Glands and Lymphatics Flashcards
what are the three major roles of lymph nodes
returns fluid from the tissues back to the heart
helps hormones and lipids enter the blood
immune surveillance
what can diffuse through pores on vascular capillaries
albumin and fluid
how many litres of fluid seep out from the capillaries every day
20 litres
how many litres of fluid remain in the interstitial space
three litres
what do lymphatic vessels do
collect excess fluid and return it to the blood
why can the course of lymphatic vessels be described at closed
the fluids get into the lymphatic capillaries to be dumped into the veins, it does not circulate throughout the lymph
describe the structure of lymphatic vessels
walls made of endothelial cells that only loosely overlap. anchored to structures in the interstitial space by collagen filaments to allow for flexibility.
describe how lymph travels if there is no pump like with the blood
smooth muscle reacts to arterial pressure, and there is squeezing of skeletal muscle throughout the day that exerts external pressure to keep the lymph going along.
there are valves to prevent the lymph going backward
what are the lymphatic trunks
lumbar
bronchio-mediastinal
subclavian
jugular
intestinal
what are the main lymphatic ducts
right lymphatic and thoracic
what do the lymphatic trunks drain into
the lymphatic ducts
what does the lymphatic duct collect from
right arm
right head
right chest
what does the thoracic duct collect
everywhere apart from what the right lymphatic duct collects
where does lymph enter the veins
the junction of the jugular and subclavian vein
what is the advantage of the porosity of the lymphatic capillaries
they can pick up molecules that are normally too large like nutrients and fatty acids that can be delivered to tissues
describe how fatty acids enter circulation
absorbed from the small intestine, packaged into chylomicrons to go into the lacteals of the villi to enter the lymphatic vessels
describe the immune function of lymphoid organs
remove foreign material from the lymph to prevent it from entering the blood
act as lookout points for the body’s immune system
what makes up the lymphatic system
lymphoid organs and diffuse lymphoid tissue
describe diffuse lymphoid tissue
loose arrangement of lymphoid cells in protein in the gastrointestinal tract and respiratory tract
what are lymph nodes
tightly packed balls of lymphoid tissue
what are peyers patches
lymph nodes in the lining of the ileum of the small intestine
describe the function of lymph nodes
unfiltered lymph drains into them, any pathogens are detected by dendritic cells to be destroyed.
the dendritic cells sample the lymph and present antigens to b cells to produce antibodies
how are antibodies produced
antigens are presented to b cells which turn into plasma cells to produce antibodies
where is the spleen located
below the diaphragm above the stomach, under the ribs on the left hand side of the body.
describe the structure of the spleen
contains white and red pulp
describe the white pulp of the spleen
giant lymph node, receives blood to filter it.
antibody coated bacteria are filtered out of circulation to generate antibodies from b cells
describe red pulp of the spleen
old or damaged red blood cells are destroyed, and their parts are broken down or recycled.
when is the thymus most active in a persons life
neonatal
preadolescence
what happens to the thymus once puberty has been reached
atrophies and begins to be replaced by fat
what is the main function of the thymus
involved in development of t cells to ensure any that react to self antigens are destroyed by apoptosis
what are the two primary lymphoid organs
the bone marrow
the thymus
what happens at the primary lymphoid organs
all immune cells are generated and developed
what are the secondary lymphoid organs
spleen
lymphatic vessels
lymph nodes
tonsils
adenoids
mucosa associated lymphoid tissue
what happens in the seconary lymphoid organs
immune cells go here to finish their development and interact with other immune. they also generate adaptive immune responses
where does maturation of myeloid and lymphoid cells begin
the bone marrow
describe the structure and location of bone marrow
spongy structure, found in the centre of many bones in the body
which form of marrow has the most active generation of blood cells
red marrow
what happens to red marrow as we age
it becomes infiltrated with fat to become yellow marrow