Lecture 26

Question 1

Where is the spleen located?

Answer 1

left-posterior abdominal wall

Question 2

what is the largest lymphoid organ in the body?

Answer 2

the spleen

Question 3

what is the embryonic origin of the spleen?

Answer 3

mesoderm

Question 4

what is the function of the spleen?

Answer 4

it filters blood, old erythrocytes/platelets and is a site where immune response to antigens occurs

Question 5

What kind of tissue covers the spleen?

Answer 5

dense connective tissue

Question 6

what is trabeculae in the spleen?

Answer 6

connective tissue septa that arise from capsule to penetrate the parenchyma

They facillitate the passage of blood vessels into the parenchyma from the capsule.

Question 7

What is the purpose of capsule myofilaments in the spleen?

Answer 7

helps with contraction because the spleen can store blood and expand

Question 8

What epithelium is found on the spleen’s capsule?

Answer 8

mesothelium/ simple squamous epithelium

look at pics to see where located

Question 9

In what pulp do you find the central artery in the spleen?

Answer 9

in the white pulp.

look at pics!

Question 10

What does the parenchyma of the spleen consist of?

Answer 10

Red pulp and White pulp

Question 11

What consists of red pulp in the spleen?

Answer 11

-Cords of cells ( cords of Billroth)
- Sinusoids (capillaries)/ venous sinuses
( these sinuses are discontinuous)

RBCs

Question 12

What consists of white pulp in the spleen?

Answer 12

Thick accumulation of lymphocytes
Lymphatic nodules-germinal centers that decrease with age
Malpighian corpuscles/ splenic nodules

Question 13

what is a penicillar arteriole?

Answer 13

when central artery leaves the white pulp area

Question 14

Describe how arteries work in the white pulp of spleen

Answer 14

a splenic artery divides into branches that run along the capsule as a capsular artery.

this capsular artery branches off into a trabecular artery and then into the central artery at the interior of the parenchyma.

LOOK at picture

Question 15

What is a peri arterial lymphatic sheath in the spleen?

Answer 15

it is when proliferating lymphocytes surround the central artery ( PALS).. they have germinal centers.. ( look at pic slide 14)

There is an inner layer of T cells followed by a layer of B lymphocytes

look at pic!

Question 16

What do central arteries give rise to? and where do they end up?

Answer 16

smaller penicillar arterioles, which end up in venous sinuses/splenic sinuses ( red pulp)

Question 17

closed versus open circulation of the spleen histo

Answer 17

closed: terminal capillary continue into venules> pulp veins

open: capillaries open into cords draining blood cells and pulp veins are formed.
Splenic sunus has holes and the older you get the more likely RBCs are to stay outside in the red pulp and not make it into circulation

Question 18

What is the marginal zone of the spleen histology ?

Answer 18

it is an outer zone filled with lymphocytes and antigen presenting cells and macrophages. In this area lymphocytes first come in contact with antigens ( look at pic slide 17)
The marginal zone of the nodule= trap antigens from circulation and present the antigen to the lymphocytes of the spleen

Question 19

What does the Red pulp consist of and what is the purpose in the spleen?

Answer 19

Dense network of reticular fibers, numerous erythrocytes, lymphocytes, plasma cells, macrophages and granulocytes..

between the splenic cords are the venous sinuses

The red pulp’s purpose is to filter antigens and senile and abnormal erythrocytes and platelets from the blood

Question 20

In red pulp what are splenic sinusoids lined by? and what kind of basal lamina do they have?

Answer 20

elongated endothelial cells called LITTORAL CELLS, they are arranged like planks in a barrel.

they have an incomplete basal lamina composed of reticular fibers.

Question 21

What is the purpose of macrophages in red pulp of spleen?

Answer 21

macrophages function in the removal of damaged or effete erythrocytes from circulation

Question 22

What occurs with healthy and old rigid erythrocytes trying to never the cords of red pulp?

Answer 22

healthy= squeeze between endothelial cells and enter the cords

old= rigid erythrocytes trapped in space to be broken down by macrophages that are outside the sinusoids.

Question 23

Where are the tonsils located? what is the function?

Answer 23

• tonsils are part of the gut associated lymphoid tissue (GALT)
• located at the back of the oral cavity in the tongue and pharynx
• they process antigens that enter the body through oral cavity and nasal passage

Question 24

What does Waleyer’s ring consist of ?

Answer 24

the palatine tonsils and the dorsal of the tongue

Question 25

where is the pharyngeal tonsil located?

Answer 25

at the posterior pharyngeal wall/ nasopharynx

Question 26

If the tonsils are infected in what part of the tonsils are you likely to find pus

Answer 26

at the cripts

Question 27

What kind of epithelium do the tonsils have?

Answer 27

stratified squamous nonkeratinzied epithelium

Question 28

What kind of connective tissue do the capsule of the palatine tonsils tonsils have?

Answer 28

dense connective tissue

Question 29

The epithelium invaginate/evaginates to form cripts of palatine tonsils?

Answer 29

invaginates

Question 30

What do crypts of palatine tonsils contain?

Answer 30

they contain desquamated epithelial cells, live and dead lymphocytes and bacteria

Question 31

What kinds of nodules are commonly found in the palatine tonsils?

Answer 31

secondary nodules

Question 32

what prevents spread of infection in palatine tonsils?

Answer 32

posteriorly separated from constrictors by a thick capsule this prevents the spread of infections

Question 33

What are the epithelia found in the pharyngeal tonsils?

Answer 33

nasal passage: respiratory epithelium= ciliated pseudostratified columnar epithelium

oral passage: stratified squamous non keratinized

when inflammed= adenoids

LOOK AT PICS

Question 34

Where are the lingual tonsils? what kinds of glands are they associated with?

Answer 34

posterior aspect of tongue, has shallow cripts, at the base of each crypt there are lymphoid aggregates, associated with mucus glands

LOOK AT PIC= this makes sense cus they’re the only ones with this

Question 35

what is the main clinical finding of Digeorge syndrome?

Answer 35

22q11.2 deletion syndrome

an absent thymus gland/ thymic aplasia= they get a lot fo infections

Question 36

where is the defect in development of the missing thymus gland in digeorge syndrome?

Answer 36

3rd and 4th brachial pouches and arches

Question 37

What ribs protect the spleen?

Answer 37

9, 10, and 11 at the left upper quadrant area

Question 38

Lymph node enlargement:

what is follicular hyperplasia? and what kind of immune response caused it?

Answer 38

increase in the number and size of cortical lymphoid follicles

Humoral response

( see pic= many lymphatic nodules/ many active B cells)

Question 39

Lymph node enlargement: Paracortical hyperplasia. what caused it?

Answer 39

expansion of paracortical zone

• viral infection

( see pic= not many lymphatic nodules/ many active T cells)

Question 40

Lymph node enlargement: what is sinus hyperplasia and what caused it?

Answer 40

Medullary sinuses are extremely prominent

• draining necrotic tumor

( see pic, large medullary sinuses not really circular like the nodules)

Question 41

Sentinel lymph node biopsy

Answer 41

sentinel node is removed to be tested for cancer cells because it is the first drained into after a dye is added. this will located the tumor. the tumor and sentinel node both get removed. this is at the breast area.

Question 42

How do cancer cells invade lymphatic channels and gain access to the regional lymph nodes?

Answer 42

afferent lymphatic channels and they enter the subcapsular sinus of the lymph node and settle at this site where they proliferate to form a secondary tumor mass.