Connective Tissue

Cells are suspended in liquid material

Mixture of cells, cell fragments, and dissolved biochemicals

Transports nutrients, oxygen, wastes, and hormones

Helps maitain the stability of interstitial fluid

Distributes heat 

Blood Volume and Composition

Volume varies with:

Body size

Change in fluid and electrolyte concentrations

Amount of adipose tissue

More blood cells are red cells (small number of white cells and blood platelets)

55% of blood sample is clear, straw-colored liquid called plasma

Biconcave discs

Allows for transporting gas

Increases surface area through which gases diffuse

Places membrane closer to hemoglobin within cell (carries oxygen)

Varies person to person, sex to sex

Increasing number of circulating red blood cells increases the bloodś oxygen-carrying capacity

Changes in this number may affect health

Produced almost exclusively in tissue lining the spaces in bones- red bone marrow

Average life span of red blood cell is 120 days

The hormone Erythropoeitin controls rate of red blood cell formation

Kidneys release this in response to prolonged oxgen deficiency

Vitamin B12 and folic acid significantly influence red blood cell formation

These are necessary for DNA sythesis

Vitamin B12-eggs, cheese, milk, kidney, liver, beef, and pork

Folic acid-Green, leafy veggies, carrots, apricots, whole wheat, beans, egg yolk

Hemoglobin synthesis and normal red blood cell production requires iron

small intestin absorbs iron slowly from food

the body reuses it during decompostion of hemoglobin from damaged RBCs

Therefore, you only need small quantities of iron in your diet

Two few red blood cells or little hemoglobin causes anemia

This reduces the oxygen-carrying capacity of the blood

Person may appear pale and lack of energy

RBCs are normally quite elestic and flexible 

With age, they become more fragile, can be damaged more eaisly

Macrophages break apart and destroy these damaged cells

-Broken down into heme (contains iron) and globulin (protein)

Heme further decomposes into iron and green pigment biliverdin

biliverdin eventually converted to an orange pigment called bilirubin

biliverdin and bilirubin are excreted as bile pigments

Newborns can develop this a few days after birth

Accumulation of bilirubn turns skin and eye yellowish 

May be the result of immature liver that ineffectively excrete bilirubin into the bile

White Blood Cells (Leukocyte) 

What does it do?

Protect against disease 

develop from hemocytoblasts in response to hormones

hormones fall into 2 groups 

1) interleukins

2) colony stimulation factors (CSFs)

Blood transport white blood cells to sites of infection

WBC then leave blood stream

5 Types of WBC are in circulating blood

Differ in:

Size 

Nature of cytoplasm 

shape of nucleus 

staing of characteristics

Leukocytes with granular cytoplasm

Typical granulocyte is about 2x the size of red blood cell 

Granulocytes develop in red bone marrow but have short life spans (about 12 hours)

Members of this group include neutrophils, eosinophils, baophils