Episode 3 - RBCs, Blood Functions and the Reticuloendothelial System (Bone Marrow, Spleen and Liver)

Question 1

Bone marrow is found mainly in:

Answer 1

Flat bones (sternum, ribs & cranial bones)
Irregular bones (coxal bones, vertebrae and scapulae)
Epihpyses of long bones (Femur and humerus)

Question 2

In cases of sever blood loss, the body an convert ____ marrow back to ___ marrow to increase blood cell production.

Answer 2

yellow, red

Question 3

In the adult, RBCs are synthesized in the ____. in the fetus, blood cells are also formed in the ____ and ____.

Answer 3

Adult - Red Bone Marrow

Fetus - Liver and Spleen (extramedullary erythropoiesis)

Question 4

In adults, ____ may occur in diseases in which the bone marrow becomes destroyed or fibroses.

Answer 4

extramedullary erythropoiesis

Question 5

In children, blood cells are actively produced in the marrow cavities of all the bones. By approx. age 20, the marrow in the long bones, except for the ____ and ____ has become inactive.

Answer 5

upper humerus and femur

Question 6

The bone marrow contains multi potent uncommitted stem cells (pluripotent) that differentiate into one or another type of committed stem cells called ____ cells or ____ units.

Answer 6

progenitor cells

colony forming units

Question 7

Erythropoiesis is under the control of many “growth factors” the most important one being ____ which is released by the kidneys (and to a smaller extent, the liver)

Answer 7

Erythropoietin (EPO)

Question 8

RBCs enter the circulation as ____ which still contain some organelles. They remain for a few days in either the bone marrow or the spleen to mature to erythrocytes.

Answer 8

reticulocytes

Question 9

Absolute ingredients for making normal RBCs are:

Answer 9

amino acids
iron
folic acid
vitamin B12

Question 10

Erythropoietin production involves a ____ feedback loop.

Answer 10

negative

RBCs increase O2 delivery, this inhibits kidney release of EPO.

Question 11

A RBC integral protein that functions in anion transport, resulting in one-for-one exchange of bicarbonate for chloride across the membrane; also provides physical linkage of the lipid bilayer to the underlying membrane skeleton. Constitutes about 25% of total membrane protein.

Answer 11

Band 3

Question 12

Negatively charged RBC integral proteins that reduce the interaction of red cells with one another and with other cells.

Answer 12

Glycophorins

Question 13

RBC integral proteins that serve as pores for water transport.

Answer 13

Aquaporin-1

Question 14

RBC integral protein that facilitates diffusion of glucose into the cytosol of RBCs.

Answer 14

GLUT 1

Question 15

RBC integral protein that actively transports Na+ out of the RBC and K+ in.

Answer 15

Na+/K+ ATPase (pump)

Question 16

RBC integral proteins for transport of Na+, K+ and others.

Answer 16

Ion Channels & Exchangers

Question 17

The most important function of ____ proteins is to provide the red cell with a flexible, yet mechanically resilient and stable membrane.

Answer 17

peripheral

Ankyrin, Protein 4.1, Protein 4.2, Spectrin

Question 18

In humans, diseases such as _____ are caused by defects in the red cell proteins. It is characterized by the production of RBCs that are sphere-shaped rather than bi-concave disc shaped.

Answer 18

Hereditary Spherocytosis

Question 19

At a partial pressure of O2 at 100 mmHg, hemoglobin is ____ saturated; O2 is bound to all four heme groups on all hemoglobin molecules.

Answer 19

98-100%

Question 20

At a partial pressure of O2 at 40 mmHg, hemoglobin is ____ saturated which means that, on average, 3 of the 4 heme groups on each hemoglobin molecule have O2 bound.

Answer 20

75%

Question 21

At a partial pressure of O2 at 25 mmHg, hemoglobin is ____ saturated which means that, on average, 2 of the 4 heme groups on each hemoglobin molecule have O2 bound.

Answer 21

50%

Question 22

The sigmoid shape of the Hemoglobin Oxygen Dissociation Curve is a result of a change in the ____ of hemoglobin as each successive O2 molecule binds to the heme site. Called _____.

Answer 22

affinity

Positive Cooperativity

Question 23

The following RBC maintenance processes require energy:

Answer 23

Red Cell membrane integrity
Red Cell shape
Hemoglobin sulfhydryl groups maintained in reduced forms
Iron kept in reduced form
Ion gradients

Question 24

If there is insufficient energy, the RBC cannot maintain itself and it adopts a ____ shape.

Answer 24

spherical

Question 25

Erythrocyte glucose metabolism depends exclusively on _____.

Answer 25

cytosolic proteins

Question 26

3 important products of glucose metabolism are:

Answer 26

ATP
NADH
NADPH

Question 27

____ is required to maintain Hemoglobin’s iron in the ferrous (reduced) state.

Answer 27

NADH

Question 28

____ is required to maintain glutathione on the RBC membrane in its reduced form; reduced glutathione appears to be essential for maintaining normal red-cell structure and normal Hgb

Answer 28

NADPH

Question 29

____ is the main source of energy for maintaining RBC ion gradients.

Answer 29

ATP

Question 30

Through glycolysis, one molecule of glucose yields ___ molecules of ATP and ___ molecules of NADH.

Answer 30

2, 2

Question 31

NADPH is produced through a process called the ____ (also called the ____) which is linked to glycolysis through ____.

Answer 31

Pentose Phosphate Pathway (also called the Hexose Monophosphate Shunt)

glucose-6-phosphate

Question 32

The Pentose Phosphate Pathway is kicked off when Glucose-6-phosphate interacts with the enzyme ____ which yields a byproduct of ____.

Answer 32

Glucose-6-phosphate dehydrogenase

NADPH

Question 33

Dead or deteriorating RBCs are removed from circulation by the ____ or ____. The waste product of RBC degradation is ____.

Answer 33

Liver or spleen

Bilirubin

Question 34

The 3 major buffers in the blood are:

Answer 34

Carbonic Acid - Bicarbonate
Phosphate
Protein (hemoglobin, albumin)

Question 35

How does blood act as a temperature regulator?

Answer 35

In cold temperatures the SNS stimulates vascular smooth muscle of skin blood vessels to constrict. Decreased blood flow to the surface of skin reduces heat loss.

In warm temperatures the SNS is inhibited causing vascular smooth muscle of skin blood vessels to vasodilator. Increased blood flow to the surface of the skin increases heat loss by radiation and convection. Shunting of blood to the surface is evidenced by redness and warmth of skin.