Chapter 27: Lymphatic System and Pathologies

What percentage of the total white blood count is represented by lymphocytes?

25%

Mucosa-associated lymphoid tissue (MALT)

A collective term to describe small groups of lymphatic tissues located along the respiratory and GI tracts. - It helps protect the body from swallowed or inhaled pathogens and invaders. - For example, Tonsils, Peyer patches, vermiform appendix, and spleen. Important for immune response.

Inflammation

A protective response to tissue damage resulting from a variety of causes, including infection and trauma. - Purpose: to eliminate pathogens and foreign agents, remove damaged tissues and create an environment that maximizes tissue repair.

Which condition is a viral infection characterized by progressive impairment of the immune response and increased susceptibility to infections and cancerous tumors?

Acquired immunodeficiency syndrome (AIDS) results from human immunodeficiency virus (HIV) infection

Hypersensitivities

Allergic reactions in which the body responds to harmless agents called allergens as if they were harmful.

What is the name of lymphatic sac located between the abdominal aorta and L2?

Cisterna Chyli

local or acute inflammation

Contained in specific areas -Characterized by swelling, heat, a loss of function, redness, and pain (SHARP) -Usually short duration - 4-6 days after the initial onset -Exudates: substances formed by products of phagocytosis and wastes - Can accumulate and contribute to pain/swelling

Immunodeficiencies

Failure of the immune system to protect the body from pathogens, causing increased susceptibility to infections.

Macrophages

Found within the lymph nodes, they are phagocytes that destroy old RBC, bacteria, cancer cells, and other foreign matter in the lymphatic stream.

From which fluid is lymph derived?

Interstitial Fluid

Primary lymphatic organs

Involved in the production and maturation of lymphocytes. - Primary organs are red bone marrow and thymus - Approx 25% of the total WBC are lymphocytes.

Susceptibility

Lack of resistance and increased risk of acquiring disease.

chronic inflammation

Lasts longer than 2 weeks - May follow unsuccessful acute inflammation Seen in several pathologies -Autoimmune disease; Ex: rheumatoid arthritis -Respiratory disease; Ex: asthma -Cardiovascular disease; Ex: atherosclerosis -Digestive disease; Ex: Crohn disease

Where the thoracic duct deliver lymph?

Left Subclavian vein

Tonsils

Located in the oral cavity and pharynx.

Peyer Patches

Located in the portions of the small intestines and are also called intestinal tonsils

Lymph Movements

Lymph enters LYMPHATIC CAPILLARIES which then merge into LYMPHATIC VESSELS which then merge into LYMPHATIC TRUNKS then merge into LYMPHATIC COLLECTING DUCTS (drains large body regions) which then enter the venous circulation at the subclavian veins.

Where is lymph filtered?

Lymph node

Which factor is part of specific immunity?

Lymphocytes

Which term is used to describe the movement of lymph the body?

Lymphokinesis

Lymphokinesis

Movement of lymph through the body - flows in one direction toward two ducts, entering the cardiovascular system at the right and left subclavian veins. - Lymph movement is dependent on outside forces because it doesn't have a pump. It is assisted in the same way as venous blood flow - it uses valves and skeletal muscle pumps. - Anything interfering with the flow of lymph, such as an obstruction, may cause tissue fluids to accumulate, resulting in Edema

Which term refers to defense mechanisms that are directed against all pathogens and foreign agents and include barriers, cellular responses, and inflammation?

Nonspecifc

Autoimmune diseases

Occurs from an inappropriate or excessive immune response in which the body no longer recognizes its own healthy tissue and attacks it because the body believes the tissue is foreign

Secondary lymphatic organs

Populated by lymphocytes, B cells, and T cells but do not produce them - Organs are lymph nodes, mucosa-associated lymphoid tissue (MALT) and the spleen.

B cells

Produce surveillance, and produce antibodies when they encounter a foreign agent. - Type of response is antibody-mediated immunity

Specific Defense Mechanisms

Selective and directed against particular pathogens, provide immunity, and involve lymphocytes or B cells or T cells.

Which factors promotes the flow of lymphatic fluid?

Skeletal Muscle movements

Which organ stores lymphocytes and serves as a reservoir for blood?

Spleen

Resistance

The body's ability to counteract the effects of pathogens and foreign agents through defense mechanisms.

Barriers: Physical and Chemical

The first line of defense. -Skin glands secrete sweat and sebum that create a chemical or hostile barrier for pathogens - Mucous membranes in the respiratory tract contain cilia, which moves particles upwards to be swallowed. - Sticky mucus in the nose and mouth trap microorganisms, allowing them to be swallowed and destroyed by enzymes and acids in the GI tract. - Cerumen (ear wax), hair in the ear and nose provide a barrier to foreign agents. - Vaginal secretions create an acidic environment, where pathogens can't stay. - Tears and urine flowing down the urethra flush microorganisms from openings to vulnerable areas

Cellular Responses

The second line of defense is activated when microorganisms penetrate the body's first line of defense such as its barriers. - Involve reactions from nonspecific white blood cells and plasma proteins. - Primary phagocyte cells are neutrophils and macrophages. - Interferons help fight against viral infections. - Natural killer (NK) cells attack and kill abnormal cells, such as tumor cells and virus-infected cells.

Immunity

The third line of defense. Is the body's capacity for identifying, destroying, and disposing of disease-causing agents - The body "remembers" the particular pathogen and therefore is able to attack quicker the next time it enters the body.

LEARNING TIP

To help remember the difference between B and T cells. B cells are named by where they mature: Bone Marrow T cells are named by where they mature: Thymus

Red bone marrow

Where all blood cells originate and include RBC, platelets, and WBC. - B cells remain in red marrow to complete maturation and then enter the bloodstream to help defense mechanisms

systemic inflammation

Widespread; not confined to specific regions -Associated with infection -Fever is common - Can last from 2 days to 2 weeks, depending on infection type

Vermiform Appendix

attached to the cecum, which is the first region of the large intestine.

lymph nodes

bean-shaped structures of the lymphatic system where pathogens and other harmful substances are filtered from the lymph by specialized cells of the immune system. - Several body regions contain clusters of superficial lymph nodes: Cervical region in the neck, the axillary region, and the inguinal region in the groin. -The only structures along the lymphatic chain that filters lymph. - Enlarges during the period of infection.

Location of superficial lymph nodes

cervical, axillary, and inguinal regions

Lymphatic Organs

characterized by the presence of lymphocytes, a type of white blood cell. Two types of lymphatic organs are primary and secondary

Non-specific defense mechanisms

directed against all pathogens and foreign agents, and include barriers, cellular responses and inflammation.

Lymphatic trunks

drain large regions of the body. -lymphatic vessels join these -trunks converge to form one of two regionally draining ducts, the right lymphatic duct and the thoracic duct.

Thoracic duct

drains lymph from the rest of the body and delivers it to the left subclavian

Right lymphatic duct

drains lymph from the right side of the head and neck, the right upper extremity, and the right half of the upper trunk and delivers it to the right subclavian vein

Lymphatics

include all lymphatic capillaries, vessels, trunks, and ducts along the lymphatic chain.

Lymphatic vessels

large vessels with more valves than veins, open in only one direction, allow lymph to flow towards the center of the body - lymphatic capillaries merge to form these

Lacteals

lymphatic capillaries located in fingerlike projections of the small intestine called villa - absorb dietary fats and fat-soluble vitamins

Lymph Capillaries

microscopic vessels that draw lymph from tissues to the lymph vessels - begin tissue spaces as closed-ended sacs - attached to lymph capillaries are anchoring fibers, which attach the capillary wall to surrounding tissues.

T cells

responsible for cell-mediated immunity and they directly attack the invading pathogen or foreign agent.

Thymus

site of T cell maturation until they enter the bloodstream to help defense mechanisms - It also produces thymosin and thymopoietin, which stimulate the maturation of lymphocytes and their differentiation.

Tree

the distribution of lymphatics is similar to a tree with its progression from smaller twigs to bigger branches yo finally large trunks

Spleen

the largest lymphatic organ is located in the left upper quadrant. - Resembles a lymph node and filters blood much in the same way a lymph node filters lymph - Lymphocytes react to pathogens in the blood and attempt to destroy or inactivate them. - releases lymphocytes when assistance is needed. - Stores blood and can release small amounts into the bloodstream during loss - Called the "graveyard of RBC"

Lymph

watery fluid circulating through lymphatics. -Derived from interstitial fluid located in the extracellular spaces between tissues. Interstitial fluid comes from blood plasma that is pushed out of blood capillaries during filtration. - When interstitial fluid enters lymphatic capillaries, it is called lymph. - After lymph is filtered by lymph nodes, it is returned to the blood, becoming plasma once more. - Plasma, Interstitial fluid, and lymph are basically the same fluid but called different names depending on location