Blood Functions and Composition

These flashcards cover the functions, composition, and regulation of blood, as well as various blood disorders and their characteristics.

Blood Function #1

Transport: Deliver O2 and nutrients to body cells and transport metabolic wastes to lungs and kidneys.

Blood Function #2

Regulation: Maintain body temperature, normal pH using buffers, and adequate fluid volume.

Blood Function #3

Protection: Prevent blood loss and infection.

Composition of Blood

Blood is the only fluid tissue in the body and is a type of connective tissue.

Components of Blood

Two main components: Plasma and cells (formed elements: erythrocytes, leukocytes, platelets).

Erythrocytes (RBCs)

Red blood cells that transport oxygen.

Leukocytes (WBCs)

White blood cells that are involved in immune responses.

Platelets

Cell fragments that initiate blood clotting.

Centrifuged Blood Layers

Three layers: erythrocytes, buffy coat (WBCs and platelets), and plasma.

Hematocrit

The percentage of blood volume that is composed of red blood cells.

Normal Hematocrit Values for Males

Approximately 47% ± 5% of blood volume.

Normal Hematocrit Values for Females

Approximately 42% ± 5% of blood volume.

Plasma Composition

About 90% water and contains over 100 dissolved solutes.

Albumin

A plasma protein that makes up 60% of plasma proteins and contributes to osmotic pressure.

Erythrocyte Characteristics

Biconcave disc shape, anucleate, flexible, containing hemoglobin.

Function of Hemoglobin

Binds reversibly with oxygen for gas transport; makes up 97% of RBC volume.

Oxyhemoglobin

Formed when oxygen binds to hemoglobin in the lungs.

Deoxyhemoglobin

Formed when oxygen is released from hemoglobin in tissues.

Hematopoiesis

The formation of all blood cells.

Erythropoiesis

The process of formation of red blood cells.

Erythropoietin (EPO)

Hormone that stimulates the formation of RBCs in response to hypoxia.

Dietary Requirements for Erythropoiesis

Includes amino acids, lipids, carbohydrates, iron, vitamin B12, and folic acid.

Life Span of RBCs

Approximately 100–120 days before they are engulfed and broken down.

Anemia

A condition marked by a blood O2-carrying capacity too low to support normal metabolism.

Symptoms of Anemia

Fatigue, pallor, dyspnea, and chills.

Hemorrhagic Anemia

Rapid blood loss that can be treated by blood replacement.

Chronic Hemorrhagic Anemia

Persistent slight blood loss that requires treatment of the primary cause.

Iron-Deficiency Anemia

Caused by low iron intake or impaired absorption, leading to microcytes.

Pernicious Anemia

Caused by lack of vitamin B12, leading to macrocytes.

Renal Anemia

Caused by lack of EPO, often associated with renal disease.

Aplastic Anemia

Destruction or inhibition of red bone marrow, often with unknown causes.

Hemolytic Anemias

Premature destruction of RBCs caused by incompatible transfusions or infections.

Sickle-cell Anemia

A genetic disorder causing RBCs to be crescent shaped and prone to rupture.