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Flashcards in Thymus/Marrow Deck (19):
1

Describe the normal gross features of Thymus

-Lobulated - Each lobule with a cortex/medulla
-Anterior mediastinum
-involutes with age

2

Microscopic normal thymus

-Network of epithelial cells
-Filled with Lymphs, Mphages. and DC
-Cortex = dense lymph populaton
-Medulla = aggregates of keratinized epithelial cells (Hassall's corpuscles)

3

Major function of the Thymus

Maturation of the T lymphs --so they do no recognize self

4

Embryonic origin of Thymus

Endoderm of 3rd pharyngeal pouch --> Epithelial reticular cells

5

Hassel's corpuscles

aka Thymic corpuscles
-Concentric clusters of reticular epithelial cells in medulla
-sometimes they keratinize

6

Combined Immunodeficiency (CID)

-Marked lymphoid hypoplasia in lymphoid organs --> secondary adenoviral bronchitis/ bronchopneumonia --> Death (before 3mo)

-autosomal recessive =Arabian foals
-X-linkd Dz = Basset

7

Lymphoid necrosis causes..

Thymic Atrophy

8

Acute Thymusitis

1. Necrotizing
-Bovine Chlamydial Abortion
-Canine Parvovirus, Equine herpesvirus, feline panleuk, FIV
2. Suppurative

9

Common species associated with Thymoma

Cat, Dog
-Neoplastic thymic epithelial cells mixed with non-neoplastic lymphocytes

10

Structure of Bone Marrow

support structure formed by a network of adventitial cells (reticular cells)

hematopoietic cells (erythrocytic, myelomonocytic, megakaryocytic, lymphocytic) and sinusoids reside with in

11

Function of bone marrow

1. Hematopoiesis
2. Fat Depot

12

What are the hemopoietically active bones in an Adult

1. Ribs
2. Sternum
3. Vertebral body
4. Pelvis

13

Causes of Hypoplasia/aplasia in Bone Marrow

1. Chemicals
- Cytostatic drugs
- Bracken fern
2. Radiation
3. Virus
- Feline Panleuk
4. Uremia

-Yellow Fatty Marrow

14

Causes of Serous atrophy of fat

1. Starvation
2. Cachexia (chronic infection / neoplasia)

- Pale gelatinous marrow

15

Causes of Acute Osteomyelitis

-Suppurative
- Staph aureus
-Necrotizing
- Embolic osteomyelitis

16

Causes of Chronic (Ganulomatous) osteomyelitis

1. Mycobacteriosis
2. Mycosis (coccidioides)
3. Actinomyces bovis ( lumpy jaw )

17

What is myeloproliferative dz?

Malignancy of one of the marrow stem cells
(Primary neoplasia)
- Myeloid = hemopoietic series cells
- Lymphoid = Lymphocytic

18

Neoplastic dz of marrow

Primary
-Myeloproliferative
-Lymphoma

Secondary
-mammary carcinoma
-prostatic carcinoma
-sarcomas

19

Nutritional Anemia

Non-regenerative
-Fe
-Cu
-Co
-B