Lymphatic system Flashcards
A small bean-shaped organ located in the lymphatic system is called a ____ ____.
Lymph node
Deep lymphatic vessels of the viscera generally follow the same routes as what structures?
Arteries
B-lymphocytes mature in the ____
Bone marrow
What are tonsils important for?
Developing immunity to oral pathogens
Briefly describe the purpose of the spleen
To filter the blood
Briefly describe the structure of the lymphatic system
Lymph vessels begin as open-ended capillaries, which feed into increasingly larger lymphatic vessels, which eventually empty into the bloodstream by a series of ducts
Blood pressure causes leakage of fluid from the ____.
Capillaries
What prompts endothelial cell flaps in lymphatic capillaries to close?
Low interstitial pressure
Which lymph nodes receive lymph from the lower limbs?
Inguinal lymph nodes
Yellow bone marrow is a site for what?
Energy storage, consisting largely of adipocytes
The right sides of the head, thorax, and upper right limb drain lymph fluid into what location?
The confluence of the right subclavian and right internal jugular veins
A major function of the lymphatic system is the drain body fluids from the ____ space and return them to the ____.
Interstitial; bloodstream
Where is the spleen located?
Against the thoracic diaphragm in the left upper abdominal quadrant
Which lymphocytes mature in bone marrow?
B-lymphocytes
Childen who suffer recurring throat infections may have their ____ tonsils removed
Palatine
What is the result of fluid leakage from capillaries?
Accumulation of fluid in the interstitial space
Approximately how many lymph nodes are in the human body?
500 - 600
The lymphatic system is closely tied to the ____ system.
Immune
Briefly describe what occurs in the primary lymphoid organs
Lymphocytes mature, proliferate, and are selected
What prevents lymph flowing backward or pooling at the lowest point of gravity?
One-way semi-lunar valves in lymphatic vessels
What are lymphoid follicles?
Germinal centres comprised of lymphocytes; a mass of lymphocytes “ready to go”
Which lymph nodes receive lymph from the gastrointestinal tract?
Mesenteric lymph nodes
In which tracts are lymphoid nodules found?
Respiratory and digestive tracts
Do lymphocytes inititate immune responses from primary lymphoid organs?
No - lymphocytes develop and mature in primary lymphoid organs, but they mount immune responses from secondary lymphoid organs
Where are the axillary lymph nodes located?
The axillary region (armpit)
What separates lymph nodes into compartments?
Trabeculae, extensions of the connective tissue capsule
The lymphatic system is the complex collection of cells and organs that destroys or neutralises ____.
Pathogens
Where does lymph re-enter the circulatory system?
Through ducts at the confluence of the internal jugular and subclavian veins in the neck
What is in the cortex of lymph nodes?
Lymphoid follicles
All ____ are produced in the red bone marrow in adults
Lymphocytes
Name the tonsils located in the oropharynx
Palatine tonsils
Lymphatic capillaries empty into ____ lymphatic vessels
Afferent
Where are the inguinal lymph nodes located?
In the inguinal region (groin)
What occurs in red bone marrow?
Haematopoiesis
Why do lymphatic vessels have a beaded appearance?
They have one-way valves that are fairly close to one another, each causing a bulge in the vessel
The spleen is approximately ____cm long
12cm
What is the cisterna chyli?
A sac-like chamber that receives lymph from the lower abdomen, pelvis, and lower limbs
Which lymph nodes receive lymph from the head and neck?
Cervical lymph nodes
What is the role of collagen fibres in enabling lymph flow?
As interstitial pressure increases the filaments pull open the endothelial cell flaps to allow easy entry of fluid (as well as anchoring the lymphatic capillaries to tissues)
What happens to lymph nodes when foreign material is encountered during filtration of lymph?
The lymph node swells
How is lymph moved through the body?
Lymph is forced through vessels by body movements, skeletal muscle contraction, and breathing
Which type of vessel are lymphatic vessels most similar to, arteries or veins?
Veins - they have similar three-tunic structures and valves are present
Affterent lymphatic vessels carry lymph to ____ ____
Lymph nodes
The name of fluid changes as it moves into the lymphatic system - what is the name before and after the move?
Interstitial fluid, then lymph fluid
If looking at a diagram of a lymph node, how would you differentiate between afferent and efferent lymphatic vessels?
The ends of open valves of afferent vessels would point towards the node, while those of efferent vessels would point away
What happens to the thymus after it has completely developed in adolescence?
Progresssive atrophy as thymus tissue is slowly replaced with adipose and connective tissue over time
What is chyle?
Dietary triglycerides combined with other lipids and proteins
What colour is the spleen, and why?
Dark red, because it is extensively vascular
Where is the thymus located?
Mediastinum of the thorax, anterior to the aorta and superior vena cava, posterior to the sternum
Where are the palatine tonsils located?
Oropharynx
What is ‘interstitial space’?
Spaced between individual cells in the tissues
What is the medulla of the lymph node?
The innermost portion of the lymph node
What happens to any foreign material that is identified in interstitial fluid?
It is taken up by lymphatic capillaries and transported to lymph nodes where it is destroyed through phagocytosis
Lymph from the lower abdomen, pelvis, and lower limbs is received in what structure?
The cisterna chyli
____ lymphatic vessels carry cells and lymph to lymph nodes, and ____ lymphatic vessels carry them away
Afferent; efferent
How thick is the wall of a lymphatic capillary?
One-cell layer of epithelial cells
The tonsils are lymphoid nodules located in the ____
Pharynx
Name four important clusters of lymph nodes
Cervical, axillary, mesenteric, and inguinal
Name five common locations of lymph nodes
Inguinal region, axillary region, neck, thorax, and abdomen
Which abdominal organ is the spleen attached to?
The stomach
What provides the structural support of lymph nodes?
The connective tissue capsule and trabeculae, and a series of reticular fibres
What is the cortex of the lymph node?
The outer portion of the lymph node, located deep to the capsule
Where is the majority of red bone marrow found in adults? There are six possible answers
Flat bones of the skull, vertebrae, ribs, sternum, os coxae, and proximal epiphyses of the humerus and femur
Superficial lymphatics generally follow the same routes as what structures?
Veins
T-lymphocytes mature in the ____
Thymus
Is the lymphatic drainage of the body symmetrical?
No - the right lymphatic duct receives lymph from the right upper side of the body only, with the left upper side and everything below the thoracic diaphragm draining into the thoracic duct
Efferent lymphatic vessels merge to form what structures?
Lymphatic trunks
Where are the cervical lymph nodes located?
In the neck, adjacent to the internal jugular vein
Where are lymphatic capillaries found?
Interlaced among the arterioles and venules of the circulatory system in the soft connective tissues of the body
Which lymphocytes mature in the thymus?
T-lymphocytes
What is the name of the lymphoid nodules in the pharynx?
Tonsils
Name five locations which do not contain lymph vessels
Central nervous system, bone marrow, bones, teeth, and the cornea
What is a lymphoid nodule?
A dense cluster of lymphocytes without a fibrous capsule
What is the purpose of the lymphatic system?
To carry excess fluids to the bloodstream and filter pathogens from the blood
The thoracic duct drains lymph from what locations of the body?
All areas of the body except the right side of the head, right arm, and right side of the thorax
What is the hilum?
The entry point of blood vessels into the lymph node
Which lymph nodes receive lymph from the upper limbs and breast?
Axillary lymph nodes
The thoracic duct drains into what location?
The confluence of the let subclavian and left internal jugular veins
What is the term used to refer to lymphatic vessels of the subcutaneous tissues of the skin?
Superficial lymphatics
What does it mean for a lymphocyte to be ‘selected’?
It is able to attack pathogens without harming the cells of the body
Name the two primary lymphoid organs
Bone marrow and thymus gland
Name the specialised lymphatic capillaries in the small intestine
Lacteals
Describe how dietary triglycerides are made ready to enter the lymphatic system
Dietary triglycerides combine with other lipids and proteins, and enter the lacteals to form a milky fluid called chyle
Why might lymphoid nodules be present in respiratory and digestive tracts in particular?
They are areas routinely exposed to pathogens
Lymphatic vessels that carry lymph away from lymph nodes are referred to as ____ lymphatic vessels
Efferent
What anchors a lymphatic capillary in the tissue?
Collagen fibres
When does the thymus reach maximum development?
Puberty
What surrounds lymph nodes?
A tough capsule of connective tissue
Where are the mesenteric lymph nodes located?
In the mesentary of the small intestines
The upper right side of the body drains lymph via what structure?
The right lymphatic duct
Where does the thoracic duct begin?
Just inferior to the thoracic diaphragm in the cisterna chyli
How many lobes does the thymus have?
Two; it is a bi-lobed organ
Lymphatic capillaries are also called ____ ____.
Terminal lymphatics
Lacteals are critical for the transport of what substances?
Dietary lipids and lipid-soluble vitamins
What is the function of lymph nodes?
To remove debris and pathogens from lymph
____ bone marrow fills the head of the femur with a core of ____ bone marrow at the centre
Red; yellow
