Lymphatic System and Immune

Question 1

Organization of Lymphatic System

Answer 1

Lymphocytes
Lymphatic Vessels
Lymph
Lymphoid Organs

Question 2

Lymphocytes

Answer 2

Lymph cells that perform specific immune functions
Defend against both environmental hazards such as pathogens
And protect against internal threats such as cancer
Classified as a specific defense or the immune response

Question 3

Lymphatic Vessels

Answer 3

Begins in peripheral tissues

Ends at a connection to the venous system

Question 4

Lymph

Answer 4

Fluid that flows through lymphatic vessels

Similar to plasma but fewer suspended proteins

Question 5

Lymphoid Organs

Answer 5

Connected to the lymph vessels

Lymph nodes, spleen and thymus

Question 6

Functions of Lymphatic System

Answer 6

Production, maintenance, and distribution of lymphocytes
Lymphocytes respond to the presence of pathogens, abnormal body cells, foreign proteins

Carry fluid and solutes from tissues to blood

Distribution of hormones, nutrients and waste to general circulation

Question 7

Lymphatic Vessels

Answer 7

Lymphatic capillaries
Lymphatic vessels
Thoracic duct
Right Lymphatic duct

Question 8

Lymphatic capillaries

Answer 8

Present in almost every tissue and organ in the body.
Lacteals in the small intestine
Act as a one-way valve

Question 9

Lymphatic vessels

Answer 9

Similar to veins including valves to prevent backflow

Question 10

Thoracic duct

Answer 10

Lymph from parts of body inferior to the diaphragm and left side superior to the diaphragm

Question 11

Lymphocytes

Answer 11

T Cells
~ 80% of lymphocytes
Various “jobs” within immunity (killer, helper, suppressor)
B Cells
Produce antibodies
NK Cells
Immunological surveillance

Question 12

Lymphocytes (origin and circulation)

Answer 12

Constantly circulating through blood, lymph and tissues
Survive for long time periods (4-20+)
Stem cells produced in red bone marrow
Differentiate into B, T, and NK Cells
As B and T Cells differentiate and mature they gain the ability to respond to the presence of a specific antigen
As NK Cells differentiate and mature they gain the ability to recognize abnormal cells
T-Cells migrate to the thymus for division and maturation
All end up in the blood-stream and peripheral tissues
Retain their ability to divide

Question 13

Lymphoid Nodules

Answer 13

Loose connective tissue and lymphocytes

Size can increase or decrease

Often have areas of actively dividing lymphocytes

Often found in areas open to the external environment
Mucosa-associated lymphoid tissue (MALT) line digestive system
Aggregated lymphoid tissue (Peyer patches) line the intestines

Appendix

Tonsils
Pharyngeal, Palatine, Lingual
Guard entrance to digestive and respiratory tracts

Question 14

Lymphoid Organs

Answer 14

Lymph Nodes
Thymus
Spleen

Question 15

Lymph Nodes

Answer 15

Afferent vessels deliver lymph to the nodes
Efferent vessels deliver lymph away from the nodes
Filters lymph and detects and removes antigens
Stimulates immune response

Question 16

Thymus

Answer 16

Gland behind the sternum above the heart

Site of T cell production and maturation

Question 17

Spleen

Answer 17

Largest lymph organ (b/t stomach and left kidney)
Filters a large amount of blood detecting and removing antigens
stimulates the immune response

Question 18

Chemical Mediator(Cytokines)

Answer 18

Interleukins
Increase T Cell sensitivity, stimulate B Cell Activity, enhance non-specific defenses, moderate the immune response
Interferons
Tumor Necrosis Factors
Inhibit tumor growth and kill sensitive cells
Phagocyte-Activating Chemicals
Colony-Stimulating Factors
Stimulate lymphocyte and RBC production
Miscellaneous Cytokines
Aid other aspects of the immune system and enhance blood cell production

Question 19

Allergies, Asthma, Autoimmune Diseases
Oh My

Answer 19

Allergy and Autoimmune Diseases are an inappropriate immune response to non-pathogen or self

Allergies have increased in prevalence across all age, sex and racial groups in the US and other “developed” countries

What is causing allergies etc… and their increase in prevalence?
Novel stimuli?
Genetics?
Pollution?
Cleanliness?

Question 20

“Diseases of the Advantaged”

Answer 20

Allergies, asthma, ulcerative colitis and Crohn’s disease have all risen in frequency in developed nations (only in developed nations)

Asthma alone increased 75% from 1980 to 1994 (again, only in developed countries)

More siblings = less asthma & allergy risk

Pet in home when young = less asthma & allergy

Question 21

The Hygiene Hypothesis

Answer 21

Dr. Erika von Mutius compared East and West Germany in 1989

Normal stimulation of the immune system during infancy and early childhood is essential for normal immune response

Without it, the immune system over reacts to harmless entities

Question 22

Additional Evidence

Answer 22

High malaria rates = low autoimmune disorders

High tuberculosis exposure = lower asthma and hay fever rates

Previous exposure to hepatitis, Toxoplasma or H. pylori = lower asthma and hay fever rates

Schistosomiasis infection = less skin allergies

Question 23

Additional Evidence

Answer 23

Asthma wheezing reduced when “cold” present

Higher endotoxin levels = less asthma and allergy

Vaginal births = less food allergies

De-worming = more digestive tract chronic diseases

Crohn’s disease and Trichuris suis