Chapter 5

lymphatic system

Consists of lymphatic vessels and organs

lymphatic system 4 main functions

•Lymphatic capillaries absorb excess and interstitial fluid and return bloodstream

•Lymphatic capillaries in small intestine, absorb fats and transport to bloodstream

•Production, maintenance and distribution of lymphocytes

•Helps defense against pathogens

Lymphatic vessels carry fluid called...

Lymph

Lymphatic vessels begin as blind-ended...

Lymphatic capillaries in tissues

2 lymphatic ducts

thoracic duct and right lymphatic duct

thoracic duct

collects lymph below thorax and left side

right lymphatic duct

Returns lymph from right side

valves prevent

Lymph from flowing back

2 types of lymphatic organs

1. Primary lymphatic organs

2. Secondary lymphatic organs

primary lymphatic organs

red bone marrow and thymus

secondary lymphatic organs

lymph nodes, tonsils, and spleen

red bone marrow

produces blood cells

Children mostly have red marrow; few bones in adults

B cells (B lymphocytes) mature in

Red bone marrow

spleen

filters blood

Thymus

Bilobed; thoracic cavity superior to heart.

It produced Thymosin, hormone mature T cells

lymph nodes

Found a long lymphatic vessels

name for location: neck, armpit, and groin

lymphatic nodules

concentrations of lymphoid tissue that don't have a capsule

tonsils

Located in pharynx, helps fight infections come in through nose and mouth

Peyer's patches

Found intestinal walls and appendix

Fight infections via digestive tract

immunity

Killing or removing foreign substances, pathogens and cancer cells from body

Two branches of the immune system

innate and adaptive

Inate

Fully functional without previous exposure to pathogen

Adaptive

Initiated when exposed to pathogen

Innate includes

Physical and chemical barriers

Inflammatory responses

Protective proteins

Physical barriers to infection

skin and mucous membranes

Skin has keratin, tough

Mucous membranes have cola sweet entrapped pathogens

chemical barriers to infection

•Acidic secretions kill bacteria on skin

•Sweat, saliva and tears have lysozyme

•Stomach acidic (pH) inhibits or kills bacteria

•normal flora prevents pathogens from staying

imflammatory response

Neutrophils and macrophages engulf in pathogens

4 symptoms: redness, heat, swelling and pain.

Neutrophils

Phagocytized debris, dead cells, and bacteria

Can localize infection and keep from spreading

complement system

Several plasma proteins to help fight bacteria

Interferons

Chemicals produced by infected cells act as warning

Buying to receptors of noninfected cells

Produce substances interfere with viral replication

T cells kill cells presenting specific

Foreign antigen

B cells produce

Identical copies of itself

Apoptosis

cell death

Neutralization

Antibodies, coat, viruses, and toxins completely and removing threat

immune complex

Clump of antigens combined antibodies, and it attracts WBCs

Five classes of antibodies

IgG, IgM, IgA, IgD, IgE

IgG

Major type, mother- fetus temporary immune protection

IgM

first antibody produced by newborn

IgA

Found in secretions such as saliva, tears, musics and breast milks

IdD

Surface of immature B cells

IgE

Antigen receptors for last cells which prevent parasitic worm infections and immediate allergic responses

Cytotoxic T cells

A type of lymphocyte that kills infected body cells and cancer cells

2 types of acquired immunity

active and passive

passive immunity

Given antibodies to combat disease not produced by individuals plasma cells, temporary

active immunity

Body makes antibodies against particular antigen by natural infection, or immunization by vaccines, contains antigens from pathogen or pathogen itself

Cytokines

Signaling molecules produced by T lymphocytes, microphages, and other cells

Hypersensitivity reactions

Immune system overreacts and causes harm to body

for example allergies receiving incompatible, blood type tissue, rejection or autoimmune disease

Hypersensitivity to allergens

Pollen food or animal hair, which is normally harmless

Immediate allergic response

Seconds of contact

Anaphylactic shock

Immediate allergic response, which can result in life-threatening drop in blood pressure because allergen enters bloodstream

Delayed allergic responses

Initiated by memory T cells at location of contact with allergy

Xenotransplantation

Transplanting organs from or the patient or the donor stem cells are

AIDS (acquired immune deficiency syndrome)

Results from infection with HIV, which king cause more suspectible infections and higher risk of cancer

rheumatic fever

Antibodies induced by streptococcal bacterial infection of throat react with heart muscle, which can damage heart muscles involves

rheumatoid arthritis

Antibodies against joints