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Flashcards in Lymphatic system Deck (44)
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1
Q

What does the lymphatic system act as?

A

Secondary defense system

2
Q

What are the 3 ways the lymphatic system acts as a defense system?

A

Humoral immune system
cell mediated immune system
Filtration of lymph & blood

3
Q

What is the difference between humoral & cell mediated immune systems?

A

Humoral: B lymphocyte antibodies

Cell mediated: T lymphocytes

4
Q

What are the 2 types of lymphatic tissue?

A

Diffuse

Dense

5
Q

Where is diffuse lymphatic tissue often found?

A

Lamina propria of

G.I. tract

6
Q

Where is dense lymphatic tissue often found?

A

submucosa of G.I. tract

7
Q

Are lymph nodules made of dense or diffuse lymphatic tissue?

A

dense

8
Q

What are peyer’s patches?

A

accumulation of nodules

9
Q

In what tissue can lymphocytes be seen invading epithelium?

A

Tonsils

10
Q

What are the structural components of a lymph node?

A

Capsule

Stroma

11
Q

What is the stroma?

A

Trabeculae that arise from the capsule and divide the parenchyma

12
Q

What is the cortex of a lymph node?

A

Outer region of parenchyma

13
Q

Where are lymph nodules located?

A

In cortex

14
Q

What is the difference between a primary and secondary nodule?

A

Primary has homogenous appearance and secondary have a germinal center due to previous antigenic exposure (active lymphocytes)

15
Q

What does the paracortex contain?

A

T lymphocytes

16
Q

Why is the paracortex considered a thymus dependent zone?

A

T lymphocytes are produced in the thymus

17
Q

What are high endothelial venules?

A

Vessels that transport T lymphocytes from the thymus to the paracortex

18
Q

What is different about pigs and elephants in regards to lymph nodes?

A

Medulla is on outside

Cortex is on inside

19
Q

What are medullary cords?

A

Lymphocytes, plasma cells, macrophages and reticular cells located in the medulla

20
Q

What is the subcapsular sinus?

A

Space between capsule and lymphatic nodule

21
Q

What are the medullary sinuses?

A

Lymph sinuses between medullary cords

22
Q

Describe lymph flow

A

Afferent vessels drain to subcapsular and trabecular sinuses (nodules)

Lymph travels from cortical sinuses to medullary sinuses

Efferent vessels transport lymph out

23
Q

What happens to B cells after being presented with an antigen by a dendritic cell?

A

B cell becomes activated & divides

Some B cells become plasma cells & some move to medullary cords to secrete antibodies

24
Q

What are hemal nodes?

A

Lymphatic organs that filter blood

25
Q

Where are hemal nodes found?

A

Associated with visceral organs

26
Q

What is the function of the spleen?

A

Removes old RBCs

Removes antigenic material

27
Q

What are the components of the spleen?

A

Capsule
Dense connective tissue
Smooth muscle
Trabeculae

28
Q

What are the big differences between spleen tissue and lymph nodes?

A

Spleen has more smooth muscle

Spleen does not have a distinct cortex & medulla

29
Q

What is the white pulp of the parenchyma?

A

Any lymphatic tissue in the spleen

30
Q

What is the PALS?

A

Periarteriolar lymphoid sheath that surrounds the central artery in the parenchyma

31
Q

Aside from the artery what else is contained inside the PALS? How does that relate to the spleen?

A

T lymphocytes

PALS is thymus dependent zone of spleen

32
Q

What is the red pulp of the spleen?

A

Venous sinuses and splenic cords

33
Q

What is a sign that extramedllary hemopoiesis is occurring in the spleen?

A

Megakaryocytes

34
Q

What is the area between the white and red pulp called?

A

Marginal zone

35
Q

Why is the marginal zone important?

A

Immune response is initiated here

36
Q

What are the types of spleens?

A

Defensive: little smooth muscle with lots of white pulp

Reserve: lots of smooth muscle with less white pulp

37
Q

What type of spleens do ruminants have?

A

Between defensive and reserve

38
Q

What is the only gland in the body with an epithelial stroma?

A

Thymus

39
Q

How does the thymus act as an endocrine organ?

A

Produces thymopoietin which influences development of T lymphocytes

40
Q

Does the thymus have nodules?

A

No

41
Q

Describe the cortex of the thymus

A

Dense accumulation of developing T lymphocytes

42
Q

Describe the medulla of the thymus

A

Thymic corpuscles

Less dense T lymphocytes

43
Q

Does the thymus have any afferent lymphatics?

A

No

44
Q

What is the Bursa of fabricius? Where is it located?

A

Location of hemopoiesis in birds

Located in dorsal wall of proctodeum