Lymphatic system

Diagram lymphatic fluid flow from a capillary to a large vein, making sure to indicate where the pressures are highest and lowest.

-Collecting vessels: course through many lymph nodes -Lymphatic trunks: drain major portions of body -Collecting ducts=6 -Subclavian veins

How is edema treated?

-Exercises -Bandages -Compression garments (socks/TEDS) -Pneumatic compression -Diuretics -NO CURE

List AND describe the mechanisms of lymph flow.

-Lymph flows at low pressure and speed -Rhythmic contractions of lymphatic vessels stretching of vessels stimulates contraction -Skeletal muscle pump -Valves -Rapidly flowing blood in subclavian veins, draws lymph into it -Exercise significantly increases lymphatic return

Explain the general flow of lymph through the human body. Where are lymphatic vessels absent?

-Lymph flows only one way= towards the heart -begins at the lymphatic capillaries (wrapped around & through capillary beds) -Absent from: •bones •bone marrow •teeth •CNS

What are the two major antigen presenting cells?

-Macrophages cells -Dendritic cells -Reticular cells

Review the types of leukocytes and make sure you know what types of infections they fight.

-Neutrophils: most numerous and they fight bacteria -Basophils: secretes histamine (vasodilator) -Eosinophils: fight parasites and allergens -Lymphocytes: has T, B and NK cells -Monocytes: fights viruses, macrophages

What can edema lead to?

-Tissue Necrosis: oxygen delivery and waste removal inhibited or impaired -Cerebral Edema (brain): headaches, nausea, seisures, and coma. -Pulmonary edema (lungs): suffocation -Circulatory shock: excess fluid in the tissues causes low blood volume and/or low Blood Pressure.

Explain how inflammation actually helps us?

-limits spread of pathogens, then destroys them -removes debris -initiates tissue repair

List AND describe the two basic functions of lymph nodes.

1) Act as lymph filters with macrophages destroying microorganisms and debris 2) Help activate immune system

List the three main functions of the lymphatic system.

1) Fluid recovery: Absorbs plasma proteins and fluid- 10-15% (2-4 L/day) from tissues and returns it to the bloodstream -interference with lymphatic drainage leads to severe edema 2) Lipid absorption lacteals in small intestine absorb dietary lipids 3) Immunity fluid has to go through lymph nodes on way back to bloodstream where immune cells stand ready

What are the four major anatomical locations of the tonsils and what are their functions.

1. Palatine tonsils (paired): posterior end of oral cavity, largest, most often infected 2. Lingual tonsils (paired): at base of tongue 3. Pharyngeal tonsil: (adenoids) posterior wall of nasopharynx 4. Tubal tonsils: tiny, surround openings of auditory tubes into pharynx -Gather and remove many pathogens entering pharynx in food or inhaled air. -Have dead-end passageways where pathogens go down and get stuck and attacked

How is a fever helpful in terms of fighting infection? What is a pyrogen?

A fever is helpful in terms of fighting infection because it accelerates metabolic rate and tissue repair and inhibits pathogen reproduction (makes a hot/undesirable environment for pathogen) Pyrogen: a cytokine, interleukin 1 it increases body temp

Describe how vaccinations result in long term immunity.

A vaccine stimulates the production of antibodies and memory cells that protect against future exposure to the pathogen.

Outline what happens when an antigen presenting cell is infected and answer the following questions: a.Which MHC protein is involved? b.What cell does an infected APC, "present" the antigen to? Be specific! c.How does the T - Cell from the question above respond when presented with a foreign antigen?

A. MHC1 B. The T-cytotoxic cell (CD8) C. Comes in and kills virus via toxin

Outline what happens when an antigen presenting cell engulfs an extracellular pathogen and answer the following questions: a.Which MHC protein is involved? b.What cell does an APC which engulfed the pathogen, "present" the antigen to? Be specific! c.How does the T - Cell from the question above respond when presented with a foreign antigen?

A. MHC2 B. T-helper cell (CD4) C. Releases cytokines

Compare and contrast active immunity and passive immunity, making sure you understand the difference between an antibody and an antigen! They are two different beasts!

Active immunity:stimulates the infected person's immune system, generally considered permanent -Immunization by vaccination give the person a weakened, dead, fragment (antigen) of the pathogen -Recover from the infection Passive immunity: person receives antibodies only so it is temporary -Maternal immunity occurs when antibodies pass from mother to baby through placenta and breast milk -Artificial injection of antibodies gives short term immunity

Compare and contrast the alternate and classical complement pathways. Make sure you include the importance of activated C3b.

Alternate pathway: nonspecific immunity -has C3b cells automatically attack bacterial antigens Classical pathway: requires antibody; specific immunity -antibodies lock down on bacteria and look for antigen -locks onto it and waits for C3b -C3b protein comes in and attaches to the antibodies and acts as enzyme to speed up the reaction

Diagram the relationship between CHP, IFHP, COP, and IFOP at the arteriole and venule end of a capillary.

Arteriole end -high hydrostatic pressure in the blood -low osmotic pressure in the blood -hydrostaic pressure wins at this end of capillary: fluid moves out -Net FILTRATION Venule end -low hydrostatic pressure in the blood -high osmotic pressure in the blood -osmotic pressure wins at this end of capillary. Fluid moves into the blood -Net RE-ABSORPTION

List AND describe the cardinal signs of inflammation.

Cardinal signs: -redness (erythema) caused by hyperemia (increase blood flow) -swelling (edema) caused by increase in capillary permeability and filtration -heat caused by hyperemia -pain caused by inflammatory chemicals (bradykinin, prostaglandins) secreted by damaged cells, pressure on nerves

Compare and contrast diffusion and osmosis. Draw a couple of pictures if you need to!

Diffusion: high to low -mixing of two or more substances from an area of high concentration to an area of low concentration -perfume in a room Osmosis: low to high -Diffusion of WATER through a membrane from a solution of low solute concentration (high water potential) to a solution with high solute concentration (low water potential)

What is an epitope? Why is it important? FINISH

Epitope: pieces of antigen from pathogen

Generally, what are the first, second, and third lines of defense against disease?

First line of defense= skin, mucous membrane Second line of defense= Phagocytic cells, antimicrobial proteins, inflammation and fever -specific defense-results from prior exposure, protects against only a particular pathogen Third line of defense= Immune system

List AND describe the functions of the thymus. What is the fate of the thymus as we age?

Functions of Thymus= -Secretes hormones thymosin and thymopoietin- causing T cells to function against specific pathogens -functions strictly in T cell maturation, so it is the only lymphoid organ that doesn't directly fight antigens Thymus is huge in fetus, during adolescence growth stops and starts to atrophy slowly, by old age it's replaced by fibrous and fatty tissue

Explain how the HIV virus affects the immune system and how this ultimately leads to an individual's death. FINSH

HIV affects the immune system by tricking the cells to internalize viruses by receptor mediated endocytosis which leads to an individual's death

Describe how HIV is transmitted and the tactics that can be used to suppress/slow down an HIV infection from progressing to full blown AIDS

HIV transmission: -blood -semen -vaginal secretions -breast milk -placenta *Most common means of transmission: -sexual intercourse (vaginal, anal, oral) -contaminated blood products -contaminated needles

Describe the general functions of IgG, IgE, IgD, IgM, and IgA. You only need to know what I covered in class!

IgG: -largest, most diverse *can cross placenta -80% of antibodies -responsible for resistance against many viruses, bacteria, and bacterial toxins IgE: -on surfaces of basophils and mast cells (inflammation & allergies) IgD: -on surfaces of B cells IgM: -"starburst" give us our blood type -found in plasma, can bind to multiple antibodies IgA: -found in secrestions= tears, mucus, saliva, & semen * increase cell lysis, can activate complement activity

List AND describe some causes of edema which were discussed in class.

Increase in Capillary filtration (increase capillary BP or permeability): -poor venous return •congestive heart failure- pulmonary edema •insufficient muscular activity -kidney failure (water retention, hypertension) -histamine makes capillaries more permeable Decrease in Capillary reabsorption: -hypoproteinemia (oncotic pressure ∞ blood albumin) cirrhosis, famine, burns, kidney disease Obstructed lymphatic drainage

Generally, what do interferons do?

Interferons: -"Dying words" secreted by certain cells invaded by viruses -diffuse to neighboring cells and stimulate them to produce antiviral proteins -activate natural killer cells and macrophages -destroy infected host cells -stimulate destruction of cancer cells

What exactly is interstitial fluid? Where does it go if it is not reabsorbed into the capillary?

Interstitial fluid: the fluid forced out of the arterial ends of capillary beds, most is reabsorbed, the part that remains in tissue is interstitial fluid (3L/day) -the interstitial fluid that was not reabsorbed by the capillaries then goes into the lymphatic system via the lymphatic capillaries

Why does it matter that the endothelium of capillaries are only one cell layer thick?

It matters that the endothelium of capillaries are only one cell layer thick so it can allow rapid diffusion

Have a general framework in your mind of the pathway to lymphocyte development.

LOOK ON POWERPOINT LS2 SLIDE 12

What are lacteals? Where are they found? What purpose do they serve?

Lacteals= special lymphatic capillaries in small intestine - transport lipids from digestive tract Found= Villi in the small intestine Purpose= absorb lipids from the digestive tract

What is a MHC protein, in your own words?

Major Histocompatibility complex- face on cell that activates immune response

Diagram how NK cells help destroy pathogens.

NK cells - destroy bacteria, transplanted cells, cells infected by viruses, and cancer cells -Perforins - Punches holes in cell walls -Granzymes - Destroy cellular enzymes and induce apoptosis (cell suicide)

Describe what osmotic pressure is. Now, explain why hydrostatic pressure is. Stop! If you don't understand this, then take some time to go over it again, or else the lymphatic system won't make sense!

Osmotic pressure: -pressure across the membrane -water wants to move to the right to equal out the concentrate, so the pressure is higher on the left -in the blood the big solutes are: Albumin (plasma protein) *High concentration in the blood (Albumin) *fluid wants to come into blood Hydrostatic pressure: -hose with holes -fluid wants to go out of blood

List the primary and secondary lymphatic organs.

Primary Lymphatic Organs -Site where T and B cells become immunocompetent (able to fight infection) -Red bone marrow and thymus Secondary Lymphatic Organs -Lymph nodes, tonsils, spleen

Compare and contrast a primary and secondary immune response, making sure to talk about immune memory.

Primary immune response:The first exposure to a pathogen produces B and T memory cells specific to that pathogen (first exposure, slower) Secondary immune response:A second exposure activates those memory cells. (quicker response)

List AND describe the functions of the spleen.

Spleen: size of fist Left side of body just beneath diaphragm, curling around anterior aspect of stomach Extracts aged and defective blood cells and platelets Macrophages remove debris and foreign matter from blood Stores products of RBC's (iron) for later use Erythrocyte production in fetus Can be removed if ruptured and liver and bone marrow take over most functions

Diagram the anatomy of a lymph node and the flow of lymphatic fluid through a lymph node. Explain how this setup allows the body to "scan" for pathogens.

Structure of a lymph node: bean-shaped, less than 2.5cm in length -Surrounded by a dense fibrous capsule -Connective tissue strands (trabeculae) divide node into compartments -Has a cortex and medulla -Lymph enters convex side through many afferent lymphatic vessels, exits through only 2 efferent vessels. This allows time for lymphocytes to cleanse fluid because fluid stagnates -Lymph travels through several nodes before it's cleansed

What immunoglobulin is involved with allergies? What cells are involved with the histamine release?

The immunoglobulin involved with allergies is IgE, the cells involved with the histamine release are B cells (plasma cells) and mast cells

Which region of the antibody determines if it can bind to a particular antigen? FINSIH

The region of the antibody that determines if it can bind to a particular antigen is the variable (V) regions

Explain why removal of axillary lymph nodes can lead to permanent lymphedema of the arm.

The removal of axillary lymph nodes can lead to permanent lymphedema of the arm because the fluid absorption and movement of lymph through the lymph node does not work on its own

Outline what happens when a B - Cell is directly stimulated by an antigen. Explain how this results in humoral immunity. If you don't know what humoral immunity is at this point, then stop and go back!

When a B cell is directly stimulated by an antigen, it becomes sensitized. Then, a T helper cell activates and gets it pumped

Explain the relationship between lymph nodes and cancer metastasis.

When a person has cancer, then the lymph nodes are blocked by the cancer and they swell due to no reuptake of fluid in the tissues (edema)

Explain the importance of mini-valves in lymphatic capillaries.

When fluid pressure in interstitial space is greater than pressure in lymphatic capillary, minivalves open the gate - but lymph can't leak back out because increased pressure in lymphatic capillaries keeps gates closed

What is the difference between splenic white pulp and splenic red pulp?

White pulp= Lymphocytes suspended on reticular fibers Red pulp= Clusters of Macrophages and Red Blood Cells