Week 7 Lymph Part 5

Question 1

Describe thymic or hassall’s corpuscles?

Answer 1

1) Isolated masses of closely packed ER cells
2) Contain keratinohyalin granules (secret A LOT of keratin)
3) Extensive keratinization near the center
4) These are distinguishing features of the thymus

Question 2

Lymphocytes reaching the thymic cortex are prevented from contact with antigens by?

Answer 2

A physical barrier of blood-thymus barrier

Question 3

What does the blood-thymus barrier do?

Answer 3

Protects developing lymphocytes from exposure to antigens; want to prevent blood from directly contacting developing lymphocytes

Question 4

Endothelium lines?

Answer 4

Capillary walls

Question 5

Epitheliorticular cells have what type of junction?

Answer 5

Tight junctions

Question 6

Epithelioreticular cell layer does what?

Answer 6

Covers entire thymus and houses tight junctions

Question 7

What is a spleen?

Answer 7

Bag of immune cells in abdomen with lots of blood flow

Question 8

How big is the spleen? Where is it found?

Answer 8

Roughly the size of your fist. Found in the upper left quadrant of abdominal cavity

Question 9

The spleen is rich in ______ supply?

Answer 9

Blood

Question 10

The spleen has a large number of?

Answer 10

Lymphocytes, macrophages, and dendritic cells

Question 11

The spleen is comprised of a meshwork of?

Answer 11

Reticular cells and reticular fibers (secreted by fibroblasts)

Question 12

What is the function of the spleen?

Answer 12

Filters blood and reacts immunologically to blood borne pathogens

Question 13

What are the two important things the spleen does when it filters blood?

Answer 13

1) Removal of old RBCs, recaputes iron

2) Converts hemoglobin to bilirubin and iron

Question 14

Just like the thymus and lymph nodes, the spleen anatomy consists of?

Answer 14

Enclosed in a dense connective tissue capsule with trabeculae extending into the parenchyma

Question 15

What type of pulp is found in the spleen?

Answer 15

Red and white; NOT based on color

Question 16

Majority of the spleen is made of what type of pulp?

Answer 16

Red

Question 17

White pulp?

Answer 17

Is mostly lymphocytes. Splenic nodules sitting in a sea of red pulp

Question 18

White pulp is considered basophilic so it stains?

Answer 18

With hematoxylin (more purple); red pulp is more pink

Question 19

White pulp is made up of what two things?

Answer 19

Periarterial lymphatic sheth (PALS) and Splenic nodules (lymph nodules)

Question 20

Periarterial lymphatic sheath (PALS)

Answer 20

Diffuse lymphoid tissue associated with and surrounding the central artery

Question 21

Splenic nodules (lymph nodes of spleen)

Answer 21

Dense lymphoid tissue, may contain germinal centers, usually located eccentrically to the central artery

Question 22

Periarterial lymphatic sheath is located?

Answer 22

Around arteries

Question 23

Red pulp contains large numbers of?

Answer 23

RBCs that are filtered and degraded, fresh tissue appears red

Question 24

Red pulp is made of?

Answer 24

Splenic sinuses and splenic cords

Question 25

What are splecnic cords composed of?

Answer 25

Loose meshwork of reticular cells and reticular fibers containing: RBCs, macrophages, lymphocytes, dendritic cells, plasma cells, and granulocytes

Question 26

Finustrated?

Answer 26

Like a filter, endothelial cells are an example

Question 27

Arteries branch along?

Answer 27

Trabeculae

Question 28

Splenic nodules are mainly white or red pulp?

Answer 28

White

Question 29

Circulation within the red pulp in the spleen allows macrophages to screen _____ in the blood

Answer 29

Antigens

Question 30

The spleen can have what type of circulation?

Answer 30

Open or closed

Question 31

Open circulation: blood enters the central artery of spleen and branches to the penicillar arterioles before?

Answer 31

Entering the sheathed capillaries which empty directly into reticular network of splenic cords

Question 32

Spleen has an extra layer of tissue that allows it to?

Answer 32

Have open circulation (as well as closed)