Exam 3 Flashcards
What are the primary functions of the lymphatic system?
Transport and house lymphocytes and other immune cells, return excess fluid in body tissues to blood to maintain blood volume
What are the main components of the lymphatic system?
Lymph vessels, lymphatic tissues, and organs
Lymph is the fluid transported within lymph vessels
What is lymph?
The fluid transported within lymph vessels
What characteristics define lymph?
Some fluid leaves capillaries and isn’t reabsorbed by them, the interstitial fluid moves into the lymphatic capillaries
this is where it’s called lymph
Contains water, dissolved solutes, small amount of protein, and sometimes cell debris, pathogens, or cancer cells
What are lymphatic capillaries?
Small, closed-ended vessels that absorb interstitial fluid
Where are lymphatic capillaries located and what is their make-up?
Interspersed around most blood capillaries; absent in avascular tissues, red marrow, spleen, and CNS
Slightly larger than blood capillaries; no basement membrane
Walls are made of overlapping endothelial cells
How do lymphatic capillaries allow fluid entry?
Walls made of overlapping endothelial cells with flaps between cells through which fluid enters but can’t exit
Anchoring filaments hold endothelial cells to nearby structures
What are lacteals?
Lymphatic capillaries in the GI tract that absorb lipid-soluble substances
What drives the movement of lymph into lymphatic capillaries?
Hydrostatic pressure of interstitial fluid pushes it into the capillary
The anchoring filaments linking endothelial cells to surrounding structures prevent vessel collapse
Pressure of lymph inside vessel forces the intercellular openings (flaps) of capillary wall to close with lymph inside
What are the larger vessels that lymph moves through?
Lymphatic capillaries, lymphatic vessels, lymphatic trunks, and lymphatic ducts
Ultimately the fluid is returned to blood circulation
What is metastasis?
The spread of cancerous cells from the original site (primary tumor) to other parts of the body
Cancerous cells break free from primary tumor and are transported in the lymph
What features do lymphatic vessels have?
Lymphatic vessels are fed by lymphatic capillaries
Have all three vessel tunics (intima, media, externa)
Have valves to prevent pooling and backflow of lymph
Located adjacent to arteries and veins
Some vessels are connected to lymph nodes for lymph filtration
How does the lymphatic system move lymph since it lacks a pump (like the heart)?
Using skeletal muscles and respiratory pumps (like veins)
pulsatile movement of blood in nearby arteries
rhythmic contraction of smooth muscle in larger lymph vessel walls
What are lymphatic trunks?
Vessels fed by lymphatic vessels that drain specific body regions
What are lymphatic ducts?
The largest lymph vessels
Bring lymph to venous blood circulation
There are 2 (right lymphatic duct and the thoracic duct)
What areas does the right lymphatic duct drain and where is it located? Also, where does it deliver lymph to?
Located near the right clavicle
Upper right quadrant of body
right side of head and neck, right upper limb, right side of thorax
Delivers lymph to junction of right subclavian and right internal jugular veins
What does the thoracic duct drain?
Left side of head and neck, left upper limb, left side of thorax, abdomen, and both lower limbs
It is the largest lymphatic vessel
What causes lymphedema?
Accumulation of interstitial fluid due to interference with lymphatic drainage
Causes swelling and pain in affected area
May interfere with wound healing and contribute to infection
Most caused by blockage of lymph vessels
Controlled with compression garments, exercise, massage
Extreme cases known as elephantiasis (caused by infection with parasitic worms)
What are primary lymphatic structures?
Red bone marrow and thymus
involved in formation and maturation of lymphocytes
What are secondary lymphatic structures?
Sites of immune response initiation
including lymph nodes, spleen, tonsils, and lymphatic nodules as well as MALT (mucosa-associated lymphatic tissue)
They do not form lymphocytes, but house them and other immune cells
Where is red bone marrow located? What is it?
Between trabeculae of spongy bone (in flat bones of skull, ribs, sternum, vertebrae, ossa coxae, heads of humerus and femur)
It is the site of hemopoiesis (production of blood’s formed elements)
the formed elements include T-lymphocytes and B-lymphocytes
The T-Lymphocytes migrate to the thymus to mature
The rest go straight from the bone marrow into the blood
What is the thymus involved in?
T-lymphocyte maturation
Located in the mediastinum (between the lungs on top of heart)
Larger in children than adults (grows until puberty then regresses being gradually replaced by adipose tissue)
What are characteristics of the thymus and its lobules?
Thymus consists of 2 thymus lobes each surrounded by connective tissue capsule
Trabeculae of capsules subdivide lobes into lobules
Each lobule has outer cortex and inner medulla regions (both regions contain lymphatic cells and epithelial tissue)
Cortex contains immature T-lymphocytes
Medulla contains mature T-lymphocytes
What do lymph nodes do and what are their characteristics?
Filter lymph and remove unwanted substances
Small, oval, encapsulated structures
Located along deep and superficial pathways of lymph vessels
Occur in clusters receiving lymph from body regions
Cervical lymph nodes receive lymph from head/neck
Axillary lymph nodes receive lymph from breast/axilla/upper limb
Inguinal lymph nodes in groin receive lymph from lower limb/pelvis
What are the components of a lymph node?
Afferent lymphatic vessels bring lymph to node
efferent vessel drains a lymph node (located at hilum)
dense connective tissue capsule encloses node (trabeculae of capsule subdivide node into compartments)
outer cortex, inner medulla
What is Hodgkin lymphoma?
A type of lymphoma affecting young adults and people over 60
Cancer of the part of the immune system called the lymphatic system.
As the cancer progresses, it limits the body’s ability to fight infection.
Lymph nodes in the neck, armpits, or groin may swell. Fatigue, fever, and chills are some symptoms.
Treatments include chemotherapy, radiation, and in rare cases stem-cell transplant.
What is the largest lymphatic organ?
The spleen
What tissues are found in the spleen?
White pulp and red pulp
What is white pulp?
Monitors blood for foreign materials and bacteria
Clusters of T and B-lymphocytes and macrophages around central artery
What is red pulp?
Macrophages in sinusoids of red pulp remove particles (phagocytize bacteria, debris, defective erythrocytes, and platelets)
Contains erythrocytes, platelets, macrophages, and B-lymphocytes
Splenic cords: cells and reticular connective tissue in red pulp
Splenic sinusoids: very permeable capillaries
A storage site for erythrocytes and platelets
What are tonsillar crypts?
Invaginations that trap material in tonsils
What is acute tonsillitis?
Inflammation and infection of tonsils
commonly affecting palatine tonsils
-redden and enlarge
-may partially obstruct pharynx
Fever, chills, sore throat, and difficulty swallowing
May be infected by viruses or bacteria
Persistent recurrent infections (chronic tonsillitis) which may require tonsillectomy (surgical removal of tonsils)
What is MALT?
Mucosa-associated lymphatic tissue
Where is MALT prominently found?
In gastrointestinal, respiratory, genital, and urinary tracts
Found in lamina propria of the mucosa
Helps defend against foreign substances
Prominent in small intestines (especially ileum)
What are Peyer patches?
Large collections of lymphatic nodules within the wall of the GI tract
What are the primary lymphatic structures?
Thymus
Red Bone Marrow
What are the secondary lymphatic structures?
Tonsils
Lymph Nodes (cervical)
Spleen
MALT (mucosa-associated lymphatic tissue) in small intestine
Lymph Nodes (inguinal)
What do the jugular trunks drain?
They drain lymph from head and neck
What do the subclavian trunks drain?
They drain the upper limbs, breasts, and superficial thoracic wall
What do the bronchomediastinal trunks drain?
They drain the deep thoracic structures
What do the intestinal trunks drain?
They drain most abdominal structures
What do the lumbar trunks drain?
They drain the lower limbs, abdominopelvic wall, and pelvic organs
What are the lymphatic ducts fed by?
The lymphatic trunks
Where is the thoracic duct located?
It runs from the diaphragm to junction of left subclavian and left jugular veins
Saclike cisterns chyli at its base that receives lipid-rich chyle from GI tract
What are secondary lymphatic structures?
They house lymphocytes and other immune cells within a reticular connective tissue matrix
They’re organized into lymphatic organs and aggregates of lymphatic nodules
What does the cortex of lymph nodes contain?
Lymphatic nodules which are reticular fibers that support a germinal center
Houses proliferating B-lymphocytes and some macrophages
the surrounding mantle zone contains T-lymphocytes, macrophages, and dendritic cells
Cortical sinuses are tiny open channels lined by macrophages
What do lymph node’s medulla contain?
Medullary cords which are connective tissue that support B-lymphocytes, T-lymphocytes and macrophages
What are medullary sinuses located in a lymph node’s medulla?
Tiny open channels lined with macrophages
How does lymph flow through lymph nodes?
1) lymph enters through several afferent vessels
-creates pressure to push it through node to the single exit vessel
2) lymph is monitored for presence of foreign material
-macrophages remove foreign debris from lymph
-lymphocytes may initiate immune response (they proliferate especially in germinal centers, can cause enlarged nodes that can be palpated in neck and axilla)
3) lymph exits node through efferent vessel
-may then pass to neighboring lymph node
What is non-Hodgkin lymphoma?
More common than Hodgkin lymphoma
Some kinds are aggressive while others are slow growing
Cancer that starts in the lymphatic system.
The condition occurs when the body produces too many abnormal lymphocytes, a type of white blood cell.
Symptoms include swollen lymph nodes, fever, belly pain, or chest pain.
Treatments may include chemotherapy, radiation therapy, stem-cell transplant, or medications.
What is lymphoma?
A cancer of the lymphatic system
Malignant neoplasm from lymphatic structures
Nontender, enlarged lymph node
Could induce night sweats, fever, and weight loss
What does the spleen do?
Filters and monitors blood (not lymph)
What does the spleen do in first 5 months of fetal life?
Makes blood cells
This function can be reactivated under certain conditions
When may surgical removal of the spleen be needed?
Ruptured spleen from abdominal injury (most common)
Infection, cyst, or tumor
Lymphoma or cancer
Blood disorders (sickle cell anemia etc.)
Where is the pharyngeal tonsil located?
In the nasopharynx
Called adenoids when enlarged
Where are the palatine tonsils located?
In the posterolateral oral cavity
Where are the lingual tonsils located?
Along the posterior one-third of tongue
What are tonsils?
Secondary lymphatic structures
Immune surveillance of inhaled and ingested substances
Contain lymphatic nodules (some with germinal centers)
What are lymphatic nodules?
Clusters of lymphatic cells with some extracellular matrix (not completely surrounded by connective tissue capsule)
Found in every body organ
Help defend against infection
In some areas they group together to form larger structures (MALT for example)
what system does the lymphatic system aid by transporting excess interstitial fluid?
the circulatory system
when blood plasma leaks out of the capillaries it is then called what?
interstitial fluid
Are lymphatic capillaries usually smaller or larger in diameter compared to blood capillaries?
larger
Lacteals pick up dietary ____.
lipids
what are normal constituents of lymph?
ions
low concentration of protein
water
what do dietary lipids enter the lymphatic system through?
tiny lymph vessels called lacteals
valves in lymphatic vessels are especially important in the upper or lower limbs?
lower
True or False: lymphatic capillaries are closed-ended vessels
True
lymph is moved through lymph vessels by:
Skeletal muscle pumps (muscle contractions)
respiratory pump (breathing)
pulsing of nearby arteries
lymph drains from lymphatic trunks into what?
lymphatic ducts
where are lacteals located?
the gastrointestinal tract
lymphatic vessels resemble small what?
veins
how many lymphatic ducts does the lymphatic system contain?
2
what are some of the secondary lymphoid structures where lymphocytes are housed after formation?
lymph nodes
tonsils
spleen
what are the larges lymph vessels?
lymphatic ducts
what is the left lymphatic duct commonly referred to as?
the thoracic duct
(the larger of the two lymphatic ducts)
what are some primary lymphoid structures where lymphocytes are produced?
red bone marrow
thymus
where do all lymphocytes originate?
red bone marrow
each thymus lobule is divides into what?
inner medulla
outer cortex
what route does lymph travel, starting with lymphatic trunk
lymphatic trunk
to
lymphatic duct
to
veins
back into circulatory system (blood)
what secondary lymphatic structures have a complete capsule?
lymph node
spleen
what is the tough connective tissue layer called that lymph nodes are surrounded by?
capsule
what connective tissue fibers support the medulla of the lymph node?
medullary cords
lymph flows through a node in what order?
1) afferent lymphatic vessel
2) lymphatic sinuses
3) efferent lymphatic vessel
what is the main difference between lymphatic organs and lymphatic nodules?
lymphatic organs have a capsule enclosing them
where does the spleen lie in relation to the left kidney?
lateral
large clusters of lymph nodes are found in what regions?
cervical (neck)
axillary (armpit)
inguinal (groin)
blood drains out of the spleen through what?
the splenic vein
what do lymphatic sinuses in the cortex and medulla of the lymph node provide for lymphatic flow?
they provide a pathway for lymphatic flow
Within a lymph node are open spaces called sinuses. In the cortex, they are called ______ sinuses and in the medulla, they are called _____ sinuses.
cortical
medullary
what is the function of white pulp in the spleen?
to monitor the blood for foreign materials
what is the outflow pipe of a lymph node?
efferent vessel
what pulp of the spleen acts as a platelet reservoir?
the red pulp
what is the region called where blood vessels enter and exit the spleen?
the hilum
True or False: the spleen filters the lymph for foreign materials and bacteria
it filter the blood for foreign materials
lymph nodes filter the lymph for foreign materials
what are some normal functions of the adult spleen?
-Phagocytosis of old Erythrocytes
-Act as a reservoir for platelets
-Phagocytosis of bacteria
The white pulp of the spleen is associated with the ____ supply of the spleen
Arterial
The adenoids are also called the _____ tonsils
Pharyngeal
the red pulp of the spleen is where _____ drainage of the blood occurs
venous
what are lymphatic nodules also called?
lymphatic follicles
in what order does blood flow through the spleen
1) splenic artery
2) central artery of white pulp
3) splenic sinusoids of red pulp
4) splenic vein
what is the function of lymphoid nodules?
to help defend against infection where they are found
