This A – Z Challenge post is brought to you by the letter “B”

I am so excited to be taking part in this, my second, A – Z Challenge!  Last year I completed the challenge using “recipes” as my inspiration.  Well, this year I’m going to draw on my nursing background and use “parts of the human body” as my inspiration!  Hmmm…a part of the body that starts with “Q” or “Z”….

It should be a lot of fun and I’m looking forward to seeing how everyone interprets the Challenge!

So, without further ado,  “B” is for Blood:

Sebastian Kaulitzki/iStockphoto.com. A close-up of blood cells

Blood is a mixture of two components:  cells and plasma. The heart pumps blood through the arteries, capillaries and veins to provide oxygen and nutrients to every cell of the body. The blood also carries away waste products.

The adult human body contains approximately 5 liters (5.3 quarts) of blood; it makes up 7 to 8 percent of a person’s body weight. Approximately 2.75 to 3 liters of blood is plasma and the rest is the cellular portion.

Plasma is the liquid portion of the blood. Blood cells like red blood cells float in the plasma. Also dissolved in plasma are electrolytes, nutrients and vitamins (absorbed from the intestines or produced by the body), hormones, clotting factors, and proteins such as albumin and immunoglobulins.  Plasma distributes the substances it contains as it circulates throughout the body.

The cellular portion of blood contains red blood cells (RBCs), white blood cells (WBCs) and platelets. The RBCs carry oxygen from the lungs; the WBCs help to fight infection; and platelets are parts of cells that the body uses for clotting.

All blood cells are produced in the bone marrow. As children, most of our bones produce blood. As we age this gradually diminishes to just the bones of the spine (vertebrae), breastbone (sternum), ribs, pelvis and small parts of the upper arm and leg. Bone marrow that actively produces blood cells is called red marrow, and bone marrow that no longer produces blood cells is called yellow marrow.

The process by which the body produces blood is called hematopoiesis. All blood cells (RBCs, WBCs and platelets) come from the same type of cell, called the pluripotential hematopoietic stem cell. This group of cells has the potential to form any of the different types of blood cells and also to reproduce itself.  This cell then forms committed stem cells that will form specific types of blood cells.

“B” is also for: 

ball-and-socket joint The most freely movable type of synovial joint(e.g., the shoulder or hip joint).

belly The thickest circumference of a skeletal muscle.

bile A liver secretion that is stored and concentrated in the gallbladder and released through the common bile duct into the duodenum. It is essential for the absorption of fats.

bone A solid, rigid, ossified connective tissue forming an organ of the skeletal system.

brain The enlarged superior portion of the central nervous system located in the cranial cavity of the skull.

brain stem The portion of the brain consisting of the medulla oblongata, pons, and midbrain.

bronchial tree  The bronchi and their branching bronchioles.

bronchiole A small division of a bronchus within the lung.

bronchus  A branch of the trachea that leads to a lung.

buccal cavity  The mouth, or oral cavity.

bulbourethral glands  A pair of glands that secrete a viscous fluid into the male urethra during sexual excitement; also called Cowper’s glands.

bursa A saclike structure filled with synovial fluid. Bursae are located at friction points, as around joints, over which tendons can slide without contacting bone.

buttocks The rump or fleshy masses on the posterior aspect of the lower trunk, formed primarily by the gluteal muscles.

There are many more “B” parts, be sure to check them out at the McGraw-Hill Applied Biology Resource Center website.

I’ll “C” you tomorrow!

The information contained in this post was obtained from How Stuff Works, MedicineNet.com. and McGraw-Hill Applied Biology Resource Center

{My theme for last years challenge was “Recipes” and my “B” post was Banana Bread.}