Lecture 8 Flashcards
Lymph nodes are capsules of what kind of cells?
White blood cells
Which direction does the lymph flow?
One way towards the circulatory system
What prevents the lymph from flowing back?
Unidirectional valves
What may happen to lymph nodes when they are fighting an infection?
They may inflame and become enlarged
Lymph fluid is received by a lymph node by which lymphatic vessels? (afferent/efferent)
Afferent
Where does lymph fluid first collect upon entering the node?
At the capsule
How is lymph filtered?
It is filterled as it percolates from the capsule down to and around nodules of lymphocytes
Where is filtered lymph collected inside a node?
the medulla
Via what kind of lymphatic vessel does the filtered lymph leave the medulla?
Via an efferent lymphatic vessel
Where does the efferent lymphatic vessel exit the node?
At the hilum of the node
Does each lymph node have a vascular supply? What does this blood supply perfuse with?
Yes. The blood supply perfuses (permeates) each of the lymphatic nodules
What can the size of most lymph nodes be compared to?
The size of a rubber eraser on a pencil
What would a node feel like if it was compressed?
Spongy/foamy/rubbery
Why are the best lymph nodes the ones that grow quickly and hurt?
Because they send an immediate signal for attention. If the nodes grow slowly the body will adapt to the growing size and the signal for attention will be attenuated
T/F Lymph nodes are water-tight?
True
What keeps lymph moving through the lymphatic system?
Physical movement
Which part of the lymph node are follicles (nodules) of lymphocytes found?
Cortex
Why isn’t gravity sufficient to move lymph?
Lymph nodes are too spongy for that
Where are germinal centers found in the lymph node?
In the middle of a follicle
What does a lighter colored center of a follicle mean?
Means they are more active due to lymphocyte proliferation
T/F Lymph nodes, tonsils, thymus, spleen, and adenoids are all part of the lymphatic system?
True
Why are tonsils classified as unencapsulated? Is this an accurate description?
They have an incomplete CT capsule.
A more accurate classification would be partially-capsulated
What type of tissue covers the surface of tonsils?
A thin squamous epithelium
Where is the partial capsule of tonsils located relative to the epithelial surface layer?
The partial capsule is underneath the epithelial surface layer
How do adenoids differ from tonsils?
Adenoids are tonsils in the roof of the nasal pharynx; tonsils proper are in the back of your throat, one on each side (known as palatine tonsils)
What is the Waldeyer ring?
AKA Tonsillar ring: It is the lymphatic tissue that surrounds the posterior orifice of the oral and nasal cavities and contains clusters of lymph nodules
What are the four main tonsils that compose the Waldeyer ring?
Pharyngeal, tubal, palatine, and lingual
Mnemonic: Pucker That Pretty Lip
Where are tubal tonsils located?
Lateral walls of the nasopharynx posterior to the opening of the auditory tube
Which tonsils are known as “the” tonsils since you can more easily see them?
Palatine tonsils
Where is the lingual tonsil located?
In the base of the tongue
Which tonsils help to fight middle ear infections?
Tubal tonsils
What is the deep aspect of each palatine tonsil isolated by from the surrounding CT?
A dense fibrous tissue
What kind of tissue covers the superficial aspect of the tonsils?
Nonkeratinized SSE
What are the dips of the superficial aspect of the tonsils called?
Crypts
About how many crypts to palatine tonsils have?
10-12
How deep do to the crypts penetrate into a tonsil?
To the parenchyma
What may be found inside the tonsillar crypts?
Food debris, dead leukocytes, bacteria, and other antigenic substances
What kind of follicles compose the tonsil tissue? What is in the middle of many follicles?
Lymphoid follicles. The middle contains germinal centers indicative of active B-cell formation
Why is otitis media (middle ear infection) more common in children?
Because of the more horizontal orientation of the Eustachian tube at that age.
What may result if food is trapped in tonsillar crypts?
Halitosis
T/F Sialoliths are the result of debris trapped in tonsillar crypts.
FALSE. Sialoliths form in salivary glands. Tonsilloliths are the result of debris trapped in tonsillar crypts
Do tonsils have a cortex or medulla?
No
What kind of glands secrete into the crypts of the lingual tonsils?
Mucous
Why do mucous glands secrete mucus into the crypts of the lingual tonsil?
To cleanse them, especially during an infection
