Week 3- Lymphatic System Flashcards
Which of the following is NOT a primary function of the lymphatic system?
A) Transport of oxygenated blood to tissues
B) Immune surveillance and defence
C) Maintenance of fluid balance in tissues
D) Absorption of fats from the digestive tra
Transport of oxygenated blood to tissues
List primary functions of lymphatic system
Maintaining fluid balance
Absorption of dietary fats
Immune function
Removal of cellular waste
Transport of WBC
Where is lymph initially formed?
Interstitial fluid spaces
What structure is responsible for filtering lymph and trapping patching ends
Lymph nodes
What is the arrest lymphatic vessel in the body
Thoracic duct
Starts in abdomen and extends to chest and neck
Function of thoracic duct
Begining in abdomen, it extends upward through chest to the neck.
It drains lymp0h from the lower half of the body (both legs and abdomen) left side of chest, left arm and left side of head and neck and empties into the subclavian vain.
What is the most common cause of lymphoedema
Blockage of lymphatic vessels
Explain how the lymphatic system contrinbutes to immune function
Transporting and filtering lymph fluid. The lymph nodes trap pathogens and foreign particles preventing them from spreading through the body. In the lymph nodes immune cells recognise these invaders and start an immune response
Lymph nodes house lymphocytes and macrophages. Once an immune cell is activated an immune respionse occurs leading to increased immune activity
Lymphoid organs like bone marrow (produces immature lymphocytes) thymus (t-cell mature and enter blood stream for immune certain acne) and spleen (filter blood) are crucial.
Immune surveillance
Absorption and transport of antyiugens
Tissue drainage and infection control
Function of T cells, b cell and macrophages
T cells are involved in identifying and destroying infected or abnormal cells.
B cells produce antibodies that target specific pathogens.
Macrophages engulf and digest pathogens, debris, and dead cells via a process called phagocytosis.
Describe the pathophysiology of lymphoedema and how it impacts normal lymphatic function
Lymphoedema is accumulatin of lymphatic fluid in tissues due to impaired lymphatic draining. Resulting in chronic swelling.
Normally, lymph system collects excess interstitial fluid and proteins from tissues, filtering through lymph nodes and returning to blood stream.
This condition there is a failure in drainage preventing return of the fluid to the circulatory system.
This leads to an accumulation of fluid. Interstitial fluid increases pressure and tissue swelling edema.
The lymphatic system normally returns proteins to the circulation, but in lymphedema, these proteins also accumulate in the tissues, further exacerbating fluid retention and attracting more fluid into the tissue spaces through osmotic forces.
The protein rich lymph in tissues triggers an inflammatory repointed
What is the significance of the thoracic duct in the lymphatic system
Drains lymph into the blood stream
Where are excillary lymph nodes located
Arm pits
List primary lymphoid organs
Thymus gland
Bone marrow
Where do T cells and b cells mature
T- thymus
B- bone marrow
List secondary lymphoid organs
Lymph nodes
Tonsils
spleen
MALT/GALT/SALT
What does MALT/GALT/SALT stand for
Skin associated lymphoid tissue
Gastro associated lymphoid tissue
Mucosa associated lymphatic tissue
Function of the thymus
• Production of T Lymphocytes
• receives immunologically incompetent stem cells from bone marrow
• In the thymus these cells divide and mature into T-
lymphocytes
• Functions at peaks levels only during childhood
• Secretes hormone thymosin which support the
activity of T-lymphocytes throughout the body
Removal of the thymus
results in decreased T-
cell production
increasing susceptibility
to infection
Functions of the tonsils
• Small masses of
lymphoid tissue around
the pharynx
• Trap and remove bacteria
and other foreign
materials
• Tonsillitis is caused by
congestion with bacteria
What is peyers patches
Tonsils of the intestine
Found in wall of s intesntine
Capture and destroy bacteria in the intestine
Function of mucosa associated lymphatic tissue
Lymphatic tissue that exists in the walls of alimentary, respiratory and genitourinary
tracts. It includes:
• Peyer’s patches
• Tonsils
• Other small accumulations of lymphoid tissue
It is subdivided into:
Bronchus associated lymphoid tissues (BALT)
Gut associated lymphoid tissues (GALT)
Skin associated lymphoid tis
Malt functions
Protects the body against foreign
materials
Transport clean fluids back to the
blood
Drains excess fluids from tissues
Removes debris from cells of body
Transports dietary fats
Production of immune cells (such as
lymphocytes, m
Where are lymph capillaries absent
Epidermis
Hair
Nails
Cornea
Articular cartilage
Brain & spinal cord
Splenic pulp
What are lymph capialries
Form vast network of intracellular spaces of most of tissues
The wall is made by a single layer of epithelial cells
Buletpoint lymphatic system
One way system towards heart
No pump
Milking action of skeletal muscle
Rhythmic contraction of smooth muscle in vessel walls
Gravity effects movement
Briefly describe lymphatic vessels valves
Lymph leaks through mini valves into lymph capillaries
Higher pressure on the inside closes mini valve
Where can lymph empty
The thoracic duct (left)
Receive lymph from lower body and pooper left quadrant
Right lymphatic duct
Receive lymph from upper right quadrant
Lymph from these ducts enter blood stream via eft and right subclavian veins
Function and location of lymph nodes
Filters lymph before its
returned to the blood.
• Medulla houses
macrophages
• B-cells are concentrated
in the follicle or the
germinal centre
• T-lymphocytes are
concentrates in the
paracotex
From the outside to the inside label a lymph node
Capsule
Subcapsular sinus
Germinal centre
Lymphoid nodule
Trabeculae
What occurs in a lymph node
…
As lymph passes through a node bacteria and other foreign material are trapped
by reticular fibres within the node.
Bacteria are then phagocytosed by macrophages.
Plasma cells produce antibodies to antigens in the lymph.
Antibodies, lymphocytes and monocytes are eventually returned to the blood via
subclavian ve
Describe proces of lymph fluid system
Lymph is formed when high arterial pressure forces
fluid out of the capillaries and into tissues.
It contains more WBC than plasma
Enters nodes through afferent lymphatic vessels.
Flows through node in one direction, through sinuses
in lymph node cortex and then into the medulla
Exits the lymph node through efferent lymphatic
vessels
Must be returned to the blood stream to maintain
bloody volume and pressure
About 30 litres of fluid passes from arterial end of
capillaries into intracellular space every day
What is elephantiasis or lymphodema
Blockage
Obstruction may lead to scar tissue that develops when lymph vessels or nodes are damaged or removed during surgery radiation infirm or infection
What is lymphangitis
Inflamed or infected lymph nodes by organisms that spread throughout the lymphatic system from original site of infection
Red painful subcutaneous streaks
Lymohadentitis
Can result in cellulitis, bacteraemia or death
What is lymphadenitis
Acute or chronic
Swollen and painful nodes
Pus
What is Hemophagocytic Lymphohistiocytosis
• Aka macrophage activation syndrome
• Systemic activation of macrophages & CD8+ cytotoxic T cells on itself
• body self destructs.
• Acute febrile illness associated with splenomegaly and hepatomegaly
• Tx with immunosuppressives, chemotherapy and antibody therapy
50% mortality rate
What is chronic lymphocitic leukemia
Chronic lymphocytic leukaemia
Most common in over 60
Bone marrow produces roo many naive lymphocytes
Fatigue, swollen lymph nodes in neck, armpit, groin. Unusual bruising or bleeding
What is acute lymphocytic leukemia
Most common type of cancer in children
Affects blood and bone marrow
Bleeding from gums or nose, bone pain, fever, frequent infections, swollen lymph nodes, pale skin, shortness of breath, fatigue, weakness, pupura (skin rashes) abdominal pain, swollen spleen or liver
What is Hodgkin’s lymphoma
A cancer which affects the lymphatic system
Affects people 15-40 and over 55.
Abnormal b-cell proliferation
Enlarged non-tender lymph nodes
Night sweats, itchy skin, fever, fatigue, weight loss, persistent cough, pain in lymph nodes after consuming alcohol
Painless enlarged lymph node is a red flag
Idiopathic but gender (men>) age, family history of the disease and Epstein Barr virus injection may increase the risk.
What is non-hodgkins lymphoma
Most common than Hodgkin’s lymphoma
Abnormal b-cell proliferation
Tumours can grow into other organs
Disseminates widely and unpredictably early in their course.
Associuatred with Epstein Barr virus, hiv, pylori infection, previous radiotherapy or chemotherapy
Can occur at any age but 30% cases is over 75
Abdominal pain/ swelling, cough (pressing on vagus nerve) fatigue, sweats, chest pain, difficulty breathing, weight loss
Where are preauricular lymph nodes found
Anterior to the ear
Where are parotid lymph nodes found
Anterior to ear lobe
Where are retropharyngeal lymph nodes found
Inferior to mandible
Where are postauricular lymph nodes found
Posterior to ear
Where are anterior lymph nodes found
Inferior to submandibular lymph nodes.
Anterior lateral neck along SCM
Where are supraclavicular lymph nodes found
Palpable a superior to clavicle
Where are posterior cervical lymph nodes found
Posterior cervical. Posterior to SCM
Where are occipital lymoph nodes found
Posterior to postauricular
What is the significance of the thoracic duct in the lymphatic system
The largest most significant lymphatic vessel in rhe body.
The thoracic duct drains lymph from 3/4 of the body in both lower limbs, left upper limb, left head and neck. This is then transported to the left subclavian view where it enters the blood stream. Curcial for fluid balance and without would cause edema.
Transport of fluid also transports fats and vitamins absorbed from digestive system which is transferred into bloodstream for distribution, crucial for body function.
Immune cells in lymph is also in blood stream so can maintain immune surveillance.
Primer to thoracic duct, lympoh nodes filter out harmful microorganism, foreign particles and cancer clues. Thoracic duct ensures lymph is efficiently returned to blood stream
Compare and contrast roles of the thymus and the spleen ion lymphatic system
Both are integral components of lymph system and immune system function.
Thymus is located in upper chets, S is upper left abdomen
T is small and decreased with age, S is larger
T function id Tcell development and maturation S is blood filtrationa dn immune surveillance.
T cell types involve T cells, S is B cells, Tcells, macrophages
T role in immunity is it establishes T cell and tolerance and S mounts immune response against blood borne pathogens
T T cells mature and enter circulation and s b cells can become long lived memory cells
A patient presents with swollen lymph nodes in the neck and fever. What might this indicate and what is the role of the lymphatic system in response
Infection.
Swollen lymoph nodes indicate lymph system is actively engaged in filtering lympoh fluid and reponding to infection. Antigens from pathogens are presented to B and T cells activating an adaptive umune response.
Lympoh nodes produce and activate T and B cells which are crucial for fighting infections.
Lymph system transports activated immune cells from lymph into circulation allowing them to reach site of infection or inflammation
Fever caused by hypothalamus can enhance activity of immune cells whilst denaturing growth of pathogens and is seen in immune response
