Module 2: Blood Chapter 10

Question 1

What is blood composed of?

Answer 1

Specialized cells (such as leukocytes, erythrocytes, and platelets) suspended in plasma

Question 2

What is hematocrit?

Answer 2

The volume of blood occupied by cells - determined through centrifugation

Question 3

What is the buffy coat?

Answer 3

Part of blood composed of leukocytes (WBC’s) and platelets: makes up <1%

Question 4

Blood plasma is composed of 90% ______ which serves as a transport medium for the cellular components of blood as well as for:

1. _____
2. _____
3. _____
4. _____
5. _____
6. _____

Answer 4

Blood plasma is composed of 90% water which serves as a transport medium for the cellular components of blood as well as for:

1. electrolytes
2. nutrients
3. gases
4. plasma proteins
5. wastes
6. hormones

Question 5

What is the function of the following blood constituent:

• Water:

Answer 5

Water serves as a transport medium and also carries heat

Question 6

What is the function of the following blood constituent:

Electrolytes:

Answer 6

• Membrane excitability
• osmotic distribution of fluid between the ECF and ICF
• buffer pH changes

Question 7

What is the function of the following blood constituent:

Nutrients, wastes, gases, hormones:

Answer 7

Transported in the blood;

The blood gas CO₂ plays a role in acid base balance

Question 8

What is the function of the following blood constituent:

plasma proteins:

Answer 8

• In general, exert an osmotic effect important in the distribution of ECF between the vascular and interstitial compartments
• Buffers pH changes

Question 9

What is the function of erythrocytes (red blood cells)?

Answer 9

Transport O₂ in the circulatory system

Question 10

How is the shape of erythrocytes (red blood cells) related to their function?

Answer 10

• A mature erythrocyte has a biconcave shape, which increases its surface area,
• a thin and flexible membrane, which allows for movement of the erythrocyte through vessels with small diameters, and
• no nucleus or organelles, which allows more intracellular space for hemoglobin.

Question 11

There are more than 250 million molecules of haemoglobin in each erythrocyte.

Each haemoglobin molecule is composed of four ________\_(called the globin portion), each of which binds to a heme group. Each heme group contains an _____\_, which binds an O2 molecule and appears red in colour when O2 is bound (e.g., in systemic arterial blood), and appears blue in colour when O2 is not bound (e.g., in systemic venous blood)

Answer 11

There are more than 250 million molecules of haemoglobin in each erythrocyte.

Each haemoglobin molecule is composed of four polypeptide chains (called the globin portion), each of which binds to a heme group. Each heme group contains an iron ion, which binds an O2 molecule and appears red in colour when O2 is bound (e.g., in systemic arterial blood), and appears blue in colour when O2 is not bound (e.g., in systemic venous blood)

Question 12

The majority of adult hemoglobin is composed of two ____\_and two ____\_ _____\_ ______.

Answer 12

The majority of adult hemoglobin is composed of two alpha and two beta polypeptide chains.

Question 13

Haemoglobin also combines with

• • ,
• _______, and
• _________.

Answer 13

Haemoglobin also combines with

• carbon dioxide (CO2),
• hydrogen ions (H+),
• carbon monoxide (CO2), and
• nitric oxide (NO).

Question 14

In addition to containing haemoglobin, erythrocytes contain

• _____\_ and
• the enzyme ______\_

Answer 14

In addition to containing haemoglobin, erythrocytes contain

• glycolytic enzymes and
• the enzyme carbonic anhydrase.

Question 15

Glycolytic enzymes are important in erythrocytes why?

Answer 15

Erythrocytes lack organelles = thus lack a mitochondria = depend on glycolytic enzymes for energy production

Question 16

What is the purpose of Carbonic anhydrase in erythrocytes?

Answer 16

Carbonic anhydrase catalyzes the rxn required to convert CO₂ into bicarbonate (HCO₃^-) which is the primary form that CO₂ is carried in the blood

Question 17

Define erythropoiesis

Answer 17

The process of erythrocyte production

Question 18

Describe erythropoiesis

Answer 18

Erythropoiesis takes place in the RED BONE MARROW at a rate of 2-3million erythrocytes/second

• In the red bone marrow, pluripotent stem cells can be stimulated to differentiate into erythrocytes, leukocytes or platelets

Question 19

Blood cells and blood cell precursors:

In the bone marrow, undifferentiated __________\_ are the precursor cells to all blood cells.

These multipotent stem cells differentiate into a _______\_line and a _________\_ line.

Myeloid stem cells will further differentiate to produce ______\_, ______\_, ______\_and ______\_.

Lymphoid stem cells will further differentiate to produce ___________.

Answer 19

Blood cells and blood cell precursors:

In the bone marrow, undifferentiated multipotent stem cells are the precursor cells to all blood cells.

These multipotent stem cells differentiate into a myeloid stem cell line and a lymphoid stem cell line.

Myeloid stem cells will further differentiate to produce platelets, erythrocytes, granulocytes and monocytes.

Lymphoid stem cells will further differentiate to produce lymphocytes.

Question 20

What hormone stimulates erythropoiesis? Where is the hormone released from?

Answer 20

The kidneys respond to low O₂ levels in the blood and release the hormone erythropoietin

Question 21

Describe what is occurring in the image:

Answer 21

Describe what is occurring in the image:

1. kidneys detect reduced O₂ - carrying capacity of the blood
2. When less O₂ is delivered to the kidneys, they secrete the hormone erythropoietin into the blood
3. Erythropoietin stimulates erythropoiesis (erythrocytes production) by the bone marrow
4. Additional circulating erythrocytes increase the O₂ carrying capacity of the blood
5. Increased O₂ - carrying capacity relieves the initial stimulus that triggered erythropoietin secretion

Question 22

The reduction of the O2 carrying capacity is called?

Answer 22

Anaemia

Question 23

What is anaemia characterized by?

What are six causes?

Answer 23

Anaemia is characterized by low hematocrit

It has many causes, six of which are:

1. Nutritional anemia → results from a dietary deficiency of a factor required for erythropoesis, such as iron
2. Pernicious anemia → results from insufficient folic acid or vitamin B12
3. Aplastic anemia → results from failure of the bone marrow to maintain an appropriate rate of erythropoeisis
4. Renal anemia → results from insufficient production of erythropoietin by the kidneys
5. Hemorrhagic anemia → results from excessive blood loss
6. Hemolytic anemia → results from premature rupture of erythrocytes, such as in sickle cell disease

Question 24

What is polycythemia?

Answer 24

elevated hematocrit

Question 25

What is the difference between Primary Polycythemia and Secondary Polycythemia?

Answer 25

Primary Polycythemia: caused by increased rates of erythropoiesis that occur in an unregulated manner

Secondary Polycythemia: increased rates of erythropoiesis that occurs as an adaptive mechanism in response to a prolonged reduction in O2 delivery to the tissues

Question 26

What is relative polycythemia?

Answer 26

Refers to a loss of plasma, such as from severe dehydration which also increases the hematocrit

Question 27

In the image, what is being depicted in each test tube:

Answer 27

Question 28

At the end of their lifespan, the majority of erythrocytes are removed from circulation in the _____\_

Answer 28

At the end of their lifespan, the majority of erythrocytes are removed from circulation in the spleen

Question 29

Explain the image showing the lifecycle of an erythrocyte?

• The life cycle of an erythrocyte begins in the bone marrow with ____\_, a process stimulated by ____\_.
• Erythropoietin is released by the ____\_in response to a _____ _____-_____ ____\_ of the blood.
• Upon production, erythrocytes are released into circulation. The average time for an erythrocyte to remain in circulation is 120 days.
• Old erythrocytes are primarily catabolized in the ____\_. Erythrocyte degradation produces ____\_ and ____\_.
• The globin is further degraded into ____\______\__ which are released into the blood for reuse.
• The heme is further degraded into iron and ____\_.
• Iron is released from the spleen and transported in the blood as - ____\_, bound to a protein called ____\_.
• This iron, as well as iron absorbed from the diet or released from F-iron (iron bound to the protein ferritin) stores in the liver, will be used to form new ____\_ in the bone marrow.
• Bilirubin is released from the spleen and transported in blood to the ____\_where further catabolism occurs with the degradation products being secreted in the ____\_ to the ____\_and to the ____\_.

Answer 29

Explain the image showing the lifecycle of an erythrocyte?

• The life cycle of an erythrocyte begins in the bone marrow with erythropoiesis, a process stimulated by erythropoietin.
• Erythropoietin is released by the kidneys in response to a reduced oxygen-carrying capacity of the blood.
• Upon production, erythrocytes are released into circulation. The average time for an erythrocyte to remain in circulation is 120 days.
• Old erythrocytes are primarily catabolized in the spleen. Erythrocyte degradation produces heme and globin.
• The globin is further degraded into amino acids which are released into the blood for reuse.
• The heme is further degraded into iron and bilirubin.
• Iron is released from the spleen and transported in the blood as T-iron, bound to a protein called transferrin.
• This iron, as well as iron absorbed from the diet or released from F-iron (iron bound to the protein ferritin) stores in the liver, will be used to form new hemoglobin in the bone marrow.
• Bilirubin is released from the spleen and transported in blood to the liver where further catabolism occurs with the degradation products being secreted in the bile to the small intestine and to the kidneys.