Path Flashcards
(18 cards)
What is the role of transferrin in iron transport?
Transferrin binds to iron absorbed through diet or released from circulation
Transferrin is known as the iron transfer protein.
What happens to iron-transferrin complexes during erythropoiesis?
They act as transferrin receptors on bone marrow erythroid cells and are internalized through receptor-mediated endocytosis
This process makes iron available for heme synthesis.
What occurs to the transferrin-receptor complex after iron is internalized?
It is recycled to the cell surface, releasing transferrin back into circulation
The transferrin receptor re-anchors into the cell membrane.
What happens to excess iron after hemoglobin synthesis?
It binds to apoferritin, forming ferritin
Ferritin serves as an iron storage protein.
What process do senescent RBCs undergo in the reticuloendothelial system?
They are phagocytosed and their hemoglobin is broken down
Globin and other proteins are returned to the amino acid pool.
How is iron transported back to transferrin after the breakdown of hemoglobin?
Iron is shuttled to the surface of the reticuloendothelial cell and taken up by transferrin via ferroportin
Ferroportin is an iron export channel.
What are the primary mechanisms by which iron is lost from the body?
Blood loss and loss of epithelial cells
Blood loss can occur via gastrointestinal bleeding, menstruation, or other forms of bleeding.
What is the normal daily iron loss from the body?
1-2 mg
There is no regulated excretory pathway for iron.
What happens to transferrin receptor mRNA concentration in iron deficiency anemia?
There is an increase in transferrin receptor mRNA concentration and synthesis
This is a compensatory response to iron deficiency.
Fill in the blank: The excess iron after hemoglobin synthesis binds to _______ to form ferritin.
apoferritin
True or False: The body has a regulated pathway for iron excretion.
False
Iron loss occurs only through blood loss and epithelial cell turnover.
What is the characteristic biopsy picture of schwannoma?
Hypocellular (Antoni B) and hypercellular areas (Antoni A)
The Antoni A area has nuclei of tumor cells aligned in palisading rows.
What are Verocay bodies?
Nuclear-free zones that lie between nuclear palisading in schwannoma
They are found in the Antoni A areas of schwannoma.
What is the correct term for the tumor type represented by the biopsy findings in the question?
Schwannoma
Which areas are present in a schwannoma biopsy?
- Antoni A
- Antoni B
- Verocay bodies
True or False: Schwannoma is characterized by only hypercellular areas.
False
Fill in the blank: The nuclei of tumor cells in Antoni A areas are aligned in _______.
palisading rows
Which tumor type is characterized by the presence of both hypocellular and hypercellular areas?
Schwannoma
