BIO G220: Ch. 24 Flashcards
Terms and concept from Chapter 24: Lymphatic System
functions of lymphatic system (4)
- return interstitial fluid back to the blood stream
- transport lipids and lipid-soluble vitamins into the bloodstream
- production and maturation of lymphocytes
- generates an immune response against antigens in the interstitial fluid
lymph
excess interstitial fluid and solutes that enter lymph vessels
the lymph network consists of increasingly larger..
vessels
lymph is returned to the..
blood-stream
lymphatic capillaries
close-ended tubes that are found interspersed among most blood capillary beds
lymphatic capillaries resemble blood capillaries, but they have..
overlapping endothelial cells that act as one-way valves
lacteals
specialized lymph capillaries contained in the gastrointestinal tract
lacteals function to..
collect interstitial fluid as well as lipids and lipid-soluble vitamins
chyle
lymph collected from the GI system
lymphatic vessels
formed from merging lymphatic capillaries
lymphatic cells resembles venules in that they have components of all three ___ ___ and possess ____
vascular tunics; valves
afferent lymphatic vessels
bring lymph to a lymph node
efferent lymphatic vessels
transport filtered lymph away from the lymph node
lymphatic trunks
left and ride; formed from merging lymphatic cessels
lymphatic trunk types (5)
jugular subclavian bronchiomediastinal intestinal lumbar
jugular trunks drain..
head and neck
subclavian trunks drain..
upper limbs, vreasts, and superficial thoracic wall
bronchiomediastinal trunks drain..
deep thoracic structures
intestinal trunks drain..
most abdominal structures
lumbar trunks drain..
lower limbs, abdominopelvic wall, and pelvic organs
lymphatic ducts
formed from the fusion of lymphatic trunks
right lymphatic duct is located..
deep to the right clavicle
right lymphatic duct returns lymph from..
the right side of the head/neck, right upper limb, and right side of the thorax at the junction of the right subclavian and internal jugular veins
thoracic duct is the __ lymphatic vessel
largest
thoracic duct location
starting inferiorly to the diaphragm and passes through the aortic opening of the diaphragm
thoracic duct begins as a rounded saclike structure called..
cisterna chyli
thoracic duct returns lymph from ________ into the junction between..
most of the body; the left subclavian and internal jugular veins
lymphatic cells (4)
- macrophages
- nurse cells
- dendritic cells
- lymphocytes
lymphocyte types (3)
- T-lymphocyte (T-cells)
- B-lymphocytes (B-cells)
- Natural killer (NK cells)
All three lymphocytes..
migrate through he lymphatic system and search for harmful antigens
T-cells make up about -% of body lymphoytes
70-85%
T-cells express a plasma membrane coreceptor ___ that can recognize a particular antigen
CD
types of T-cells (2)
- helper t-lymphocytes
2. cytotoxic t-lymphocytes
helper t-cells contain the __ coreceptor and are aka
CD4; CD4+ or T4
Each T4 responds to a ___ antigen
different
T4 cells inititate and oversee the immune response by secreting ____
cytokines
cytokines
molecules that activate other lymphatic cells
cytotoxic t-lymphocytes contain __ coreceptor and are aka
CD8+ cells or T8 cells; CD8
T8 cells come in __ ___ with infected and foreign cells and ___ them
direct contact; kill
T8 cells must be activated by ___ from helper t-cells
cytokines
helper t-cell mechanism (3 steps)
- helper t-cell recognizes antigen
- helper t-cell secretes cytokines and undergoes mitosis for more helper t-cells
- cytokines secreted initiate and control the immune response (b-lymphocytes, t-lymphocytes, macrophages)
cytotoxic t-cell mechanism (3 steps)
- in response to cytokines of helper t-cell, CD8 coreceptors in cytotoxic t-cells attach to a foreign cells and initiate process for cell death
- cytotoxic t-cell detaches from foreign cel
- foreign cells dies
B-lymphocytes make up about -% of body lymphocytes
15-30%
B-cells contain __ ___ to only 1 antigen and produce ___ or ___ against the same antigem
antigen receptors; immunoglobins; antibodies
b-cells are activated by..
cytokines from helper t-cells
activated b-cells becoem ___ ___ to produce and secrete large amounts of ___
plasma cells; antibodies
some activated b-cells become ___ ___ and confer immunity to certain antigens for many years or a lifetime
memory b-cells
b-cells mechanism (4 steps)
- helper t-cells secrete cytokines and presents an antigen to a b-cell
- b-cell divides, differentiating into plasma cells and memory b-cells
- plasma cells (short lived) secrete antibodies that immobilize the antigen. memory b-cells remain to protect against future attachs by the same antigen.
- if same antigen enters the body, memory b-cells divide to make more plasma cells and memory cells
natural killer cels (NK) are also called…
large cranular lymphocytes
NK cells are a ___ percentage of all lymphocytes
small
NK express the __ receptors
CD16
unlike t-cells and b-cells, NK cells can kill a ___ variety of infected cells and some cancerous cells
WIDE
regulatory t-lymphocyte
helps ‘turn off’ the immune response once it has been activated
lymphopoiesis
process of lymphocyte development
final result of lymphopoiesis is that the lymphocyte becomes..
immunocompetent
immunocompetent
cell can participate in the immune response
all lymphocytes originate in the __ ___ ___ but their maturation sites differ
red bone marrow
b-cells and NK cells mature in __ ___ ___, while t-cells mature in the ____
red bone marrow; thymus
lymphatic nodules
oval clusters of lymphatic cells with some ECM but without a connective tissue capsule
germinal center
center of nodule
germinal center contains ____ in its germinal center and ____ outside the germinal center
proliferating b-cells and macrophages; t-cells
lymphatic nodules function to..
filter and attack antigens
MALT
mucosa-associated lymphatic tissue
MALT consists of..
lymphatic nodules located in the mucosa of the GI, respiratory, genital, and urinary tracts
MALT nodules function to..
monitor and respond to antigens that may enter the tracts
MALT is very prominent in the ___; the nodules are called __ __
ileum; Peyer patches
tonsils
large clusters of lymphatic cells and ECM that do not have a completed surrounded capsule
tonsils are located..
mainly in the pharynx
tonsils outer edges are invaginated to form __
crypts
crypts
allow for trapping of antigens to be presented to the lymphocytes
types of tonsils (3)
- pharyngeal
- palatine
- lingual
pharyngeal tonsils (adenoids) location
posterosuperior wall of nasopharynx
palatine tonsils location
posterolateral wall of oral cavity
lingual tonsils location
posterior one-third of the tongue
lymphatic organs
consists of lymphatic cells and ECM and is completely surrounded by a connective tissue capsule
main lymphatic organs (3)
thymus
lymph nodes
spleen
thymus
bilobed organ located superficial to the heart
thymus consists of..
two fused thymic lobes divided into lobules
each lobule of the thymus has an outer __ and and inner __
cortex; medulla
thymus continues to grow until ___ and then begins to regress in size and function
puberty
thymus is the site of..
t-cell differentiation and maturation
cortex of thymus contains
immature t-cells
medulla of thymus contains
mature t-cells
in adulthood, t-cells can only be produced by ___ ___ and not by the ___ of new cells in the thymus
cell devision; maturation
lymph nodes
small, round, or oval structures located along the pathway of lymph vessels
lymph nodes are usually found in clusters ranging from - in diameter
1-25
lymph node primary function
filter antigens from the lymph and initiate an immune response
lymph node clusters (3)
axillary
inguinal
cervical
lymph nodes are surrounded by a tough CT ____
capsule
trabeculae of lymph nodes
internal extensions of the capsule projecting into the node
lymphatic cells surround the ___ and lymphatic ____ provides a pathway for lymph flow
trabeculae; sinuses
lymph node is divded into outer ___ and inner ___
cortex; medulla
cortex of lymph nodes consists of nodules and sinuses called _____ ____
cortical sinuses
medulla of lymph nodes contains __ ___ and ___ ___
medulllary cords; medullary sinuses
afferent vessels deliver lymph to ___
nodes
lymph exists nodes via ___ vessels at an indentation of the node called the ____
efferent; hilum
spleen functions (4)
- initiates immune response when antigens are found in blood
- serves as a reservoir for erythrocytes and platelets
- phagocytizes old, defective erythrocytes and platelets
- phagocytizes bacteria and other foreign materials
spleen
largest lymphatic organ in body
splenic artery and splenic vein enter and leave the spleen via its ___
hilum
spleen is surrounded by a dense irregular CT ___, which sends extensions called ___ into the organ
capsule; trabeculae
trabecular vessels
branches of splenic arteries and veins that extend within the trabeculae
cells around the trabecular in the spleen are subdivided into..
white pulp and red pulp
red pulp surrounds each cluster of…
white pulp
white pulp
associated with arterial supply and consists of t and b-cells and macrophages
in the center of each cluster of the spleen is a..
central artery
red pulp
associated with venous supply
red pulp consists of __ ___ and ___ ___ that contain erythrocytes, platelets, macrophages, and some plasma cells
splenic cords; splenic sinusoids
blood cells can easily enter and leave the blood stream in the spleen because the capillaries are..
sinusoidal