Ch. 12 Host Defenses 1 LS

Normal human body temperature is approximately ___________ degress Celsius.

37

pyrogen

A substance that causes a rise in body temperature. It can come from pyrogenic microorganisms or from polymorphonuclear leukocytes (endogenous pyrogens).

The ______ response is a reaction to any traumatic event in the tissues.

inflammatory At its most general level, the inflammatory response is a reaction to any traumatic event in the tissues. It is so commonplace that all of us manifest inflammation in some way every day. It appears in the nasty flare of a cat scratch, the blistering of a burn, the painful lesion of an infection, and the symptoms of allergy. When close to our external surfaces, it is readily identifiable by a classic series of signs and symptoms characterized succinctly by four Latin terms: rubor, calor, tumor, and dolor. Rubor (redness) is caused by increased circulation and vasodilation in the injured tissues; calor (warmth) is the heat given off by the increased flow of blood; tumor (swelling) is caused by increased fluid escaping into the tissues; and dolor (pain) is caused by the stimulation of nerve endings. A fifth symptom, loss of function, has been added to give a complete picture of the effects of inflammation.

Lymph nodes located in the groin area are called ______ nodes.

inguinal

Small proteins produced naturally by white blood and tissue cells that are involved in defenses against microbes and immune communication are called

interferons Interferons are small proteins produced naturally by certain white blood and tissue cells. Although the interferon system was originally thought to be directed exclusively against viruses, it is now known to be involved also in defenses against other microbes and in immune regulation and intercommunication. Three major types are interferons are alpha and beta (which are produced by many cells, including lymphocytes, fibroblasts, and macrophages), and interferon-gamma (a product of T cells) Their biological activities are extensive. In all cases, interferons bind to cell surfaces and induce changes in genetic expression, but the exact results vary. In addition to antiviral effects discussed in the next section, all three IFNs can inhibit the expression of cancer genes and have tumor suppressor effects.

Eosinophils are...

involved in immunologic responses to fungal and helminth worm infections, allergy, and inflammatory reactions.

all white blood cells are called

leukocytes

The fluid that is carried by the lymphatic circulation is called ______.

lymph

Which fluid moves in and out of tissues, but does not contain red blood cells?

lymph Lymph is a plasmalike liquid carried by the lymphatic circulation. It is formed when certain blood components move out of the blood vessels into the extracellular spaces and diffuse or migrate into the lymphatic capillaries. Like blood, it transports numerous white blood cells (especially lymphocytes) and miscellaneous materials such as fats, cellular debris, and infectious agents that have gained access to the tissue spaces.

Bean-shaped organs in clusters situated along lymphatic channels and large blood vessels are

lymph nodes

Small, encapsulated, bean-shaped organs located along lymphatic channels and large blood vessels of the thoracic and abdominal cavities are called ______.

lymph nodes

The type of fluid that is very similar in composition to that of blood, but differs in that it does not contain erythrocytes is called ____________ fluid

lymph/lymphatic/interstitial fluid

A compartmentalized network of vessels, cells, and specialized accessory organs that renders surveillance, recognition, and protection against foreign materials is the ______ system.

lymphatic

The ________ system is a system of vessels and organs that serve as sites for the development of immune cells, immune surveillance, and immune reactions.

lymphatic

B cells and T cells belong to a group of leukocytes called ______.

lymphocytes

Which term refers to a group of leukocytes that include B cells, NK cells, and T cells?

lymphocytes

A large, phagocytic white blood cell, derived from a monocyte, that leaves the circulation and has a high capacity for killing microbes is called a(n) ______.

macrophage

Which of the following is a large phagocytic cell that has a high capacity for killing microbes and cleaning up dead cells?

macrophage

The agranulocytic leukocytes are include two general types, the ___________ and ____________.

monocytes and lymphocytes

All organs and tissues contain a network of fibers and macrophages called the ________ system.

mononuclear phagocyte *not the immune system, which is a functional system, meaning that it involves much more than what is described here *not the lymphatic system, which includes the lymphatic vessels, lymph, and associated lymphoid organs

A network of fibers and macrophages that permeates the tissues of the body is called the

mononuclear phagocyte system

Because it provides a passageway within and between tissues and organs, the ________ ____________ system is intrinsic to the functions of the immune system.

mononuclear; phagocyte

basophils are....

motile granulocytic cells that function in inflammatory events and allergies.

Where are cervical lymph nodes located?

neck

The 3 main types of phagocytes are ______.

neutrophils dendritic cells macrophages

Which are granulocytic white blood cells?

neutrophils, basophils, eosinophils

The granulocytic leukocytes are composed of three general types, the ________, the __________, and the ___________.

neutrophils, eosinophils. basophils

mast cells are...

non-motile cells that are bound to connective tissue along capillaries. They release mediators such as histamine that trigger local inflammatory reactions and many allergic symptoms.

mast cells are...

nonmotile cells that are bound to connective tissue along capillaries. They release mediators such as histamine that trigger local inflammatory reactions and many allergic symptoms.

Which of the following materials are NOT transported by lymphatic fluid?

normal microbiota clotting factors oxygen and CO2

The mononuclear phagocyte system functions as a passageway within and between ______.

organs tissues (NOT airways in the lungs; this is a separate system from the MPS)

neutrophils are...

phagocytes and the most common leukocyte

Which of the following is NOT a nonspecific host defense?

physical and chemical barriers are, but antibody production are not

Nonspecific host defense mechanisms include chemical barriers and

physical/anatomical barriers The inborn defenses are the physical and chemical barriers that impede the entry of not only microbes but any foreign agent, whether living or not

Interferons are small ______.

proteins

Major functions of the lymphatic system include ______.

providing a route to return extracellular fluid to the circulatory system acting as a drain-off system for the inflammatory response supporting surveillance through lymphocytes, phagocytes and antibodies NOT: maintaining a constant temperature and regulating fever responses (describes immune system!) transporting oxygen and carbon dioxide to tissues throughout the body (describes cardiovascular system!)

A host barrier with an acidic pH and high fatty acid content that are inhibitory to many microbes is the ______________

skin

A host barrier with an acidic pH and high fatty acid content that are inhibitory to many microbes is the

skin The high lactic acid and electrolyte concentrations of sweat and the skin's acidic pH and fatty acid content are also inhibitory to many microbes. Likewise, the hydrochloric acid in the stomach renders protection against many pathogens that are swallowed, and the intestine's digestive juices and bile are potentially destructive to microbes. Even semen contains an antimicrobial chemical that inhibits bacteria, and the vagina during reproductive years has a protective acidic pH maintained by normal biota.

As an external, protective barrier that is highly impervious and waterproof, human ____________ provides significant protection from microbes.

skin The skin and mucous membranes of the respiratory and digestive tracts have several built-in defenses. The outermost layer (stratum corneum) of the skin is composed of epithelial cells that have become compacted, cemented together, and impregnated with an insoluble protein, keratin. The result is a thick, tough layer that is highly impervious and waterproof. Few pathogens can penetrate this unbroken barrier, especially in regions such as the soles of the feet or the palms of the hands, where the stratum corneum is much thicker than on other parts of the body. In addition, outer layers of skin are constantly sloughing off, taking associated microbes with them.

Which host barrier offers protection against microorganisms due to the presence of sebum, which has a high fatty acid content and acidic pH?

skin (not hair and nails, not mucous membranes) The skin and mucous membranes of the respiratory and digestive tracts have several built-in defenses. The outermost layer (stratum corneum) of the skin is composed of epithelial cells that have become compacted, cemented together, and impregnated with an insoluble protein, keratin. The result is a thick, tough layer that is highly impervious and waterproof. Few pathogens can penetrate this unbroken barrier, especially in regions such as the soles of the feet or the palms of the hands, where the stratum corneum is much thicker than on other parts of the body. In addition, outer layers of skin are constantly sloughing off, taking associated microbes with them.

Which of the following is NOT a lymphoid organ?

stomach (thymus and spleen are both lymphoid organs)

homeostasis define

the maintenance of a stable internal environment.

hemostasis

the plugging of broken blood vessels to stop bleeding.

lymphocytes are...

the second most common of the leukocytes and include B cells and T cells.

A triangular structure in the lower neck region that serves as a maturation site for T lymphocytes is the ______.

thymus

Naive T lymphocytes originate in the bone marrow and migrate to the _____________ to complete their maturation.

thymus The thymus originates in the embryo as two lobes in the lower neck region that fuse into a triangular structure. Lymphocytes that originate in the bone marrow as naïve T lymphocytes migrate to the thymus to complete their maturation. Under the influence of thymic hormones, these cells develop specificity and are released into the circulation as mature T cells. The mature T cells subsequently migrate and settle in other secondary lymphoid organs, just as mature B cells do.

Which of the following is not a major function of the lymphatic system?

transporting oxygen and carbon dioxide to tissues throughout the body (this is a function of the CV system) functions of the lymphatic system: acting as a drain-off system for the inflammatory response supporting surveillance through lymphocytes, phagocytes and antibodies providing a route to return extracellular fluid to the circulatory system

Inflammation may be triggered by the immune response or by ____________ due to tissue infection or tissue injury.

trauma/damage/necrosis/injury

Which is NOT a second line host defense mechanism?

vomiting things that are second line defenses: Inflammation, Fever, phagocytosis, antimicrobial proteins (complement, interferon, antimicrobial peptides like defensins and protegins) Events of inflammation, including phagocytosis and fever, are second line defenses.

Leukocytes are ______.

white blood cells

Which of the following materials are transported by lymphatic fluid?

white blood cells infectious agents cellular debris *NOT oxygen, CO2, normal microbiota, nor clotting factors

A liquid connective tissue consisting of erythrocytes, leukocytes, and platelets suspended in plasma is called

whole blood

The liquid substance that moves through the arteries, veins, and capillaries is called ______.

whole blood The substance that courses through the arteries, veins, and capillaries is whole blood, a liquid consisting of blood cells suspended in plasma. One can visualize these two components with the naked eye when a tube of unclotted blood is allowed to sit or is spun in a centrifuge. The cells' density causes them to settle into an opaque layer at the bottom of the tube, leaving the plasma, a clear, yellowish fluid, on top. Serum is essentially the same as plasma, except it is the clear fluid from clotted blood. Serum is often used in immune testing and therapy.

The liquid connective tissue consisting of erythrocytes, leukocytes, and platelets suspended in plasma is called ________.

whole blood whole blood=A liquid connective tissue consisting of blood cells suspended in plasma (the carrier fluid element of blood)

blood components:

whole blood=A liquid connective tissue consisting of blood cells suspended in plasma. blood cells=Cellular components of the blood consisting of red blood cells, primarily responsible for the transport of oxygen and carbon dioxide, and white blood cells, primarily responsible for host defense and immune reactions. plasma=the carrier fluid element of blood

secondary lymphatic organs

Locations in the body where immune cells become activated, reside, or carry out their functions are called secondary lymphatic organs.

Which of the following are considered to be lymphoid organs?

Lymph nodes Thymus Spleen

lymph nodes description

Lymph nodes are small, encapsulated, bean-shaped organs stationed, usually in clusters, along lymphatic channels and large blood vessels of the thoracic and abdominal cavities (see figure 12.3). Major aggregations of nodes occur in the loose connective tissue of the armpit (axillary nodes), groin (inguinal nodes), and neck (cervical nodes).

primary lymphatic organs

Sites where B and T lymphocytes are generated and become mature. In the human, the red bone marrow and the thymus are primary lymphatic organs. In the lymphatic system, the sites of immune cell birth and the locations where they mature are considered primary lymphatic organs.

functions of lymphatic system:

Some major functions of the lymphatic system are as follows: to provide a route for the return of extracellular fluid to the circulatory system proper; to act as a "drain-off" system for the inflammatory response; and to render surveillance, recognition, and protection against foreign materials through a system of lymphocytes, phagocytes, and antibodies.

Monocytes and lymphocytes can be described as ______

agranulocytes

The lymph nodes located in the armpits are called ________ nodes.

axillary

Hematopoiesis is the process by which all __________ cells are formed in bone marrow

blood

________ allow for a close association between the fluid compartments of the body, an important part of effective immune responses..

blood vessels

Communication between separate fluid compartments of the body is conducted primarily through _____.

capillaries The body is partitioned into several fluid-filled spaces called the intracellular, extracellular, lymphatic, cerebrospinal, and circulatory compartments. Although these compartments are physically separated, they have numerous connections. For effective immune responsiveness, the activities in one fluid compartment must be communicated to other compartments. At the microscopic level, clusters of tissue cells are in direct contact with the mononuclear phagocyte system (MPS), which is described shortly, and the extracellular fluid (ECF). Blood and lymphatic capillaries penetrate into these tissues. This close association allows cells that originate in the MPS and ECF to diffuse or migrate into the blood and lymphatics. Any products of a lymphatic reaction can be transmitted directly into the blood through the connection between these two systems. Certain cells and chemicals originating in the blood can move through the vessel walls into the extracellular spaces and migrate into the lymphatic system.

Lymph nodes are located in the neck are called ___________ nodes.

cervical

Identify the three main types of phagocytes.

dendritic cells macrophages neutrophils

Skin, the protective layer that surrounds the body, is composed of ____________ cells that have become compacted, cemented together, and impregnated with __________.

epithelial; keratin NOT: Lymph is found flowing in the lymphatic system. Phagocytic cells engulf and destroy microbes; hydrochloric acid is found in the stomach. Dendritic cells are involved in antigen presentation.

Which of the following is part of the body's second line of defense?

fever (NOT skin, mucous membranes, or intestinal enzymes) Now that we have introduced the principal anatomical and physiological framework of the immune system, we address four mechanisms that play important roles in host defenses and are categorized as the second line of defense: (1) phagocytosis, (2) inflammation, (3) fever, and (4) antimicrobial products. Because of the generalized nature of these defenses, they are considered innate in their effects, but they also support and interact with the adaptive immune responses described in chapter 13.

Select the nonspecific host defenses.

first line second line (the third line of defense is characterized by specific acquired immunity)

granulocytes vs. agranulocytes

granulocytes=A mature leukocyte that contains noticeable granules in a Wright stain. Examples: neutrophils, eosinophils, and basophils. agranulocytes=One form of leukocyte (white blood cell) having globular, nonlobed nuclei and lacking prominent cytoplasmic granules.

________ is the process by which all blood cells are formed in bone marrow.

hematopoiesis

eosinophils are involved in...

immunologic responses to fungal and helminth worm infections, allergy, and inflammatory reactions.

where are the thoracic lymph nodes located?

in the chest

Core body temperature is typically ______.

98.6 degrees F The body temperature is normally maintained by a control center in the hypothalamus region of the brain. This thermostat regulates the body's heat production and heat loss and sets the core temperature at around 37°C (98.6°F) with slight fluctuations during a daily cycle. Fever is initiated when circulating substances called pyrogens (py′-roh-jenz) reset the hypothalamic thermostat to a higher setting. This change signals the musculature to increase heat production and peripheral arterioles to decrease heat loss through vasoconstriction. Fevers range in severity from low grade (37.7°C to 38.3°C, or 100°F to 101°F) to high (40.0°C to 41.1°C, or 104°F to 106°F). Fevers above 104°F to 105°F should be treated to prevent serious damage to host tissues.

mononuclear phagocyte system (MPS)

A collection of monocytes and macrophages scattered throughout the extracellular spaces that function to engulf and degrade foreign molecules.

How does lymphatic fluid differ from blood?

Does not contain red blood cells *only blood transports red blood cells. *Lymph fluid is similar to plasma in that it contains water and white blood cells.

overview of defenses

The host defenses are a multilevel network of innate protections and adaptive protections that are commonly referred to as the first, second, and third lines of defense (figure 12.1). The interaction and cooperation of these three levels of defense normally provide comprehensive protection against infection. The first line of defense includes any barrier that blocks invasion at the portal of entry. This nonspecific line of defense limits access to the internal tissues of the body. It is very general in action. The second line of defense, called innate immunity, is a more internal system of protective cells, fluids, and processes that includes inflammation and phagocytosis. It acts rapidly at both the local and systemic levels once the first line of defense has been overcome. The highly specific third line of defense is acquired only as each foreign substance is encountered by white blood cells called lymphocytes. The goal of this response is to make lymphocytes that are specifically adapted to each individual invader. For that reason, it is called adaptive immunity. The reaction with each different foreign microbe produces unique protective substances and cells that can come into play if that microbe is encountered again. The third line of defense provides long-term immunity. It is discussed in detail in

hematopoiesis

The process by which the various types of blood cells are formed, such as in the bone marrow. the production of blood cells There are two primary lines of cells that arise from stem cells, and are still considered immature. These are (1) those that differentiate from a common myeloid cell, such as red blood cell precursors (erythroblasts) and platelet precursors (megakaryoblasts), and (2) those that differentiate from a common lymphoid precursor cell, such as precursors of many white blood cells (myeloblasts) and precursors of lymphocytes (lymphoblasts). White blood cells (leukocytes) can generally be divided into two categories according to their staining patterns when viewed with a microscope: granulocytes, which have dark staining granules, and agranulocytes, which do not have granules and typically have large nuclei. The granules in granulocytes can be released to kill foreign cells or affect host tissues. Figure 12.5 sorts out all these cells. They are vitally important to innate and adaptive immunity.

three main types of phagocytes:

The three main types of phagocytes are neutrophils, macrophages, and dendritic cells