Lymphatic System

Question 1

The lymphatic system carries out the immune response through a network of lymphatic vessels that collect _________ from the body’s interstitial spaces, filters the fluids through the _______________ and returns it to the _______________.

Answer 1

Lymph

Lymph nodes

Bloodstream

Question 2

What’s the difference between interstitial fluid and lymph?

Answer 2

Not much, just location.

When the fluid leaves the interstitial space and enters the lymphatic vessels, it becomes the lymph.

Question 3

What are lacteals?

Answer 3

Specialized lymphatic capillaries

Question 4

Where are lacteals and what do they do?

Answer 4

These specialized lymphatic capillaries are in the lining of the small intestine (fingerlike projections) and they absorb lipids from the intestinal tract

Question 5

When lymph is in the lacteals, what is it called?

Answer 5

Chyle.

Creamy white in color

Question 6

3 functions of the lymphatic system

Answer 6

1. Drains excess interstitial fluid from tissue spaces
2. Transports dietary lipids form the GI tract to the blood
3. Protects against invasion through the immune responses

Question 7

Besides lymph, the lymphatic system consists of:

Answer 7

Lymphatic capillaries
Lymphatic vessels
Agranular leukocytes called lymphocytes (t,b,natural killer)
Thymus and spleen
Lymph nodes
Lymphoid nodules (peyers patches, tonsils, appendix)

Question 8

Lymphatic vessels begin as…

Answer 8

Closed ended vessels called lymphatic capillaries in spaces between tissues

Question 9

If lymphatic vessels are in the viscera, they run along…

Answer 9

Arteries

Question 10

If lymphatic vessels are in the subcutaneous tissue, they run along…

Answer 10

Veins

Question 11

Where are lymphatic vessels absent from?

Answer 11

CNS
Bone marrow
Teeth
Avascular tissues (cornea, epidermis, hyaline cartilage)

Question 12

What are the lymphatic vessel valves for?

Answer 12

To prevent the backward flow of the lymph

Question 13

How are lymphatic vessels similar to veins?

Answer 13

They both have valves to prevent backflow

Consist of the same 3 tunics, but calls are thinner and poorly defined in lymph vessels

Question 14

Lymphatic vessels receive nutrients from…

Answer 14

Vasa vasorum

Question 15

What has a larger diameter, lymph vessels or veins?

Answer 15

Lymph vessels

Question 16

Collagenous type fibers extending from the endothelial cells of lymphatic capillaries to surrounding tissue space

Answer 16

Anchoring filaments

Question 17

Flow pattern of lymph

Answer 17

Interstitial spaces (as interstitial fluid)
To
Lymph capillaries (as lymph)
To
Lymphatic vessels (as lymph)
To
Lymphatic trunks (as lymph)
To
Lymphatic ducts (as lymph)
To
Subclavian veins (as blood plasma)
To
Arteries (as blood plasma)
To
Blood capillaries (as blood plasma)

Question 18

What is a lymphatic trunk? How many are there?

Answer 18

Where the lymphatic vessels merge.

9

Question 19

What are the nine major lymphatic trunks?

Answer 19

Pairs:
Lumbar
Jugular
Subclavian
Bronchomediastinal

Single:
Intestinal trunk

Question 20

What’s another name for the thoracic duct?

Answer 20

Left lymphatic duct

Question 21

What makes up the cisterna chyli?

Answer 21

Intestinal trunk + right lumbar trunk + left lumbar trunk

Question 22

Thoracic duct and right lymphatic duct drains lymph into the…

Answer 22

Right and left subclavian veins

Question 23

The flow of lymph from tissue spaces is maintained by…..(2)

Answer 23

1. Primarily by the contraction of skeletal muscles

2. One-way valves

Question 24

Primary lymphatic structures of the body

Answer 24

Red bone marrow and the thymus gland

Because they produce T-cells, B-cells and Natural killer cells

Question 25

Major secondary lymphatic structures

Answer 25

Lymph nodes, spleen, and lymphatic nodules Where most immune responses occur

Question 26

Agranular leukocytes

Answer 26

Lymphocytes T-cells, b-cells, and natural killer cells

Question 27

Lymphocytes that attack fungi, transplanted cells, and cancer cells

Answer 27

T-cells

Question 28

Lymphocytes that destroy bacteria

Answer 28

B-cells

Question 29

Lymphocytes that attack certain spontaneously arising tumor cells

Answer 29

Natural killer cells

Question 30

Thymus

Answer 30

Does NOT provide a filtering function, like lymph nodes, since there are NO afferent lymphatic vessels leading into the thymus. ``` Afferent = arrive Efferent = exiting ```

Question 31

Function of thymus

Answer 31

Promote the maturation of t-cells (they migrate from the red bone marrow to the thymus cortex, then to thymus medulla) Secretes thymosin (assists in promotion and maturation of T-cells)

Question 32

Why does the spleen not provide a filtering function? Like the thymus

Answer 32

There are not afferent lymphatic vessels leading into the spleen

Question 33

2 areas of the spleen

Answer 33

1. White pulp (mostly b-cells) | 2. Red pulp (venous sinuses filled with blood, and splenic/Billroth's cords that lie between sinuses)

Question 34

Function of white pulp in spleen

Answer 34

The site of B-cell proliferation into plasma cells

Question 35

Function of red-pulp in spleen

Answer 35

Carries out the main function of the spleen which is phagocytosis of bacteria and worn out or damaged red blood cells and platelets Also functions as reservoir for blood platelets

Question 36

Where the lymph nodes heavily concentrated

Answer 36

Inguinal, axillary, and mammary

Question 37

Lymph nodes are specialized into 2 regions

Answer 37

Cortex = outer region, t cells and immature b cells Medulla = inner region of mature b cells

Question 38

Germinal centers in lymph nodes

Answer 38

Contain masses of actively proliferating lymphocytes

Question 39

Medullary cords of lymph nodes

Answer 39

Thin inward extension, from the cortex toward the hilum, of t cells, b cells, and macrophages

Question 40

Afferent lymphatic vessels

Answer 40

Carry lymph from tissues to the lymph nodes Enter the convex side of the node ARRIVING

Question 41

Efferent lymphatic vessels

Answer 41

Carry lymph from the hilum (concave side of a node) to venous circulation EXITING

Question 42

Where is the subcapsular sinus?

Answer 42

Between the capsule and cortex of the lymph nodes

Question 43

Direction of lymph flow in lymph nodes

Answer 43

``` From subcapsular sinus Through cortex via cortical sinuses Through medulla via medullary cords Into hilum Exit lymph node via efferent lymph vessels ```

Question 44

What are the functions of the lymph nodes?

Answer 44

ONLY lymphatic tissue that filters lymph Foreign substances are filtered from lymph before it passes back to blood (due to macrophages by phagocytosis of immune response) plasma cells and t cells that have proliferated within a lymph node also leave and circulate to other parts of the body

Question 45

Lymphatic nodules

Answer 45

Are NOT surrounded by a capsule Clusters that guard in all mucous membranes MALT (mucosa-associated lymphoid tissue)

Question 46

Example of lymphatic nodules:

Answer 46

Peyers Patches. In mucosa lining the lieu of the small intestine

Question 47

Other examples of lymphatic nodules

Answer 47

Paryngeal tonsil/adenoid, two palatine tonsils, and two lingual tonsils

Question 48

Lymphatic nodules and the large intestine

Answer 48

Contains a large grouping of lymphatic nodules (located in lamina propria of mucosa)