4B Lympahtic

Question 1

Name the parts of the lymph system

Answer 1

Spleen and thymus
Nodes - encapculated
Nodules:tonsils
red bone marrow
Scattered cells
Lymph fluid and vessels

Question 2

3 functions of the lymph system

Answer 2

Drain excess interstitial fluid
Transport dietary lipids (and lipid soluble vitamins)
Carry out immune response

Question 3

Lymph overall movements

Answer 3

Lymph caps to lymph vessels (like veins but thinner walls more valves) through nodes
Sub q lymp follow veins
Lymph vessels of viscera follow arteries

Question 4

Lymph capillaries

Answer 4

Can absorb large molecules
One way flow
Interstitial fluid pressure being greater than lymph cap, fluid flows in, but when pressure drops it can’t flow back
Anchoring filaments are pulled during tissue swelling to further open spaces between cells
Not in CNS

Question 5

Lymph formation

Answer 5

About 3 litres a day of interstitial fluid goes through lymph
Proteins that make it into interstitial fluid can’t flow back into plasma because of concentration gradient, so lymph returns it to blood

Question 6

Sequence of fluid flow

Answer 6

Blood caps to interstital to lymph caps to lymph vessels to lymph ducts to junction of internal jugular and subclavian veins

Question 7

Two pumps for lymph (same as venous blood)

Answer 7

Skeletal muscle milks lymph fluid
Respiratory pressure changes create movement (Inhalation lymph goes belly to thoracic, exhale it goes thoracic to belly)
Also smooth muscle contraction in wall of lymph vessels

Question 8

Primary lymphatic organs

Answer 8

Stem cells divide and become immunocompetent here. Red bone marrow and thymus
Pluripotent stem cells -> B cells and pre t cells

Question 9

Secondary lymphatic organs

Answer 9

Most immune responses occur.

Lymph nodes, spleen and lymphatic nodules (follicles)

Question 10

Ducts

Answer 10

Lymph vessels to nodes then form trunks
Trunks go into thoracic and right duct
Thoracic is 15-18 inches long

Question 11

Thoracic duct drains

Answer 11

Left side of body, head neck and chest, and entire body inferior to ribs
Drains into left internal jug and left sub clav veins

Question 12

Right lymph duct drains

Answer 12

Right jugular and subclav, right bronchomediastinal trunks

Drains at right internal jug and right sub clav veins

Question 13

Thymus

Answer 13

Bilobed between sternum and aorta
Lobes are separated by capsule
Trabeculae or extensions of capsule and divide each lobe into lobules

Question 14

Thymus lobules

Answer 14

Outer cortex and central medulla

Question 15

Thymus lobules: Cortex

Answer 15

Contains t cells, scattered dendritic, epithelial cells and macrophages
Here t cells mature
Dendritic cells (from monocytes, resemble dendrites) assist maturation process
Only 2% survive, and macrophages clean the dead ones up

Question 16

Thymus lobules: medulla

Answer 16

More mature T cells, epithelial and dendritic cells, macrophages
Thymic corpuscles here which may be site for T cell death

Question 17

Number of lymph nodes

Answer 17

600, in clusters, lots around mammary glands, axillae, groin

Question 18

Lymph node capsule

Answer 18

Dense connective tissue, extensions called trabeculae divide nodes into compartments, provide support and a route for blood vessels into interior of node
Internal to capsule is reticular fibers and fibroblasts

Question 19

Function of lymph nodes

Answer 19

Filter foreign substances from lymph as it passes through lymph node
Lymphocytes in lymph can interact and respond with foreign antigens

Question 20

Tonsils

Answer 20

Areas of  lymph tissue (uncapsulated nodes)
2 palatine (posterior region of oral cavity on each side)
2 lingual (base of tongue)
1 pharygenal (adenoids, posterior wall of nasopharynx)

Question 21

Spleen location

Answer 21

Left hypochondriac region between stomach and diaphragm, lateral to liver

Question 22

Functions of spleen (3)

Answer 22

Site of lymphocyte proliferation
Filtering of blood (foreign substances, old RBCs, platelets)
Blood storage
*Spleen does not filter lymph, only Efferent lymph vessels are present

Question 23

Thymus gland location

Answer 23

Located in mediastinum

Site of T cell maturation under effects of thymic hormone thymosin

Question 24

Facts about thymus gland

Answer 24

Large in infants (functional are 70g, 3g in oldies)
Maxes at 10-12 years old
Atrophies after puberty, is replaced with areolar and adipose tissue