BIOL 431: Lymphatic System & Resistance to Disease (Lec 1 & 2)

lymphatic system

one way vessel system toward the heart

harmful material that enter lymphatic vessels

bacteria, virus, cell debris, cancer cells

returned to blood

water, proteins, blood cells

functions of lymphatic system

1. drain excess interstitial fluid
2. transport dietary lipids & lipid-soluble vitamins
3. filter fluid for immune response (destruction of specific invaders by B & T cells)

lymphatic capillaries

1. closed-ended tubes, walls overlap to form 1 way valves
2. found in body except: in avascular tissue, CNS, parts of spleen & red bone marrow
3. unite to form large lymphatic vessels, passes through lymph nodes

lacteals

lymphatic capillaries in small intestine

lacteals function

dietary lipid & lipid-soluble vitamin uptake

chyle components

lymph, lipids

lymph nodes

1. encapsulated organs w/ masses of B & T cells
2. locations: cervical, axillary, inguinal

which 2 channels do lymph trunks drain?

thoracic and right lymphatic duct

thoracic duct

1. cisterna chyli dilation at beginning of thoracic duct
2. receives lymph from left upper half & everything below ribs
3. drains lymph into venous blood at junction between left subclavian and left internal jugular vein

right lymphatic duct

1. receives lymph from upper right side of body and head


1. drains lymph into venous blood at junction between right subclavian and right internal jugular vein

lymph flows as a result of?

one way flaps on capillaries

which 2 pumps aid lymph return to venous blood?

skeletal muscle and respiratory pump

skeletal muscle pump function

milking action

respiratory pump function

pressure changes during breathing

Trace the route of lymph from interstitial fluid to venous blood flow.

1. blood capillaries
2. interstitial fluid
3. lymphatic capillaries
4. lymphatic vessels
5. lymph nodes
6. lymphatic ducts (thoracic/left/right lymphatic duct)
7. junction between subclavian and internal jugular veins

primary lymphatic organs

stem cells divide, become immunocompetent, red bone marrow: hemopoiesis; thymus

red bone marrow fxn

hemopoiesis

thymus gland

site of t-cell maturation

secondary lymphatic organs

site where most immune response occurs, lymph, spleen, malt

lymphatic nodules

clusters of lymphocytes that stand guard in all mucous membranes/malt

where is the thymus gland located?

between sternum and heart

What’s the function of the lymph nodes’ cortex?

site of plasma cells, memory B cells, T cells, and dendritic cells

What’s the function of the lymph nodes’ medulla?

mainly macrophages

Trace the route of lymph flow through a lymph node.

1. Afferent lymphatic vessels
2. Subcapsular sinus
3. Trabecular sinus
4. Medullary sinus
5. Efferent lymphatic vessels

Metastasis

ability of cancer cells to break off and travel through blood or lymph

The _____ can be predicted knowing the direction of lymph flow.

secondary tumor site

Lymph nodes function as a ___. Foreign substances are trapped and destroyed by ____ or immune response of lymphocytes.

filter, macrophages

spleen

largest mass of lymphatic tissue in body

white pulp is made of lymphatic tissue (lymphocytes & macrophages)

has B and T cells, macrophages engulf foreign antigens

Red pulp has venous sinuses filled with blood and splenic cords consisting of RBCs, macrophages, lymphocytes, plasma cells, and granulocytes.

1. Macrophages remove ruptured, worn out, or defective blood cells
2. Storage of up to 1/3 of body’s platelet supply
3. Production of blood cells during fetal life

resistance

ability to ward off pathogens producing disease

susceptibility

lack of resistance

the body system that carries out immune responses is the ____.

lymphatic system

innate/nonspecific resistance

1. present at birth
2. no specific recognition of invaders or memory component
3. 1st and 2nd line of defense

adaptive or specific immunity

1. specific recognition of invaders with memory component
2. 3rd line of defense

What two barriers do the first line of defense (skin and mucous membranes) provide?

physical and chemical barriers

What are the 4 physical barriers apart of the 1st line of defense?

epidermis, mucous membranes, cilia in upper respiratory tract, nose hair

epidermis function

periodic shedding, acts as shield

mucous membranes function

mucus traps microbes and foreign substances

cilia in upper respiratory tract (trachea)

propel trapped particles up and out

nose hair

traps and filters anything that may enter

What enzyme do tears, saliva, nasal secretions, sweat, and tissue fluids contain that has antimicrobial properties?

lysozyme

saliva function

washes mouth

urine function

cleanses urinary system

2 chemicals apart of the 1st line of defense?

sebum and acids

sebum function

protective film, protects anything water-soluble from entering, lipid-protective film

acid function

inhibit bacterial growth (in stomach, sebum, sweat, vagina)

In the 2nd line of defense, what’s the function of interferons?

prevents replication of neighboring uninfected cells produced by lymphocytes, macrophages, and fibroblasts

What are interferons produced by in the 2nd line of defense?

lymphocytes, macrophages, and fibroblasts infected by viruses

What is the complement system?

20+ inactive proteins in blood plasma that enhance certain immune responses

complement system function

microbe cytolysis, promotes phagocytosis, contributes to inflammation

natural killer cell function (lymphocyte, but not a B or T cell)

kill wide variety of infected body cells and certain tumor cells

What do NKCs release?

perforin and granzymes

perforin function

poke holes in cell membrane of infected cell

granzyme function

induce apoptosis, programmed cell death

What are the 5 phases of phagocytosis?

chemotaxis, adhesion, ingestion, digestion, killing

What is chemotaxis?

chemically stimulated movement of WBCs to site of infection, phagocytosis

What is adherence?

binding of invading microbe to phagocyte

What is ingestion?

bringing microbe into a vesicle

What is digestion?

digested microbe in phagolysosome

What is the result of killing?

residual body, indigestible material

What is inflammation?

nonspecific defensive response of body to tissue damage

What are the four symptoms of inflammation?

redness, heat, pain, swelling

What is redness?

increased blood flow and hemoglobin

What’s heat?

increased blood flow, heat, and metabolic reactions

What’s pain?

injury to neurons, chemicals (kinins, prostaglandins)

What’s swelling?

increased blood flow and capillary permeability, increased IFOP

What does inflammation attempt to do?

dispose of microbes, prevent spread, prepare site for tissue repair

neutrophil

phagocytosis, destroy microbes

basophil

intensify immune response

eosinophil

kills parasites

monocyte

macrophage, phagocytosis

lymphocyte

immune responses like antigen-antibody reactions

pharynx 3 functions

passageway for air and food, resonating chamber, houses tonsils

pleural effusion

fluid in pleural cavity

pneumothorax

air in pleural cavity

What are the 3 basic stages of inflammation?

vasodilation and increased permeability of blood vessels, emigration, tissue repair

What contributes to inflammation?

histamine, prostaglandins, leukotrienes, complement proteins

What does vasodilation and increased permeability of blood vessels mean?

more nutrients and removing debris, more antibodies and clotting factors

histamine function

increase vasodilation and capillary permeability

prostaglandins function

increase pain and emigration of phagocytes

leukotrienes function

chemotaxis, increase permeability of capillaries

What does emigration depend on?

chemotaxis, need chemicals released to call blood cells in the area

What’s pus?

pocket of dead phagocytes and damaged tissue

What does a fever do?

intensifies effects of interferons, inhibits growth of some bacteria, speeds up body reactions aiding repair

What is the specific resistance, 3rd line of defense called?

adaptive immunity

Adaptive immunity is the ability of the body to defend itself against _____ invading agents.

specific

______ are substances recognized as foreign by the immune responses.

antigens

How is adaptive immunity different from innate immunity?

specificity and memory

What is the branch of science dealing with the responses of the body when challenged by antigens?

immunology

_______ is the ability to carry out adaptive immune response. Must have antigen receptors to identify specific antigen. Recognize self vs nonself.

immunocompetence

What is the immune response that’s against endogenous antigens, involves cytotoxic T cells, and cells attack infected cancer cells?

cell mediated immunity

What’s the immune response against exogenous antigens, involves B cells, and antibodies directly attack antigens?

antibody mediated immunity

_____ are chemical substances recognized as foreign by antigen receptors when introduced into the body. Entire microbes can act as this.

antigens

What determinant is small parts of a large antigen that triggers response?

epitope/antigenic

_______ antigens, or human leukocyte associated (HLA) antigens, are unique to each person’s body cells.

major histocompatibility complex

What is the normal function of MHC antigens?

help T cells recognize foreign VS self-antigens

Which MHC is displayed on ALL cells EXCEPT red blood cells?

MHC-1