Episode 3 RBCs, Blood Functions, and the Reticuloendothelial System

Question 1

Where and at what rate are RBCs synthesized?

Answer 1

Bone marrow at 200 Billion per day

Question 2

Where in the fetus are RBCs synthesized?

Answer 2

Liver and spleen

Question 3

Where is yellow marrow found?

Answer 3

In the medullary cavity (middle of long bones)

Question 4

What does a stem cell become once it is committed?

Answer 4

Colony-forming unit (CFU) or Lymphocyte Progenitor cell.

Question 5

What do CFUs go on to become?

Answer 5

RBCs, Myeloid WBCs, Monocytes, Megakaryocytes (platelets)

Question 6

What do Lymphocyte progenitor cells go on to become?

Answer 6

T cells, B cells, and NK cells (all are lymphocytes)

Question 7

What is the most important growth factor for controlling erythropoiesis?

Answer 7

Erythropoietin (EPO)

Question 8

What organ releases EPO?

Answer 8

Kidneys

Question 9

What do RBCs enter the circulation as?

Answer 9

Reticulocytes (have some residual organelles but no nucleus)

Question 10

Do RBCs have mitochondria?

Answer 10

No. They produce ATP anaerobically only.

Question 11

Where do reticulocytes remain to mature into RBCs?

Answer 11

Bone marrow or spleen

Question 12

What are the absolute ingredients you need for making normal RBCs?

Answer 12

Amino acids, iron, folic acid, and Vit B12 - deficiency in these causes anemia

Question 13

What is EPO production controlled by?

Answer 13

A negative feedback loop - kidneys sense level of oxygen delivery to tissues and decrease EPO production if sufficient

Question 14

What happens to EPO levels during hypoxia?

Answer 14

EPO levels rise and RBC production increases until oxygenation returns to normal

Question 15

How many major types of protein are found in the lipid bilayer cell membrane of RBCs?

Answer 15

10-15

Question 16

T/F RBC cytopskeleton has unique protein filaments?

Answer 16

True

Question 17

What is a Band-3 protein?

Answer 17

An integral protein that constitutes about 25% of total membrane protein

Question 18

What anions does the Band-3 exchange across the membrane?

Answer 18

Bicarbonate for chloride exchange

Question 19

What are glycophorins?

Answer 19

Little combinations of carbs that stick out from some of the integral proteins like Band 3.

Question 20

What do glycophorins do?

Answer 20

Reduce interaction of RBCs so they don’t stick together

Question 21

Which GLUT allows for facilitated diffusion of glucose into RBCs?

Answer 21

GLUT 1

Question 22

What is the most important function of peripheral and cytoskeleton proteins?

Answer 22

Maintain the disc shape of RBCs yet allow for great flexibility for travel thru narrow blood vessels

Question 23

What are four important peripheral proteins of an RBC?

Answer 23

Ankyrin, Protein 4.1, Protein 4.2, and Spectrin

Question 24

What is hereditary spherocytosis?

Answer 24

Defects in RBC proteins - RBCs become sphere shaped rather than biconcave

Question 25

How long do cells with spherocytosis live?

Answer 25

5-7 days

Question 26

What is NADH needed for in the RBC?

Answer 26

maintain Hb's iron in the ferrous (reduced) state (Fe++)

Question 27

What is NADPH needed for in the RBC?

Answer 27

Required to maintain reduced glutathione

Question 28

What is reduced glutathione needed for in the the RBC?

Answer 28

Needed to maintain shape

Question 29

In the RBC, how much ATP and NADH is generated from each molecule of glucose?

Answer 29

2 ATP and 2 NADH

Question 30

What percentage of glucose is metabolized in the PPP pathway?

Answer 30

10% (the 90% is by anaerobic glycolysis)

Question 31

Which enzyme oxidizes Glucose-6-Phosphate, thereby allowing it to enter the PPP?

Answer 31

G-6-P Dehydrogenase

Question 32

What does bilirubin leave the body as?

Answer 32

Feces, not in urine

Question 33

Which organ is often injured in abdominal trauma?

Answer 33

Spleen

Question 34

What percentage of NaCl is isotonic with plasma?

Answer 34

0.9% NaCl. Hypertonic solution causes RBCs to shrink, hypotonic to swell and burst leaving "ghosts"

Question 35

What are the three buffer systems in blood?

Answer 35

Bicarbonate/Carbonic Acid, Phosphate, and Protein (Hb, albumin) - all function as buffers by taking on or releasing H+

Question 36

How does blood participate in temperature regulation?

Answer 36

Vasoconstrictions reduce flow to surface of skin, thereby reducing heat loss

Question 37

Cold temperatures do what to the SNS fibers?

Answer 37

Stimulate them to constrict blood vessels

Question 38

What do warm temperatures do to blood vessels?

Answer 38

Dilate blood vessels to increase blood flow to surface of skin to cool down

Question 39

By what receptors on the blood vessels does the SNS control smooth muscle constriction/relaxation

Answer 39

Alpha-1