Lymphatic system

Question 1

what general parts make up the lymphatic system:

Answer 1

lymph, lymphatic vessels, lymphoid organs/ tissues

Question 2

components of lymphatic vessels:

Answer 2

capillaries, lymphatic vessels, ducts, trunks

Question 3

components of lymphoid organs/ tissues:

Answer 3

primary:

• red bone marrow
• thymus

secondary:

• spleen
• lymph nodes
• lymphatic nodules

Question 4

general functions of lymphatic system:

Answer 4

• drains excess interstitial fluid
• transports dietary lipids/ lipid soluble vitamins

(carries out immune responses)

Question 5

general flow of lymph:

Answer 5

interstitial fluid (lymph) –> lymphatic capillaries –> lymphatic vessels –> lymphatic trunks –> lymphatic ducts –> veins

Question 6

general features: lymph vessels

Answer 6

• thin walled
• have valves
• similar in structure to veins
• lymph nodes (along lymph vessels)

Question 7

location: lymph trunks

Answer 7

lumbar, intestinal, bronchomediastinal, subclavian, jugular

Question 8

two lymphatic ducts:

Answer 8

• left lymphatic duct (thoracic duct)

- right lymphatic duct

Question 9

what areas are drained: L lymphatic duct

Answer 9

• L side of head/ neck/ chest
• L upper limb
• whole body inferior to ribs
• drains: junction of L internal jugular and L subclavian veins

Question 10

what areas are drained: R lymphatic duct

Answer 10

• upper R side of body (inc. head, neck, chest)
• R upper limb
• drains: junction of R internal jugular and R subclavian veins

Question 11

what pumps help lymph flow:

Answer 11

• skeletal muscle pump

- respiratory pump

Question 12

lymphedema: eg

Answer 12

swelling of tissue due to insufficient functioning of lymph system
- retention of fluid

Question 13

features/ function: red bone marrow

Answer 13

• main site of haematopoiesis
• pluripotent cells give rise: erthrocytes/ leukocytes
• B Lymphocytes mature in bone marrow
• T Lymphocytes migrate to thymus -> immunocompetent

Question 14

features/ function: thymus

Answer 14

• bilobed organ: superior mediastinum btw sternum/ aorta, surrounded by thin capsule
• fully functional at birth, matures at puberty, involutes
• site of T Lymphocyte maturation
• rich blood supply

Question 15

features/ function: thymic lobule cortex

Answer 15

• peripheral, dark zone
• site of proliferation/ maturation of T Lymphocytes
• dendritic cells, specialised epithelial cells (thymic hormones)
• most T cells die via apoptosis

Question 16

thymic lobule: main parts

Answer 16

cortex and medulla

Question 17

features/ function: thymic lobule medulla

Answer 17

• central, light zone
• mature T cells
• dendritic, epithelial, cells, macrophages
• Hassall’s corpuscles: epithelial cells become filled with keratin, degenerate, calcify
• more with maturity

Question 18

features/ function: spleen

Answer 18

• left hypochondriac region (btw 9-11) ct. capsule
• invaginates into spleen forming trabeculae
• superior/ visceral surface
  s: convex- diaphragmatic
  v: visceral- gastric, renal, colic impressions

Hilum: splenic artery and vein, lymphatics, sympathetic nn.

Question 19

parts: parenchyma of the spleen

Answer 19

white pulp

red pulp

Question 20

parenchyma of the spleen: white pulp

Answer 20

• lymph tissue around branches of splenic artery, central artery
• immune function (B T cells) destruction of pathogens

Question 21

parenchyma of the spleen: red pulp

Answer 21

venous sinuses/ cords of splenic tissue -> splenic (Billroth’s) cords
- removal of old blood cells and platelets, storage of platelets, site haematopoiesis (foetal life)

Question 22

function: spleen

Answer 22

• mounts primary immune response,
• filtering blood,
• destruction of blood cells
• storage of platelets
• production of erythrocytes (foetal)

not essential for life

Question 23

Splenomegaly: eg

Answer 23

enlargement of spleen

Question 24

features/ function: lymph nodes

Answer 24

small encapsulated organs located along pathway of lymphatic vessels
- small bean shaped, filters
- widely distributed throughout the body but concentrated in:
axilla, inguinial, mesenteries

Question 25

lymph node: network of sinuses/ flow

Answer 25

irregular channels through lymph node, contain reticular fibres, lymphocytes, macrophages afferent lymphatic vessels --> subcapsular sinus --> trabecular sinuses --> medullary sinuses --> efferent lymph vessel (hilum)

Question 26

features/ function: lymphatic nodules

Answer 26

small, egg shaped mass of lymphatic tissue without capsule - found in lamina propria of mucous membranes of digestive, urinary, reproductive, respiratory systems - mucosa-associated lymphoid tissue (MALT)

Question 27

aggregations of lymphatic nodules:

Answer 27

tonsils, Peyer's patches

Question 28

features/ function: tonsils

Answer 28

incompletely encapsulated lymphoid tissue at junction of oral cavity , oropharynx and nasal c. and nasopharynx - palatine - pharyngeal - lingual

Question 29

immunity: general definition

Answer 29

body has system of cells which can distinguish self from non-self (foreign substance) immune responses provide defence of body against invasion from - outside: bacteria, virus etc. - inside: abnormal cells

Question 30

cells of immune system and distributed how:

Answer 30

lymphocytes, plasma cells, mast cells, neutrophils, eosinophils, phagocytic cells - blood - lymph - epithelial tissue - connective tissue

Question 31

features/ function: antigen

Answer 31

molecule capable of inducing immune response/ production of antibodies can be: - protein - polysaccharide - bacteria - protozoa - virus infected cell - tumor cell

Question 32

2 types of responses to antigens:

Answer 32

humoral: - immunoglobulins (antibodies Ab) secreted by plasma cells are involved in response cellular: - lymphocytes are involved

Question 33

features: antibody

Answer 33

glycoprotein, in immunoglobulin protein family (Ig)

Question 34

classes of antibodies:

Answer 34

IgG, IgA, IgE, IgD, IgM

Question 35

function/ action of antibodies:

Answer 35

neutralisation, opsonisation, complement system activation, cytotoxicity

Question 36

two types of immunity: general

Answer 36

innate: present from birth | adaptive (acquired/ specific)

Question 37

innate immunity:

Answer 37

fast, non specific, no memory - skin - mucous membranes - phagocytic cells (macrophage, neutrophils, monocytes, natural killer cells)

Question 38

adaptive immunity:

Answer 38

more efficient, high specific, has memory, activation of B/ T lymphocytes to destroy invading organisms