PRELIM: Hemoglobin and Iron Kinetics (2)

Decreased affinity with a right shift

A patient develops a fever and increased carbon dioxide levels. What change in hemoglobin oxygen affinity would be expected based on the lecture?

Alkalosis

Which condition is associated with a left shift of the oxygen dissociation curve?

HbF

Which hemoglobin type is associated with a left shift of the oxygen dissociation curve?

Alkalosis, HbF, and carbon monoxide poisoning

Which combination is associated with a left shift according to the lecture?

Alkalosis

Which condition would be expected to produce the opposite direction from a fever-induced shift?

Diet → absorption → transport → bone marrow → hemoglobin → RBC destruction → recycling

Which sequence best describes the general movement of iron through the body?

Heme iron

Which type of dietary iron generally has the higher absorption percentage?

Meat, fish, and poultry

Heme iron is primarily obtained from:

15–35%

What is the approximate absorption range for heme iron given in the lecture?

Vegetables, cereals, and beans

Non-heme iron is commonly obtained from:

2–10%

What is the approximate absorption range for non-heme iron?

Duodenum and upper jejunum

Where does most intestinal iron absorption occur according to the lecture?

DMT1 (divalent metal transporter 1)

Which protein is involved in intestinal iron absorption?

Allows iron to be released from cells

What is the primary role of ferroportin in iron metabolism?

Intestinal iron absorption

Hephaestin is associated with which part of iron handling?

Intestinal iron uptake

A defect affecting DMT1 (divalent metal transporter 1) would most directly affect which process?

Transferrin

Which protein is the major transport protein for iron in the blood?

Fe³⁺

Transferrin primarily carries which form of iron?

• Carrying Fe³⁺

• Delivering iron to the bone marrow

• Helping prevent iron toxicity

Which are listed function of transferrin?

Transferrin

A patient requires iron for erythrocyte production. Which protein delivers circulating iron toward the bone marrow?

Ferritin

Which form of stored iron is soluble and readily available?

Hemosiderin

Which form of stored iron is insoluble and is stored in macrophages?

Liver, spleen, and bone marrow

Which group contains the storage sites listed for iron?

Ferritin

A laboratory test is used to estimate the body's iron stores. Which test is most directly associated with iron stores?

Macrophages

Old red blood cells (RBCs) are destroyed and their iron is recycled primarily through:

120 days

Approximately how long do old RBCs circulate before being destroyed, according to the lecture?

It is recycled for production of new erythrocytes.

Which statement best describes what happens to iron after old RBC destruction?

Recycling for new erythrocyte production

A macrophage has broken down an old RBC. What is the most appropriate next step for the iron released from the RBC?

Liver

Which organ produces hepcidin?

Master regulator of iron metabolism

Hepcidin is best described as the: