BPK 110 Chapter Notes - Chapter 12: Iron Poisoning, Myelin, Red Blood Cell

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sapphiresnake846

19 Sep 2012

School

Simon Fraser University

Department

Biomedical Physio & Kines

Course

BPK 110

Professor

Leah Esplen

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Document Summary

Kin 110 chapter 12 trace minerals. Total amount found in body less than 5grams. Most common deficiency in world: 6-24month old children. 2 types of iron: hemeiron (animal sources, 2-3 times more absorbed) and nonheme (plant sources) Hemochromatosis: disease of excess iron absorption: inherited disorder. Changes to ferrous iron and ferric iron: ferrous iron: reduced form of iron most commonly in food, ferric iron: oxidized form of iron which may be bound to transferring for transport, controlled by gastric acid. Iron is a component of two heme proteins, hemoglobin and myoglobin (oxygen transporting protein of muscle that resembles blood hemoglobin in function) Myoglobin facilitates movement of oxygen into muscle cells: enzymes. Cytochromes: heme-containing compounds critical to the electron transport chain. Cofactor for antioxidant enzymes: immune function, brain function. Myelinization: development of myelin sheath around nerves. Regulation: absorbed in intestine, stored as ferritin or hemosiderin, carried away by transferrin.

Related Questions

Iron Metabolism Case Study

A 54-year old man complains of weakness, lassitude, and moderate weight loss (20 kg in the previous 7 mo). Pulse and respiratory rates were normal, as were the electrocardiographic and chest roentgenographic studies. Blood pressure was 145/75 mm Hg. The liver was firm and moderately enlarged, and the spleen was palpable. The patient remarked that his skin had become darker during the past few years, a change he attributed to time spent outdoors. The patient denied exposure to toxic chemicals or metal fumes. Laboratory results were as follows:

Fasting serum glucose	100 mg/dL (5.6 mmol/L)
Random urine glucose	Normal
Hemoglobin	17 g/dL (2.55 mmol/L)
Hematocrit	52%
Methemoglobin	Not detectable
Serum iron	2.4 mg/dL (43 umol/L)
Total serum iron-binding capacity	3.14 mg/dL (56 umol/L); ~77% saturation
Total serum bilirubin content	1.17 mg/dL (20umol/L)

On the basis of these observations, a biopsy of the liver was performed. Microscopic examination revealed fatty vacuolization of the hepatocytes and moderate deposits of hemosiderin in the cytoplasm of the cells. A diagnosis of hemochromatosis was made; the iron overload was later confirmed by a differential deferoxamine test.

BIOCHEMICAL QUESTIONS:

Define specialized terms.

Note the significance of quantities given and compare to normal values.

What foodstuffs are particularly rich sources of iron? Should this patient be advised to avoid these?

In what form is iron absorbed from the gastrointestinal tract? How is this absorption regulated?

How is iron transported in the blood? What proteins are involved in iron transport and storage?

What is the normal disposition of excess iron?

Explain why repeated phlebotomy is used to reduce the body burden of iron.

purplemallard200

Which statements about mineral bioavailabilty are true?

	A.	Vitamin E increases the bioavailability of calcium.
	B.	Ascorbic acid decreases the bioavailability of none-heme iron.
	C.	Non-heme iron is absorbed better than heme iron.
	D.	Phytate decreases the absorption of some minerals.

What is the best route to maintain adequate intakes of copper, cobalt, chromium, manganese and molybdenum?

	A.	Take a mineral supplement that contains 200% RDA for all 5 minerals every other day.
	B.	Drink water that has not been âsoftenedâ chemically
	C.	Eat foods that have not been heavily processed such as whole grains.
	D.	Use enriched bread and cereal products.

Identify correct functions for the minerals listed below.

	A.	phosphorus: component of niacin compound
	B.	chloride: component of gastric acid
	C.	sulfur: part of teeth and bones
	D.	calcium: coenzyme

orangeeel431

1. The dominant motif found in hemoglobin and myoglobin is: a) twisted beta sheet b) beta barrel c) helix-loop-helix d) 7-TM 2. Myoglobin has how many polypeptide chains? A) 1 b) 2 c) 3 d) 4 3. Structurally and functionally, hemoglobin closely resembles a(n) a) transmembrane protein b) mucopolysaccharide c) bile salt d) allosteric enzyme 4. The oxygen binding site in hemoglobin and myoglobin is called: a) BPG b) heme c) proximal-His d) N-terminal carbamate 5. The proximal His residue in hemoglobin and myoglobin binds to which atom or molecule? A) CO2 b) O2 c) Fe d) BPG 6. The distal His residue in hemoglobin and myoglobin binds to which atom or molecule? A) CO2 b) O2 c) Fe d) BPG 7. BPG binds to: a) N-terminal carbamate b) proximal His c) heme group d) central cavity 8. Indirect activity of CO2 is a result of increased concentration of which chemical species? A) BPG b) H+ c) heme iron d) distal His 9. Direct activity of CO2 is a result of binding to which molecular feature? A) the heme group b) the N-terminal ends of the 4 polypeptide chains c) the central cavity d) the proximal His 10. The sigmoidal, cooperative binding curve commonly observed for hemoglobin is a result of: a) competition between CO2 and O2 for heme binding. B) competition between heme and distal His for O2 binding c) competition between BPG and CO2 for binding at the central cavity site d) T to R transition 11. Hemoglobin has a tendency to release its oxygen to the tissues because: a) in this region pH is high and O2 concentrations are low b) in this region both pH and O2 concentrations are low c) in this region both pH and O2 concentrations are high d) there is much BPG in this region 12. Which statement about fetal hemoglobin is not true? A) fetal hemoglobin has gamma chains instead of beta chains b) fetal hemoglobin binds BPG less strongly than maternal hemoglobin c) fetal hemoglobin binds oxygen less strongly than maternal hemoglobin d) fetal hemoglobin binds oxygen more strongly than maternal hemoglobin 13. Which process is most responsible for the sickling of cells seen in sickle cell disease? A) aggregation of the oxygenated R form of hemoglobin-S to form insoluble fibers b) aggregation of the deoxygenated T form of hemoglobin-S to form insoluble fibers c) Hemoglobin-S does not contain heme d) Hemoglobin-S contains a mutant form of heme which will not bind oxygen 14. A person with sickle-cell trait is very unlikely to catch which disease? A) malaria b) colon cancer c) avian flu d) whooping cough 15. A person with a genetic defect which results in the synthesis of an insufficient amount of the alpha chain of hemoglobin is said to have which disease? A) alpha thalassemia b) beta thalassemia c) pernicious anemia d) Crohnâs disease

BPK 110 Chapter Notes - Chapter 12: Iron Poisoning, Myelin, Red Blood Cell

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