Dr Gawad Physiology Course Online Exam - Blood – Course Lecture 2 - Rbcs

2.

•all the following are true concerning erythropoietin except:

•it is mainly released from the kidney.
•its main stimulus is hypoxia.
Anemia stimulate its release.
•polycythemia stimulate its release.

Correct Answer

A. •polycythemia stimulate its release.

Explanation

Erythropoietin is a hormone that stimulates the production of red blood cells. It is mainly released from the kidney and its main stimulus is hypoxia, which is a low oxygen level in the body. Anemia, which is a condition characterized by a decrease in red blood cells, stimulates the release of erythropoietin. However, polycythemia, which is the opposite of anemia and is characterized by an increase in red blood cells, does not stimulate the release of erythropoietin. Therefore, the statement "polycythemia stimulates its release" is incorrect.

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3.

•erythropoiesis:

•decrease in response to hypoxia.
•occurs mainly in the kidney of the adults.
•increase in rate with age.
•occurs in bone marrow when stimulated by erythropoietin.

Correct Answer

A. •occurs in bone marrow when stimulated by erythropoietin.

Explanation

Erythropoiesis is the process of producing red blood cells. The given answer states that erythropoiesis occurs in the bone marrow when stimulated by erythropoietin. This is correct because erythropoietin is a hormone produced by the kidneys in response to low oxygen levels in the body. It stimulates the bone marrow to produce more red blood cells, which helps to increase the oxygen-carrying capacity of the blood. Therefore, the statement accurately describes the relationship between erythropoiesis, bone marrow, and erythropoietin.

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4.

•The polypeptides in the globin part of normal adult Hb consist of:

•2 alpha and 2 beta chains.
•2 alpha and 2 gamma chains.
•2 alpha and 2 delta chains.
2 beta and 2 gamma chains.

Correct Answer

A. •2 alpha and 2 beta chains.

Explanation

The correct answer is 2 alpha and 2 beta chains. Hemoglobin (Hb) is composed of four polypeptide chains, two alpha chains and two beta chains. These chains come together to form a tetramer structure. Each chain contains a heme group, which is responsible for binding oxygen. The alpha and beta chains are essential for the normal functioning of adult Hb, allowing it to transport oxygen throughout the body. The other options, 2 alpha and 2 gamma chains, 2 alpha and 2 delta chains, and 2 beta and 2 gamma chains, do not accurately represent the composition of normal adult Hb.

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5.

•The production of erythrocytes:

Is decreased in high altitudes.
•Occurs in the spleen in normal adults.
•Is stimulated by an decrease in the arterial PO2.
•Requires the integrity of the nervous system.

Correct Answer

A. •Is stimulated by an decrease in the arterial PO2.

Explanation

The production of erythrocytes is stimulated by a decrease in the arterial PO2. This is because when the arterial PO2 decreases, it indicates that there is a lower oxygen level in the blood. In response to this, the body triggers the production of more erythrocytes, which are responsible for carrying oxygen to the tissues. This helps to increase the oxygen-carrying capacity of the blood and ensures that enough oxygen is delivered to the body's cells, especially in conditions of low oxygen availability like high altitudes. The other statements are incorrect or unrelated to the production of erythrocytes.

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6.

•Which of the following increase the affinity of Hb to O2:

Alkalosis
•increase body temperature
Increase 2,3, DPG
•None of the above

Correct Answer

A. Alkalosis

Explanation

Alkalosis increases the affinity of hemoglobin (Hb) to oxygen (O2). Alkalosis refers to a condition where the blood pH level is higher than normal, usually caused by a decrease in carbon dioxide levels or an increase in bicarbonate levels. In alkalosis, the increased pH causes a shift in the oxygen dissociation curve to the left, resulting in a higher affinity of Hb for O2. This means that Hb is more likely to bind with O2 and less likely to release it to the tissues, improving oxygenation in the body.

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7.

•which of the following is an important maturation factor for RBCs development:

•Vit B 12 & folic acid
•Vit B 12 & Vit C
•Folic acid & Vit C
•All the above

Correct Answer

A. •Vit B 12 & folic acid

Explanation

Vitamin B12 and folic acid are important maturation factors for RBCs development. Both of these vitamins play crucial roles in the synthesis of DNA, which is necessary for the proper maturation of red blood cells. Vitamin B12 is involved in the formation of red blood cells and helps in the production of DNA, while folic acid is essential for the production and maturation of red blood cells. Therefore, the correct answer is Vitamin B12 and folic acid.

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8.

•regarding iron metabolism and physiology, which of the following is incorrect:

•daily intake must be 20mg/d
•it is important for formation of Hb, myoglobin but not cytochrome enzymes
•female losses may exceed male losses especially in menstruation time
•none of the above.

Correct Answer

A. •it is important for formation of Hb, myoglobin but not cytochrome enzymes

Explanation

Iron is important for the formation of hemoglobin (Hb), myoglobin, and cytochrome enzymes. Hemoglobin is responsible for carrying oxygen in the blood, myoglobin stores oxygen in muscle cells, and cytochrome enzymes are involved in various metabolic processes. Therefore, the statement that iron is important for the formation of Hb and myoglobin but not cytochrome enzymes is incorrect. Iron is essential for the proper functioning of all three.

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Dr Gawad Physiology Course Online Exam - Blood – Course Lecture 2 - Rbcs

•all of the following increase hematocrit value except:

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•all the following are true concerning erythropoietin except:

•erythropoiesis:

•The polypeptides in the globin part of normal adult Hb consist of:

•The production of erythrocytes:

•Which of the following increase the affinity of Hb to O2:

•which of the following is an important maturation factor for RBCs development:

•regarding iron metabolism and physiology, which of the following is incorrect: