Circulatory System: Blood

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Functions of Blood

-Transport=02,CO2, nutrient, waste, heat, hormones

-Regulation=pH, body temp, water content

-Protection=clotting & immunity

Components of Blood

-55% is plasma which includes water and solutes (including plasma proteins)

-Note in Table 19.1 -albumin, globulins, fibrinogen (determine % and function)

-45% is formed elements

-erythrocyte (RBCs)

-Hematocrit=percentage volume of RBCs; males avg 47%, females avg 42%

-leukocyte (WBCs)

-thrombocyte (platelets)

Erythrocytes

-Size=7.5 micrometers (diameter)

-Number=5 million per microliter of blood (NOTE: 1 drop of blood is 50 microliters)

-Shape=biconcave (kind of like a basketball; gets rid of nucleus & loses it's shape (a deflated basketball)

-Does it have a nucleus? No (anucleated)

-Function is oxygen transport

-What structure allows it to perform this function? hemoglobin (Hb)

Hemoglobin

-consists of 1 globin and 4 hemes

-1 RBC has about 280 million Hb molecules

-How many oxygen molecules would you expect in one drop of blood?

A LOT OF O2!!

RBC Lifespan

-About 120 days

-What happens to each of the following after breakdown?

-Globin=recycle & reuse amino acids

-Iron=recycle & reuse

-Noniron portion of heme=excreted as bilirubin & biliverdin

-NOTE: Figure 17.7

Erythropoiesis

-Making of RBCs

-Where does it occur? red bone marrow (spongy bone)

-Process:

1. Stem cell

2. progenitor cell

3. committed cell

4. immature cells

5. mature cell

Process is regulated by oxygen levels in the blood.

What monitors the levels? kidneys

What is released when levels are low? EPO

Leukocytes

-Function is immunity

-Size = 5-25 micrometers

-Number = less numerous than RBCs (increase with immune response)

-Shape = spherical

-Do they have a nucleus? Yes

-Types:

1. Eosinophil

2. Basophil

3. Neutrophil

4. Lymphocyte

5. Monocyte

How are WBCs formed?

myeloid stem cell - all other WBCs

lymphoid stem cell - lymphocytes