lymphoid system

Question 1

classification of lymphoid organs

Answer 1

Encapsulated – LN, thymus & spleen
Partially encapsulated - tonsils
Non-encapsulated – Peyer’s patches

Question 2

composed of non-encapsulated, localized lymphocyte infiltration and lymphoid nodules in the mucosa of the GIT, respiratory & urinary tract.

Answer 2

MALT (mucosa-associated lymphoid tissue)

Question 3

Distribution of lymphoid organs and lymphatic vessels in the body.

Found throughout the body along the course of lymphatic vessels that carry lymph into the thoracic and right lymphatic duct.

Answer 3

lymph nodes

Question 4

lymph nodes location

Answer 4

Located in the mesentery, axilla, groin, along the great vessels of the neck & in the thoraco-abdominal cavities

Question 5

lymph circulation

Answer 5

Afferent lymphatic vessels
Systems of lymph sinuses within the node
Efferent lymph vessels

Question 6

path of lymph circulation

Answer 6

Afferent lymph vessels - marginal sinus -cortical sinus paracortical sinus -medullary sinus-efferent
lymphatic vessels

Question 7

functions of the lymph node

Answer 7

Production of lymphocytes
Production of antibodies
Important role in the phagocytosis of foreign materials

Question 8

lymph node

Answer 8

The only lymph organ located in the course of lymphatic vessels

With both efferent & afferent lymphatic vessels

Only lymph organ with lymph sinuses & filters lymph

Question 9

Dense accumulation of lymphatic tissues in the tunica propria of the oral cavity and pharynx

Partially encapsulated

Lymphoid Ring of Waldeyer

Lymphocyte & anti-body production

Answer 9

tonsils

Question 10

Lined by stratified squamous epithelium

With tonsillar crypts

Salivary corpuscles

Answer 10

palatine tonsils

Question 11

Lined by pseudostrat. ciliated col. epith w/ patches of stratified squamous epithelium

With shallow infoldings (pleats)

Adenoids

Answer 11

pharyngeal tonsils

Question 12

Found in the upper portion of the tongue behind the circumvallate papillae

W/ deep & wide-mouth crypt

Lined with stratified col. epithelium

Answer 12

lingual tonsils

Question 13

Found in the tunica propria of the ileum

Lined by simple col. epithelium w/ striated border

Answer 13

peyer’s patches

Question 14

are there villi over peyer’s patches?

Answer 14

no

Question 15

With few or absent intestinal glands

Most prominent in children

Affected in TB of the intestines & Typhoid fever

Answer 15

peyer’s patches

Question 16

Major lymphatic organ

Located in the anterior mediastinum

Capsulated

Undergoes “age involution”

Answer 16

thymus

Question 17

No germinal centers

Abundant lymphocytes

Few endodermal reticular cells / thymic epithelial reticular cells

Answer 17

cortex

Question 18

Structures separating blood from the cortical tissues

Answer 18

Endothelial cells joined by occluding junction
Basal lamina of the capillary endothelium
Perivascular space
Basal lamina of the epithelial reticular cells
Thymic epithelial reticular cells (epithelial barrier)

Question 19

More epithelial reticular cells

Less lymphocytes

Hassall’s body / thymic corpuscles

Answer 19

medulla

Question 20

functions of hassall’s body

Answer 20

Lymphopoiesis

Important role in immune mechanism

        * rejection of grafts / transplants
          * Myesthenia Gravis

Question 21

Largest lymphoid organ

Found in the course of blood vessels

W/ a fibroelastic capsule with smooth muscles

Distensible

Answer 21

spleen

Question 22

Billroth cord / Pulp cord

Venous sinuses

Atypical type

Answer 22

red pulp

Question 23

receives the incoming arterial blood; first to come into contact with particulate matters and blood borne cells

Answer 23

Marginal zone

Question 24

theories

Answer 24

Open / Slow circulation theory

Closed / Rapid circulation theory

Compromise theory
(combination of open & close theories)