Chapter 17 - Blood Flashcards Preview

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1

Composition of the Blood

2 components:
1) Formed Elements
2) Plasma

2

Erythrocytes

Red blood cells, function to transport O2 and some CO2. They make up about 45% of blood volume. They give blood it's color, are anuclear, and biconcave.

3

Leukocytes

White blood cells, their main function is protection. Make up less than 1% of blood volume. Numbers increase during disease. They are ameboid, and can move around the tissues as well as the circulatory system.

4

Platelets

Function in the blood clotting process. Make up less than 1% of blood volume

5

Plasma

The fluid, nonliving part of blood. Makes up about 55% of blood volume.

6

Blood color

Depends on the amount of O2 the blood is carrying.

7

pH of blood

Between 7.35 and 7.45

8

Major Functions of Blood

1) Transport - the major highway for moving material around the body.
2) Regulation - maintains normal pH, adequate blood volume, and body heat.
3) Protection - Prevents infection, allows blood clotting.

9

Importances of being biconcave

1. Larger surface area, which allows for faster gas exchange.
2. Can form stacks to help blood flow
3. Enables bending, making blood more flexible

10

Spectrin

Fibrous protein which makes the RBCs more flexible

11

Average lifespan of blood

100-120 days

12

Hemoglobin

Protein made of 2 alpha and 2 beta globulin polypeptides. It has 4 heme groups, each with an iron in the center

13

O2 and CO2 bonding to the hemoglobin

When O2 binds directly to the Fe in the heme group, it is called oxyhemoglobin. When it's not carrying O2, it's deoxyhemoglobin. CO2 can bind to hemoglobin, but it binds to the amino acids, NOT the Fe.

14

Hematopoiesis

Formation of RBCs. Red bone marrow is the only site for formation of RBCs, and the primary site for WBCs,.

15

Hemocytoblasts

The stem cells for all formed elements.

16

Proerythroblast

The committed cell for red blood cells

17

Myeloblasts

The committed cell for 3 types of WBCs, the neutrophils, basophils, and eosinophils.

18

Lymphoblasts

The committed cell for lymphocytes

19

Monoblasts

The committed cell for monocytes

20

Erythropoiesis

1. The bone marrow stem cell, the hemocytoblast, differentiates into a proerythroblast.
2. Hemoglobin synthesis begins and the proerythroblast transforms into an erythroblast, or normoblast.
3. When hemoglobin content reaches about 34%, the erythroblast extrudes its nucleus and becomes a reticulocyte.
4. It is this form that is released into circulation. After 1-2 days, it becomes a mature red blood cell.

21

Control of erythropoieses

The kidneys produce a glycoprotein called erythropoietin (EPO). This stimulates erythropoiesis in the myeloid tissue.

22

Control of Fe in the blood

When hemoglobin disintegrates, Fe is released, but too much Fe is toxic. It must be bound to proteins and stored. In the pasma, it's bound to transferrin which can then be removed by the bone marrow and liver and bound to two other proteins, ferritin and hemosiderin.

23

Downside of Lack of Nucleus

They're unable to synthesize proteins, unable to grow, unable to divide.

24

Erythrocyte Destruction

After 100-120 days, the cell dies, and hemoglobin breaks down losing it's Fe. It becomes biliverdin, which is then converted to bilirubin and transported to the liver and excreted into the intestinal tract.

25

Anemia

A decrease in O2. May be because of insufficient RBCs, reduced amounts of hemoglobin, or reduced amounts of whole blood.

26

Aplastic Anemia

Red marrow has shut down, due to either radiation toxic chemicals, bleeding problems, or antibiotics.

27

Pernicious Anemia

Due to a deficiency of vitamin B12, or the low production of the intrinsic factor.

28

Abnormal homoglobin

Usually genetic. The rate of RBCs destruction is increased due to fragile or defective cells.

29

Polycythemia

Increase in RBCs, high hematocrit. Blood pressure increases,and viscosity increases.

30

Granulocytes

Have lobed nuclei and cytoplasmic granules which are actually vesicles or lysosomes. They are formed in the red marrow from myeloblasts.