Exam 2 Study Guide: Lymphatic, Immune, Respiratory, & Digestive

Exam 2 Study Guide: Lymphatic,
Immune, Respiratory, & Digestive


Lymph is propelled by - Ans---Pulsation of nearby arteries
-Contractions of smooth muscle in the walls of the lymphatics
-Contractions of nearby skeletal muscles

Lymph node functions - Ans---Filter lymph- macrophages destroy
microorganisms and debris
-Immune system- lymphocytes are activated and mount an attack against
antigens

Lymphoid organs - Ans---Spleen
-Thymus
-Tonsils
-Peyer's Patches
-Appendix

Spleen - Ans---Largest lymphoid organ
-Served by splenic artery and vein, which enter and exit at the hilus
-Functions:
--->Site of lymphocyte proliferation and immune surveillance and response
--->Cleanses the blood of aged cells, platelets, and debris
--->Stores breakdown products of RBCs (iron) for later reuse
--->Stores blood platelets
--->Site of fetal erythrocyte production (normally ceases after birth)
--->Contains lymphocytes, macrophages, and huge numbers of
erythrocytes

Structure of the Spleen
1. White pulp
-Around central arteries
-Mostly lymphocytes on reticular fibers and involved in immune functions

,2. Red pulp
-Venous sinuses and splenic cords
-Rich in macrophages for disposal of worn-out RBCs and bloodborne
pathogens

Thymus - Ans---Thymic lobes contain an outer cortex and inner medulla
-Cortex contains densely packed lymphocytes and scattered macrophages
-Medulla contains fewer lymphocytes
-Thymic (Hassal's) corpuscles involved in regulatory T cell development
-Functions:
--->T lymphocyte maturation
--->It does not directly fight antigens
-Thymocytes provide the environment in which T lymphocytes become
immunocompetent

Tonsils - Ans---Simplest lymphoid organs
-Contains follicles with germinal centers
-Are not fully encapsulated
-Epithelial tissue overlying tonsil masses invaginates, forming tonsillar
crypts
-Crypts trap and destroy bacteria and particulate matter

Peyer's Patches - Ans---Clusters of lymphoid follicles
-In the wall of the distal portion of the small intestine
-Functions:
--->Destroy bacteria, preventing them from breaching the intestinal wall
--->Generate "memory" lymphocytes

Appendix - Ans---Lymphoid follicles concentrated in the walls
-Functions:
--->Destroy bacteria, preventing them from breaching the intestinal wall
--->Generate "memory" lymphocytes

Lymphatic Disorders - Ans---Lymphedema
-Buboes
-Elephantiasis
-Hodgkin's Disease

, Lymphedema - Ans---Anything that prevents normal return of lymph to the
blood
-Severe localized edema

Buboes - Ans---Infected lymph nodes
-Wrongly called "swollen glands"
-The main symptom of those contracting the bubonic plague that killed
many Europeans

Elephantiasis - Ans---Typically a tropical disease
-Lymphatics of lower limbs clogged with parasitic roundworms

Hodgkin's Disease - Ans---Malignancy of lymphoid tissues
-Swollen lymph nodes, fatigue, intermittent fevers, and night sweats
-Treated with chemotherapy and radiation

Innate vs. Adaptive Immune system - Ans--1. Innate (nonspecific) defense
system
2. Adaptive (specific) defense system

Components of the innate immune system - Ans---Two lines of defense
1. Surface Barriers
-Skin and mucosa first line of defense
-Functions:
--->Mechanical barrier
--->Inhibit entrance of pathogens
--->Mucous, acidity, lysozyme

2. Internal Defenses
-Cellular and chemical defenses are second line of defense
-Protection if microorganisms invade deeper in tissues
--->Cells: Phagocytes, Natural Killer (NK) cells, Mast cells, WBCs
--->Chemicals: Interferons, complement
--->Inflammation
--->Fever

Different types of phagocytes - Ans---Macrophages- develops from
monocytes and become the chief phagocytic cells