Lymphatic system Flashcards
what does the lymphatic system do
returns fluids that have leaked from the vascular system back to the blood.
what are the 3 parts of the lymphatic system
lymphatic vessels, lymph, and lymph nodes
what is lymph
the fluid contained in those lymphatic vessels
what are Lymph nodes
nodes that cleanse the lymph as it passes through
them
The lymphoid organs and tissues provide the structural
basis of the
immune system
the lymphoid organ and tissues play a huge role in what
in the body’s defense mechanisms and its resistance to disease
name some structures of the lymphatic system
spleen, thymus, tonsils, and other lymphatic tissue scattered throughout the body
the ______ and ___________ operating at capillary beds force fluid out of the blood at the _____ ends of the beds (“____”) and cause
most of it to be reabsorbed at the ______ ends (“_____”). The fluid that remains behind in the tissue spaces, as much as 3 L daily, becomes part of the ________
hydrostatic colloid osmotic pressure arterial upstream venous downstream interstitial fluid
__________
elaborate networks of ______ vessels that collect the excess _____________and return it to the bloodstream.
lymphatic vessels/lymphatics
drainage
protein-containing interstitial fluid
Once interstitial fluid
enters the lymphatic vessels, it is called
lymph
The lymphatic vessels form a ______ system in which lymph flows only _____ the heart.
one way
towards
The transport of lymph begins in microscopic blind-ended
lymphatic capillaries
lymphatic capillaries
weave between the __________ and __________- in the _______ of the body.
tissue cells
blood capillaries
loose connective tissues
Lymphatic capillaries are widespread,
but they are absent from
bones (including bone marrow) and teeth
Lymphatic capillaries were long thought to be absent
from the central nervous system, but recent evidence shows that they are present but restricted to limited locations in the
meninges
the lymphatic capillaries in the brain meninges help do what
drain the extracellular fluids in the brain
interstitial and cerebrospinal fluids
what are the two unique structural modifications that allow lymphatic capillaries to be permeable
1) The endothelial cells forming the walls of lymphatic capillaries are not tightly joined. 2)Collagen filaments anchor the endothelial cells to surrounding structures
The endothelial cells forming the
walls of lymphatic capillaries are
not tightly joined. Instead what is going on
the edges of adjacent cells overlap each other loosely, forming easily opened, flaplike ,minivalves
(shown at right).
why do Collagen filaments anchor the
endothelial cells to surrounding structures
so that any increase in interstitial fluid volume opens the minivalves, rather than causing the lymphatic capillaries to collapse.
When fluid pressure in the interstitial space is greater than the pressure in the lymphatic capillary, the minivalve flaps gape
open, allowing fluid to enter the lymphatic capillary.
when the pressure is greater inside the lymphatic capillary, it forces the endothelial minivalve flaps
shut, preventing lymph from leaking back out
as the pressure moves it along the vessel
Proteins in the interstitial space are unable to enter _____, but they enter _______ easily.
blood capillaries
lymphatic capillaries
when tissues become inflamed, lymphatic capillaries
develop ____________ such as cell debris, pathogens (disease-causing microorganisms such as bacteria and viruses), and cancer cells.
openings that permit the uptake of even larger particles
the particles that lymphatic capillaries pick up where do they go
These particles travel with the lymph to the lymph nodes, where they are removed by cells of the irnmune system
The process of pathogens meeting up with immune cells in lymph nodes is critical for
activating an immune response
In some cases, unfortunately, pathogens or cancer cells manage to pass through the ____ and can then travel throughout the ____
lymph nodes
body
A special set of lymphatic capillaries called lacteals transports _____ from the _______ to the
_______
absorbed fat
small intestine
blood stream
Lacteals are so called because of the __________ that ____through them
milky white lymph
drains
what is the fatty lymph flowing in lacteals
chyle
where does the fatty lymph chyle drain from
drains from the fingerlike villi of the intestinal mucosa.
From the lymphatic capillaries, lymph flows through successively
larger and thicker walled channels
what is the sequence of the flow of lymph
Lymphatic capillaries
Collecting lymphatic vessels
lymphatic trunks
lymphatic ducts
The collecting lymphatic vessels have the same three tunics as veins, but the collecting vessels have ________ and _______, and they ______ more.
thinner walls
more internal valves
anastomose
In general, lymphatics in the skin travel along with _______, while the deep lymphatic vessels of the _______ travel with the ______
superficial veins
trunk and digestive viscera
deep arteries
The largest collecting vessels unite to form
lymphatic trunks
lymphatic trunks drain fairly ___ areas of the body.
large
name the major trunks, named mostly for the regions from which they drain lymph
the paired lumbar, bronchomediastinal, subclavian, and
jugular trunks, and the single intestinal trunk
Lymph is eventually delivered to ______ in the ______ region.
one of the 2 large ducts
thoracic
which duct drains lymph from the right upper limb and the right side of the head and thorax
The right lymphatic duct
The much larger_______receives
lymph from the rest of the body
thoracic duct
the thoracic duct collects lymph from the _____________ that drain the lower limbs and from the _______ that drains the digestive organs
two large lumbar trunks
intestinal trunk
In about half of individuals, the thoracic duct begins as an enlarged sac, the
cisterna chyli
where is the cisterna chyli located
in the region between the last thoracic and second lumbar vertebrae
As the thoracic duct runs superiorly, it receives lymphatic drainage from the _______,_______, and _________. Each terminal duct empties its lymph into the_____ circulation at the junction of the________ and _______ on its own side of the body
left side of the thorax left upper limb left side of the head venous internal jugular vein subclavian vein
The lymphatic system lacks an organ that
acts as a pump
Under normal conditions, lymphatic vessels are ____ pressure conduits,
low
the same mechanisms that promote _______ in blood vessels act in lymphatic vessels
venous return
the milking action of active skeletal muscles, pressure changes in the thorax during breathing, and valves to __________
prevent backflow
Lymphatic vessels are usually bundled together in __________ along with _______ and ______ of nearby arteries also promote ________
connective tissue sheaths
blood vessels
pulsations
lymph flow
where does the thoracic duct collect lymph from
from the two large lumbar trunks that drain the lower limbs
and
from the intestinal trunk that drains the digestive organs.
