Lecture 7 Blood: RBCs, Anemia and Blood Typing (Ch. 33, 36)

Question 1

55% of the blood is plasma; what are the different components of plasma?

Answer 1

Albumin, Globulins, Fibrinogens (& Miscellanous)

Question 2

At age 30, where does the production of RBCs occur?

Answer 2

Vertebra, Sternum and Ribs

Question 3

RBCs are viable for ~120 days. How are they discarded?

Answer 3

Aged RBCs are enlarged and trapped by the spleen and the liver. They’re then digested by macrophages & processed for reuse or excretion.

Question 4

What globins chains are present in our blood postnatal (~12 weeks and onward)?

Answer 4

Alpha chain 1, Alpha chain 2, Beta chain 1, Beta chain 2

Question 5

What are the 3 categories of hemolytic anemias?

Answer 5

Transfusion reaction, immunity-based RBC destruction and genetic

Question 6

What are the differences in the processes that encourage Pluripotent Hematopoetic Stem Cell (PHSC) maturation?

Answer 6

Growth inducers promote proliferation (interleukin-3), and differentiation inducers drive the cell to maturation (ex. PHSC+erythropoetin ->RBC; PHSC+cytokines/lymphokines->WBC)

Question 7

Give two examples that reflect the adaptivity of hematopoiesis?

Answer 7

Hypoxia will increase erythropoiesis and RBCs

Infection/inflammation will increased WBC production

Question 8

Describe the hormonal stimulation of RBC production.

Answer 8

Hypoxia triggers eryhtropoietin (EPO) synthesis in the kidney.
EPO stimulates RBC production in bone marrow.

Question 9

Describe the two types of polycythemia pathology.

Answer 9

Physiologic secondary polycythemia is when the RBC’s are elevated due to being in high altitudes.
Compensatory polycythemia can occur with lung disease due to inadequate ventilation, and in heart failure, due to inadequate blood flow to the heart.

Question 10

During which stages of RBC maturation does hemoglobin synthesis occur, and what physiologic changes reflect this?

Answer 10

Hemoglobin synthesis occurs from the proerythroblast to the reticulocyte stage. Reticulocyte retraction expels the endoplasmic reticulum and Golgi apparatus, decreasing Hgb synthesis

Question 11

Compare erythropoietin synthesis in normal O2 and low O2 conditions.

Answer 11

In normoxia (normal O2 conditions), HIF-alpha is hydroxylated by prolyl-4lhydroxylase (PHD) and FIH-1. HIF-1 is targeted for destruction by ubiquitin.
In hypoxia (low O2 conditions), PHD and FIH-1 are inhibited by hypoxia. HIF-1 translocates to the nucleus and bind HIF-1beta ->  Transcription of target genes including EPO

Question 12

Describe the general pathophysiology of anemia

Answer 12

1. tissue hypoxia and necrosis (lethargy, shortness of breath), high metabolic tissue (brain, heart, kidney) most affected
2. reduced osmolarity: edema
3. reduces blood viscosity (low blood pressure): increases heart rate and may cause cardiac failure

Question 13

What determines ABO blood classification, and what are the names of the different blood types?

Answer 13

glycoproteins on RBCs that are antigenic and produce antibodies.
Blood types: O, A, B, AB

Question 14

What is physiologic secondary polycythemia?

Answer 14

RBCs are elevated because of high altitude

Question 15

How long are RBCs viable?

Answer 15

~120 days