The Lymphatic System

Question 1

What are the 2 Parts of the Circulatory system?

Answer 1

Cardiovascular and Lymphatic

Question 2

What is Lymphatic system?

Answer 2

Similiar to CV but forms basis of Immune System

Question 3

What are the 3 Components of the Lymphatic System?

Answer 3

1. Extensive network of Capillaries and collecting Vessels
2. Lymph Nodes
3. Lymphoid Organs

Question 4

How is Interstitial Fluid formed?

Answer 4

More Fluid with plasma proteins leaving Capillaries than entering it, the fluid accumulates in Intercellular Spaces

Question 5

What can the build up of Plasma Proteins lead to?

Answer 5

Oedema

Question 6

What happens to Plasma Proteins when they cant re-enter capillaries?

Answer 6

Enter Lymphatic Vessels

Question 7

What type of System is Lymph whilst flowing to the heart?

Answer 7

One-way system, begins in tiny lymph capillaries

Question 8

What type of Lymphatic Vessels are they?

Answer 8

Capillary -> Collecting Vessel -> Trunk -> Duct

Question 9

How does fluid get into Interstitial Space?

Answer 9

Hydrostatic and Osmotic pressures at arterial ends of capillary beds force it toward venous end

Question 10

What happens to the 3L/day Institial Fluid leaked and not absorbed by the capillaries?

Answer 10

They need to return to the blood

Question 11

Where does Lymph Transport begin and what are the exceptions?

Answer 11

Lymph Capillaries and Bone, Bone Marrow, Teeth, CNS

Question 12

What is the Lymph Capillaries?

Answer 12

Similiar to Blood Capillaries but V. Permeable

Question 13

What are the 2 Structural Modifications of the Lymph Capillaries?

Answer 13

1. Endothelial cells looseley overlap to create MINI-VALVES
2. Endothelial cells Anchored to Surrounding structures by fine filaments, expose gaps in capillary wall but close to avoid leakage

Question 14

What happens when the tissue becomes inflamed?

Answer 14

The Lymph Capillaries take up large particles e.g Debris, Pathogen, Cells

Question 15

What filters and examines the particles?

Answer 15

Lymph Nodes

Question 16

What are Lacteals? describe them?

Answer 16

Highly Specialised Lymph Capillaries in Villi of Intestinal Mucosa
Lymph is milky white due to carrying digested intestinal fats called CHYLE

Question 17

Describe Collecting Vessels?

Answer 17

3 tunics like Veins which are/have

thin-walled, more internal valves, anastomising

Question 18

Where do larger Lymphatic Vessels recieve Blood supply from?

Answer 18

Vaso Vasorum

Question 19

What do the Lymphatic Collecting Vessels and Lymphatics travel with?

Answer 19

Collecting Vessels with Superficial Veins

Deep Lymphatics travel with Deep Arteries

Question 20

What does Lymphatic Trunks do?

Answer 20

Drain large areas of the body, named after the area they drain lymph from i.e Lumbar, Subclavian

Question 21

What are the 2 Types of Lymphatic Ducts?

Answer 21

1. Right Lymphatic Ducts - drains lymph from right upper arm, right side of head, thorax
2. Thoracic Duct - Larger arises from CISTERNA CHYLI, drains rest of body

Question 22

How do the Lymphatic Ducts work?

Answer 22

Each Ducts empties Lymph into Venous Circulation at junction of internal jugular and subclavian veins

Question 23

What is the Mechanism of Lymph Transport?

Answer 23

Pump-less so slow moving, same as veins i.e

milk actions of muscles, use of valves, rhythmic contractions of smooth muscles and breathing-induced pressure change

Question 24

What is Lymphoid Tissue?

Answer 24

Loose Connective tissue (important for immune tissue) in all L. organs except Thymus
Macrophages live on fibres and Lymphocytes reside in spaces temporarily

Question 25

What 2 ways are Lymphoid Tissues 'Packaged'?

Answer 25

1. Diffuse - in most body organs inc Mucous membranes and Lymphoid organs 2. Follicles/Nodules - Solid, Tight Packed with Germinal centres containing B Cells e.g in Lymph nodes

Question 26

How do Lymph Nodes work?

Answer 26

Lymph filtered through LN that cluster along lymphatic vessels of the body, provides protective function via Phagocytes and activate immune system

Question 27

Where are the Lymph Nodes?

Answer 27

They cluster where lymphatic vessels converge to form trunks e.g inlingual, axillary

Question 28

What do Lymph Nodes look like?

Answer 28

small bean-shaped organs, contain fibrous capsule from which connective tissue (trabeculae) form, emerge and divide into nodes Provides support to residing L cells 2 regions, outer cortex - inner medulla

Question 29

What does the Lymph Node Cortex Region look like?

Answer 29

densely packed follicles with germinal centres, dendritic cells wrap around follicles to seperate from T-Cell interspaces (for immune surveillance)

Question 30

What does Lymph Node Medulla Region look like?

Answer 30

Contains Cords inward extensions of the cortex which contains L's and Plasma Cells

Question 31

What are Lymph Sinuses?

Answer 31

Spanned by reticular fibres, enter nodes and phagocytose materials

Question 32

How does Lymph enter Afferent Lymphatic Vessels?

Answer 32

on Convex side, moves through large subscapular sinus into smaller sinuses through to the medulla

Question 33

How does Lymph leave Efferent Lymphatic Vessels?

Answer 33

At Hilus, causes Lymph stagnation, passesseveral nodes before its cleaned

Question 34

Describe the Lymphoid organ the Spleen?

Answer 34

Largest, soft rich-blood organ, fist size on left abdomen, served by large splenic artery and s.vein that enter hilus on concave side

Question 35

What are the Functions of the Spleen?

Answer 35

Immune serveillance, Cleans blood, Store RBC, Store Platelets, Site of RBC production Thin capsule with trabeculae

Question 36

What are the 2 Distinct Regions of the Spleen?

Answer 36

1. Areas of L on reticular fibres - white pulp and forms 'cuffs' around arteries 2. Areas of red cells, venous sinus, splenic cord and red pulp

Question 37

Describe the Lymphoid organ the Thymus?

Answer 37

Bilobular organ in lower neck, prominent in newborns (turns into fatty tissue with age) , secretes thymosin

Question 38

Describe the Thymus Structure?

Answer 38

Compare to cauliflower head, florets the thymic lobules with outer cortex (dark-stain - rapid divide) and inner medulla (light stain- fewer L's)

Question 39

What does the Light-Staining Medulla of thymus contain?

Answer 39

Hassals or Thymic Corpuscle - Responsible for conversion of self-reactive T-Lymphocytes

Question 40

In what 2 Ways does the Thymus differ from other L organs?

Answer 40

1. Functions only in T-cell maturation, doesnt fight antigents directly Blood-thymus-Barrier 2. Stroma (framework) has star shaped endothelial cells, secrets hormones

Question 41

Describe the Lymphoid organ the Tonsils?

Answer 41

smallest, ring of tissue around entrance to throat | Gather and remove pathogens entering in

Question 42

What are the 4 Types of Tonsils?

Answer 42

Named by location; 1. Palatine - larger located at either side of oral cavity (often infected) 2. Lingual (base of tongue) 3. Pharyngeal (adenoids - posterior walls of nasopharynx) 4. Tubal (surrounding of auditory tubes)

Question 43

What does the Tonsils contain?

Answer 43

nodules with germinal centres Exterior surface- squamous epithelium deep into tonsils to from CRYPTS that trap bacteria (killed in L tissue- memory immune cells)

Question 44

What is Peyers Patches?

Answer 44

Large isolated cluster of nodules (similiar to tonsils) -located in wall of ileum

Question 45

What is Appendix?

Answer 45

Cluster of Nodules

Question 46

What does Peyers Patches and Appendix do?

Answer 46

Destroy bacteria, Generate memory for immunity, MALT for resp and digestive tract protection