Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
34 Cards in this Set
- Front
- Back
|
spleen specs |
150 g; enclosed in thin, glistening, slate-gray CT capsule; extenisve red pulp dotted with gray specs (white pulp follicles) |
|
|
splenic pulp
|
artery with eccentric collar of T lymphocytes-expands to form lymphoid nodules composed mainly of B cells |
|
|
red pulp transversed by
|
numerous thin-walled vascular sinusoids, separated by splenic cords or 'cords of Billroth' |
|
|
endothelial lining of sinusoids
|
discontinuous-provides passage for blood cells btwn sinusoids and cords
|
|
|
cords of spleen contain
|
labyrinth of macrophages loosely connected through long dendritic processes to create both physical and fxnal filter |
|
|
spleen 4 fxns that impact disease states
|
1) phagocytosis of blood cells and particulate matter 2) antiboy production 3) hematopoiesis 4) sequestration of formed blood elements |
|
|
platelets and speen
|
normally harbors 30-40% total platelet mass; with splenomegaly up to 80-90% platelet mass can be sequestered in interstices of red pulp producing thrombocytopenia |
|
|
main bacteria patients susceptible to after splenectomy
|
pneumococcus, meningococcus, and Haemophilus influenzae |
|
|
hypersplenism
|
anemia, leukopenia, thrombocytopenia, alone or in combination; likely due to sequestration and enhanced phagocytosis |
|
|
nonspecific acute splenitis
|
occurs in any blood-borne infection |
|
|
nonspecific acute splenitis morphology
|
acute congestion of red pulp which may encroach on and virtually eface the lymphoid follicles |
|
|
congestive splenomegaly
|
chromic venous outflow obstruction-intrahepatic disorders, extrahepatic disorders impinging on portal or splenic veins, cardiac decompensation, pulmonary |
|
|
congestive splenomegaly morphology
|
firm, capsule thickened and fibrous; red pulp congested early, but increasingly fibrotic and cellular with time |
|
|
bland infarcts of spleen
|
pale, wedge-shaped, subcapsular in location; overlying capsule often covered with fibrin |
|
|
septic infarcts of spleen
|
dvlp suppurative necrosis-in course of healing large, depressed scars often dvlp |
|
|
most common neoplasm ariseing in spleen
|
lymphangiomas and hemagiomas-often cavernous type
|
|
|
accessory spleens
|
20-35% postmortem exams; small, spherical structures histologically identical to normal spleen |
|
|
where are accessory spleens found
|
within abdominal cavity
|
|
|
most common predisposing factor to splenic rupture
|
mono, malaria, typhoid fever, lymphoid neoplasms |
|
|
thymus dvlps from
|
3rd and inconstantly 4th pair of pharyngeal pouches |
|
|
cortical. Epithelial, and peripheral cells in thymus
|
polygonal in shape and have abundant cytoplasm with dendritic extensions that contact adjacent cells
|
|
|
epithelial cells in medulla of thymus
|
densely packed, often spindle-shaped, and have scant cytoplasm devoid of interconnecting processes |
|
|
myoid cells
|
muscle-like; may play role in myasthenia gravis |
|
|
DiGerorge syndrome
|
thymic hypoplasia/aplasia, variable parathyroid dvlp associations; 22q11 deletion syndrome
|
|
|
thymic cysts
|
usually discovered incidentally
|
|
|
thymic follicular hyperplasia
|
appearance of B-cell germinal centers within thymus
|
|
|
when is thymic hyperplasia most commonly seen
|
myasthenia gravis (65-75% cases); sometimes Graves', Lupus, scleroderma, RA, and other autoimmune diseases
|
|
|
thymomas
|
tumor of thymic epithelial cells
|
|
|
3 histological subtypes of thymomas
|
1) clinically benign and noninvasive 2) benign, but invasive/metastatic 3) cytologically malignant
|
|
|
morphology of thymoma
|
lobulated, firm, gray-white masses up to 15-20 cm; sometimes areas of cystic necrosis and calcification; most encapsulated
|
|
|
noninvasive thymomas
|
medullary-type epithelial cells or mixture with cortical-type epithelial cells; 50% thymomas
|
|
|
invasive thymoma
|
cytologically benign, locally invasive; usually cortical variety with abundant cytoplasm and rounded vesicular nuclei; 20-25% thymomas
|
|
|
thymic carcinoma
|
5% thymomas; usually fleshy, most squamous cell carcinomas,
|
|
|
lymphoepithelioma-like carcinoma
|
rare thymic carcinoma with sheets of cells with indistinct borders-close histological resemblance to nasopharyngeal carcinoma; 50% EBV
|
