Immunology USMLE Step 1 | 178 Questions and
Answers with Complete Solutions | Graded A+ | New
Update 2025
Where is the site of b-cell localization in lymph nodes? - ANSWER Follicle
(within the cortex)
Secondary follicles with pale central germinal centers are inactive/acitve? -
ANSWER active
Primary follicles are dense and inactive/active? - ANSWER inactive
Where are T-cells house in the thymus? - ANSWER paracortex
High endothelial venules containing B-cells and T-cells lie in what region of lymph
nodes? - ANSWER Paracortex
Lymph drainage: Upper limb, Breast - ANSWER Axiallry LN
Lymph drainage: Stomach - ANSWER Celiac LN
Lymph drainage: Duodenum, Jejunum - ANSWER Superior Mesenteric LN
Lymph drainage: Sigmoid Colon - ANSWER Inferior Mesenteric LN
,Lymph drainage: Rectum (above the pectinate line) - ANSWER Internal Iliac LN
Lymph drainage: Anal canal (below the pectinate line) - ANSWER Superficial
Inguinal LN
Lymph drainage: Testes - ANSWER Para aortic LNs (note: don't biopsy testes
b/c testes have different lymph drainage from scrotum so you can seed cancerous
cells from one to the other)
Lymph drainage: Scrotum - ANSWER Superficial Inguinal LN
Lymph drainage: Thigh - ANSWER Superficial Inguinal LN
Lymph drainage: Lateral side of dorsum of the foot - ANSWER Popliteal LN
Lymph drainage: Umbillicus to feet (excluding lateral dorsum of foot and posterior
calf) - ANSWER Superficial Inguinal LN
Lymph from the right arm and the right side of the head drain into _______. -
ANSWER Right lymphatic duct which drains into the right subclavian vein
Where are T-cells found in the spleen? - ANSWER Periarterial Lymphatic
Sheath (PALS) and the white pulp.
Asplenia leads to suscepetibilty to what 4 organisims? - ANSWER "SSHiN-
encapsulated" Samonella, Strep pneumo, H. flu, Nessiera meningitidis
, Following what procedure do you find howell-jolly bodies, target cells and
thrombocytosis? - ANSWER Splenectomy
What structure arises from the 3rd brachial pouch? - ANSWER Thymus
Where does postive selection and negative selection take place in the thymus for
T cells? - ANSWER corticomedullary junction (note: hassall's corpuscles are
also present here)
How does Asplenia lead to susceptibility to encapsulated organisms? -
ANSWER you get a decrease in IgM, leads to decreases complememnt
activation (via classic pathway), leading to a decrease in C3b opsonization thus
leading to increased suceptibility to encapsulated bacteria
HLA-A, HLA-B, HLA-C code for what type of major histocompatibility complex? -
ANSWER MHC I
HLA-DR, HLA-DQ, HLA-DP code for what type of major histocompatibility
complex? - ANSWER MHC II
HLA B7 is associated with what diesase(s)? - ANSWER Psoriasis, Ankylosising
Spondylitis, IBD, Reiter's syndrome (Reactive Arthritis-ureitis, conjunctivitis,
athritis)
HLA D3 is associated with what disease(s)? - ANSWER DM1
Answers with Complete Solutions | Graded A+ | New
Update 2025
Where is the site of b-cell localization in lymph nodes? - ANSWER Follicle
(within the cortex)
Secondary follicles with pale central germinal centers are inactive/acitve? -
ANSWER active
Primary follicles are dense and inactive/active? - ANSWER inactive
Where are T-cells house in the thymus? - ANSWER paracortex
High endothelial venules containing B-cells and T-cells lie in what region of lymph
nodes? - ANSWER Paracortex
Lymph drainage: Upper limb, Breast - ANSWER Axiallry LN
Lymph drainage: Stomach - ANSWER Celiac LN
Lymph drainage: Duodenum, Jejunum - ANSWER Superior Mesenteric LN
Lymph drainage: Sigmoid Colon - ANSWER Inferior Mesenteric LN
,Lymph drainage: Rectum (above the pectinate line) - ANSWER Internal Iliac LN
Lymph drainage: Anal canal (below the pectinate line) - ANSWER Superficial
Inguinal LN
Lymph drainage: Testes - ANSWER Para aortic LNs (note: don't biopsy testes
b/c testes have different lymph drainage from scrotum so you can seed cancerous
cells from one to the other)
Lymph drainage: Scrotum - ANSWER Superficial Inguinal LN
Lymph drainage: Thigh - ANSWER Superficial Inguinal LN
Lymph drainage: Lateral side of dorsum of the foot - ANSWER Popliteal LN
Lymph drainage: Umbillicus to feet (excluding lateral dorsum of foot and posterior
calf) - ANSWER Superficial Inguinal LN
Lymph from the right arm and the right side of the head drain into _______. -
ANSWER Right lymphatic duct which drains into the right subclavian vein
Where are T-cells found in the spleen? - ANSWER Periarterial Lymphatic
Sheath (PALS) and the white pulp.
Asplenia leads to suscepetibilty to what 4 organisims? - ANSWER "SSHiN-
encapsulated" Samonella, Strep pneumo, H. flu, Nessiera meningitidis
, Following what procedure do you find howell-jolly bodies, target cells and
thrombocytosis? - ANSWER Splenectomy
What structure arises from the 3rd brachial pouch? - ANSWER Thymus
Where does postive selection and negative selection take place in the thymus for
T cells? - ANSWER corticomedullary junction (note: hassall's corpuscles are
also present here)
How does Asplenia lead to susceptibility to encapsulated organisms? -
ANSWER you get a decrease in IgM, leads to decreases complememnt
activation (via classic pathway), leading to a decrease in C3b opsonization thus
leading to increased suceptibility to encapsulated bacteria
HLA-A, HLA-B, HLA-C code for what type of major histocompatibility complex? -
ANSWER MHC I
HLA-DR, HLA-DQ, HLA-DP code for what type of major histocompatibility
complex? - ANSWER MHC II
HLA B7 is associated with what diesase(s)? - ANSWER Psoriasis, Ankylosising
Spondylitis, IBD, Reiter's syndrome (Reactive Arthritis-ureitis, conjunctivitis,
athritis)
HLA D3 is associated with what disease(s)? - ANSWER DM1
