Lymphatic-Innate Review

Lymph (fluid)

essentially blood plasma that has left the blood vessels and become interstitial fluid

Lymph nodes

a “battleground” for germs leaving tissues and white blood cells; collects lymph

Lymph ducts

returns lymph to your bloodstream

Spleen

synthesizes antibodies in its white pulp and removes antibody-coated bacteria and antibody-coated blood cells by way of blood and lymph node circulation

Tonsils

lymphoid tissues of the upper pharynx; upper (superficial) tissues made of M cells which capture pathogens and antigens and alert T and B cells deeper in the tissue

Mini valves

loose connects that allow fluid to rush in; collagen connections open these when tissue is under high fluid pressure; open during periods of inflammation, infection, and hypertension; large openings allow entry for large proteins and pathogens associated with infections

Capillaries

endothelial cells making up lymph vessels are very loosely connected and attached to surrounding tissue; mini valves allow fluid to rush in; absorb the fluid via pressure; high fluid pressure caused by buildup of fluid, abnormally high pressure can be caused by inflammation/infection; blind ended and aren't continuous

Lymphedema

swelling caused by a lymphatic system blockage

Diapedesis

monocytes mature into macrophages which can leave the blood vessels and enter tissues

AMP

antimicrobial peptides; tiny proteins secreted from the skin to prevent infections, a chemical barrier; dendritic, macrophages, B lymphocytes

Fever

presence of certain PAMPs results in another chemical cascade that triggers the hypothalamus to increase the normal temperature of the body; increases the efficiency of complement and decreases growth rate of pathogens

Inflammation

acute and chronic; reddened skin, localized heat, edema and pain; increased temperature heat stresses the bacteria, and they don’t grow as fast

Acute inflammation

dilates blood vessels and makes them more permeable; delivers more blood and resources to the site of infection, results in rapid healing; recruits phagocytes to kill infections pathogens and prevent the spread of infection

Chronic inflammation

long, lasting, generally damaging reaction to infection which itself can cause disease

Mucus

traps bacteria in its viscous and acidic fluid which eats away at the bacteria

Opsonization

antibodies or other proteins mark the pathogen for death

Complement

the proteins in the blood plasma that bind to pathogens and mark them for destruction; immobilize germs but they can also act as MAC to kill the cell

Complement binding

the process of proteins in the blood plasma binding for opsonization

Membrane attack complex

complement products produce this; bores a hole in the pathogen’s cell membrane, killing the cell

Chemotaxis

recruits WBCs to the pathogen; release a smell to attract them

Interferon

non-specific chemical defenses of blood; protein molecules released by host cells to inhibit virus spread; infected cells produce this and causes neighboring cells to produce antiviral proteins which inhibit viral mRNA synthesis and protein translation at ribosomes

PAMP

pathogen associated molecular patterns; all are antigens; identifies pathogens and reveals them to the immune system to activate innate immune response; specific immune responses for specific PAMPs; are located ON the pathogen

Pathogen

virus, bacteria, or microorganism that will cause a disease; unicellular, parasites are multicellular

Phagocytosis

WBCs surround and engulf pathogens

ROS

reactive oxygen species formed from enzymes in the cell membrane of cells such as eosinophils and lymphocytes; toxic compounds that are secreted onto cells to kill them

T-lymphocytes

produce cytokines that direct immune response; destroy infected cells

B-lymphocytes

produce antibodies to pathogens

Dendritic cells

modified monocytes- phagocytose invading microorganisms

What are the functions of the lymphatic system?

Collects interstitial fluid from tissues and puts this fluid back into the blood; pathogens and other substances drain into the lymph ducts; white blood cells reside in ducts to neutralize pathogens and other foreign materials

How can the lymphatic system help a doctor diagnose an infection?

The swelling of the lymph nodes is a sign of infection; lymph nodes fill with lymph and infection debris (cell fragments, germs, etc.)

How does the lymphatic system distribute fluid around the body? In other words, it is not connected to the circulatory system proper, so the heart cannot push lymph around the body. How then does it move?

It moves through muscle pump and gravity. Lymph vessels merge into 2 major ducts- right duct which collects lymph from right side of thorax, right arm, and right side of head; thoracic duct collects lymph from rest of body. All lymph rejoins the blood via these ducts at the right and left jugular veins

An infectious agent enters your body after cutting your finger. Describe the innate immune responses put into place to intercept and destroy the infectious agent.

Pathogen enters the blood, travel to the lymph nodes via blood plasma, PAMPs reveal the pathogen to the immune system, complement binding and opsonization, complement products facilitate chemotaxis and produces membrane attack complex to bore a hole in the pathogen’s cell membrane, killing the cell

What are some behavioral responses to systemic infection and how are they beneficial?

Systemic infection is an infection through the blood stream, e.g. flu. Gives headache and makes you tired so that you isolate yourself to prevent spreading and allows your body to use all your energy to fight.

Why is fever beneficial in the long run?

Raises temperature to slow down bacteria growth and/or kill them and denature its enzymes

What is a differential WBC count and what does it tell us?

A count of the different types of WBCs that tells us what kind of infection we have/what the body is fighting

What characteristics of the skin prevent infection?

The high salt concentration rids the skin of moisture, preventing bacterial growth. Dead, dry skin cells because no moisture means no growth. Dendritic cells phagocytose invading microorganisms. AMPs prevent infections. Lysozyme lyses bacterial cell membranes and causes the virus to pop

Why is the lymphatic system so important to immunity?

Provides the WBCs and pathogens with a battleground and drains them from the body, effectively killing and removing the invading pathogen.

What is an infection? (Think about it from the human point of view AND from the pathogen’s point of view).

Pathogen will continuously mutate as the body’s B-cells continue producing antibodies to fight against them. An example is how each time you get the flu, it’s a different strain because it adapts itself to your body having an antibody against its old version.