Functions and Composition of Blood

Flashcards covering the functions, composition, formed elements (erythrocytes, leukocytes, platelets), disorders, and blood groups of human blood based on lecture notes.

What are the three general functions of blood?

Transport, Regulation, and Protection.

What are the primary transport functions of blood?

Delivering O2 and nutrients to body cells, transporting metabolic wastes to lungs and kidneys for elimination, and transporting hormones to target organs.

What are the primary regulation functions of blood?

Maintaining body temperature, maintaining normal pH using buffers, and maintaining adequate fluid volume in the circulatory system.

How does blood provide protection?

By preventing blood loss (via clot formation by plasma proteins and platelets) and preventing infection (carrying antibodies, complement proteins, and white blood cells).

What are the two main components of blood identified as a fluid tissue?

Nonliving fluid matrix called plasma, and living blood cells called formed elements.

What are the three types of formed elements found in blood?

Erythrocytes (red blood cells), Leukocytes (white blood cells), and Platelets.

When a tube of blood is spun, what are the three layers that separate, from bottom to top, and what do they contain?

Erythrocytes (bottom, ~45%), Buffy coat (middle, <1%, containing WBCs and platelets), and Plasma (top, ~55%).

What is hematocrit?

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

What is the normal pH range of blood?

7.35–7.45.

What is the most abundant protein in blood plasma, making up 60% of plasma proteins?

Albumin.

What are the functions of albumin in blood plasma?

Functions as a carrier of other molecules, as a blood buffer, and contributes to plasma osmotic pressure.

Which formed elements are complete cells with nuclei and organelles?

Leukocytes (white blood cells).

Describe the structural characteristics of erythrocytes that make them efficient for gas transport.

They have a biconcave disc shape (huge surface area for gas exchange), are filled with hemoglobin (97% of cell volume), and have no mitochondria (produce ATP anaerobically, so they don't consume O2 they transport).

What is hemoglobin and what are its components?

Hemoglobin is a protein in RBCs dedicated to respiratory gas transport. It consists of a red heme pigment bound to the protein globin, which is composed of four polypeptide chains (two alpha and two beta). Each heme has a central iron atom that binds one O2 molecule.

What is the process of formation of all blood cells called, and where does it primarily occur in adults?

Hematopoiesis; it occurs in the red bone marrow.

What hormone stimulates the formation of red blood cells, and which organ primarily releases it?

Erythropoietin (EPO), primarily released by the kidneys.

What are some causes of hypoxia that trigger the release of EPO?

Decreased RBC numbers (due to hemorrhage or destruction), insufficient hemoglobin per RBC (e.g., iron deficiency), or reduced availability of O2 (e.g., high altitudes or lung problems).

What is the average life span of an erythrocyte?

100–120 days.

What are the three main categories of erythrocyte disorders?

Anemia (due to blood loss, too few RBCs produced, or too many RBCs destroyed) and Polycythemia.

What is the difference between hemorrhagic anemia and chronic hemorrhagic anemia?

Hemorrhagic anemia is caused by rapid blood loss (e.g., severe wound), while chronic hemorrhagic anemia results from slight but persistent blood loss (e.g., hemorrhoids, bleeding ulcers).

What type of anemia is characterized by the production of small, pale RBCs due to lack of iron?

Iron-deficiency anemia.

What is pernicious anemia and how is it caused?

An autoimmune disease that destroys stomach mucosa, preventing the production of intrinsic factor, which is needed to absorb Vitamin B12. Without B12, RBCs enlarge but cannot divide, leading to large macrocytes.

What is polycythemia vera?

A bone marrow cancer leading to an abnormal excess of red blood cells, which increases blood viscosity.

What is the primary function of leukocytes (WBCs)?

Function in defense against disease.

What is leukocytosis?

A white blood cell count over 11,000 per ml, which is a normal response to infection.

Name the two major categories of leukocytes and list the types within each.

Granulocytes (Neutrophils, Eosinophils, Basophils) and Agranulocytes (Lymphocytes, Monocytes).

Which type of leukocyte is the most numerous, acting as "bacteria slayers" through phagocytosis and respiratory burst?

Neutrophils.

Which leukocyte type has a bilobed nucleus resembling "ear muffs" and releases digestive enzymes on large parasitic worms, also playing a role in allergies and asthma?

Eosinophils.

Which rare leukocyte contains large, purplish-black granules that release histamine, acting as a vasodilator and attracting other WBCs to inflamed sites?

Basophils.

What are the two types of lymphocytes and their primary functions?

T lymphocytes (T cells) act against virus-infected cells and tumor cells; B lymphocytes (B cells) give rise to plasma cells, which produce antibodies.

Which leukocyte type differentiates into macrophages in tissues and are actively phagocytic against viruses, intracellular bacteria, and chronic infections?

Monocytes.

What are platelets, and what is their primary function?

Cytoplasmic fragments of megakaryocytes; their primary function is to form a temporary platelet plug that helps seal breaks in blood vessels (involved in clotting).

What are agglutinogens in the context of blood transfusions?

Antigens on the surface of RBC membranes that are perceived as foreign by the immune system of a recipient if mismatched, promoting agglutination.

What are the four main ABO blood groups?

Type A, Type B, Type AB, and Type O.

Which ABO blood type is considered the "universal donor" and why?

Type O, because its RBCs have neither A nor B agglutinogens, so they are not attacked by anti-A or anti-B antibodies in a recipient's plasma.

Which ABO blood type is considered the "universal recipient" and why?

Type AB, because its plasma contains no anti-A or anti-B antibodies, so it can receive RBCs from A, B, AB, or O blood types without agglutination related to ABO antigens.

How do Anti-Rh antibodies form in an Rh- individual?

They are not spontaneously formed; they form if an Rh- individual receives Rh+ blood, or if an Rh- mother is carrying an Rh+ fetus, due to exposure to Rh antigens.

What is hemolytic disease of the newborn (erythroblastosis fetalis)?

A condition that occurs in an Rh- mother with an Rh+ fetus, where the mother's anti-Rh antibodies (formed during a previous Rh+ pregnancy) cross the placenta and destroy the RBCs of the Rh+ baby.