Lymphatic anatomy session Flashcards
What is lymph
lymphatic fluid is a clear or slightly yellowish fluid that flows through the lymphatic system
The system helps protect the body from infections and removes waste
Main components of lymph
water
white blood celks
proteins
fats
waste products
nutrients
Describe water in relation to lymph
largest part of lymph and helps transport nutrients and waste
Describe WBC in relation to lymph
special immune cells fight infection and keep body healthy
Describe proteins in relation to lymph
Contain antibodies which help the immune system recognize and fight harmful invaders like bacteria and viruses
Describe fats in relation to lymp
some fats from food enter the lymphatic system before the blood streem, this is important for digestion especially in species that eat a lot of fat
Describe waste products in relation to lymph
lymph carries away toxins, dead cells, and other waste materials from body tissues to keep body clean
Describe nutrients in relation to lymph
Transports, vitamins, minerals and other nutrients to different parts of the body
why is lymph important
lymphatic fluid plays a makor role in immunity, fluid balance and nutrient transport, and it helps fight infections and maintain overall health
Lymph formation in relation to blood capillaries
Blood capillaries smallest blood vessels where exchange of gases, nutrients and waste occur
Due to hydrostatic pressure, some plasma leaks out into interstitial space
most of leaked fluid is reabsorbed but about 10% remains and becomes lymphatic fluid
remaining fluid contain proteins, waste products and immune cells and needs to be drained to prevent swelling(lumphoedema)
What is role of post-capillary venules in relation to lymph formation
Post capillary venules are small veins that collect blood from capillaries
They HELP REGULATE FLUID BALACNE by allowing some fluid to be reabsorbed to blood stream
Large molecules and excess fluid cant re-enter venules so taken up by lymphatic capillaries
What happens when lymphatic capillaries absorbed the excess interstitial fluid
now called lymph it is transported in the lymphatic vessels and the system returns this fluid to the blood stream via the veins maintaining overall fluid balance
Describe the origin of the lymphatic system from the interstitial space
network of initial lymphatics called capillary lymphatics COMPOSED OF BLIND- ENEDED TUBES, sacs or bulbs that move lymph centrally toward collecting lymphatic vessels
Where are lymphatic capillaries found
smallest lymphatic vessels found throughout body especially connective tissue
What are lymphatic capillaries
they have thin, overlapping endothelial cells that act as one- way valves allowing interstitial fluid to enter but not leave
Function of lymphatic capillaries
Absorbed excess fluid, proteins and immune cells from tissues
What are larger lymphatic vessels
Lymph from capillaries drains into larger lymphatic vessels, which have one-way valves to prevent backflow
difference of larger lymphatic vessels from blood vessels
they rely on muscle movement, breathing and body motion to push lymph forward
What are lymph nodes/ what leads to them
lymphatic vessels lead to lymph nodes, which act as filtration stations
Function of lymph nodes
Contain immune cells (macrophages and lymphocytes) that trap and destroy pathogens, toxins and foreign particles to clean lymph nodes
Where are major lymph nodes groups
neck, forelimb, chest, abdomen and hindlimb
What do lymphatic trunks do
after passing through lymph nodes, lymph drains into larger lymphatic trunks, which collect fluid from different regions of the body
Name 2 examples of lymphatic trunks and where they are
Left and right jugular trunk (head/neck), lumbar trunk(caudal abdomen, pelvic cavity and hindlimb)
What do lymphatic ducts do
Lymphatic trunks merge into 2 major lymphatic ducts, which return lymph to the blood stream
Name the 2 major lymphatic ducts
thoracic duct and right lymphatic duct
What is the thoracic duct and where does it drain to
largest lymphatic vessel, draining lymph from most of the body into the left jugular vein/cranial vena cava
What is the right lymphatic duct and where does it drain to
Drain lymph from right side of the head, right arm, and right chest into the right jugular vein/ cranial vena cava
What is it called when there is excessive interstitial fluid causing swelling
Lymphoedema
How much fluid stays between interstitial space after hydrostatic pressure pushes it there
10% which is then absorbed by lymphatic system
What moves lymph
Body, breathing and muscle activity
What prevents backflow for lymph
One way valves inside the vessels
Where is right lymphatic duct found
It is found on the right side and is smaller than thoracic duct
Where is the thoracic duct found
Originates in abdomen and passes through diaphragm with the aorta and a zygotes vein and continuous cranial key on medial aspect of the aorta and as passes level with heart crosses to join left face of the oesospahgus
What is the thoracic duct called in the abdomen
Cisterna Chyli
Name the lymphatic organs
Thymus, tonsils, spleen, lymph nodes
Primary role of lymph in the body
Carrying waste, immune cells and nutrients
How does the lymphatic system maintain fluid balance
It collects excess interstitial fluid that is not reabsobred by capillaries
How does hydrostatic pressure influence fluid movement in blood capillaries
It pushes fluid out of capillaries into the surrounding tissues
Why is lymphatic system essential for fluid balance in the body
It provides the only pathway for removing proteins and large molecules from the interstitium
What is the final step in lymphatic drainage before lymph returns to the bloodstream
Lymph flows into the thoracic duct or right lymphatic duct
Where do lymphatic tissue and lymphatic nodules commonly present
many mucous membranes- mucosa associated lymphoid tissue (MALT)
Name some cellular components of the immune system
Lymphatic tissue found as sinle cells or diffusely dispersed within tissues as aggregations of lymphatic cells lymphoid nodules or in lymphatic organs (thymus, lymph nodes and spleen)
Name some circulating component of immune system
lymphocytes, monocytes and plasma cells, found in various places
Where are lymphocytes, monocytes and plasma cells found
lymphatic organs, blood, tissue spaces, lymph stream
What does the lymphatic vascular system contain
lymph capillaries, lymph vessels and lymph collecting ducts
Shape of lymph nodes
ovoid or bean shaped, encapsulated structures
Where are lymph nodes found in general
along the course of the medium-sized lymphatic vessels,
What do lymph nodes function as
filters and germinal centres for lymphocytes
What are lymphocentres
groups/ clusters of lymph nodes draining the same region of the body in all species
What is the venous angle
ducts or trunks empty into large veins in the thoracic inlet
Where is the parotid lymph centre
consists of one or more parotid lymph node at the base of the ear close to the temporomandibular joint and covered by the parotid gland or the masseter muscle
What do the afferent lymphatics of the parotid lymph centre drain
dorsal half of the head, the orbit and the masticatory muscle
Where is the mandibular lymph centre
between the hemimandibles, near the greater sublingual salivary gland and the mandibular gland
What do the afferent lymphatics of the mandibular lymph centre drain
oral cavity, including tongue and teeth, the salivary gland, the intermandibular space and the masticatory muscles
What do the afferent lymphatics of the retropharyngeal lymph centre drain
parts of the head, including the pharynx, larynx and the cranial part of trachea and oesophagus
Where does lymph from the head drain into
tracheal/jugular trunk
Where is the superficial lymph centre
located cranial to the should jointw
what does the superficial cervical lymph centre drain
skin and underlying structures of cervical region, the thorax and the proximal part of the thoracic limb
Where is the deep cervical lymph centre
along the trachea
what does the deep cervical lymph centre drain
deep strucutres of cervical region, oesophagus, trachea, thymus and thyroid gland
Where do efferent lymph vessels of deep cervical lymph nodes open into
cranial vena cava or thoracic duct
What does the axillary lymph centre drain
deeper strucutre of the entire limb and superficial strucutres of distal part of the limb, cranial mammary gland
What lymph nodes drain the walls of the thorax
dorsal thoracic lymph centre and ventral thoracic lymph centre
What lymph nodes drain the organs within the thoracic cavity
mediastinal lymph centre and bronchial lymph centre
Where is the dorsal thoracic lymph centre
intercostal lymph node, thoracic lymph node
where is the ventral thoracic lymph centre
lymph node dorsal to the sternum
where is the mediastinal lymph centre
lymph node located in the mediastinal spacee
where is the bronchial lymph centre
tracheobronchial lymph nodes located above the bifurcation of the trachea
What consists of the lumbar lymph centre
lumbar aortic lymph nodes and renal lymph nodes
what consist of the coeliac lymph centre
coealic, splenic, gastric and pancreaticoduodenal lymph nodes
What consists of the cranial and caudal lymph centre
cranial and caudal mesenteric, jujunal, caecal and colic lymph nodes
What are the lymph centres of the abdomen that drain the abdominal viscera
lumbar lymph centre
coeliac lymph centre
cranial and caudal mesenteric lymph centre
What are the important lymph nodes of the pelvic cavity and pelvic limb
mammary/superficial inguinal lymph node, and popliteal lymph node
What is a lymphogram
x-ray or computer image of lymphatic systemW
How is a lymphogram taken
dye injected to make vessels and nodes easier to see
What may and lymphangiogram be used for
to check for blockages or leaks in lymphatic system
What is the largest lymphoid organ
spleen
Where is the spleen
caudal to diaphram within left cranial part of abdomen
what are the 2 surfaces of the spleen
diaphragmatic surface and the visceral surface which visceral is marked by the hilus
What makes up the parenchyma of the spleen
red and white splenic pulp
What makes up the splenic red pulp
venous sinus lined by an endothelium
what makes up the splenic white pulp
diffuse and follicular lymphoid tissue
How much of the splenic volume does the white pulp account for
one-fifth
What lymphatically drains the spleen
splenic lymph nodes located at the hilus of the organ
Where do the efferent vessels of the splenic lymph node go to
joins coeliac trunk to drain into the chyle cistern
What does the pulp do in the spleen
in foetus produces RBC and in adult it stores RBC to be squeezed into circulation when needed.
also produces lymphocytes; stores iron and destroys worn out RBC
When is the thymus most important
young animal and reaches maximum development 3 weeks in dogs, 9 months in pigs and 1 year old in the horse
What happens to thymus after maximum development
gradually involute until the animal reaches sexual maturity
What is the thymus made of
lobules each with its own cortex and medulla
What does the cortex of the thymus lobules do
produces immunocompetent T lymphocytes, which enter the bloodstream for distribution to the peripheral lymphoid organs( nodes and scattered lymph nodules) where they settle and multiply
What does the medulla of the thymus lobules do
formed of epitheliod cells, relevance to postnatal development and maintenace of immunological competence
What is the cloacal bursa
site of maturation of B lymphocytes
What species has a cloacal bursa/ bursa of fabricius
birds
where is the clocal bursa
dorsal appendage of the proctodaeum
What happens in the bursa of fabricius
bone marrow- derived lymphocytes mature within the bursa into b lymphocytes that are then repsonsible for humoral immunity
What happens to the cloacal bursa at sexual maturity
involution
