A&P Term 3 Lab #5: Lymphatic & Immune System Flashcards
Lymphatic system
a diverse group of organs, tissues, and vessels that works in parallel to the cardiovascular system to maintain fluid homeostasis, works with the immune system by helping combat harmful agents, and functions as a clean-up crew
where does the lymphatic system work?
in the gastrointestinal system to absorb fats
lymphatic vessels
thin-walled, low-pressure vessels that return excess tissue fluid to venous circulation, along with damaged cells, bits of tissues, and microbes that might be present in the tissues
lymph
a mixture of tissue fluid, cells, and microorganisms that flows back towards the venous system through lymphatic vessels
Lymph nodes
small filters that lymph passes through
Major operational sites for the immune system
lymphatic vessels, lymph nodes, and lymphatic tissues
Immune system
a collection of cells and proteins that specifically targets foreign cells to prevent the spread of infection and protect the body from cellular injury such as trauma or pathogens
Pathogens
disease-causing organisms, cells, or chemicals
Lymphocytes
cells of the immune system
3 primary functions of the lymphatic system
- Transporting excess interstitial fluid back to the heart
- Absorbing Dietary fats
- Activating the immune system
The process of filtration pushes ____ of water out of the blood and into the interstitial fluid
1.5 mL/min
Lymphatic system picks up this ___, carries it through ___, and returns it to the ____
lost interstitial fluid,
lymphatic vessels,
cardiovascular system
steps of transporting excess intersititial fluid back to the heart
- First enters lymph capillaries that surround blood capillary beds.
- lymph is delivered to larger lymph-collecting vessels
- Lymph-containing vessels drain into larger lymph trunks.
- The lymph trunks drain into the final vessels of the lymphatic circuit: lymph ducts
what kind of walls do blood capillary beds have?
highly permeable walls that allow substances to enter and exit
Once inside the lymph capillaries, the fluid is called ____
lymph
lymph-containing vessels contain ____. Why?
valves to enure that the lymph flows in one direction
9 main lymph trunks that drain lymph from major body regions. Each has 2 except for….
- Jugular trunks
- Subclavian trunks
- Bronchomediastinal trunks
- Intestinal trunk
- Lumbar trunks
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all have 2 except for intestinal trunk
2 lymph ducts
- Right Lymphatic duct
- Thoracic duct
what does the jugular trunk drain?
head and neck
what does the subclavian trunk drain
upper limbs
what does the bronchomediastinal trunk drain?
thorax
what does the intestinal trunk drain?
abdomen
what does the thoracic trunk drain
pelvis and lower limbs
what does the right lymphatic duct drain?
where does it deliver blood?
drains the right upper limb and the right side of the head, neck, and thorax.
Delivers the lymph to the blood at the junction of the right subclavian and
internal jugular veins.
what does the thoracic duct drain?
where does it deliver blood?
drains the remainder of the body.
Delivers the lymph to the blood at the
junction of the left subclavian and internal jugular veins
dietary fats cannot be absorbed from the ______ ______ directly into the blood capillaries. why? what do they enter instead?
small intestine
because they are too large to enter the small vessels
Instead, fats enter a lymphatic capillary called a lacteal
The lacteal delivers the fats to lymph-collecting vessels and intestinal trunks, and then enters a large lymphatic duct called the ____ _____
cisterna chyli
what does the cistern chyli drain into?
the thoracic duct, where the fats join the rest of the lymph
steps of the lymphatic system absorbing dietary fats
- fats enter a lacteal (lymphatic capillary)
- lacteal delivers fats to lymph-collecting vessels and intestinal trunks
- fats get drained into cisterna chyli (large lymphatic duct)
- cisterna chyli drains into thoracic duct
- fats join rest of lymph in thoracic duct
which lymphatic organs activate the immune system?
-thymus
-lymph nodes
-spleen
-Mucosa-associated lymphatic tissue and tonsils
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thymus composition and location
composed of two lobes and many small lobules that is located in the anterior mediastinum
thymus hormone secretion and function
secretes hormones thymosin and thymopoietin that stimulate T lymphocyte maturation
when is the thymus most active?
largest and most active in infants and young children
what happens to the thymus in adults?
it shrinks and becomes filled with adipose/other connective tissue
lymph nodes structure and function
-arrangements of lymphatic tissue surrounded by a connective tissue capsule
-act as filters that remove potential pathogens from the lymph before it is delivered to the blood
why are lymph nodes not considered a gland?
because they do not secrete any products
lymph are located along…
lymphatic vessels
afferent vs efferent lymphatic vessels
lymph is delivered by afferent lymphatic vessels and drained by an efferent lymphatic vessel
lymph is delivered by _____ lymphatic vessels
afferent
lymph is drained by _____ lymphatic vessels
efferent
lymph are individual but there are 4 well known clusters:
→ cervical node
→ axillary node
→ inguinal node
→ mesenteric/intestinal node
Can Anyone Interest Me??
a lymph node consists of 2 main parts
outer lymph node cortex and an inner lymph node medulla
lymph node cortex contains…
immune cells such as lymphocytes (mostly B-lymphocytes) and macrophages
immune cells in the lymph node cortex are arranged into clusters called…
lymphoid follicles
lymphoid follicles
clusters of immune cells (lymphocytes, mostly B-lymphocytes and macrophages) that are arranged into clusters
what separates the lymphoid follicles in the lymph node?
trabeculae
trabeculae
inward extensions of the lymph node capsule that separate the lymphoid follicles
germinal centers
the lighter areas in the center of lymphoid follicles that contains dendritic cells, macrophages, and a large number of B lymphocytes
spleen location and function
a lymphatic organ that resides in the upper left quadrant of the abdominopelvic cavity that filters the blood and houses phagocytes
spleen’s 2 histologically distinct regions
red pulp and white pulp
red pulp
contains macrophages surrounding trabecular veins that destroy old or damaged erythrocytes
white pulp
ontains T lymphocytes, B lymphocytes, macrophages, and dendritic cells that surround branches of the splenic artery called central arteries
branches of the splenic artery are called
central arteries
blood flows through the central arteries and a series of arterioles until it gets to the____
spleen’s capillaries: the sinusoids
what are the spleen’s capillaries called
sinusoids
sinusoids
spleen’s capillaries
pathogens leak from the blood into the ____, where they encounter the ____
white pulp
immune cells that attempt to remove them from the blood.
flow of blood filter in the spleen
- flows through red pulp that destroys old or damaged erythrocytes
- flows through white pulp with central arteries
- central arteries to sinusoids
- pathogens leak from blood into white pulp where immune system removes them from blood
MALT
mucosa-associated lymphatic tissue
mucosa-associated lymphatic tissue
clusters of loosely organized lymphatic tissue that are scattered throughout mucous membranes in locations such as the gastrointestinal tract
MALT lacks a ____, but…
a connective tissue capsule, but specialized MALT are partially encapsulated
example of specialized MALT
tonsils
tonsils
found in the posterior oropharynx and nasopharynx, are specialized MALT
list the tonsils
→ pharyngeal tonsil (adenoid)
→ paired palatine tonsils
→ inguinal tonsil
→ tubal tonsils
PP’s Present In Tempe
Peyer’s patches
clusters of MALT located in the terminal position of the small intestine, the ileum
what’s the difference between peyer’s patches and lymph nodes?
somewhat resemble lymph nodes, but their lymphoid follicles & germinal centers are less well defined, and the capsules are incomplete/absent
how to easily identify tonsil histology?
look for the tonsilar crypts
