Oxygenated blood exits the heart via

Arteries

Oxygen-deficient blood enters the heart via

Veins

Blood is a

specialized connective tissue in which living blood cells, called the formed elements, are suspended in a nonliving fluid matrix called plasma

Erythrocytes

red blood cells (RBCs) that transport oxygen

Leukocytes

white blood cells (WBCs) that act in various ways to protect the body, and platelets, cell fragments that help stop bleeding

Erythrocytes

constitute about 45% of the total volume of a blood sample, a percentage known as the hematocrit

Blood is a

sticky, opaque fluid with a metallic taste

Oxygen rich blood

has a scarlet color

Oxygen poor blood

has a dark red color

Blood has a pH between

7.35 and 7.45

Distribution functions of blood include

• Delivering oxygen from the lungs and nutrients from the digestive tract to all body cells
• Transporting metabolic waste products from cells to elimination sites
• Transporting hormones from the endocrine organs to their target organs

Regulatory functions of blood include

• Maintaining appropriate body temperature
• Maintaining normal pH in body tissue
• Maintaining adequate fluid volume in the circulatory system

Protective functions of blood include

• Preventing blood loss
• Preventing infection

Blood plasma

is a straw-colored, sticky fluid

Albumin

acts as a carrier to shuttle certain molecules through the circulation, is an important blood buffer, and is a major blood protein contributing to the plasma osmotic pressure

Blood performs three major functions

• Distribution
• Regulation
• Protection

The buffy coat contains

Leukocytes and platelets

Erythrocytes are also known as

red blood cells (RBCs)

The three formed elements of blood are

• Erythrocytes
• Leukocytes
• Platelets

Two of the three formed elements are not true cells

• Erythrocytes (no nuclei or organelles)
• Platelets (cell fragments)

Mature erythrocytes are

bound by a plasma membrane, but lack a nucleus and have no organelles

RBCs transport

respiratory gases, such as oxygen and carbon dioxide

A protein that makes RBCs red

Hemoglobin

Blood cell formation that occurs in the red bone marrow

Hematopoiesis

The various formed elements all arise from

Hematopoietic stem cell, sometimes called a hemocytoblast

Erythrocyte production

Erythropoiesis

The erythrocyte production pathway

1. Proerythroblast
2. Basophilic erythroblast
3. Polychromatic erythroblast
4. Orthochromatic erythroblast
5. Reticulocyte

Erythropoietin (EPO)

a glycoprotein hormone that stimulates the formation of erythrocytes

Anemia

a conditioning which the blood's oxygen-carrying capacity is too low to support normal metabolism

The causes of anemia is divided into three groups

• Blood loss
• Not enough red blood cells produced
• Too many red blood cells destroyed`

Polycythemia

an abnormal excess of erythrocytes that increases blood viscosity

Leukocytes are grouped into two major categories

• Granulocytes
• Agranulocytes

Granulocytes include

• Neutrophil
• Eosinophils
• Basophils

Agranulocytes include

• Lymphocytes
• Monocytes

The most numerous white blood cells

Neutrophil

Eosinophils

lead the counterattack against a parasitic worms

The rarest white blood cells (WBCs) that contain histamine granules

basophils

The second most numerous leukocytes in the blood

Lymphocytes