Exam 2 Study Guide Flashcards
The lymphatic system is comprised of:
lymphatic vessels, lymphatic organs, lymph
What is the main function of lymphatic vessels?
transport
What is the main function of lymphatic organs?
body defense
What is lymph?
interstitial fluid that has entered the lymphatic vessels
What is resistance?
ability to ward off pathogens; avoid illness
What is susceptibility?
lack of resistance
What is a pathogen?
disease producing microbes
What are the three basic functions that the lymphatic system carries out?
- return excess interstitial fluid back to the bloodstream
- transport dietary lipids and lipid soluble vitamins (A,D,E,K) to bloodstream
- carry out immune responses via production of lymphocytes
Lymph enters lymphatic _______ and then flows through a series of larger vessels.
capillaries
The route of travel for lymph is lymphatic capillaries; _______; _______; _______.
- lymphatic collecting vessels
- lymphatic trunks
- lymphatic ducts
What are some characteristics of lymphatic capillaries?
close ended vessels; lack basement membrane; endothelial cells overlap; found everywhere except avascular
Why is it important that lymphatic capillaries lack a basement membrane?
Lymph capillaries are far more permeable than blood capillaries - thus nothing in the interstitial fluid is excluded from lymph capillaries
Why is it important that the endothelial cells in lymphatic capillaries slightly overlap each other?
Allows for the endothelium to serve as a series of one-way valves in the region of cell overlap; allows fluid to enter the capillaries but prevents it from passing back into interstitial spaces
Where are lymphatic capillaries found?
Lymphatic capillaries are found everywhere in the body except for the CNS, bone marrow, and avascular tissue (cartilage, epidermis)
What are lacteals?
Highly specialized lymphatic capillaries that are found in the villi of the small intestinal mucosa. The lymph draining from the lacteals is milky white because of the presence of digested fats. The creamy lymph is referred to as chyle.
Lymphatic collecting vessels have the same three layers as veins but have thinner walls. True/False
True
What is the primary function of a lymphatic trunk?
Drain large areas of the body
How many principal lymphatic trunks are there in the human body?
5 (4 paired, 1 unpaired)
9 total trunks
What are the names of the lymphatic trunks?
Left/ Right Lumbar
Left/ Right Bronchomediastinal
Left/ Right Subclavian
Left/ Right Jugular
Intestinal
Lymphatic trunks are formed by the union of the largest __________ ______________.
collecting vessels
How many lymphatic ducts are there?
2; right lymphatic and thoracic duct
The right lymphatic duct drains lymph from the right side of the body superior to the _______.
diaphragm
The right lymphatic duct is much shorter and smaller in diameter than the thoracic duct. True/False
True
What region of the body are the lymphatic ducts located in?
thoracic
The thoracic (left lymphatic) duct drains lymph from ________________.
the rest of the body
(right l.d. drains from right side superior to diaphragm)
The thoracic duct is the largest lymph vessel in the body. True/False
True
Each lymphatic duct empties lymph into its respective ________ vein.
subclavian
Lymph flow is one way. True/False
True
Lymph flow is not pump driven. True/False
True
Lymphatic vessels are (low pressure/ high pressure) vessels.
low pressure
The same mechanisms that aid in venous return also aid in lymph flow; these mechanisms are:
- skeletal muscle pump
- respiratory pump
- valves that prevent backflow
- in addition, when lymphatic vessels distend, smooth muscle in its wall contracts, which helps move the lymph
How many liters of lymph return to the bloodstream each day?
Approximately 3L
Where do T-cells reach maturation?
T-cells mature in the thymus
Where do B-cells reach maturation?
red bone marrow
Where do NK-cells reach maturation?
ANSWER
What are the three major types of cells found in lymphoid organs?
T-cells, B-cells, and NK cells (lymphocytes)
What are the general characteristics of lymphoid organs?
Lymphocytes and lymphoid tissue
What is lymphoid tissue?
A type of loose connective tissue called reticular connective tissue:
- it houses and provides proliferation site for lymphocytes
- it furnishes an ideal surveillance vantage point for both lymphocytes and macrophages
Where is lymphoid tissue found?
All lymphoid organs except thymus gland
Aside from lymphocytes, what other cells are present in lymphoid organs?
macrophages, dendritic
Where are lymph nodes heavily concentrated?
axillae, neck, mammary gland, and the groin
What are lymph nodes?
600 bean shaped organs along lymphatic vessels
What are the functions of trabeculae?
- divide the node into compartments
- provide support
- provide a route for blood vessels into the interior
What covers lymph nodes?
a capsule of dense connective tissues
What are the four components of the stroma (the framework of the lymph node)?
capsule, trabeculae, reticular fibers, and fibroblasts
What is the parenchyma?
functional components of the lymph node; specialized into two regions (the cordex and the medulla)
The inner cortex contains which kind of lymphocytes?
T-cells
The medulla contains what kind of cells?
B-cells and plasma cells (in tightly packed strands called medullary cords)
Where does lymph enter a lymph node?
afferent lymphatic vessels
Within the node, lymph enters ________; which are a series of irregular channels that contain branching reticular fibers, lymphocytes and macrophages.
sinuses
The medullary sinuses drain into _________ lymphatic vessels.
efferent
Why are there fewer efferent lymphatic vessels than afferent lymphatic vessels?
ANSWER
What are the functions of lymph nodes?
- filter the lymph
- act as a site to carry out immune responses
The thymus gland is the site of which kind of cell maturation?
T-cell (T-lymphocyte)
What is the importance of thymic hormones?
ANSWER
Which organ has the largest single mass of lymphatic tissue?
spleen
The spleen consists of two different types of tissue, what are they?
white pulp lymphatic tissue and red pulp blood filled sinuses
Describe white pulp lymphatic tissue.
lymphatic tissue that is found in the spleen; including lymphocytes and macrophages that carry out immune responses
What are the three functions of red pulp blood filled sinuses?
- removal of worn out red blood cells
- storage of platelets
- production of blood cells during fetal life
Where can you find lymphatic nodules scattered throughout the body?
mucosa of the GI, urinary, and reproductive tracts
What does MALT stand for?
mucosa-associated lymphoid tissue
(lymphatic nodules)
Where can aggregates of the lymphatic nodules be found?
tonsils, appendix, and Peyer’s patches
The body contains two major defense systems to fight against pathogens. What are they?
non-specific defense system
specific defense system
What are the characteristics of the non-specific defense system?
- does not target specific pathogens
- responds immediately to threats from foreign substances
What are the characteristics of specific defense systems?
- confers a state of protection known as immunity
- targets specific pathogens
- involves T- and B-lymphocytes and macrophages
The cortex is divided into an ______ and _______ cortex.
inner; outer
The outer cortex contains lymphatic nodules of ____ lymphocytes.
B
The inner cortex contains ___ lymphocytes.
T
What is the first line of defense?
Intact skin and mucous membranes and the secretions these membranes produce
What consists of the second line of defense?
phagocytes; natural killer cells; and microbial proteins
What are the three types of antimicrobial proteins?
transferrins, interferons, inflammation, fever, and a “complement system”
There are two pathways that can activate the complement system; what are they?
Classical pathway and alternate pathway
What are the functions of the activated complement system?
Activation of inflammation, opsonization, cytolysis
What are the two major types of phagocytes?
neutrophils and macrophages
What are the four cardinal signs of inflammation?
redness, heat, swelling, and pain
What is opsonization?
complement fragment C3b binds to the surface of the microbe and then interacts with receptors of phagocytes to promotoe phagocytosis
What is cytolysis?
Several complement proteins come together to form a membrane attack complex that forms large holes in the membrane of microbes
What is phagocytosis?
the ingestion of microbes; one of the major mechanisms involved in destroying foreign substances in the body
How do natural killer cells destroy pathogens?
NK cells destroy pathogens either through direct contact or by releasing perforins that make the membrane of the pathogen leaky so that cytolysis occurs
What are the primary functions of inflammation?
Aid in the disposal of microbes; prevent spread of infection; prepares site of tissue repair
What are the three basic stages of inflammation?
vasodilation and increased permeability of blood vessels; phagocyte migration; tissue repair
What are four substances that contribute to the inflammation?
Histamine; heparin; kinins; prostaglandins
What is specificity?
the immune sustem targets particular antigen
What is memory?
when the immune system encounters an antigen a second time, the response to the antigen is faster and more vigorous
What is tolerance?
The immune system responds to a foreign substances but ignores normal tissues
What is versatility?
The immune system is ready to confront any antigen at any time
What are antigens?
Substances that will provoke an immune response because they are recognized as foreign by the body
What are characteristics of antibodies?
- protein molecules that bind to one specific antigen
- antibodies constitute the gamma globulin portion of blood proteins
- antibodies are also referred to as immunoglobins or Igs
What are the three subpopulations of T cells?
cytoxic T cells; helper T cells; suppressor T cells
T cell activation does not occur without exposure to antigen and ____________.
costimulation
What are the two major classes of MHC proteins?
(major histocompatibility complex)
Class I and Class II
What is the concept of antigen recognition?
Unique receptors on the T cells plasma membrane allow them to recognize and bind a specific antigen.
