Lymphatic System

Question 1

Lymphatic is open circulation system. What does that mean?

Answer 1

It allows transfer of matter in or out of system

Question 2

Lymph moves in one direction:

How to does lymph move?

Answer 2

Towards the neck

By muscle contractions

Question 3

2 main functions of lymphatic system

Answer 3

Transport WBCs through body and provide environment for immune function to occur

Question 4

1. Lymphatic system derives from what germline?

2. What week does it begin to develop?

Answer 4

1. Mesoderm

2. 5th week of embryonic development (2 weeks after cardiovascular system)

Question 5

What part of lymph system is developing at each time and where do the capillary plexuses spread to?

1. 5 weeks
2. 6 weeks
3. 9 weeks

Answer 5

1. Jugular lymph sacs - thorax, UE, neck, head
2. Retroperitoneal: abdominal viscera and diaphragm; posterior (iliac) lymph sac (abdominal wall, pelvic region, LE) and cisterna chyli
3. R and L thoracic duct

Question 6

During development, cisterna chyli drains into ____ which develop into?

Answer 6

2 thoracic lymph ducts which develop further and drain into internal jugular and subclavian veins

Cisterna chyli serves as a connecting sac for lymph going through ducts during beginning of development

Question 7

How do those lymph sacs get converted into secondary lymphatic organs?

Exception?

Answer 7

They become invaded by mesenchymal cells

Exception- cisterna chyli

Question 8

Name a secondary lymphatic organ and what it develops from?

Answer 8

Spleen = develops from mesenchymal cells between layers of dorsal mesentery of stomach

Question 9

Why is thymus considered a primary lymphatic organ?

Answer 9

Is arises from two basic germ layers (endoderm and mesoderm)

Question 10

1. Right shoulder/ UE/ thorax/ head and neck region drain into what vein?
2. Path of parts of body below abdomen?

Answer 10

1. Right subclavian; rest of body drains into left

2. Cisternae chyli- thoracic duct - left subclavian vein

Question 11

Name the draining trunk of the following part of body:

1. Right thoracic cavity drains via?
2. Right arm?
3. Right side of head and neck

Answer 11

1. Right bronchomediastinal trunk to right lymph duct
2. Subclavian trunk to right lymph duct
3. Jugular trunk to right lymph duct

Question 12

~ look at slide 13 and name this lymph nodes

Answer 12

!!

Question 13

3 primary lymphoid organs?

2 secondary?

Answer 13

Primary= thymus, bone marrow, and fetal liver

Secondary= lymph nodes and spleen

Question 14

What is MALT?

Name the 5 cells of MALT

Role of MALT?

Answer 14

MALT is mucosa associated lymphatic tissue (diffuse lymphatic tissue)

T lymphocytes, B cells, plasma cells, macrophages, and microfold cells (GI tract)

Encounter antigens passing through the mucosal epithelium

Question 15

Lymph nodules are more ___ than lymph tissue

Definition of lymph nodule

Answer 15

Organized

Lymph tissue localized in regions that are most frequently exposed to microorganisms

Question 16

Name some ways that lymph nodules differ from lymph nodes

Answer 16

Most importantly: lymph nodules are not located along the lymphatic vessel - no filtration. Also, nodules are much smaller and do not have a well defined capsule boundary

Question 17

How does a lymph nodule differ from diffuse lymphatic tissue?

Answer 17

Nodules have germinal centers (which are located in the middle of a follicle)

Question 18

What happens at germinal center?

Answer 18

Site of B cell proliferation and differentiation into plasma cells in response to an antigen

Question 19

Two groups of lymphatic nodules. One has 4 subsections.. what are they?

Answer 19

Primary lymphatic nodules (esophagus) and aggregated lymphatic nodules

Aggregated= peyers patches (small intestine), white pulp (spleen), tonsils and vermiform appendix

Question 20

All tonsils in the body are considered ___; aka NALT which stands for?

Name the 4 tonsils

Answer 20

Waldeyers ring
Nasopharynx associated lymphoid tissue

Palatine (x2), tubal (x2), lingual, and pharyngeal tonsil-adenoid

Question 21

Where are lymph nodes located?

Function of lymph nodes?

Function of the following:

1. Dendritic cells
2. Follicular dendritic cells

Answer 21

Along the pathway of lymphatic vessels

Filter lymph and maintain and produce several types of immune cells

1. Present antigens to T and B lymphocytes
2. (Non migratory) Capture antigen and retain for further presentation to B cells

Question 22

What is contained in each part of the lymph nodes structure:

1. Cortex-
2. Follicle germinal centers-
3. Paracortex-
4. Medulla-

Answer 22

1. Contains B and T cells
2. Site of B cell activation
3. Contains T and DC cells
4. Contains densely packed B and T cells, macrophages, and plasma cells

Question 23

What are high endothelial venules (HEVs)?

Present in what organs?

Answer 23

Where lymphocytes enter the lymph node from blood

Present in all secondary lymphoid organs except the spleen

Question 24

Functions of the spleen? (3)

Answer 24

Filters blood from senescent blood cells (removes pathogens from blood)
Supplies immunocompetent B and T lymphocytes
Major site for antibody production

Question 25

The spleen is the ___ lymphatic organ Tissue of spleen is divided into two regions:

Answer 25

Largest Red pulp and white pulp

Question 26

Significance of splenic cords in the red pulp of the spleen?

Answer 26

Splenic cords contain half of the body’s monocytes as a reserve so that after tissue injury they can aid locally sourced monocytes in wound healing

Question 27

1. White pulp of spleen consists of what? | 2. 3 cells contained in the white pulp?

Answer 27

1. Lymphocytes surrounding splenic artery referred to as PALS (periarteriolar sheaths) 2. T cells, B cells, and follicular dendritic cells

Question 28

Splenic circulation: Once it gets to central arteries what happens?

Answer 28

Arterial splenic blood supply from celiac trunk to spleen artery to trabecular arteries to central arteries. Once it gets to central arteries, it branches to radial arteries for the white pulp and penicillar arteries for red pulp. Penicillar arteries branch end at splenic sinusoids (closed circulation) and empty into the red pulp (open circulation)

Question 29

Two ways that the spleen filters the blood

Answer 29

Mechanical - as blood passes through spleen, endothelium will trap defective RBCs and prevent their reentry to the blood Biological - macrophages remove non functional RBCs from circulation by phagocytosis

Question 30

1. Spleen derives from? | 2. Primary follicles assembly ___ weeks of gestation

Answer 30

1. Mesenchymal cells (mesoderm germline) | 2. ~23

Question 31

Thymus a ___ lymphoid organ Thymus is site of?

Answer 31

Primary T cell maturation (learning to differentiate between self and non-self antigens)

Question 32

Difference between a primary lymphoid organ and secondary?

Answer 32

Primary develops first and is the site of maturation of lymphocytes Secondary are sites of action of immunological activity of T or B cells

Question 33

What are thymocytes? Thymic epithelial cells are derived from what germ layer? What is the precursor for a thymocyte?

Answer 33

Future T cells (located in the thymus; mature into T cells that identify non-self antigens) Endoderm (all epithelial tissue is from endoderm) of third pharyngeal pouch Thymic hematopoietic bone marrow (mesoderm)

Question 34

During what time in your life is thymus most active? Cortex of thymus is inhabited by what kind of cells? Medulla of thymus is inhabited by what kind of cells?

Answer 34

Fetal and neonatal period (starts to disappear during puberty) Thymocytes (immature form) T cells (mature form)

Question 35

Hassall’s corpuscles are always found where? Shape? What kind of cells are these?

Answer 35

Always found in the medulla of the thymus Concentric Epithelial reticular cells

Question 36

Purpose of blood thymus barrier What kind of capillary is the blood thymus barrier made of?

Answer 36

Protects developing T lymphocytes from pathogens; Blood thymus barrier prevents antigens from reaching the T cells Non fenestrated (so things cant permeate through); macrophages are also present just in case something does end up getting through

Question 37

Thymus has no lymphatic drainage vessels (to help protect developing T cells from unwanted exposures) but it does have its own 3 lymph nodes. Name?

Answer 37

Internal mammary-parasternal Tracheobronchial-hilar Mediastinal-brachiocephalic

Question 38

developmental conditions: What is congenital asplenia? Brief description of the 2 types: 1. Syndromic asplenia 2. Isolated congenital asplenia

Answer 38

When a child is born without a spleen 1. Child dies very early on - spleen produces immunoglobulins so child is unable to fight infections without one 2. Same disease but if child is not exposed to anything it can live until about 5-6 years

Question 39

developmental condition: What is thymus hypoplasia (DiGeorge syndrome)

Answer 39

Underdeveloped thymus and deficiency in mature T cells (diminished adaptive immunity)

Question 40

What is lymphoid hyperplasia?

Answer 40

Broad category This is a symptom, not a disease: Abnormal proliferation of one or more components of the lymphatic system (ex: enlarged lymph nodes) can be present in tonsilitis, strep throat, etc.

Question 41

Follicular hyperplasia? Paracortical hyperplasia?

Answer 41

Abnormal proliferation of secondary follicles (B cells) Abnormal expansion of the interfollicular zones (T cells) can be cancerous (if they overgrow the capsule) or non cancerous (if they stay confined in the capsule)

Question 42

Sinus hyperplasia

Answer 42

Preferential stimulation of the macrophages within a lymph node

Question 43

Appendicitis

Answer 43

Type of lymphoid hyperplasia as well. | Obstruction of appendiceal lumen, filling of appendix with mucous, increase of internal pressure, inflammation, necrosis

Question 44

Reasons why you may need a splenectomy? Effect splenectomy has on body?

Answer 44

Trauma mostly, but also sickle cell anemia When spleen is removed, it causes diminished levels of antibodies and susceptibility to infections (will need different vaccinations if you dont have a spleen)