EXERCISE 1: THE FORMED ELEMENTS OF BLOOD

Sickle Cell Disease/Anemia

-Caused by the production of abnormal hemoglobin molecule -Inherited genetic disease and has no known cure present -In low oxygen tension, the abnormal hemoglobin molecule changes from its globular configuration to a spiky shape, and precipitates out of solution -The RBCs which contain the abnormal molecules assume a crescent shape -These cells rupture easily and the oxygen-carrying capacity of the blood is thus lowered. -Abnormally shaped and ruptured cells can easily clog small arterioles and capillaries, keeping oxygen and nutrient molecules from tissues and cells

Thrombocytes

-Fragments of cells formed from the cytoplasm of megakaryocytes -contain a collection of granules, which are enclosed in a cell membrane generated from the giant red bone marrow cells -Function in the formation of platelet plugs and in the process of blood clotting at the site of an injury

What are the 2 groups of leukocytes?

-Granuloctyes: have distinct granules in the cytoplasm (neutrophils, eiosiniphils, basophils) -Agranulocytes: lack distinct granules in the cytoplasm (lymphocytes and monocytes)

Leukocytes

-Larger than RBCs and have large, irregularly shaped nuclei -Functions: phagocytosis and the production of antibodies in response to an antigen

Monocytes

-Largest of the leukocytes -Large, kidney shaped nucleus and pale gray blue cytoplasm -Very active phagocytes -Leave the blood stream and can wander in the tissues eating bacteria -AKA wandering macrophages -If they take up residence in the tissue, they become fixed macrophages

Lymphocytes

-Most numerous of the agranulocytes and the second most numerous of the leukocytes -Large, spherical nucleus takes up most of the cell -Mostly found outside of the blood in the lymphoid tissues of the body -T-lymphocytes are a type of lymphocytes produced in the red bone marrow, and processed in the thymus (once mature, they can direct an immune response against tumor cells and virus-infected cells) -B-lymphocytes are also produced in the red bone marrow and can mature there. These cells are responsible for antibody production. -Both T and B lymphocytes are involved in generating a specific attack against a specific antigen

Neutrophils

-Most numerous of the leukocytes -Multilobed nucleus and cytoplasm that is finely granular, staining pale lavender or pink (takes of both basic and acidic stains) -Very active phagocytes -They can squeeze through capillary walls by amoeboid motion (diapedesis) and go to the site of infection where they phagocytize bacteria

Eiosinophils

-Not very numerous -Bilobed nucleus -Cytoplasm has large reddish-orange staining granules -Looks like a cell with measles -Acidic stain -Granules contain enzymes that destroy the outer covering of parasitic worms -Can also phagocytize the antigen-antibody complexes involved in generating an allergic reaction, thus inactivating the inflammation of an allergy attack

Basophils

-The least numerous of the leukocytes -Large, U-shaped nucleus -Cytoplasm has large granules staining bluish-black (basic staining dye) -The granules of basophils contain histamine (vessel dilator and makes the blood vascular system more leaky, producing some of the symptoms seen in inflammation) -Contain the chemical heparin, an anti-clotting substance

Hemopoiesis (Hematopoiesis)

-The process by which the formed elements of blood are produced -Before birth, this process occurs in various parts of the body -Organs such as lymph nodes, thymus, liver, spleen, and bone marrow may be involved in this process -After birth, the red bone marrow (myeloid tissue) is the site of formed element production

When RBCs wear out...

-they are broken down by phagocytes in the spleen and liver -some of their components are recycled

What are the 3 types of formed elements in the blood?

1. Erythrocytes (RBCs) 2. Leukocytes (WBCs) 3. Thrombocytes (platelets)

How much oxygen and carbon dioxide is carried to the tissues?

98% oxygen to the tissues and 20-25% carbon dioxide from the tissues

What associates with oxygen and carbon dioxide?

Iron associates with oxygen and the hemoglobin's amine groups associate with carbon dioxide

What are the proportions of leukocytes in the blood?

Neutrophils: 60-70% Eosinophils: 2-4% Basophils: .5-1% Lymphocytes: 20-25% Monocytes: 3-8% *These proportions may change during an infection or allergic reaction and many have diagnostic value.

What does the shape of erythrocytes do?

Provides lots of surface area for the exchange of oxygen and carbon dioxide and allows flexibility for slipping through tiny vessels.

Red blood cells...

are described as "little cells of hemoglobin" and as such function to carry oxygen to all other cells of the body

Platelets...

are primarily responsible for stopping bleeding

Hemoglobin can also transport...

carbon dioxide, thus relieving the cells of this waste product

The fibers participate in the...

clotting or coagulation of blood to help stop bleeding

White blood cells...

defend the body against infection, scavenge cellular debris, and are a major part of immunity

Which is the most abundant of the formed elements?

erythrocytes

As a type of connective tissue, blood is composed of...

formed elements (cells and cell fragments) and a fluid matrix

Plasma, along with the formed elements,...

helps to maintain the body's homeostasis

The formed elements are produced by a process called...

hemopoiesis or hematopoiesis

The matrix is the...

liquid component of blood, and it is called plasma

What is the carrier?

the hemoglobin

Before birth...

the process occurs in several places in the body

After birth...

the process occurs in the red bone marrow of certain bones

The plasma...

the transporting component of blood, is composed of water, proteins, glucose, lipids, amino acids, vitamins, minerals, hormones, gases, and metabolic waste products.

Fibers are also a part of this tissue, but...

they appear only under abnormal conditions when there is injury

What is a consequence of RBCs not having a nucleus and having limited organelles?

they cannot reproduce or carry out metabolic activities so they only remain in circulation about 120 days

What is the function of erythrocytes?

to carry oxygen and carbon dioxide