) **Chronic inflammation** ongoing inflammation and is associated with **major tissue destruction and fibrosis**. It can be caused by persistent acute inflammation, foreign bodies, persistent pathogens, and autoimmune reactions. cells: mononuclear cells (monocytes, macrophages, lymphocytes, plasma cells, fibroblasts)

Answer 16

1) **Tissue Injury**. The released contents of injured cells stimulate the release of mast cell granules ex histamine (vessel dilation and permeability), leukotrienes (recruit neutrophils), prostaglandins (vasodilation) 2) **Vasodilation** - causes increased blood flow and is responsible for the heat and redness of inflamed tissue. 3) **Increased Vascular Permeability** - leakage of fluid into the interstitial space, resulting in edema 4) **Recruitment of Phagocytes** - Leukotrienes attract neutrophils from the blood to the site of infection by chemotaxis. Following an early neutrophil infiltrate stimulated by macrophage cytokines, more macrophages are recruited to clean up the debris left over at the site. When local infections are severe, neutrophils are attracted to the sites of infections in large numbers, and as they phagocytose the pathogens and subsequently die, their accumulated cellular remains are visible as pus at the infection site - important to clear out the pus if it's not dispelling naturally

lymphatic system Flashcards

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